Dissertations / Theses: 'Geometrical influences'

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Seroto, Ngwako. "Exploration of geometrical concepts involved in the traditional circular buildings and their relationship to classroom learning." Thesis, University of Limpopo (Turfloop Campus), 2006. http://hdl.handle.net/10386/1035.

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Thesis (M.Ed. (Mathematics)) --University of Limpopo, 2013
Traditionally, mathematics has been perceived as objective, abstract, absolute and universal subject that is devoid of social and cultural influences. However, the new perspective has led to the perceptions that mathematics is a human endeavour, and therefore it is culture-bound and context-bound. Mathematics is viewed as a human activity and therefore fallible. This research was set out to explore geometrical concepts involved in the traditional circular buildings in Mopani district of Limpopo Province and relate them to the classroom learning in grade 11 classes. The study was conducted in a very remote place and a sample of two traditional circular houses from Xitsonga and Sepedi cultures was chosen for comparison purposes because of their cultural diversity. The questions that guided my exploration were: • Which geometrical concepts are involved in the design of the traditional circular buildings and mural decorations in Mopani district of the Limpopo Province? • How do the geometrical concepts in the traditional circular buildings relate to the learning of circle geometry in grade 11 class? The data were gathered through my observations and the learners’ observations, my interviews with the builders and with the learners, and the grade 11 learners’ interaction with their parents or builders about the construction and decorations of the traditional circular houses. I used narrative configurations to analyse the collected data. Inductive analysis, discovery and interim analysis in the field were employed during data analysis. From my own analysis and interpretations, I found that there are many geometrical concepts such as circle, diameter, semi-circle, radius, centre of the circle etc. that are involved in the design of the traditional circular buildings. In the construction of these houses, these concepts are involved from the foundation of the building to the roof level. All these geometrical concepts can be used by both educators and learners to enhance the teaching and learning of circle geometry. Further evidence emerged that teaching with meaning and by relating abstract world to the real world makes mathematics more relevant and more useful.

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Escrig, Josep. "Influence of geometrical parameters on gas-liquid intermittent flows." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/47085/.

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The influence of geometrical parameters on the development of intermittent flow is studied in this thesis. The geometrical parameters considered are the diameter of the pipe, the angle of inclination of the pipe, and the distribution of the area of the gas injection. Intermittent flow in gas-liquid two-phase flows occurs when, from a fixed point, a gas dominated structure followed by a liquid dominated structure seems to repeat at a certain mean frequency. It is mainly slug flow but churn and cap bubble flow also fall into this broad category. Intermittent gas-liquid two-phase flow was investigated in a 67 mm diameter, 6 m long rig and also in a 127 mm diameter, 12 m long rig. The test section of the 67 mm rig was mounted in a steel frame supported by a pivot that allowed changing the inclination of the pipe from vertical to horizontal in steps of 15°. The 127 mm rig can only be operated in the upwards vertical position. The fluids utilised were air and silicon oil of viscosity = 5 cP and density = 0.912 kg/m3. The interfacial surface tension was measured at 0.02 N/m. The facilities were both operated at atmospheric pressure. The gas superficial velocity (Ugs) was varied from 0.17 to 2.9 m/s and liquid superficial velocity (Uls) from 0.023 to 0.47 m/s. The void fraction generated by each set of conditions was captured for 60 seconds using a Wire Mesh Sensor and a twin plane Electrical Capacitance Tomography probe. The effect of the diameter and the angle of inclination of the pipe under different gas and liquid superficial velocities was reported. The main findings can be summarised as that the velocity of the periodic structures was found to be higher in large diameter pipes and increases with increasing the angle of inclination reaching a maximum around 50° then decreases. In addition, the frequency of the gas structures was found to be higher in small diameter pipes and increases with increasing the inclination of the pipe for all the gas and liquid superficial velocities investigated. Additionally, two correlations to predict the velocity and the frequency of the periodic gas structures as a function of the diameter, the inclination of the pipe, the gas superficial velocity and the liquid superficial velocity were developed. The proposed correlations were found to not only be in excellent agreement with the present experimental results (less than 20% difference), but also in good agreement with data published by other researchers. This include data produced using different fluids, different diameters of pipe and different gas and liquid superficial velocities to the ones investigated in this work. It was also found that the gas injection area, modified using different gas-liquid mixers, do not have an influence on the development of the intermittent two-phase flows at 75 diameters axial length from the mixing point.

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Zemánek, Miroslav. "Influence of Geometrical Parameters on Rupture Risk of Abdominal Aortic Aneurysm." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-233934.

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Tato práce je zaměřena na problematiku výpočtového a experimentálního modelování deformačně napjatostních stavů měkkých tkání se zaměřením na riziko ruptury u výdutě břišní aorty (AAA). V první části (kap. 1) je stručně nastíněn současný stav dané problematiky. Tato část shrnuje důležité poznatky publikované v dostupné literatuře. Pozornost je věnována zejména klíčovým faktorům pro stanovení rizika ruptury AAA. V další kapitole (kap. 2) je stručně popsána histologie cévní stěny a její výsledné mechanické chování, jakož i její patologie, především AAA. Druhá část práce (kap.3) je věnována experimentálnímu vyhodnocování deformačně napjatostního chování měkkých tkání, které je nutným předpokladem k věrohodnému výpočtovému modelování tohoto chování. V této kapitole je stručně popsáno experimentální zařízení speciálně vyvinuté pro testování měkkých tkání a typy zkoušek, které lze na tomto zařízení provádět. Dále jsou shrnuty klíčové faktory ovlivňující deformačně napjatostní chování měkkých tkání a experimentální ověření těchto faktorů na vzorcích z prasečích hrudních aort. V závěru této kapitoly jsou shrnuty nové poznatky vyplývající z experimentálního testování. Třetí část disertační práce (kap.4) je zaměřena na matematický popis deformačně napjatostního chování měkkých tkání, stručný popis používaných konstitutivních vztahu a postup při identifikaci parametrů pro tyto konstitutivní modely určované na základě provedených experimentálních zkoušek. Poslední část disertační práce (kap.5) je věnována výpočtovému modelování deformačně napjatostního chování AAA. V této kapitole jsou nejdříve shrnuty klíčové faktory a předpoklady pro vytváření modelů a pro vyhodnocování výsledku a dále jsou uvedeny materiálové parametry pro konstitutivní modely implementované do programu ANSYS. Byly provedeny testovací výpočty při použití hypotetické zjednodušené geometrie AAA, na kterých byly vyhodnoceny vlivy změny geometrie a vliv změny konsitutivního modelu na extrémní napětí ve stěně AAA. U reálné geometrie AAA byla navržena a otestována metoda výpočtu nezatížené geometrie z reálných CT snímků. Dále byl testován vliv zvýšení vnitřního tlaku jako rizika ruptury AAA. V závěru práce jsou shrnuty poznatky a možnosti výpočtového modelování a návrhy na další práce.

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Teh, Lay Seong. "Library of geometric influences for stress intensity factor weight functions." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566060.

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This research thesis reports the development of a novel concept for Linear Elastic Fracture Mechanics (LEFM) analysis - Composition Theory of Stress Intensity Factor Weight Functions (CToWF). A generic closed form composition model has been derived to generate Mode I SIFs for an edge crack propagating in a symmetrically loaded two-dimensional body. The CToWF concept has demonstrated, by verification with published solutions and Finite Element Analysis (FEA), that the SIF weight function for a new cracked body can be evaluated by isolating and combining appropriate constituent geometries. Being a unique property of crack and component geometry, the newly determined weight function enables rapid generation of SIFs for the same cracked component under different stress systems. Over two thousand Finite Element (FE) models were analysed to provide constituent geometrical configurations and to validate the SIFs calculated from the CToWF model where published solutions were not available. These are Mode I SIFs for edge cracks emanating from two-dimensional notches i. e. semi-elliptical, U- and V-notches in semi-infinite bodies along with their associated stress distributions. Hence, a comprehensive database has been established. Using the versatile composition model with the database, a large number of new SIF solutions for edge cracks from equivalent notches in finite bodies have been obtained. This `Library' of geometric influences, which are presented as weight function coefficients in tabular form, can now be composed by the CToWF approach to generate SIFs for modelling crack propagation through residual stress fields and other complex stress systems. In general, this universal approach, which is easy-to-implement yet maintaining high accuracy, has tremendous potential in allowing rapid assessment of defects prone to linear elastic fracture behaviour via the evaluation of SIFs. Further work to enhance the understanding of this novel concept is proposed to develop a broader practical use in real engineering applications.

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Richards, Lynn Valerie. "Children's production of locative expressions in English : the influence of geometric and extra-geometric factors." Thesis, University of Plymouth, 2001. http://hdl.handle.net/10026.1/456.

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The research in this thesis examines the influence that both geometric and extrageometric factors have on children's spatial language production. Over the years it has widely been assumed that spatial prepositions identif' where objects are in the world (geometric factors) and that this is reflected in the semantic representations of these words. More recently, researchers investigating the lexical semantics of spatial prepositions have begun to question this assumption by demonstrating that what objects are and how they are interacting can also affect the way we describe where they are in the world (extra-geometric factors). Following on from research conducted with adults that has demonstrated the importance of both of these factors on spatial language, the main aim of this thesis was to ascertain for the first time whether these factors also influenced children's spatial language production, and if so, when they became important in children's development of spatial expressions. Additionally, due to the paucity of research investigating the production of spatial terms, the Experiments reported in this theis set out to redress the balance. The research in this thesis demonstrated for the first time that both geometric and extra geometric factors influence the production of children's spatial expressions from an early age. In doing so, however, the Experiments reported here were not necessarily revealing as to the nature of the semantic representation of spatial terms, rather they highlighted a different issue; how people make distinctions during a verbal interaction. Evidence is presented that suggests a level of agreement between people regarding the nonconventional use of words. In order to distinguish between functional and non-functional situations, both adults and children used different types of spatial terms to locate an object even when they had a limited number of words in their lexicon. An approach to the whole process of prepositional production is suggested rather than concentrating on what is represented in an individual's lexicon.

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Souza, Walter Rauen de. "Subsolador : a influencia de parametros geometricos na distribuição das forças." [s.n.], 1989. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257347.

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Orientador : Paulo S. G. Magalhães
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
Made available in DSpace on 2018-07-14T03:54:29Z (GMT). No. of bitstreams: 1 Souza_WalterRauende_M.pdf: 4375688 bytes, checksum: e555ee265d29321f62bbc5d8fc94132c (MD5) Previous issue date: 1989
Mestrado
Mestre em Engenharia Agrícola

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Hörberg, Thomas. "Influences of Form and Function on Spatial Relations : Establishing functional and geometric influences on projective prepositions in Swedish." Thesis, Stockholm University, Department of Linguistics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6867.

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The present work is concerned with projective prepositions, which express the relation between two objects by referring to a direction in three-dimensional space. The projective prepositions have been regarded as expressing simple schematic relations of a geometric nature. A theory of the apprehension of projective relations can account for their meanings when they express strictly geometric relations. However, many studies have shown that the appropriateness of the prepositions also depends on the functional relation between the objects and that a number of functional factors influence the comprehension of English prepositions. This experimental study investigates if the acceptability of the Swedish prepositions över, under, ovanför and nedanför are influenced by functional factors as well, and whether acceptability judgments about över and under are more sensitive to functional influences than judgments about ovanför and nedanför, as has been shown for the corresponding English prepositions over and under, and above and below, respectively. It also investigates how the shapes and the parts of the related objects influence their functional interaction, and how the acceptability of the prepositions is in consequence influenced by the shapes of the objects. It was found that the theory of apprehension can indeed account for the acceptability of the prepositions when the relation between the objects is strictly geometric. It was further found that acceptability judgments about them are influenced by functional factors in a similar manner to the corresponding English prepositions when the objects are functionally related, although judgments about under and nedanför are not differentially influenced by these factors. Furthermore, the shapes and the parts of both of the related objects influence acceptability judgments about the prepositions in predictable manners. An extension of the theory of apprehension is suggested which can account for the functional influences indicated in the present study.

