Impact of rain drops at relatively high velocities, which is known as rain erosion, causes severe damages on various materials. Every material can withstand the rain erosion up to a specific impact velocity. However, this damage is critical for optical windows which are very important components for Electro-Optical (EO) systems such as thermal camera. Even a small scratch may affect the transmission capability of the optical window adversely and leads to some functional problems in the device due to insufficient transmitted data. Since it has a vital effect on the EO systems, the rain erosion is needed to be investigated on the special optical windows, particularly for determining the velocity that a damage initiates. In this study, the rain erosion is investigated on germanium which is a kind of optical window, by means of numerical simulations in LS-DYNA. Damage Threshold Velocity (DTV) is examined for two different water shapes (which are spherical water drop and water jet) within a velocity range between 100 and 250 m/s. Both single and multiple impact cases are considered for both water shapes up to ten consecutive collisions. By using the results, the &ldquo / DTV versus number of impact curves&rdquo / are obtained in order to understand the amount of damage with respect to both single and multiple impacts. Results are compared with both literature and the experimental data within the scope of DTV and shape of the damage. In the numerical simulations, ALE (Arbitrary Lagrangian Eulerian) method is used for modelling water. &ldquo / JOHNSON-HOLMQUIST-CERAMICS (JH-2)&rdquo / which is recommended for both ceramics and glass applications is used as the material model for Germanium. JH-2 is a complete material model which contains damage effects, failure criteria, and Equation of State (EOS) all together. Among the material models available in the library of LS-DYNA, &ldquo / MAT-NULL + EOS-GRUNEISEN&rdquo / is used for water.

How is it that we feel that we own our body? And how does the brain create this feeling? By manipulating the integration of multisensory signals, researchers have recently begun to probe this question. By creating the illusory experience of owning external body-parts and entire bodies, researchers have investigated the neurofunctional correlates of body ownership. Recent attempts to quantitatively synthesize the neuroimaging literature of body ownership have shown inconsistent results. A large proportion of functional magnetic resonance imaging (fMRI) findings on body ownership includes region of interest (ROI) analysis. This analysis approach produces inflated findings when results are synthesized in meta-analyses. We conducted a systematic search of the fMRI literature of ownership of body-parts and entire bodies. Two activation likelihood estimation (ALE) meta-analyses were conducted, testing the impact of including ROI-based findings. When ROI-based results were included, frontal and posterior parietal multisensory areas were associated with body ownership. However, a whole-brain meta-analysis, excluding ROI-based results, found no significant convergence of activation across the brain. These findings highlight the difficulty of quantitatively synthesizing a neuroimaging field where a large part of the literature is based on findings from ROI analysis. We discuss the difficulty of quantitatively synthesizing results based on ROI analysis and suggest future directions for the study of body ownership within the field of cognitive neuroscience.

Bwaise III in Kampala, Uganda is a densely populated informal settlement with a shallow groundwater table and inadequate basic services. High risk of groundwater contamination will bring health problem to the local residents. In this study, a large dimension (300 m in length) 2D model was developed to depict the hydrogeological condition and to examine the response to different rainfall infiltration rate on the groundwater table. The boundary condition of the drainage system plays an important role in modeling the groundwater flow. The simulation results show that water in the drain will flow into the aquifer when the drain is full, otherwise the drain will act as a sink for ground water. Advective transport of phosphorus results in no pollutants reaching or percolating into the drain. The integration of phosphorous concentra-tion flowing out of Domain 3 (pollutant inlet) corresponds to the infiltration rate and the plume moves faster during the wet season which brings in more phosphorous compared with the dry season. With sorption, all the phosphorus was adsorbed within the top soil. A simplified 3D model was set up to illustrate the flow field. Additional simulation can be undertaken within this 3D frame for more realistic calculation and consistent prediction.