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Ebermann, Marko. "Influence of geometric form deviations on operating parameters in hydrodynamic bearings." Technische Universität Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A21225.

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Hydrodynamic plain bearings are important machine elements. They are used in many areas of mechanical engineering, such as turbomachines, crankshaft bearings and gears. The geometry of the lubrication gap elemen-tarily influences the function as shown in several examples of abrupt failures in turbochargers. Due to toleranc-ing, the manufacturing requirements are very high. However, the question remains how large these deviations can be. ISO 12129-2 gives recommendations on form deviations depending on the minimum of plain bear-ing clearance (hmin). Nevertheless, there is no direct reference on the size or the strain on bearing. In DIN 31652-3, the tolerance of the bearing clearance is divided into -1/3 and +2/3 of itself. However, this tolerance merely has an indirect correlation with the size of the bearing and strain on the bearing. If these tolerance recommenda-tions are applied, the function of the plain bearing will not be completely fulfilled. Nonetheless, tolerances pro-vided by standards are used in geometric specifications. If these tolerances are used for in-company manufacturing, this is unproblematic in most cases. But if technical drawings are sent to an external manufacturer, toler-ance limits may be exhausted and the function cannot be ensured. Within the framework of the research project presented here, a tolerance evaluation matrix has been developed. For this, the existing standards were analyzed. In this case, the ignorance of size (diameter and width) and signif-icant operating properties (speed, load, temperature, etc.) are insufficient. The project examined and simulated various possible deviations. Selected form deviations were manufactured. The validation of the simulation results were carried out on 30mm.

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Weidle, William Scott. "Influence of Trimaran Geometric Parameters on Intact and Damaged Ship Stability." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/81101.

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Multi-hull vessels have been considered for high-speed, military and commercial applications for decades. More recently the trimaran vessel, with three hulls, has captured interest among naval ship designers and stakeholders. A definition of multi-hulls is introduced as a continuum with monohulls on one end, catamarans on the other, and trimarans in-between. A review of methods to assess intact and damaged stability follows in addition to an overview of current research in the area of dynamic stability for monohulls and trimarans. An investigation of intact stability characteristics for multi-hulls along the continuum is presented and their trends are examined. Next, a series of trimaran configurations are modeled in CAD with subdivision to determine their allowable KG according to USN deterministic criteria and using quasi-static methods. A response surface model was determined for allowable KG as a function of center hull length to beam, side hull beam to draft, transverse position, and displacement for use as a rule of thumb measure and potential optimization constraint.
Master of Science

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FILHO, GERALDO GURGEL. "INFLUENCE OF GEOMETRICAL PARAMETERS IN THE PERFORMANCE OF A CARDANICALLY SUSPENDED GYROSCOPE WITH TWO DEGREES OF FREEDOM." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1999. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=18972@1.

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Este trabalho visa a avaliar o comportamento dinâmico de um Giroscópio em Suspensão Cardânica com dois graus de liberdade a partir de suas equações de movimento, obtidas analiticamente, considerando possíveis imprecisões de fabricação ou variações na geometria esperada. A partir do resultado de simulações de um sistema real em voo, pretende-se compará-las com o resultado de simulações realizadas com o modelo analítico e avaliar as causas de possíveis discrepâncias. Assim, analisa-se a influência da variação de parâmetros geométricos na precisão de medição de um giroscópio cardânico de 2 eixos sob a ação do sistema em uma manobra de inclinação e sob a ação de uma elevada aceleração linear, quando houver uma excentricidade no centro de gravidade do rotor. Duas hipóteses vão ser exploradas: uma idealizando o rotor do giroscópio como livre no espaço outra imaginando a influência dos quadros da suspensão cardânica, tomados todavia como rígidos. Apresenta-se uma implementação que testa vários parâmetros geométricos e procura-se adequar a forma de representar os resultados de tal forma que seja possível uma validação do modelo matemático proposto.
This paper evaluates the dynamic performance of a Two Axes Cardanic Gyroscope, based on the development of its equation of motion, considering possible manufacturing imprecisions or geometric variations on the expected geometry. Simulation results of a real guided vehicle system are used to compare with those obtained from the analytical model, in order to determine the origin of discrepancies. The simulation will allow the specification of manufacturing tolerances based on the needed precision of the dynamic behavior to keep small the overall cost. Special attention is dedicated to the influence of geometric parameters in the measurement accuracy of a two axes cardanic gyroscope, such as the eccentricity of the center of gravity of its rotor, when located inside a guided vehicle that experiences a high longitudinal acceleration and performs afterwards a specific manoeuvre. Two hypothesis for the analytical description will be explored, one considering the gyro rotor free in space and the other including the inner gimbals inertia and friction influences, while all components are considered rigid. This will show the need for a more precise model. An implementation Is presented, testing some geometric parameters, with the purpose of showing the results properly, in order to allow the mathematical model validation.

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Joubert, Retief. "Influence of geometric and environmental parameters on air-cooled steam condenser performance." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4153.

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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: Air-cooled steam condensers (ACSCs) are used in the power generation industry to directly condense turbine exhaust steam in areas where cooling water is expensive or unavailable. Large axial flow fans force ambient air through A-frame heat exchanger bundles made up of a number of rows of finned tubes through which the steam is ducted and consequently condensed during the heat transfer process to the air. The heat rejection rate or performance of an ACSC is proportional to the air mass flow rate, determined by fan volumetric performance, and the temperature difference between the finned tubes and the air. The air flow through a 30 fan ACSC (termed the generic ACSC) operating under windy conditions is solved using the commercial computational fluid dynamics (CFD) code FLUENT and the required data is extracted from the solution to calculate performance trends. It is found that fan performance is reduced due to a combination of factors. The first is additional upstream flow losses caused by separated flow occurring primarily at the leading edge of the ACSC and secondarily at the fan bellmouth inlets. The second factor leading to reduced fan performance is the presence of distorted flow conditions at the fan inlets. Hot plume air recirculation is responsible for decreased ACSC thermal performance due to increased fan inlet air temperatures. It is found that reduced fan performance is the greater contributor to reduced ACSC performance. The performance effects of varying two geometrical parameters of the generic ACSC, namely the fan platform height and the windwall height, are investigated under windy conditions. It is found that each parameter is linked to a specific mechanism of performance reduction with the fan platform height affecting fan performance and the windwall height affecting recirculation. The respective platform and windwall heights specified for the generic ACSC are found to provide acceptable performance results. To mitigate wind induced performance reductions a number of modification and additions to the ACSC are investigated. These primarily aim at improving fan performance and included the addition of walkways or skirts, the addition of wind screens beneath the fan platform, removing the bellmouth fan inlets, using different types of fans and increasing fan power. The addition of a periphery walkway and windscreens is considered to be the most practical methods of improving ACSC performance under windy conditions. The generic ACSC is modified to include both modifications and under high wind conditions the performance is found to increase measurably. The modifications also resulted in the ACSC performance being less sensitive to wind direction effects.
AFRIKAANSE OPSOMMING: Lugverkoelde kondensators word in die kragopwekkings industrie gebruik om turbine uitlaatstoom te kondenseer, veral in gebiede waar verkoelingwater duur of onbeskikbaar is. Aksiaalvloei-waaiers forseer omgewingslug deur A-raam warmteuitruiler bondels wat bestaan uit verskeie rye vinbuise. Die uitlaatstoom vloei in die vinbuise en kondenseer as gevolg van die warmteoordrag na die lug. Die warmteoordragkapasiteit van die lugverkoelde stoom kondensator is eweredig aan die massavloei-tempo van die lug, wat bepaal word deur die waaierwerkverigting, en die temperatuur verskil tussen die vinbuise en die lug. Die lugvloei deur 'n 30 waaier lugverkoelde stoom kondensator (genoem die generiese lugverkoelde stoom kondensator) onderworpe aan winderige toestande word opgelos deur die gebruik van die kommersiële vloeidinamika-pakket, FLUENT. Die nodige data is onttrek uit die oplossing en werkverrigting neigings is bereken. Dit is gevind dat waaierwerkverigting verminder as gevolg van 'n kombinasie van faktore. Die eerste is bykomende vloeiverliese wat veroorsaak word deur vloeiwegbreking wat plaasvind primêr by die voorste rand van die lugverkoelde stoom kondensator asook by die klokvormige waaier-inlate. 'n Tweede faktor wat lei tot vermindere waaierwerkverigting is die teenwoordigheid van lugvloeiversteurings by die waaier-inlate. Hersirkulering van warm pluim lug is ook verantwoordelik vir verminderde lugverkoelde stoom kondensator werkverrigting. Daar word bevind dat die vermindering in waaierwerkverrigting die grootste bydraende faktor tot vermindere lugverkoelde stoom kondensator werkverrigting is. Die effek van verandering van twee geometriese lugverkoelde stoom kondensator parameters, naamlik die waaierplatformhoogte en die windwandhoogte is ondersoek onder winderige toestande. Daar word bevind dat elk van die parameters gekoppel is aan 'n spesifieke meganisme van vermindere lugverkoelde stoom kondensator verrigting: Die waaierplatformhoogte beïnvloed waaierverrigting terwyl die windwandhoogte hersirkulering beinvloed. Daar word ook bevind dat die onderskeie waaierplatform- and windwandhoogtes van die generiese lugverkoelde stoom kondensator, van so 'n aard is dat dit aanvaarbare werkverrigting tot gevolg het. Om verlaging in werksverrigting in winderige toestande te verminder is verskeie modifikasies en byvoegings tot die lugverkoelde stoom kondensator ondersoek wat primêr gemik is op verbetering in waaierwerkverigting. Die ondersoek dek die byvoeging van 'n loopvlak, die byvoeging van windskerms onder die waaierplatform, verwydering van die klokvormige waaier-inlate, die gebruik van verskillende waaiers en die verhoging van waaierdrywing. Daar was besluit dat die byvoeging van 'n loopvlak rondom die rand van die lugverkoelde stoom kondensator en die byvoeging van windskerms die mees praktiese manier was om die lugverkoelde stoom kondensator verigting te verbeter. Die generiese lugverkoelde stoom kondensator was aangepas om beide veranderings in te sluit en meetbare verbetering in werkrigting was verkry. Die veranderings het ook meegebring dat die lugverkoelde stoom kondensator minder sensitief is vir windrigting effekte.

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Ayadh, Mohammed Thabet. "Influence of the city geometric features on the two fluid model parameters." Thesis, Virginia Tech, 1986. http://hdl.handle.net/10919/45683.

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The traffic flow in an urban street network is a complicated system which involves many variables. Some of these variables relate to the networkâ s geometric features; some of these variables reflect the characteristics of the vehicles, drivers and pedestrians using the network.

The Two Fluid Model was introduced to help evaluate the quality of traffic service in urban street networks. The model parameters, T_m and n, are used as a scale to compare traffic quality in two or more urban street networks. It is known that the higher the values of the two parameters in a network, the lower the quality of the network's traffic service.

This report presents material which may be used to predict the correlation between the Two Fluid Model parameters and the geometric features of a specific street network.

The Two Fluid Model parameters will be used as dependent variables in this analysis. Seven network geometric features were selected to be used as independent variables. Using linear regression techniques, the variables will be analyzed to formulate two models. One model will explain the relationship between Tm and corresponding geometric features; the other model will explain the relationship between T_m and its corresponding features. A basic understanding of these two models will allow traffic engineers to develop strategies and/or network changes to improve traffic service in a city's street network. This will especially help networks still in the planning and/or design stage.

Because the trip time per unit distance, T, is an important traffic variable for both the Two Fluid Model and in fuel consumption models, portions of this report concentrated on establishing a relation between the two models.

Master of Science

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Wood, Alan Michael. "The influence of fault geometric uncertainty on hydrocarbon reservoir and simulation models." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5885/.

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The impact of uncertainty in the geometry of normal faults upon hydrocarbon reservoir models has been assessed at the exploration-, field- and individual fault scale. At the exploration-scale synthetic 2D seismic sections generated using mapped geometries from the Gulf of Corinth rift illustrate the uncertainty in along strike fault geometry and displacement continuity when correlating between disparate seismic lines. This uncertainty has implications for pore pressure prediction, spill point identification and calculation of hydrocarbon column heights. At the hydrocarbon field-scale, incorporation of sub-seismic structure has been quantified using reservoir production simulations. Although the inclusion of sub-seismic fault tips often leads to increased reservoir segmentation, this does not necessarily imply a detrimental impact upon hydrocarbon production. Earlier onset of oil production decline for more segmented reservoirs is offset by a lower rate of decline due to an enhanced sweep pattern as well as a lower volume of produced water when compared to less segmented cases. 3D seismic forward modelling highlights the discrepancies between realistic, outcrop-derived fault geometries and those geometries resolvable in seismic data, with seismically resolvable faults significantly simplified in comparison to those observed at outcrop. Complex geometries such as displacement partitioning across multiple slip surfaces are hence not incorporated within reservoir models leading to the area of across-fault reservoir:reservoir juxtaposition being severely underestimated. In turn faults are modelled as overly retardant to flow, with the influence of fault rock properties being overstated. Where realistic (i.e. larger) areas of across-fault juxtaposition are modelled, the fault rock properties have less impact upon acrossfault hydrocarbon flux. Juxtaposition is therefore the first order control on hydrocarbon flow across faults.

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Maletzke, Fabian. "Investigation Of The Influence Of Geometrical Parameters On Heat Transfer In Matrix Cooling : A Computational Fluid Dynamics Approach." Thesis, Linköpings universitet, Mekanisk värmeteori och strömningslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-177185.

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Modern gas turbine blades and vanes are operated at temperatures above their material’s melting point. Active external and internal cooling are therefore necessary to reach acceptable lifetimes. One possible internal cooling method is called matrix cooling, where a matrix of intersecting cooling air channels is integrated into a blade or vane. To further increase the efficiency of gas turbines, the amount of cooling air must be reduced. Therefore it is necessary that heat transfer inside a cooling matrix is well understood. In the first part of the thesis, a methodology for estimating heat transfer in the flow of matrix cooling channels was established using Computational Fluid Dynamics. Two four-equation RANS turbulence models based on the k-ε turbulence model showed a good correlation with experimental results, while the k-ω SST model underpredicted the heat transfer significantly. For all turbulence models, the heat transfer showed high sensitivity towards changes in the numerical setup. For the k-ω SST turbulence model, the mesh requirements were deemed too computationally expensive and it was excluded from further investigations. As the second part of the thesis, a parameter study was conducted investigating the influence of several geometric parameters on the heat transfer in a cooling matrix. The matrix was simplified as a channel flow interacting with multiple crossing flows. The highest enhancement in heat transfer was seen with changes in taper ratio, aspect ratio and matrix angle. Compared to smooth pipe flow, an increase in heat transfer of up to 60% was observed. Rounded edges of the cooling channels showed a significant influence on the heat transfer as well. In contrast, no influence of the wall thickness on the heat transfer was observed. While no direct validation is possible, the base case and the parameter sweeps show a good correlation with similar cases found in the literature.

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Bruttomesso, Douglas Allen. "Laser ultrasonic techniques to determine the influence of geometric features on Rayleigh waves." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/21471.

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Choi, Taehoon. "Influence of the black-box approach on preservice teachers’ preparation of geometric tasks." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5439.

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The nature of geometric tasks that students engage with in classrooms influences the development of their geometric thinking. Although mathematics standards emphasize formal proofs and mathematical reasoning skills, geometric tasks in classrooms remain focused on students’ abilities to recall mathematical facts and use simple procedures rather than conceptual understanding. In order to facilitate students’ high-level mathematical thinking, teachers need to provide sufficient opportunities for students to engage in cognitively demanding mathematical tasks. The use of dynamic geometry software (DGS) in classrooms facilitates conceptual understanding of geometric proofs. The black box approach is a new type of task in which students interact with pre-constructed figures to explore mathematical relationships by dragging and measuring geometric objects. This approach is challenging to students because it “requires a link between the spatial or visual approach and the theoretical one” (Hollebrands, Laborde, & Sträßer, 2008, p. 172). This study examined how preservice secondary mathematics teachers make choices or create geometric tasks using DGS in terms of cognitive demand levels and how the black box approach influences the way preservice teachers conceptualize their roles in their lesson designs. Three preservice secondary mathematics teachers who took a semester-long mathematics teaching course participated in this qualitative case study. Data include two lesson plans, before and after instructions for geometric DGS tasks, pre- and post-interview transcripts, electronic files of geometric tasks, and reflection papers from each participant. The Mathematical Task Framework (Stein, Smith, Henningsen, & Silver, 2009) was used to characterize mathematical tasks with respect to level of cognitive demand. A Variety of geometric task types using DGS was introduced to the participants (Galindo, 1998). The dragging modalities framework (Arzarello, Olivero, Paola, & Robutti, 2002; Baccaglini-Frank & Mariotti, 2010) was employed to emphasize the cognitive demand of geometric tasks using DGS. The PURIA model situated the participants’ conceptualized roles in technology use (Beaudin & Bowers, 1997; Zbiek & Hollebrands, 2008). Findings showed that the preservice teachers only employed geometric construction types on low level geometric DGS tasks, which relied on technological step-by-step procedures students would follow in order to arrive at the same results. The preservice teachers transformed those low level tasks into high level tasks by preparing DGS tasks in advance in accordance with the black box approach and by encouraging students to explore the tasks by posing appropriate questions. However, as soon as they prepared high level DGS tasks with deductive proofs, low level procedure-based tasks followed in their lesson planning. The participants showed positive attitudes towards using DGS to prepare high level geometric tasks that differ from textbook-like procedural tasks. Major factors influencing preservice teachers’ preparation of high level tasks included teachers’ knowledge of mathematics, pedagogy, and technology, as well as ways of using curriculum resources and teachers’ abilities to set appropriate lesson goals. Findings of this investigation can provide guidelines for integrating DGS in designing high level geometric tasks for teacher educators, researchers, and textbook publishers.

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Goswami, Ishan. "Influence of geometric and flow variations on coronary diagnostic parameters: An in-vitro study." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367937429.

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Pickup, Brian A. "Influence of Material and Geometric Parameters on the Flow-Induced Vibration of Vocal Folds Models." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2221.

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The vocal folds are an essential component of human speech production and communication. Advancements in voice research allow for improved voice disorder treatments. Since in vivo analysis of vocal fold function is limited, models have been developed to simulate vocal fold motion. In this research, synthetic and computational vocal fold models were used to investigate various aspects of vocal fold vibratory characteristics. A series of tests were performed to quantify the effect of varying material and geometric parameters on the models' flow-induced responses. First, the influence of asymmetric vocal fold stiffness on voice production was evaluated using life-sized, self-oscillating vocal fold models with idealized vocal fold geometry. Asymmetry significantly influenced glottal jet flow, glottal area, and vibration frequency. Second, flow-induced responses of simplified and MRI-based synthetic models were compared. The MRI-based models showed remarkable improvements, including less vertical motion, alternating convergent-divergent glottal profile patterns, and mucosal wave-like movement. Third, a simplified model was parametrically investigated via computational modeling techniques to determine which geometric features influenced model motion. This parametric study led to identification and ranking of key geometric parameters based on their effects on various measures of vocal fold motion (e.g., mucosal wavelike movement). Incorporation of the results of these studies into the definition of future models could lead to models with more life-like motion.

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McMurray, Jennifer Marie. "Response and Failure of Internally Pressurized Elliptical Composite Cylinders." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/79679.

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Presented is an overview of a semi-analytical solution which was developed to study the response of internally pressurized elliptical composite cylinders with clamped boundaries. Using a geometrically linear analysis and the solution scheme, the response of a quasi-isotropic elliptical cylinder is compared with the response of a quasi-isotropic circular cylinder in order to study the effects of elliptical geometry. The distinguishing features of the response of an elliptical cylinder are the inward normal displacement of the cross section at the ends of the major diameter that occur despite the outward force of the internal pressure, the presence of circumferential displacements, and the presence of inplane shear strains. These effects lead to spatial variations, including sign reversals, of a number of displacement, strain, and curvature responses. The responses of a quasi-isotropic elliptical cylinder evaluated using a geometrically linear analysis are then compared to the responses evaluated using a geometrically nonlinear analysis. It is shown that geometric nonlinearities tend to flatten certain responses at the ends of the minor diameter, and reduce the magnitude of certain responses in the boundary region. To study the influence of material orthotropy, the responses of axially-stiff and circumferentially-stiff elliptical cylinders evaluated using geometrically nonlinear analyses are examined. It is shown that in some instances material orthotropy can be used to mitigate the influence of the elliptical geometry and make particular responses look like those of a circular cylinder. An evaluation of failure using the maximum stress and Hashin failure criteria and geometrically linear and nonlinear analyses is presented for elliptical cylinders. These failure criteria involve interlaminar shear stresses which are computed by integrating the equilibrium equations of elasticity through the thickness of the cylinder wall. The failure criteria are used to assess the mode of failure (e.g., tensile or compressive fiber or matrix modes), the location of failure, and the pressure at failure. Both criteria predict first failure to occur at the clamped boundaries because of matrix cracking. The predicted failure pressures and circumferential locations are very similar for the two criteria, and the nonlinear analyses predict slightly higher pressures at somewhat different circumferential locations. First fiber failure is also considered. For this failure the two criteria predict similar failure scenarios for the linear analyses, but they differ in their predictions for the nonlinear analyses. Specifically, using the maximum stress criterion, the circumferentially-stiff elliptical cylinder is predicted to fail due to fiber compression, but the Hashin criterion predicts failure to be due to fiber tension, and at a different circumferential location. Also, first fiber failure pressures are at least a factor of two greater than the first matrix failure pressure.
Master of Science

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Santos, Jorge André Piedade Pinhal dos. "The influence of geometric factors on the wall shear stress distribution in realistic human coronary arteries." Master's thesis, FCT - UNL, 2009. http://hdl.handle.net/10362/2665.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Biomédica. A presente dissertação foi desenvolvida no Erasmus Medical Center em Roterdão, Holanda
Background: Atherosclerosis is the main cause of death in the Western society. It is a geometrically focal disease, affecting preferentially vessel areas of low wall shear stress (SS), which induces the expression of atherogenic genes. To predict wall SS several options are available. Among them Computational Fluid Dynamics (CFD) simulations on 3D reconstructed coronaries using Finite Element Modeling (FEM). However, to perform CFD a 3D representation is needed. To obtain a 3D representation of the coronary under study different methods can be applied. Methods: CFD calculations were performed using FEM on ten 3D reconstructed coronary arteries by the state-of-the-art ANGUS method (biplane angiography + Intravascular Ultrasound (IVUS)). The SS outcomes of the CFD calculations were compared with SS calculated by the Poiseuille equation, and with the SS outcomes of CFD simulations of the same 3D reconstructed arteries by QCA-3D (biplane angiography – no cross-sectional information) and Straight (IVUS images stacked on a straight centerline – no curvature information) methods. Results: The Poiseuille equation did not have any sensitivity in predicting any low SS (<0.5 Pa) per cross-section. However, the average correlation coefficient between the average SS per cross section from the Angus geometries and SS based on the Poiseuille equation was r2 = 0.65  0.09. A strong correlation was obtained for the SS from the ANGUS and the Straight method, while only an average correlation was obtained between ANGUS and QCA-3D average SS. Bland-Altman analysis was performed to confirm the results agreement. The sensitivity and specificity of the QCA-3D and Straight method in predicting low and high SS was measured. Geometric factors, such as local curvature, area gradient and torsion were found to be related to the presence of SS peaks or to regions prone to plaque development. These geometric risk factors were utilized to give some guidelines on meshing optimization. Conclusions: The use of a simpler 3D reconstruction approach, such as the QCA-3D or the Straight method, in combination with the optimization of meshing based on the geometric features of the coronaries, has the potential to, in the future, bring CFD calculations of wall SS from bench to bedside.