Sökmotorer har blivit en allt viktigare del i människors informationshantering för att uppfylla olika behov. I en pressad situation ställs detta på sin spets, antingen det rör sig om en akut kris eller bara den moderna människans tidspress. I en sådan situation är det viktigt att enkelt kunna hitta rättinformation.I det här arbetet undersöktes hur tre västsvenska kommuners sökmotorer presterar för användare som försöker hitta tillbaka till ett bestämt dokument, en av kommunens webbsidor. Det var ett tänkt scenario som handlade om användare som redan var bekanta med innehållet, till exempel för attnågon behjälplig bekant läste delar av texten för dem, eller att de hade sidan utskriven från tidigare, eller att användaren hade besökt sidan tidigare och mindes delar av innehållet. Oavsett bakgrund tänktes en situation där informationen blev relevant och användaren var i behov av uppdaterad detaljinformation.Syftet var att jämföra de kommunala sökmotorernas prestation jämfört med en egenkonstruerad sökmotor där NLP-metoder användes. NLP – Natural Language Processing – handlar om attspråkvetenskapliga metoder används i systemutvecklingen. Undersökningen utfördes kvantitativt genom att sätta en poängskala för hur högt upp i sökresultaten den eftersökta webbsidan hamnade. Resultaten visade hur de respektive kommunerna presterade parallellt med resultaten från den egna sökmotorn. Genom att särskilja sökningarna beroende på användningen av olika NLP-metoder (separat eller i kombination) kunde de specifika metodernas effektivitet förtydligas.Resultaten visade tydliga brister hos samtliga av de undersökta kommunernas sökmotorer, medan den NLP-stödda sökmotorn konsekvent presterade bättre. De undersökta kommunernas sökmotorer gav likartade resultat, både gällande den generella prestationen och i fråga om vilka sökord som fungerade bättre samt andra detaljer. Arbetet visade att NLP-metoder kan ge bättre resultat, framför allt på grund av att de kommunala sökmotorerna var bristfälliga. / <p>Opponeringsdatum</p>

Although the finite impulse response (FIR) Adaptive Line Enhancer (ALE) was developed in 1975 and has been used in a host of applications, no comprehensive performance analysis has been performed for this method, meaning no general equation exists for its signal-to-noise ratio (SNR) gain. Such an equation would provide practitioners an avenue for determining the amount of noise reduction the ALE provides for a particular application and would add to the general knowledge of adaptive filtering. Based on this motivation, this work derives the general equation for the FIR ALE SNR gain and verifies the equation through computer simulation, under the following assumptions: (1) A simplified Least Mean Squares (LMS) method is used for updating the embedded adaptive filter located within the ALE, (2) The received signal (i.e. the input signal to the ALE) is a summation of sinusoids buried in additive zero-mean white-Gaussian noise (AWGN), (3) The received signal is oversampled (i.e. the sampling rate is larger than the Nyquist rate), and (4) The ALE filter length is an integer multiple of the number of samples within one fundamental period of the original, noiseless signal.

No description available.

During machining, the cutting tool wears out and affects the machined surface quality and overall production cost. The prediction of tool wear and analysis of cutting mechanics has significant importance for process optimization and cutting-edge design. In this present study, an efficient FE simulation approach (Arbitrary Eulerian-Lagrangian) on the Abaqus/Explicit platform has been developed to improve the predictability of flank wear and to select the appropriate tool edge geometry in the orthogonal turning operation. The FE model was calibrated by comparing the simulation and experimental force values. A new approach was applied to capture the worn tool geometry based on the frictional stress value acting on the cutting tool. The effect of wear geometry on the cutting zone was investigated with respect to temperature, normal stress, sliding velocity, and plastic deformation. The experimental tool wear pattern and characteristics for the differently prepared edges were studied and compared to the thermo-mechanical value retrieved from the FE model. Tool wear for differently prepared edges was calculated using Usui’s wear rate equation, which was calibrated using a hybrid calibration method. The efficiency of the calibration method was investigated at different cutting speeds and feed rates. The performance of pre-coating edge preparation was evaluated in both experimental and numerical studies. / Thesis / Master of Applied Science (MASc)