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Teixeira, Cleiton Rodrigues. "Influencia dos erros geometricos de afiação nas brocas helicoidais de aço rapido na qualidade dos furos produzidos." reponame:Repositório Institucional da UFSC, 1995. http://repositorio.ufsc.br/xmlui/handle/123456789/76274.

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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnologico
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Estudo das correlações existentes entre os desvios geométricos gerados nas brocas helicoidais e suas influências sobre as características do processo de furação e sobre o resultado do trabalho. Partindo-se dos desvios geométricos mais freqüentes encontrados em brocas afiadas manualmente e mecanicamente em indústrias, procurou-se reproduzir estes erros individualmente em três níveis de intensidade, permitindo assim verificar a influência destes sobre a furação. As alterações geométricas foram introduzidas uma a uma em três lotes de brocas helicoidais de aço rápido ABNT BR 7438 (DIN 338), com o diâmetro nominal de 10mm e ângulos de ponta de 106º (gumes convexos), 118º (gumes retos) e 130º (gumes côncavos) em três grupos de materiais mais empregados na indústria (alumínio 2011-73, bronze TM-23 e o aço ABNT 1020). Os ensaios foram realizados na furação maciça até uma profundidade de 25mm. Como grandezas características do processo foram medidas a força de avanço e o momento torçor e como resultado do trabalho foram determinados os desvios de circularidade e de cilindricidade, a rugosidade da parede do furo, o diâmetro médio do furo e observou-se ainda a forma dos cavacos gerados.

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Cangiani, Marcos Blanco. "Influencia da geometria da junção soldada na resistencia a fadiga de ligas do sistema cobalto-cromo." [s.n.], 1998. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289574.

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Orientador: Lourenço Correr Sobrinho
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O propósito deste estudo foi investigar a resistência à fadiga das ligas do sistema Co-Cr (Dentorium e Degussa), submetidas ou não ao procedimento de soldagem convencional. Oitenta corpos-de-prova cilíndricos com 1,7 mm de diâmetro foram obtidos por fundição odontológica, utilizando maçarico à oxigênio e acetileno para cada tipo de liga. O procedimento de soldagem foi realizado em sessenta corpos-de prova de cada uma das ligas, sendo que vinte serviram de controle. A soldagem foi efetuada com uma liga à base de Co-Cr utilizando um maçarico à oxigênio e gás (G.L.P.). Uma distância de 0,3 mm foi padronizada entre as extremidades dos três tipos de preparo (topo a topo, chanfro de 30° e ponta de lápis) a serem soldadas. O ensaio de resistência à fadiga foi realizado numa máquina de cargas cíclicas AMSLER (Alfred J. Amsler & Co.), calibrada com carga constante de tração de 1 kgf, com os corpos-de-prova solicitados à flexão por ciclo oscilatório de 2° para cada lado. Após a fratura, o número de ciclos foi registrado e a superfície de fratura analisada sob M.EV.. Os resultados foram estatisticamente analisados usando a análise ,de variância e o teste de Tukey, nos quais verificamos que: 1 - Para a liga Dentorium, os três tipos de preparo (com solda) apresentaram valores de resistência estatisticamente semelhante entre si, porém, foram estatisticamente inferiores ao controle (sem solda); 2 - Para a liga Degussa, os preparos tipo ponta de lápis e topo a topo (com solda) mostraram valores de resistência à fadiga estatisticamente semelhantes entre si, porém, estatisticamente inferiores ao controle (sem solda) e preparo em chanfro de 30°. Nenhuma diferença estatística foi encontrada entre o controle e o preparo em chanfro de 30°; 3 -. a liga Dentorium apresentou valores de resistência à fadiga estatisticamente superior à liga Degussa, quando a solda foi efetuada no preparo tipo ponta de lápis. Nenhuma diferença estatística foi observada para o controle e os tipos de preparos em chanfro de 30° e topo a topo
Abstract: The purpose of this study was to investigate the fatigue stength of the system Co-Cr (Dentorium and Degussa), submitted or not to the procedure conventional soldering. Cylindrical eighty specimens with 1,7 mm in diameter were casted utilizing oxi-acetilene torch for each alloys kind. The soldering procedure was realizated in sixty specimens of each alloy and twenty were control. the soldering were obtained by Co-Cr welding rods and gas-oxygen torch. the solder gap selected was 0.3 mm for each prepared (top to top, chamfer 30° and pencil point). The fatigue strength was conducted in a AMSLER (alfred J. Amsler & Co. - Shaffhausen Schaweis - Switzerland) fatig~e testing machine and the specimens were sujected to a tensile load of 1 kg, and a ciclic stress amplitude of 2°. After failure, the cycles were registered and the fracture surface was examined with (S.E.M.). The results were statistically analysed using a Mann-Whitney. The results of this study indicated that: 1 - For the Dentorium alloy the three types of prepare (with solder) presented- values of strength statistically similar to each other but inferior statistically than control (without solder); 2 - For the Degu'ssa alloy, the type of prepared pencil point and top to top (with solder) showed the similar results statistically, but inferior statistically to the control (without solder) in chamfer of 30°. No statistical difference wás found between the control and prepared in chamfer of 30°; 3 - The Dentorium alloy presented resistance values of fatigue superior statistically the degussa alloy, when it solde r was made in prepare pencil point. No statistical difference was observed for the control and ty pes of prepared in chamfer 30° and top to topo
Mestrado
Materiais Dentarios
Mestre em Ciências

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RODRIGUES, LARA. "INFLUENCE OF INITIAL GEOMETRIC IMPERFECTIONS ON THE INTERNAL RESONANCES AND NON-LINEAR VIBRATIONS OF THIN-WALLED CYLINDRICAL SHELLS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35757@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
A análise das ressonâncias internas em sistemas estruturais contínuos é uma das principais áreas de pesquisa no campo da dinâmica não linear. A ressonância interna entre dois modos de vibração ocorre quando a proporção de suas frequências naturais é um número inteiro. De particular importância, devido à sua influência na resposta estrutural, é a ressonância interna 1:1, geralmente associada às simetrias do sistema, a ressonância interna 1:2, devida às não linearidades quadráticas e a ressonância 1:3 decorrente de não linearidades cúbicas. A ressonância interna permite a transferência de energia entre os modos de vibração relacionados, levando geralmente a novos fenômenos com profunda influência sobre a estabilidade da resposta dinâmica. As cascas de revolução geralmente exibem ressonâncias internas devido à inerente simetria circunferencial e um denso espectro de frequência em sua faixa de frequências mais baixas. Isso pode levar não apenas a ressonâncias internas do tipo m:n, mas a múltiplas ressonâncias internas. Nesta tese é realizada a análise de múltiplas ressonâncias internas em cascas cilíndricas delgadas, em particular as ressonâncias internas de 1:1:1:1 e 1:1:2:2 são investigadas em detalhes, um tópico pouco explorado na literatura técnica. A investigação de ressonâncias internas em sistemas contínuos geralmente é realizada usando modelos discretos de baixa dimensão. Embora alguns trabalhos anteriores tenham investigado ressonâncias internas do tipo m:n em cascas cilíndricas, muitos resultados não são consistentes, uma vez que os modelos discretos derivados não consideram os acoplamentos modais devido a não linearidades quadráticas e cúbicas. Aqui, usando um procedimento de perturbação, expansões modais consistentes são derivadas para um número arbitrário de modos de interação, levando a modelos de baixa dimensão confiáveis. A precisão desses modelos é corroborada usando o método Karhunen-Loève. Finalmente, é bem sabido que pequenas imperfeições geométricas da ordem da espessura da casca têm uma forte influência na sua resposta não linear. No entanto, sua influência nas ressonâncias internas, instabilidade dinâmica e transferência de energia é desconhecida. Assim, a influência de diferentes tipos de imperfeição modal é devidamente considerada na presente análise. Utilizando os modelos discretos aqui derivados, é apresentada uma análise detalhada das bifurcações, utilizando técnicas de continuação e o critério de estabilidade de Floquet, esclarecendo a importância das ressonâncias internas nas vibrações não lineares e instabilidades de cascas cilíndricas. Os resultados também confirmam que a forma e a magnitude das imperfeições geométricas iniciais têm uma influência profunda nos resultados, permitindo ou impedindo a transferência de energia entre os modos ressonantes considerados.
The analysis of internal resonances in continuous structural systems is one of the main research areas in the field of nonlinear dynamics. Internal resonance between two vibration modes occur when the ratio of their natural frequencies in an integer number. Of particular importance, due to its influence on the structural response, is the 1:1 internal resonance, usually associated with system symmetries, the 1:2 internal resonance, due to quadratic nonlinearities, and the 1:3 resonance arising from cubic nonlinearities. The internal resonance enables the energy transfer between the related vibration modes, leading usually to new phenomena with profound influence on the stability of the dynamic response. Shells of revolution usually exhibit internal resonances due to the inherent circumferential symmetry and a dense frequency spectrum in their lower frequency range. This may lead not only to m:n internal resonances, but also multiple internal resonances. In this thesis, the analysis of multiple internal resonances in slender cylindrical shells is conducted, in particular 1:1:1:1 and 1:1:2:2 internal resonances are investigated in detail, a topic rarely found in the technical literature. The investigation of internal resonances in continuous systems is usually conducted using low dimensional discrete models. Although some previous works have investigated m:n internal resonances in cylindrical shells, many results are not consistent since the derived discrete models do not consider the modal couplings due to quadratic and cubic nonlinearities. Here, using a perturbation procedure, consistent modal expansions are derived for an arbitrary number of interacting modes, leading to reliable low dimensional models. The accuracy of these models is corroborated using the Karhunen-Loève method. Finally, it is well known that small geometric imperfections of the order of the shell thickness has a strong influence on the shell nonlinear response. However, their influence on internal resonances, dynamic instability and energy transfer is largely unknown. Thus, the influence of different types of modal imperfection is properly considered in the present analysis. Using the derived discrete models, a detail bifurcation analysis, using continuation techniques and Floquet stability criterion, is presented, clarifying the importance of internal resonances on the nonlinear vibrations and instabilities of cylindrical shells. The results also confirm that the form and magnitude of initial geometric imperfections has a profound influence on the results enabling or preventing the energy transfer among the considered resonant modes.

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Sarfaraz, Wakil. "The geometric influence of domain-size on the dynamics of reaction-diffusion systems with applications in pattern formation." Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/79452/.

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This thesis presents through a number of applications a self-contained and robust methodology for exploring mathematical models of pattern formation from the perspective of a dynamical system. The contents of this work applies the methodology to investigate the influence of the domain-size and geometry on the evolution of the dynamics modelled by reaction-diffusion systems (RDSs). We start with deriving general RDSs on evolving domains and in turn explore Arbitrary Lagrangian Eulerian (ALE) formulation of these systems. We focus on a particular RDS of activator-depleted class and apply the detailed framework consisting of the application of linear stability theory, domain-dependent harmonic analysis and the numerical solution by the finite element method to predict and verify the theoretically proposed behaviour of pattern formation governed by the evolving dynamics. This is achieved by employing the results of domain-dependent harmonic analysis on three different types of two-dimensional convex and non-convex geometries consisting of a rectangle, a disc and a flat-ring.

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Metin, Tolga. "A Parametric Study On The Influence Of Semi-rigid Connection Nonlinearity On Steel Special Moment Frames." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615725/index.pdf.