L’originalité de notre apport parmi les recherches sociologiques et anthropologiques roumaines porte sur l’analyse de la relation multidimensionnelle entre la migration et l’habitation rurale, mettant l’accent sur la compréhension du logement comme lieu de rencontre des modèles culturels différents. En effet, la maison doit être analysée comme un produit social et par rapport à la vie sociale et privée de la famille qui y réside. Donc, notre cadre théorique s’appuie sur le croisement entre l’analyse sociologique des processus migratoires et leur expression architecturale et matérielle. La question centrale de la recherche porte sur les continuités et discontinuités - observées par rapport à la tradition - qu’on trouve, après la chute du communisme, dans les habitations des migrants roumains, issus du milieu rural. Pour répondre à cette question, nous avons choisi une approche anthropologique du logement, en menant des enquêtes de terrain, de type qualitatif (auprès de villageois et migrants de village de Marginea), durant les années 2009, 2010 et 2011. On remarque que les nouvelles maisons se présentent comme des formes hybrides, qui articulent les références locales aux éléments nouveaux, apportés par la migration. Ainsi, nous avons introduit deux dimensions essentielles dans l’analyse du concept de la maison du migrant: les «traces du passé» et les «traces de la migration». La première dimension se réfère aux influences des anciennes formes, modèles, pratiques, mentalité etc., alors que la deuxième dimension désigne les éléments nouveaux et les innovations qui ont pénétré dans la conception, la construction et l’utilisation des maisons. / The originality of our contribution to the Romanian sociological and anthropological research concerns the analysis of the multidimensional relation between migration and the rural dwelling, emphasizing an understanding of the house as the meeting place of the different cultural models. Indeed, the house must be analyzed as a social product, with regard to the social and private life of the family which dwells there. Thus, our theoretical frame is based on the interplay between the sociological analysis of the migratory processes and their architectural and material expression. The central question of our research concerns the continuities and the discontinuities - observed with regard to the local tradition - which we find, after the fall of the communism regime, in the houses of the Romanian migrants, of rural origin. To answer this question, we chose an anthropological approach to the house, by conducting a qualitative field research (with villagers and migrants of Marginea village), in 2009, 2010 and 2011. We noticed that the new houses appear as hybrid forms, which articulate the local models to the new elements, brought by migration. So, we introduced two essential dimensions into the analysis of the concept of the migrant house: the "traces of the past" and the "traces of the migration". The first dimension refers to the influence of the old forms, models, practices, mentalities etc., while the second dimension indicates the new elements and innovations which penetrated the house design, its construction process and its exploitation. / Originalitatea contributiei noastre noastre intre cercetarile sociologice si antropologice romanesti consta in analiza relatiei multidimensionale migratie-locuinta rurala, subliniind intelegerea locuintei migrantilor din tara de origine ca loc de intalnire a diferitelor modele culturale. Intr-adevar, casa trebuie vazuta ca un produs social si in relatie cu viata sociala si privata a familiei ce o locuieste. In consecinta, cadrul teoretic si de analiza imbina analiza sociologica a migratiei internationale cu expresia arhitecturala si materiala a acesteia. Intrebarea centrala a cercetarii priveste continuitatile si discontinuitatile - observate in raport cu modelele de dinainte de 1989 – ce se manifesta, dupa caderea regimului comunist, in proiectarea, realizarea si utilizarea locuintelor migrantilor din mediul rural. Pentru a raspunde la aceasta intrebare, am optat pentru o abordare antropologica a locuintelor migrantilor, realizand un studiu de caz in comuna Marginea, jud. Suceava. Anchetele de teren s-au desfasurat in intervalele iulie – octombrie 2009, iulie-octombrie 2010 si in august 2011. Am remarcat cum locuințele migrantilor se prezinta asemenea unor forme hibride ce combina elementele noi, aduse de migratie (« urmele migratiei »), cu referintele locale, de dinainte de 1989 (« urmele trecutului »). Am introdus astfel doua dimensiuni esentiale in analiza conceptului de locuinta a migrantului in tara de origine: « urmele trecutului » si « urmele migratiei ». Prima dimensiune se refera la influentele vechilor forme, modele, practici, mentalitati etc., in timp ce a doua dimensiune indica elementele noi si inovatiile ce au patruns in proiectarea, construirea si utilizarea acestor case.

Um método lagrangeano-euleriano arbitrário para a resolução de escoamentos dominados por tensão superficial é apresentado neste trabalho. Tais escoamentos são importantes em muitas aplicações, especialmente em canais capilares que frequentemente aparecem em escoamentos em microescala. A resolução deste tipo de escoamento apresenta vários desafios que são abordados neste trabalho. O escoamento é resolvido somente para a fase líquida, com condições de contorno apropriadas para a superfície livre que delimita o líquido e o gás, que é representada por arestas e vértices da malha computacional. Esta se move e se deforma, sendo que sua qualidade é mantida sob controle para não degradar a solução numérica. As equações de Navier-Stokes são discretizadas pelo método de elementos finitos em um referencial arbitrário. O método de incorporação dos efeitos de tensão superficial e linha de contato é explicado em detalhes. Validações comprovam a precisão do método proposto, com comparações através de soluções pseudo-analíticas para casos simples. Finalmente alguns resultados sobre escoamentos em capilares são apresentados / An arbitrary lagrangian-eulerian finite element method to solve surface tension dominated flows is presented. Such flows are important in many applications, particularly in capillary channels, that appear in microscale flows. The resolution of such flows presents several challenges that are addressed in this work. The flow is solved only in the liquid phase, and proper boundary conditions are applied on the free-surface, bounding the liquid and gas, which is explicitly represented by vertices and edges of the computational mesh. The mesh is moved and deformed, but its quality is kept under control in order to control errors in the numerical solution. The Navier-Stokes equations are discretized by standard Galerkin finite element method in an arbitrary reference. Details of the computation of surface tension and contact line effects are presented. The methodology is validated for a number of simple test cases against known pseudo-analytical solutions, and numerical results are presented, showing the robustness and accuracy of the methodology. Finally, some results about surface-tension-driven flows in capillaries are presented