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In practice, steel frames are analyzed and designed by assuming all beam to column connections as either rigid or simple. In real life, there are no such idealizations as rigid or simple and all connections would actually belong to a group of connections named as semi rigid connections. Various difficulties exist in modeling an accurate non-linear behavior of a steel structure, where one of these challenges is the modeling of semi-rigid behavior of connections. A detailed finite element model would take into account the complex interaction between all surfaces due to contact, friction and bolt pretension besides the material and geometrical nonlinearity effects. All these nonlinearity effects could be simply lumped as a moment-rotation type model at the connection region. Such a methodology is followed in this thesis and the main aim is to study the lumped nonlinear behavior of steel semi-rigid connections on the overall structural responses of steel Special Moment Frames. In this thesis three, nine and fifteen story steel Special Moment Frames are analyzed and designed as rigid frames first, and then the frames are reanalyzed considering non-linear effects due to semi-rigid connections. Changes in the ductility and overstrength reduction factors obtained from pushover curves are compared between the rigid and semi rigid modeling alternatives.

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Andrade, Ricardo Batista de. "Analise das influencias da geometria e do material do molde na formação da microestrutura de ligas aluminio-cobre." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265540.

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Orientador: Rezende Gomes dos Santos
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: Este trabalho apresenta uma análise experimental da influência do material e da geometria do molde em parâmetros térmicos e estruturais durante a solidificação de ligas alumínio-cobre. Para tanto placas e cilindros das ligas Al-4,5%Cu e Al-15%Cu foram solidificadas em moldes de areia e de aço. Foram obtidas, através de um sistema de aquisição de dados, as curvas de resfriamento em diferentes posições nas peças e na superfície externa dos moldes. Os resultados obtidos permitiram a determinação dos tempos de solidificação nas diferentes condições analisadas. Através de análise metalográfica foi possível determinar a influência da geometria e do material do molde na formação da macroestrutura e da microestrutura durante o processo de solidificação. Um modelo numérico para simulação do processo de solidificação em moldes maciços foi desenvolvido e otimizado. Alguns resultados obtidos com a aplicação do modelo, comparados com resultados experimentais, são apresentados
Abstract: This work presents an experimental analysis of the influence of material and geometry of mold in thermal and structural parameters during solidification of aluminum-copper alloys. Slabs and cylinders of Al-4.5wt%Cu and Al-15wt%Cu alloys were solidified in sand and steel molds. Curves of the variation of temperature in different positions in the solidifying alloy and on the external surface of the mold were determined. From the results solidification times were estimated for all cases analyzed. From metallographic analysis of the influences of geometry and mold material on macrostructure and microstructure were determined. A numerical model to analyze the solidification of alloys in massive molds was developed. Examples of the application of the model compared with experimental results are shown
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica

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Cingi, Guney. "The Influence Of Digital Technologies On The Interaction Of Design And Manufacturing Processes." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12606944/index.pdf.

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This study aims to analyze and evaluate the influence of digital technologies on the inter-action of design and manufacturing processes by representing an outlook of digital tech-nologies through developments in modeling capabilities, manufacturing techniques, mate-rial science, and design strategies. The digital era reached by the technological developments in different fields of sci-ence influenced the field of architecture, just like the others. Thus, a new kind of spa-tial and tectonic quality in architecture is emerging with the lately introduced design tools and materials that are novel to the building industry, while redefining the role of architect in this contemporary medium. The evolutionary process of Frank O. Gehry and his office, being a pioneer in using digital design and manufacturing tools in architecture, is represented with realized examples that point out the formerly discussed developments in the realm of architecture and visualize the tectonics of the digitally designed and produced buildings
culminating with the case study of Guggenheim Museum, Bilbao.

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Pardy, Shelley Ann. "Influence of balsam fir stand condition on the abundance and diversity of eastern hemlock looper, Lambdina fiscellaria fiscellaria (Guen.) (Lepidoptera: Geometridae) natural enemies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0029/MQ62413.pdf.

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Karimi, Neghlani Paria. "Electron beam melting of Alloy 718 : Influence of process parameters on the microstructure." Licentiate thesis, Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-13140.

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Additive manufacturing (AM) is the name given to the technology of building 3D parts by adding layer-by-layer of materials, including metals, plastics, concrete, etc. Of the different types of AM techniques, electron beam melting (EBM), as a powder bed fusion technology, has been used in this study. EBM is used to build parts by melting metallic powders by using a highly intense electron beam as the energy source. Compared to a conventional process, EBM offers enhanced efficiency for the production of customized and specific parts in aerospace, space, and medical fields. In addition, the EBM process is used to produce complex parts for which other technologies would be either expensive or difficult to apply. This thesis has been divided into three sections, starting from a wider window and proceeding to a smaller one. The first section reveals how the position-related parameters (distance between samples, height from build plate, and sample location on build plate) can affect the microstructural characteristics. It has been found that the gap between the samples and the height from the build plate can have significant effects on the defect content and niobium-rich phase fraction. In the second section, through a deeper investigation, the behavior of Alloy 718 during the EBM process as a function of different geometry-related parameters is examined by building single tracks adjacent to each other (track-by-track) andsingle-wall samples (single tracks on top of each other). In this section, the main focus is to understand the effect of successive thermal cycling on microstructural evolution. In the final section, the correlations between the main machine-related parameters (scanning speed, beam current, and focus offset) and the geometrical (melt pool width, track height, re-melted depth, and contact angle) and microstructural (grain structure, niobium-rich phase fraction, and primary dendrite arm spacing) characteristics of a single track of Alloy 718 have been investigated. It has been found that the most influential machine-related parameters are scanning speed and beam current, which have significant effects on the geometry and the microstructure of the single-melted tracks.

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Becker, Jamie Erin. "The influence of urbanization on arthropod water demand and lipid and protein consumption in mesic environments." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1510869685967938.

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Jones, Simon Philip. "Influence of modifiers on Palladium based nanoparticles for room temperature formic acid decomposition." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:873277f2-c4f7-45b7-a16d-bba064e24bee.

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Heterogeneous catalysts form a highly important part of everyday life, ranging from the production of fertiliser enabling the growth of crops that sustain much of the world's population to the production of synthetic fuels. They constitute a key part of the chemical industry and contribute towards substantial economic and environmental benefits. Heterogeneous catalysts are also believed to have an important role to play in a future hydrogen economy, reducing our requirements for fossil fuels. To this end, formic acid has been proposed as a potential hydrogen storage material for small portable devices. Additionally, formic acid has historically been used as a probe molecule to study catalyst materials and recent developments in the knowledge of its decomposition pathways and the preferred sites of these reactions, establish a good foundation for further study. This work explores a range of novel modification techniques that alter the activity of Pd nanoparticles to decompose formic acid to H₂ and CO₂. The methods used are the addition of polymers, attaching various functional groups to the surface of the catalyst support and decoration of nanoparticles with sub-monolayer coverages of another metal. Using a range of characterisation methods including FTIR of an adsorbed CO probe, XRD and XPS coupled with computational modelling, it is found that these methods result in some significant electronic and/or geometric alterations to the Pd nanoparticles. For polymer modification, the nature of the pendent group is highly important in determining the effects of the polymer on the Pd particles, with all the tested polymers resulting in varying degrees of electronic donation to the Pd surface. The geometric modifications caused by the polymers also varied with pendent groups; with amine containing pendent groups found to selectively block low coordinate sites, preventing the undesired dehydration of formic acid which results in poisoning of the Pd catalyst by the resulting CO. Attachment of amine groups to the surface of metal oxide catalyst supports, is demonstrated to result in dramatic electronic promotional effects to the supported Pd nanoparticles, and when an amine polymer is attached to the support surface the geometric modification is again observed. Finally decoration of Pd nanoparticles with a sub-monolayer coverage of a second metal is examined, resulting in some similar electronic and geometric effects on Pd nanoparticle surfaces to those observed with polymer modification with corresponding changes in formic acid decomposition activity. Overall, a number of methods are displayed to tune the catalytic activity and selectivity of Pd nanoparticles for formic acid decomposition, resulting in catalysts with some of the highest reported TOF's at room temperature. These modification methods are believed to be potentially applicable to a wide range of other catalytic reactions that operate under mild conditions.

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Newberry, Simon David. "An experimental investigation into the influence of geometric properties and construction techniques on the packing density of rock armour layers for coastal engineering structures." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406440.

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Ablitzer, Frédéric. "Influence des paramètres mécaniques et géométriques sur le comportement statique de l’archet de violon en situation de jeu." Thesis, Le Mans, 2011. http://www.theses.fr/2011LEMA1023/document.

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L'archet, élément indispensable à la production sonore des instruments à cordes frottées, a jusqu'à présent fait l'objet de peu d'études scientifiques. Le travail présenté a pour objectif de mieux comprendre son comportement mécanique en situation de jeu. À cette fin, des modèles numériques sont développés. La baguette, précontrainte par la tension du crin, est modélisée par des éléments finis de poutre en formulation corotationnelle, afin de prendre en compte la non-linéarité géométrique inhérente au problème. Un premier modèle (2D) rend compte du comportement de l'archet dans le plan. Il donne lieu à une étude numérique sur une géométrie standard, visant à mettre en évidence l'influence des paramètres de fabrication et de réglage sur le comportement de l'archet sous tension. Un second modèle (3D) intègre le caractère tridimensionnel des sollicitations rencontrées en situation de jeu, prenant en compte la flexion latérale de la baguette. Une procédure non destructive de détermination des propriétés mécaniques du bois et de la mèche, basée sur une méthode inverse utilisant le modèle 2D, est proposée. À titre de validation expérimentale, des résultats numériques obtenus avec le modèle 3D sont confrontés aux résultats de mesures sur deux archets, pour différents réglages du cambre et de la tension. L'effet de la précontrainte sur la raideur de flexion latérale de la baguette est mis en exergue. Le bon accord observé confère au modèle un caractère prédictif, offrant des perspectives d'utilisation en tant qu'outil d'aide à la facture. Par ailleurs, la stabilité de l'archet est un problème que les facteurs doivent prendre en considération. Un modèle phénoménologique basé sur un système mécanique simple est présenté. Il vise à donner certaines tendances sur les conditions d'apparition d'une instabilité par bifurcation ou par point limite, en faisant une analogie avec les propriétés de l'archet. Le calcul numérique du comportement pré- et post-critique de l'archet permet d'identifier des cas d'instabilité similaires, dont on discute les conséquences possibles sur le jeu et la facture. Dans une dernière partie, des essais en jeu axés sur les réglages du cambre et de la tension sont effectués par des musiciens. Les résultats de ces tests subjectifs tendent à montrer l'influence des paramètres de réglage examinés dans l'appréciation des qualités de jeu
The bow, which is essential to produce the sound of bowed string instruments, has been little studied. The present work aims to better understand its mechanical behavior in playing situation. To this end, numerical models are developped. The stick, which is prestressed due to hair tension, is modelized by beam finite elements. A corotational formulation is adopted to take into account geometric nonlinearity. A first model (2D) concerns the in-plane behavior of the bow. It is used within a numerical study aiming at showing the influence of making and adjusting parameters on the tightened bow. A second model (3D) takes into account out-of-plane loading that makes the stick bend laterally. A non-destructive procedure to determine mechanical properties of wood and hair is proposed. It is based on an inverse method using the 2D model. As an experimental validation, numerical results obtained with the 3D model are confronted to measurement on two bows, for different settings of camber and hair tension. The effect of prestress on lateral bending stiffness is highlighted. A good agreement is observed. Thus, the model can be considered as predictive and might be used as an aid to bow making. Furthermore, the stability of a bow is a problem considered by bow makers. A phenomenological model based on a simple mechanical system is presented. It aims to give tendancies on conditions at which bifurcation or limit point instability can occur, by drawing an analogy with the bow. The numerical computation of pre- and post-critical behavior of the bow shows similar instability cases. Their possible consequences on playing and making are discussed. Finally, playing tests with musicians are carried out, focusing on the adjustment of camber and hair tension. The results tend to show the influence of the considered adjustment parameters on the assessment of playing qualities

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Cavalcante, Rodrigo Gusmão. "Uma analise da influencia da curvatura do espaço em sistemas de comunicações." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261084.

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Orientador: Reginaldo Palazzo Junior
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Em geral, o espaço EucIidiano é utilizado no projeto e na análise de desempenho da maior parte dos sistemas de comunicações atuais. Nesta tese, verificamos que o modelo de um sistema de comunicação não necessariamente está restrito ao espaço Euclidiano, mas sim a uma variedade Riemanniana. Com isso, os sistemas de comunicaçoes podun ser analisados em um contexto mais geral, no qual constatamos que a curvatura do espaço influencia em seus desempenhos. Corno exemplo, estudamos a curvatura de meios ópticos e propomos novos perfis de guias de ondas, fibras ópticas e lentes de interesse prático. Além disso, caracterizamos a curvatura de modulações não-lineares (twisted) e verificamos que o valor máximo permitido para a energia média do ruído está relacionada ao valor da curvatura da modulação. Neste contexto, as moclulações associadas a superfícies mínimas apresentaram bons desempenhos, pois tais modulações são pontos críticos do erro quadrático médio. Mostramos também que o espaço de sinais possui métrica induzida da superfície associada à modulação. Com isso, foi possível demonstrar que os espaços de sinais com curvatura negativa são os que apresentam melhor desempenho segundo a probabilidade média de erro. Dessa forma, alguns exemplos de constelações de sinais geometricamente uniformes foram construídos e analisados em variedades Riemannianas. Finalizamos este trabalho notando que na maioria das vezes que o espaço hiperbólico é utilizado nos blocos ele um sistema ele comunicações, o desempenho desse sistema tende a se aproximar do ponto ótimo de operação
Abstract: ln general, the Euclidian space is used in the design and performance analysis in most of the current communication systems. ln this thesis, we note that the model of a communication system is not necessarily restricted to the Euclidian space, more precisely, the model can be linked to Riemannian manifolds. Thus, the communication systems could be analyed in a broader context, in which the curvature of space influence on their performance. As an example, we studied the curvature of optical medium and propose new profiles of waveguides, optical fibers and lenses of practical interest. Moreover, we have characterized the curvature of twisted modulations and found that the maximum value allowed for the average energy of noise is related to the value of the curvature of the modulation. ln this context, the modulation associatecl with minimal surfaces showed good performance, because these modulations are critical points of minimum the mean-square error. VVe show that the signal space has induced metric associated with surface of the modulation. Thus, we have shown that the signal space with negative curvature is the space where the average error probability decrease a function of the curvature. Thus, some examples of geometrically uniform signal constellations were constructecl and analyzed on Riemannian manifolds. Finally we note that most of the time that hyperbolic space is considered in blocks of a communication system, then the performance of this system tends to be closer to the optimum point of operation
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica

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MELO, H. A. S. "Influencia do Comprimento e Geometria de Pinos de Fibra de Vidro no Comportamento Biomecânico de Incisivos Centrais Superiores Tratados Endodonticamente: Uma Análise Pelo Método de Elementos Finitos." Universidade Federal do Espírito Santo, 2017. http://repositorio.ufes.br/handle/10/8122.

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Made available in DSpace on 2018-08-01T23:26:00Z (GMT). No. of bitstreams: 1 tese_10845_DISSERTAÇÃO versão final para impressão pós- defesa Hosana .pdf: 2851280 bytes, checksum: 8f1119cb040a3a1217c059d48dc16834 (MD5) Previous issue date: 2017-03-29
A reabilitação de dentes tratados endodonticamente representa um desafio para a odontologia e é alvo de pesquisas que buscam compreender as propriedades físicas, químicas e biomecânicas existentes entre dentes vitais e não vitais e assim indicar o complexo restaurador que seja esteticamente aceitável, com adequada função clínica e longevidade. Para dentes com extensa perda estrutural, os pinos de fibra de vidro têm sido considerados como uma alternativa aos retentores metálicos. O objetivo deste estudo foi avaliar a influência do comprimento e geometria dos pinos de fibra de vidro, sobre o comportamento biomecânico de incisivos centrais superiores tratados endodonticamente, sob uma carga de 100N aplicada a 130° com a superfície palatina, nas seguintes condições: Pinos de Fibra de Vidro (PFV) lisos (L), serrilhado (S), com profundidades de 5mm e 10mm. As diferentes formas de tratamento foram simuladas a partir do modelo computacional tridimensional de um incisivo superior hígido e analisadas qualitativamente através do método de elementos finitos. Os resultados foram avaliados pelo deslocamento dos modelos, critério de falha de von Mises e de tensão máxima principal. Os modelos PFVL5mm, PFVL10mm e PFVS5mm apresentaram um deslocamento na faixa de 0,0458mm a 0,512mm, enquanto que no modelo PFVS10mm, este deslocamento foi de 0,0116. O pino de fibra de vidro liso apresentou uma distribuição de tensões homogênea, enquanto que o pino serrilhado apresentou uma concentração de tensão na interface da geometria serrilhada. O padrão de distribuição nos modelos de pinos de fibra de vidro foi similar ao do dente hígido, porém os modelos restaurados com pinos de comprimentos maiores, resultaram em um gradiente de tensões mais uniforme e com uma maior área de distribuição. Os resultados obtidos indicaram que o pino de fibra de vidro de geometria serrilhado, em maior profundidade, influencia na redução do deslocamento do modelo. Além disso a geometria do pino de fibra de vidro influencia na concentração de tensões ao longo do pino e o aumento da profundidade desses pinos, aumenta a área de distribuição das tensões, de maneira que elas fiquem mais homogêneas.

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Serra, Michele. "Influence of Metastases' Location and Size on the Strain Field Distribution in Metastatically Involved Human Vertebrae: An In Vitro Study." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19365/.

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Con l’aumento della speranza di vita per pazienti afflitti da metastasi, l’attuale pratica clinica tende ad orientarsi verso terapie che ne possano aumentare la qualità della vita. Per fare ciò è necessario esplorare la meccanica del tessuto metastatico. Con questo lavoro abbiamo deciso di concentrarci sullo studio del comportamento meccanico di vertebre metastatiche. Abbiamo rivolto la nostra attenzione alla posizione e alla dimensione della lesione all’interno del corpo vertebrale; un argomento di dibattito per il quale non è disponibile nessuno studio conclusivo. Otto segmenti di varia lunghezza sono stati ottenuti da cinque colonne vertebrali, con metastasi di differente tipo (i.e. osteolitico e osteoblastico). I segmenti sono stati testati con una combinazione compressione e flessione anteriore, la distribuzione del campo di deformazione registrata per mezzo di DIC. La distribuzione del campo di deformazione è stata analizzata sia quantitativamente che qualitativamente. Le lesioni localizzate anteriormente risultavano influenzare fortemente la distribuzione del campo di deformazione, a prescindere dalla loro dimensione. L’influenza di lesioni posizionate posteriormente era trascurabile. Le vertebre con metastasi litiche e blastiche mostravano campi omogenei con deformazioni di bassa intensità, anche se sottoposte a carichi significativi (i.e. 1.5 BW). In aggiunta, è stato progettato uno “strumento” per la localizzazione delle lesioni nel corpo vertebrale a partire dagli scan CT. Questo “strumento” era composto di maschere personalizzabili e di un semplice modello geometrico per studiare la dimensione delle lesioni, Abbiamo concluso che la distribuzione del campo di deformazione è principalmente influenzata dal tipo di metastasis. Nel caso di metastasi litiche, l’influenza della posizione sulle deformazioni è più significativa di quella della dimensione.

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Seret, Anthony. "Influence de la mise en forme sur les cinétiques de précipitation durcissante dans les superalliages base nickel Inconel® 625 et AD730™." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEM030.

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Les superalliages base nickel possèdent d'exceptionelles propriétés mécaniques et de résistance à la corrosion à haute température. Ces propriétés mécaniques proviennent en partie de la précipitation durcissante des phases Ni3Nb γ″ ou Ni3(Al, Ti) γ′. L'objectif de cette thèse est de mieux comprendre comment les opérations de mise en forme de pièces industrielles peuvent influencer cette précipitation. Deux superalliages ont été étudiés dans cette thèse : Inconel® 625 mis en forme par déformation à température ambiante et renforcé par la phase γ″, et AD730™ mis en forme par forgeage à chaud et renforcé par la phase γ′. Des traitements thermiques, essais mécaniques et thermomécaniques ont été réalisés afin d'une part de reproduire les niveaux de déformation plastique et/ou la structure de grains obtenus à la fin d'étapes de mise en forme industrielle, et d'autre part de déclencher la précipitation ou d'induire l'évolution des précipités existants. Les microstructures ont ensuite été caractérisées quantitativement par microscopie à balayage au regard de la structure de grains, l'organisation des dislocations et d'état de précipitation. Dans l'alliage Inconel® 625, la précipitation γ″ lors d'un traitement thermique à 650 °C n'est pas influencée par une déformation préalable appliquée, validant la pertinence de la température de 650 °C pour procurer un durcissement homogène aux pièces industrielles. Dans l'alliage AD730™, la germination de précipités γ′ lors d'un refroidissement après compression à chaud a lieu plus tôt dans les grains non recristallisés que dans les grains recristallisés, par relaxationélastique à la germination. De manière concomitante, le front de recristallisation dissous ces précipités γ/γ′ présents dans les grains non recristallisés pour éviter toute interface γ/γ′ incohérente. Des précipités γ′ reprécipitent ensuite dans le front de recristallisation avec une interface γ/γ′ cohérente dans les grains recristallisés, et peuvent par la suite se subdiviser pour diminuer l'énergie élastique globale. Cette thèse comprend le développement d’outils spécifiques : réduction du bruit de mesure de cartographies EBSD pour une estimation plus précise des densités de dislocations géométriquement nécessaires, analyse d’image et modèle de précipitation
Nickel-based superalloys possess exceptional mechanical properties and corrosion resistance at high temperature. These mechanical properties result partly from the hardening precipitation of Ni3Nb γ″ or Ni3(Al, Ti) γ′ phases. The objective of this PhD is to better understand how forming operations of industrial parts may influence this precipitation. Two superalloys have been studied in this PhD : Inconel® 625 alloy formed a room temperature and reinforced by the γ″ phase, and AD730™ alloy hot forged and reinforced by the γ′ phase. Thermal treatments, mechanical and thermomechanical tests have been performedin order to, on the one hand, reproduce the plastic strain levels and/or the grain structure obtained at the end of industrial forming operations, and on the other hand to trigger the precipitation or the evolution of already existing precipitates. The microstructures have then been quantitatively characterizedby scanning electron microscopy regarding the grains structure, the dislocationsorganization and the precipitation state.In the Inconel® 625 alloy, the nucleation of γ″ precipitates during a thermal treatment at 650 °C is not influenced by a strain applied before, supporting the relevancy of the 650 °C temperature to bring an homogeneous hardening to industrial parts. In the AD730™ alloy, the γ′ precipitation during a cooling after a hot compression takes place sooner in unrecrystallized grains than in recrystallized grains, by elastic relaxation when nucleating. Concomitantly, the recrystallization front dissolves these γ′ precipitates present in unrecrystallized grains to avoid any incoherent γ/γ′ interface. Then γ′ precipitates reprecipitate on the recrystallization front with a coherent γ/γ′ interface in recrystallized grains, and can afterwards subdivide to reduce the global elastic energy. This PhD includes the development of specific tools : reduction of the measurement noise of EBSD maps for a more accurate assessmentof geometrically necessary dislocations densities, image analysis and precipitation model

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Antonio, Graziella Colato. "Influencia da estrutura celular e da geometria da amostra na taxa de transferencia de massa do processo de desidratação osmotica de banana nanica (Musa cavendishi) e de mamão formosa (Carica papaya L.)." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256330.