Gegenstand dieser Arbeit ist die Bereitstellung eines geeigneten Simulationswerkzeuges für die numerische Untersuchung der beim Rollkontakt zwischen Rad und Schiene auftretenden Phänomene. Hierbei liegt das Hauptaugenmerk auf der kontinuumsmechanischen Formulierung des mechanischen Feldproblems kontaktierender Körper sowie dessen numerischer Lösung mittels der Finite-Element-Methode. Zur Reduzierung des bei der Simulation von Rollkontakt aus der notwendigen sehr feinen Diskretisierung der Kontaktgebiete resultierenden numerischen Aufwandes wird eine relativkinematische Beschreibung herangezogen. Diese gemischte LAGRANGE-EULER-Betrachtungsweise beruht auf der Zerlegung der Bewegung in einen Starrkörperanteil und eine dazu relative Deformation. Die Herleitung der Bewegungsgleichung für das Kontaktproblem erfordert die relativkinematische Formulierung der kontinuumsmechanischen Grundgleichungen, d.h. der Bilanzgleichungen sowie der konstitutiven Beziehungen. Eine geeignete Kontaktmechanik einschließlich der Berücksichtigung des Kontakts rauer Oberflächen und veränderlicher Kontaktrandbedingungen ist ebenfalls notwendig. Die physikalische Einbindung der Körper in die Umgebung erfolgt über NEUMANNsche und DIRICHLETsche Randbedingungen. Auf dieser Basis können die Bewegungsgleichungen der Elastomechanik hergeleitet werden, welche sich jedoch einer analytischen Lösung verschließen. Somit werden sie in ihrer schwachen Form im integralen Mittel formuliert, was der Anwendung des Prinzips der virtuellen Verschiebungen als Ausgangspunkt für die numerische Lösung entspricht. Die rechentechnische Umsetzung erfordert die inkrementelle und diskrete Formulierung der Bewegungsgleichungen unter besonderer Beachtung der Trägheits-und Kontaktterme, wobei auf die Unterscheidung zwischen Haften und Gleiten beim Tangentialkontakt besonderes Augenmerk gelegt wird. Die numerische Lösung des Finite-Element-Gleichungssystems liefert den aktuellen Beanspruchungszustand zweier Körper im Rollkontakt. Die Funktionsfähigkeit der entwickelten Algorithmen wird abschließend anhand aussagekräftiger Beispielrechnungen zum statischen Kontakt und zum stationären Rollkontakt demonstriert, deren Ergebnisse gute Übereinstimmung mit analytischen Vergleichslösungen, soweit verfügbar, aufweisen. / Scope of this work is the preparation of a suitable simulation tool for the numerical investigation of rolling contact phenomena. The main focus lies on the continuum–mechanical formulation of the mechanical field problem of contacting bodies and its numerical solution within the framework of the Finite Element Method. For reducing the numerical effort in rolling contact simulation, induced by the necessity of a very fine discretization within the expected contact area, a relative–kinematical description is utilized. This arbitrary LAGRANGian–EULERian approach is based upon the decomposition of the total motion into a rigid body motion and a superimposed deformation. The derivation of the equation of motion for the contact problem requires the relative–kinematical formulation of the continuum–mechanical fundamental equations, i. e. the balance equations and the constitutive relations. A suitable contact model including the contact of rough surfaces and varying contact boundary conditions is also necessary. The physical embedding into the environment is accomplished by NEUMANN and DIRICHLET boundary conditions. Based upon that foundation the elastomechanics’ equations of motion are derived, which however can not be solved analytically in general. Hence, the equations of motion are transferred into their weak form by the application of the principle of virtual displacements serving for the numerical solution. The implementation of the problem demands for an incremental and discrete formulation of the equations, especially regarding the terms of inertia and the contact terms. Thereby, special attention has to be paid to the distinction between sticking and sliding within the framework of the tangential contact analysis. The numerical solution of the finite elements’ system of equations provides the state of stress, displacement and contact of two bodies in rolling contact. The reliability of the developed algorithms is finally verified by means of meaningful numerical examples for both static contact and for stationary rolling contact, whereby the numerical results coincide well with available analytical reference solutions.