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Orientador: Fernanda Elizabeth Xidieh Murr
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Neste trabalho foi estudada a transferência de massa na Banana Nanica (Musa cavendishi) e no Mamão Formosa (Carica papaya 1.) no processo de desidratação osmótica. Foi analisada a influência da geometria e estruturas celulares, para a verificação do mellior desempenho na transferência de massa. A etapa de desidratação osmótica foi conduzida com agitação constante de 80rpm e analisada através de um planejamento experimental fatorial 24-1com 3 repetições no ponto central para cada geometria estudada. As variáveis analisadas foram temperatura (30, 45 e 60°C), concentração da solução de sacarose (45, 55 e 65°Brix), concentração de ácido láctico (O, 0,05, 0,1M), e geometria da amostra (placa plana e cubo). As respostas analisadas foram perda de água, ganho de sólidos e atividade de água. A temperatura foi a variável que mais influenciou na perda de água e ganho de sólidos, seguida da concentração de sacarose da solução. A geometria de placa foi a que mais facilitou a perda de água no processo de desidratação osmótica tanto para a banana quanto para o mamão. O Modelo de Peleg e Azuara ajustaram-se bem os dados experimentais, sendo que os dados de equilibrio de perda de água que mais se aproximaram dos dados experimentais foram os calculado pelo Modelo de Azuara. Pela análise de imagens obtidas através da microscopia eletrônica de varredura foi possível verificar que as células da banana apresentam-se de forma alongada com presença de grânulos de amido e tanino, enquanto que as células do mamão apresentam-se forma oval. A geometria da amostra mostrou ser a variável que mais influenciou nas modificações ocorridas durante o processo de desidratação osmótica de ambas frutas, seguida da temperatura.
Abstract: In this work was studied mass transfer in banana (Musa cavendish) and papaya (Carica papaya L.) in osmotic dehydration process. It was analyzed the influence of geometry and cells structures to verify the best performance in mass transfer. Osmotic dehydration was carried on with constant agitation of 80 rpm and analyzed through a factorial experimental design 24-1with 3 repetitions of central point for each geometry. Analized variables were temperature (30, 45 and 60°C), sucrose concentration (3,5; 4,5 and 5,5 M), lactic acid concentration (O; 0,05 and O,lM) and sample geometry (fIat plate and cube). Analyzed responses were water 1055,solid gain and water activity. Water loss and solid gain were influenced more by temperature and after by sucrose concentration. In osmotic dehydration process, fIat plate geometry facilitated water loss in both banana and papaya. Peleg and Azuara's models fitted well to experimental data, but equilibrium data were better approached when they were calculated by Azuara's model. Analyzing obtained images through electronic microscopy scanning it was possible to verify that banana cells presented elongated shape with starch granules and tanine, while papaya cells presented egg-shaped. The variable that caused more influence in occurred changes during osmotic dehydration was sample geometry and after the temperature.
Mestrado
Mestre em Engenharia de Alimentos

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Moura, Camila Alexandrino. "Aplicação de formulação baseada no método dos elementos finitos posicional na análise bidimensional elástica de compósitos particulados." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-27052015-172626/.

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A utilização de materiais compósitos tornou-se uma alternativa importante em muitas aplicações dentro de diversas áreas da engenharia, pois seus constituintes podem agregar propriedades mecânicas, térmicas e acústicas ao compósito, garantindo eficiência e baixo custo. Com isso, faz-se necessário um maior conhecimento do comportamento mecânico desses materiais diante das solicitações, principalmente no que diz respeito aos campos de deslocamento, deformações e tensões. O presente trabalho tem por finalidade a análise, em nível macroscópico, de estruturas bidimensionais elásticas constituídas de materiais compósitos particulados, utilizando formulação desenvolvida no contexto do Grupo de Mecânica Computacional (GMEC), do Departamento de Engenharia de Estruturas (SET), da Escola de Engenharia de São Carlos (EESC), da Universidade de São Paulo (USP), no qual se insere a presente pesquisa. A formulação utilizada baseia-se no Método dos Elementos Finitos Posicional (MEFP) e foi desenvolvida em nível mesoscópico por tratar da interação entre matriz e partículas. Tal formulação possibilita a consideração da interação partícula-matriz sem a necessidade de coincidência entre as malhas da matriz e das partículas e sem o aumento do número de graus de liberdade dos problemas, admitindo-se aderência perfeita entre as fases. A formulação considera material isotrópico e comportamento não-linear geométrico das fases. A aplicação da formulação foi aqui proposta com o intuito de avaliar a influência da geometria, tamanho, fração volumétrica, distribuição e propriedades mecânicas das partículas adotadas, no comportamento global da estrutura em nível macroscópico. Foram desenvolvidos e apresentados exemplos de aplicação, com comparação dos resultados numéricos das análises com resultados de ensaios experimentais encontrados na literatura, bem como com resultados de modelos matemáticos de homogeneização e modelos numéricos propostos por outros autores, que utilizaram o método dos elementos finitos e técnicas de homogeneização assintótica.
The use of composite materials has become an important alternative in many applications in different areas of engineering, because their constituents can add mechanical, thermal and acoustic properties to the composite, ensuring efficiency and low cost. Thus, it is necessary a better understanding of the mechanical behavior of these materials, mainly regarding displacement, stress and strain fields. This study aims to analyze, in macroscopic scale, two-dimensional elastic structures made of particulate composite materials, using formulation developed in the context of the Grupo de Mecânica Computacional (GMEC), of Departamento de Engenharia de Estruturas (SET), of Escola de Engenharia de São Carlos (EESC), of Universidade de São Paulo (USP). The formulation is based on the Positional Finite Element Method and was developed in mesoscopic level, considering the matrix-particles interaction and neglecting the interface, by means of kinematic relations used to ensure adherence of the particles to the matrix without introducing new degrees of freedom in the problem. The formulation considers isotropic material and geometric non-linear behavior of the composite phases. The application of the formulation was proposed in this work in order to evaluate the influence of geometry, size, volume fraction, distribution and mechanical properties of the particles adopted in the global behavior of the structure in macroscopic level. Numerical examples were developed and presented in order to compare the numerical results of the analysis with results obtained in experimental studies found in the literature, as well as results of mathematical models and numerical models using finite element method and the asymptotic homogenization technique.

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Zabot, Giovani Leone 1988. "Obtaining bioactive compounds from clove and rosemary using supercritical technology: influence of the bed geometry, process intensification and cost of manufacturing of extracts = Obtenção de compostos bioativos de cravo-da-índia e alecrim utilizando tecnologia supercrítica: influência da geometria do leito, intensificação de processos de extração e custo de manufatura dos extratos." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254901.

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Orientador: Maria Angela de Almeida Meireles
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-26T17:00:04Z (GMT). No. of bitstreams: 1 Zabot_GiovaniLeone_D.pdf: 24740321 bytes, checksum: 93e515a410574c1037b0a53340db63d2 (MD5) Previous issue date: 2015
Resumo: Substâncias naturais extraídas de plantas têm propriedades funcionais que as tornam preferíveis em relação às substâncias sintéticas, havendo grande interesse para aplicação farmacológica e na elaboração de bioprodutos. Técnicas de extração, como a que utiliza fluidos supercríticos, vêm se destacando por proporcionarem a obtenção seletiva de compostos bioativos com elevada qualidade. No campo da tecnologia supercrítica, pesquisas são desenvolvidas para aumentar o rendimento de extração através da alteração de condições de processo, como pressão e temperatura. No entanto, há a necessidade de discriminar mais a influência tecno-econômica de outras variáveis, como a geometria do leito de extração. Em vista disso, realizou-se a avaliação técnica da extração com CO2 supercrítico de compostos bioativos de cravo-da-índia e alecrim em uma unidade de extração laboratorial constituída por dois extratores de 1 L com diferentes razões de altura do leito (HB) pelo diâmetro (DB), sendo para o extrator 1 (E-1) a razão de 7,1 e para o extrator 2 (E-2) a razão de 2,7. Dois critérios utilizados para mudança de geometria e aumento de escala foram aplicados, consistindo em: (1) manutenção da velocidade intersticial do solvente igual em ambas as geometrias; e (2) manutenção da razão de massa de solvente por massa de matéria-prima (S/F) igual em ambas as geometrias para um determinado tempo de processo. De acordo com os resultados cinéticos de rendimento de extrato e composição química, o critério (1) não se mostrou indicado para ser aplicado em processos de extração com fluidos supercríticos (SFE) de compostos de cravo-da-índia. O critério (2) mostrou-se apropriado para a obtenção de óleo volátil de cravo-da-índia, pois houve igualdade nos perfis das curvas de extração em E-1 e E-2, avaliados em termos de parâmetros cinéticos como taxa de transferência de massa, duração dos períodos de taxa constante de extração (CER) e taxa decrescente de extração (FER), rendimento de extrato e razão mássica de soluto no solvente. No entanto, o critério (2) não se mostrou adequado para a obtenção de compostos bioativos de alecrim, sendo que o leito de extração E-2 proporcionou rendimentos até 86 % maiores em relação ao E-1, sendo a diferença mais notória no final do período FER. Houve diferença também no custo de manufatura (COM) dos extratos de alecrim simulado pelo SuperPro Designer 8.5®, sendo 23 % menor em E-2 do que em E-1 para uma planta industrial com 2 extratores de 100 L. Com relação ao alecrim, terpenoides majoritários como 1,8-cineol e cânfora foram extraídos com CO2 supercrítico. No entanto, alguns compostos fenólicos foram extraídos em pequena quantidade (ácido carnósico) ou nem foram extraídos via SFE (ácido rosmarínico). Logo, o conceito de intensificação de processos foi utilizado para facilitar a extração das duas frações presentes em alecrim. O processo consistiu em extrair inicialmente a fração rica em terpenoides com CO2 supercrítico (SFE-CO2) e logo após, no mesmo equipamento e sem desempacotar o leito, a fração rica em terpenos fenólicos foi extraída com água líquida pressurizada (PWE). Com isso, aproximadamente 2,5 % (m/m, base seca) de óleo volátil contendo terpenoides e 18,6 % (m/m, base seca) de extrato não-volátil contendo terpenos fenólicos foram obtidos em frações separadas. Um método analítico para quantificação de terpenos fenólicos por cromatografia líquida de alta eficiência foi desenvolvido e validado, com tempo total de análise de apenas 10 min. O custo operacional anual de uma planta produtiva instalada no Brasil com 2 extratores de 100 L foi simulado para os processos SFE-CO2 + PWE para obtenção de compostos de alecrim. O aproveitamento maior da matriz vegetal para a obtenção diversificada de compostos bioativos permitiu a redução em 28 % dos custos anuais de produção em relação ao processo SFE-CO2
Abstract: Natural substances extracted from plants present functional properties which are preferable against the synthetic ones, being useful in formulating bioproducts and in the pharmaceutical area. Novel extraction techniques, as the use of supercritical fluids, are acquiring notoriety by providing the selective extraction of bioactive compounds with high quality. In the supercritical technology field, researches are performed to increase the extraction yield by changing process conditions (i.e., pressure, temperature). However, there is a need for further techno-economic discriminations about the influence of other variables, as the bed geometry. Thus, we performed the evaluation of the supercritical CO2 extraction of clove and rosemary bioactive compounds using a laboratory equipment containing two extractors of 1 L with different height (HB) to bed diameter (DB) ratios. Bed 1 (E-1) and 2 (E-2) present HB/DB ratios of 7.1 and 2.7, respectively. Two criteria used for geometry shift and scale up were applied: (1) maintaining the solvent interstitial velocity equal in both bed geometries; and (2) maintaining the solvent mass to feed mass (S/F) ratio equal in both bed geometries for a fixed processing time. According to the kinetic results of extraction yields and chemical composition, the criterion (1) is not indicated for supercritical fluid extraction (SFE) of rosemary compounds. Criterion (2) is suitable for obtaining clove extract, because the extraction curves profiles were similar in E-1 and E-2. We evaluated the extraction curves in relationship to kinetic parameters as mass transfer rate, duration of constant extraction rate (CER) and falling extraction rate (FER) periods, extraction yield and mass ratio of solute in the fluid phase. However, criterion (2) is inappropriate for obtaining rosemary bioactive compounds. E-2 provided extraction yields up to 86% higher than E-1. The difference was more pronounced in the end of FER period. We observed differences on the cost of manufacturing (COM) of rosemary extracts simulated by SuperPro Designer 8.5®. COM¿s were 23% lower in E-2 than in E-1 for an industrial plant of 2 extractors of 100 L. With respect to rosemary, major terpenoids as 1,8-cineole and camphor were extracted with supercritical CO2, while some phenolic compounds were low (carnosic acid) or no extracted (rosmarinic acid) using SFE. Thus, process intensification concept was used for becoming possible the extraction of two fractions of bioactive compounds found in rosemary. The procedure comprised the initial extraction of the terpenoids-rich fraction with supercritical CO2 (SFE-CO2) and, thereafter, in the same equipment without unloading the bed, performing the extraction of the polyphenols-rich fraction with pressurized water (PWE). Approximately 2.5 wt.% (dry basis) of volatile oil containing terpenoids and 18.6 wt.% (dry basis) of non-volatile extract containing phenolic terpenes were obtained in separated fractions. We developed and validated an analytical method for quantifying phenolic terpenes by high performance liquid chromatography, presenting a total time of analysis of 10 min. Also, we simulated the annual operating cost of a plant installed in Brazil containing 2 vessels of 100 L applying SFE-CO2 + PWE processes for obtaining rosemary compounds. The higher use of the vegetal matrix for diversifying the extraction of bioactive compounds enabled 28% reduction in the annual production costs whether compared to SFE-CO2 process alone
Doutorado
Engenharia de Alimentos
Doutor em Engenharia de Alimentos

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Yu, Chi-Heng, and 余其衡. "Influences of the geometrical and material parameters on the static characteristics of metallic and polymer aerostatic thrust bearings." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/79354021167300607231.

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碩士
國立雲林科技大學
機械工程系
103
A flexible bearing surface is combined with the concept of polymer restrictor to enhance the load capacity of aerostatic bearing in this thesis: Firstly a flexible disk, which is circularly supported near its rim, is adopted as the bearing component so that it can create a concave geometry and keep the air pressure to increase the load capacity. On the other hand, a polymer restrictor with capillary is set in the central outlet of air. The inner diameter of the capillary can expand with respect to the increase in load for compensating the air flux. Finally, the whole bearing is made of polymer body covered with metallic membrane. The polymer body can be fabricated conveniently by injection or molding and generates a damping effect under dynamic forces; while the metallic membrane possesses the ready-to-use roughness and prevents the polymer bulk from wear in case of over-thin air gap. The research proceeds from understanding the influences of the geometries, metallic materials and the supporting position on the characteristics of bearing. Then change the metals into polymer, which is combined with metallic membrane, and carry out a series of numerical simulations. Lastly use the Taguchi method to optimize the key factors that affect the load capacity and static stiffness. The experiments show that the circularly supported aerostatic bearing with polymer restrictor can tremendously improve the load ability. A thinner disk together with circular support at the position of approximately 5/6 of the disk radius can generate better results. The numerical analysis indicates that the Young’s modulus of the membrane has great impact on the bearing performance. The bearing with PU body and stainless steel membrane exhibits both the greatest loading capability and stiffness. Taking the bearings of radius 30 mm as examples, at elevation 9.5µm the stiffness soars from 16 N/µm of typical bearing to 350 N/µm under supply pressure 5 bar; meanwhile the load capacity also enhances from 346 N to 704N.

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Chia, Hsu, and 徐嘉. "Geometrical Effects on the Fiber Micro-structure Variations and the Influences on the Warpage Behavior in Long Fiber Reinforced Thermoplastics (FRT) Injection Molding Product Development." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7x4pcu.

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碩士
淡江大學
化學工程與材料工程學系碩士班
106
Due to its great potential and capability, the fiber reinforced thermoplastics (FRT) material and technology have been applied into industry recently. However, due to the microstructures of fiber inside plastic matrix are very complex, they are not easy to be visualized. The connection from microstructures to the final shrinkage/warpage is far from our understanding. In this study, we have performed a benchmark with three standard specimens based on ASTM D638 where those specimens have different gate designs. Due to the geometrical effect, the warpage behaviors are quite different for those three specimens. Although we expect long fiber reinforced to enhance strength, it causes one specimen warped downward and bended inward, another warped upward, and the other slightly upward at the same time. The difference might be due to the interaction of the entrance effect of molten plastic with fiber content to cause high asymmetrical fiber orientation distribution (FOD). We further studied that the asymmetrical FOD is introduced by the entrance effect from the sprue entrance of the part to the gate of each standard specimen. This entrance effect will cause the variation of FOD and further influence the fiber distribution and the bundle phenomena. Moreover, the experimental study is also performed to validate the simulation results. From short shot testing to the warpage and bending measurement for each individual model, overall, the tendency for both numerical simulation and experimental results is in a reasonable agreement. However, some deviation still existed which needs for further study. Furthermore, in the fiber length effect study experimentally, the longer fiber reinforced the less warpage. Also, the elongation and strength of injected parts can be enhanced significantly as fiber length increased. For example, from pure PP to FRP with 25 mm fiber inside, the strength can be increased from 20 N/mm2 to 140 N/mm2 .

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HE, YAO-DONG, and 何耀東. "The influence of plane geometrical configuration of structure on the R-curve." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/32286887828105145669.

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Li, Ming-Chou, and 李明州. "Volute Geometric Influence on the Performance of a low." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/69087874194306250047.

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碩士
國立屏東科技大學
機械工程系所
96
The purpose of this research is to investigate the pump performance by using different sectional volute shape such that a design principle can be followed. The pump type discussed in this research is restricted to low specific speed only. According to the Chinese National Standard (CNS) ‘s Small Size Volute Pump Regulation[3], the pump impeller diameter is assigned to 400 mm, and its operation condition (flow rate, speed, head) is in the low specific speed range, approximately 200. Input these operation information into Chiang’s pump design code CPD.for [2], the pump’s 3-D geometry can be acquired, then the 3-D model’s mesh can be constructed by using Gambit, and detailed flowfield data can be derived by using the flow solver Fluent. Observations on the flowfield concludes the reasons of how the flow energy losses occur. Analysis on the suitable operational range, efficiency, average efficiency in the operational range, the results shows the 60° fan type volute gives the best overall performance.

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"Subsolador : a influencia de parametros geometricos na distribuição das forças." Tese, Biblioteca Digital da Unicamp, 1989. http://libdigi.unicamp.br/document/?code=vtls000045427.

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HOU, WONG TECK, and 王荻皓. "Influences of Different Geometric Parameters on Rudder Characteristics for High-Speed Crafts." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/04628585374665116098.

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碩士
國立臺灣大學
造船及海洋工程學研究所
89
The turbulent flow around rudders is computed and analyzed by solving the Reynolds-averaged Navier-Stokes equations to investigate the hydrodynamic performance, such as lift, drag, stock moment and stall angle, of several rudders used on high-speed craft with various geometric parameters. A second order finite volume method with multi-block structured grid system is applied to discretize the equation and space respectively. The standard k-ε turbulent model is employed to take account of the turbulent effect. Good agreements are obtained between the computational and experimental results. The present studies focus on the performance analysis of several practical rudders with NACA 00XX, NACA 16, NACA 66, WedgeXX, EllipseXX and RectangleXX profiles (see Appendix A and B) at Reynolds number Re of 106. Three basic non-dimensional coefficients: lift CL(α), drag CD(α) and moment CM(α), being functions of the angle of attack α of the rudder are evaluated to investigate the influences of Reynolds number, profile shape, aspect ratio, taper ratio and profile thickness, on the performance of high-speed craft rudders. Also, the position of the rudder shaft center was varied along the nose-tail line, in order to find out the stock location of minimum moment for each rudder. Furthermore, the pressure coefficient Cp and the shear stress distribution on each rudder surface are presented. In general, the NACA 00XX rudders show a better performance compared to other calculated rudders in this work.

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Liu, Mei-Ting, and 劉美廷. "Influences of colour, size and smoothness on visual conspicuity of basic geometric shapes." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/3qsjj9.

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碩士
國立臺灣科技大學
色彩與照明科技研究所
104
In this colourful world which is information overload, how can we efficiently get the right information we need? Efficiently visual searching is important. More conspicuous the target is, more attention the target can attract. The relationship between conspicuity and colour attributes, size and smoothness was investigated in this study. Two experiments were conducted in this study. The first experiment was psychological quantification of size and smoothness of rounded triangles, with various round corner ratio, i.e. the diameter of the round corner divided by the height of the shape. The second experiment was conspicuity experiment. The first experiment used psychophysical methods to develop models of psychological quantification of size and smoothness. The models were used to set up the test shapes for use in the second experiment. The visual conspicuity was defined in this study as the reciprocal of reaction time. Observers were asked to find the target from twenty-four shapes as soon as possible. The experiment had four parts : (1) the test of reaction time for mouse movement, (2) the influence of characteristics of the shape on conspicuity, (3) the influence of colours on conspicuity, (4) developing and testing the conspicuity model. The model of mouse movement was derived in the first part of the experiment to exclude the influence of the position of the target. The conspicuity models based on the impact of size, smoothness and colour were developed in the second and the third parts. A final version of the conspicuity model was derived on the basis of the three models for size, smoothness and colour, and was tested in the fourth part of the experiment with satisfactory predictive performance.

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林宏興. "Influence of magnetization switching with exchange coupling effect in geometric asymmetry disk." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/98321269816657269377.

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碩士
國立彰化師範大學
物理學系
97
Abstract The geometric asymmetry disk can control the chirality on disk. There are many study about patterned ferromagnetic disk. The research about geometric asymmetry disk in antiferromagnetic/ferromagnetic are not vary popular. The article in this study is compare antiferromagnetic/ferromagnetic magnetization switching with the ferromagnetic in geometric asymmetry disk. The NiFe and NiFe/IrMn structure are fabricated by sputtering system. Determining the geometric asymmetry pattern by e-beam lithography and etching by ICP-RIE. The excised angles are 15, 30, 60, and 90 degree. The diameter are 500 and 800nm. The M-H loop ware measured by magnetic magneto-optical Kerr effect. In 500 and 800 nm NiFe/IrMn disk, the nucleation field (Hn) are deceasing when excised angle increase. The annihilation field (Han) are smaller than NiFe one and have similar tendency. In NiFe/IrMn structure 800-nm-diameter 90-degree-excised angle, the magnetization switching can find vortex nucleation field easily. The exchange bias are not larger to observe in 500 and 800-nm-diameter NiFe/IrMn structure. But, M-H loop has clear shift in 2μm disk array.

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CHI, HSU HAN, and 徐漢圻. "Study on Influences of Geometric Parameters of a Bulbous Bow on Ship Wave Resistance." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/80284465267241567308.

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Chen, Yu-Min, and 陳俞閔. "Influences of Salt Valence and Geometric Shape of a Nanochannel on Its Rectification Behavior." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/mn45tg.

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碩士
國立臺灣大學
化學工程學研究所
106
The overlapping of electric double layer in a nano-scaled system is usually significant, rendering it having profound and interesting electrokinetic phenomena, such as ion concentration polarization (ICP) and ion current rectification (ICR), and thus fabrication of nanodevices becomes a trend of nanotechnology. In Chapter 1, by taking account of various electrolyte solution LaCl3、CaCl2、KCl、KNO3, and K2SO4, a thorough numerical simulation is conducted to illustrate the influence of asymmetry of various ionic valence ratio on the ICR behavior in a conical nanochannel. We show that the electrokinetic phenomena depend highly on ionic strength and ion diffusivity. The qualitative behavior of the ion current rectification of a positively charged conical nanochannel is similar to that of a negatively charged one.In Chapter 2, we consider a bioinspired cigar-shaped nanochannel where its surface is pH-regulated, and has zwitterionic groups. The influences of the solution pH, the bulk concentration, the base opening radii, and the nanochannel shape on the associated ICR behavior and ionic selectivity are examined, focusing on discussing the underlying mechanisms in detail. We show that the best nanochannel performance can be achieved by adjusting the base orifice radii and surface curvature appropriately. In addition to proposing underlying mechanisms for the phenomena observed, the results gathered in this study also provide necessary information for designing relevant devices.

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