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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Estudo do processo de estampagem incremental em chapa de latão 70/30

Fritzen, Daniel January 2012 (has links)
O presente trabalho tem como objetivo avaliar o comportamento da chapa de latão 70/30 para o processo de Estampagem Incremental de Chapas (ISF - Incremental Sheet Forming), baseado nos parâmetros: ângulo de parede (ψ), passo vertical ( Z) e estratégia do caminho da ferramenta. Os experimentos baseiam-se na variante da Estampagem Incremental denominada Estampagem Incremental com Ponto Simples (SPIF - Single Point Incremental Forming). Foram realizados 18 ensaios usando uma ferramenta de estampar com raio (RT) de 5 mm. Para execução dos testes práticos, foram utilizados os recursos: softwares CAD/CAM, centro de usinagem CNC com três eixos, matriz incremental, ferramenta de estampagem incremental e um dispositivo prensa chapas. Além disso, o acabamento da superfície conformada foi medido através do parâmetro de rugosidade RZ nos principais ensaios, bem como a medição das deformações verdadeiras (j) e da espessura (s1). Os testes práticos demonstraram que a estratégia de usinagem espiral proporcionou um maior ângulo de parede, comparado à estratégia paralela de contorno. / This study aims to evaluate the behavior of 70/30 brass plate to the process of Incremental Sheet Forming - ISF, based on the parameters: wall angle (ψ), vertical step ( Z) and tool path strategy. The experiments were based on a variation of the ISF process, called SPIF (Single Point Incremental Forming). Eighteen tests were conducted using a punching tool with a radius (RT) of 5 mm. For the execution of practical tests, the resources were used: CAD / CAM software, CNC machining center with three axis. It was also used an incremental matrix, a tool for incremental forming and a sheet-press device. In addition, the surface finish was measured by RZ roughness parameter in the main tests, the same way the measurement of true strains (φ) and thickness (s1). The practice tests showed that the spiral machining strategy has provided a greater wall angle, compared to the parallel strategy contour.
182

A aprendizagem musical e as contribuições sociais nas bandas de música: um estudo com duas bandas escolares / Musical learning and contributions to the social brass bands: a studying with two school bands

Silva, Francinaldo Rodrigues da Silva 31 March 2014 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-11-04T20:07:25Z No. of bitstreams: 2 Dissertação - Francinaldo Rodrigues da Silva - 2014.pdf: 7637692 bytes, checksum: 06fd3fca0b1795bede4b60f2cbeef94a (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-11-05T09:17:32Z (GMT) No. of bitstreams: 2 Dissertação - Francinaldo Rodrigues da Silva - 2014.pdf: 7637692 bytes, checksum: 06fd3fca0b1795bede4b60f2cbeef94a (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-11-05T09:17:32Z (GMT). No. of bitstreams: 2 Dissertação - Francinaldo Rodrigues da Silva - 2014.pdf: 7637692 bytes, checksum: 06fd3fca0b1795bede4b60f2cbeef94a (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-03-31 / The bands are an important area of musical learning. There are many perspectives of education involved in them: instrumental teaching in group and individual, musical theory lessons, music theory, martialness and discipline. The brass bands have an active participation in Brazilian communities. They play in public ceremonies, civic and military parades, religious festival, and many others different events. Taking Part of a band gives to the members a kind of learning that goes beyound playing an instrument. With a view to these bands particularities this study was developed by taking two martial bands of the city of Aparecida de Goiania/GO, in order to inquire how the bands contribute to the musical and social process of the students whom participate. The research includes both qualitative and quantitative datas. In order to obtain meaniful results toarch, the study was achieved by literature review, direct observation of theoretical lessons, rehearsals and select bands performances. It was applied questionnaires to these groups of students who take part in these bands. And for teachers, teachers’ aides, group manager of the institutions in which the bands belongs to were performed semistructured interviews. In answer to the questionnaires and interviews were collected datas which support the objectives of this research. / As bandas constituem um espaço importante de aprendizagem musical. Nelas estão envolvidas muitas perspectivas de ensino: ensino de instrumento individual e coletivo, aulas de teoria musical, marcialidade e disciplina. As bandas de música tem uma participação ativa nas comunidades brasileiras, se apresentando em solenidades públicas, desfiles cívico-militar, festas religiosas e eventos culturais de natureza diversa. Fazer parte de uma banda proporciona aos integrantes aprendizados que vão além do tocar um instrumento. Com vistas a estas peculiaridades das bandas, esta pesquisa foi desenvolvida tomando duas bandas marciais da cidade de Aparecida de Goiânia/GO, com o objetivo de averiguar de que forma as bandas de música contribuem para o processo musical e social dos alunos que dela participam. A pesquisa é de natureza qualitativa e quantitativa. Visando obter resultados significativos para a análise dessa pesquisa, o trabalho foi realizado a partir de revisão de literatura, observação direta das aulas teóricas, dos ensaios e das apresentações das bandas selecionadas. Foram aplicados questionários para os alunos participantes dessas bandas. Para os maestros, professores auxiliares, grupo gestor das instituições que cediam as bandas foram realizadas entrevistas semiestruturadas. Nas respostas obtidas aos questionários e entrevistas foram colhidos dados que corroboram com os objetivos dessa pesquisa.
183

Corrosion of copper alloys in natural seawater : effects of hydrodynamics and pH / Corrosion d'alliages de cuivre en eau de mer naturelle : effets de l'hydrodynamique et du pH

Carvalho, Maria Leonor 29 September 2014 (has links)
Cette thèse, réalisée en étroite collaboration avec le partenaire industriel RSE S.p.A (Italie), s’inscrit dans le cadre du projet européen BIOCOR ITN. Les alliages de cuivre habituellement utilisés dans les circuits de refroidissement de centrales électriques peuvent être affectés par la biocorrosion induite par la formation d’un biofilm. L’objectif de ce travail était d’étudier the comportement à la corrosion de l’alliage 70Cu-30Ni et d’un laiton contenant 2% d’aluminium en milieu marin, dans des conditions industrielles réelles (expériences sur le terrain) et en laboratoire. L’influence de différents paramètres, tels que la solution (eau de mer naturelle filtrée (FNSW) vs eau de mer artificielle (ASW)), la concentration en biomolécules (biomolécules naturellement présentes dans l’eau de mer vs une protéine modèle, l’albumine de sérum bovin (BSA)), l’hydrodynamique (conditions statiques, sous circulation et agitation, électrode à anneau tournant) et le pH (8,0 ; 6,0 et 3,7), a été évaluée. Sur le terrain, le comportement global à la corrosion et les traitements antifouling ont été suivis en utilisant des techniques électrochimiques (potentiel de corrosion Ecorr vs temps, LPR), gravimétriques (pertes de masse) et génétiques. En laboratoire, des mesures électrochimiques (Ecorr vs temps, courbes de polarisation, spectroscopie d’impédance électrochimique), réalisées pendant les toutes premières étapes de formation des couches d’oxydes (1 h d’immersion), ont été combinées à des analyses de surface par XPS et ToF-SIMS. A partir des expériences sur le terrain, l’analyse microbiologique et moléculaire des biofilms formés sur les deux alliages de cuivre dans l’eau de mer naturelle montre la présence des espèces bactériennes Marinobacter, Alteromonas et Pseudomonas. In the case of Al brass, the single experimental loop illustrates both anodic charge transfer and anodic mass transport. A partir des expériences en laboratoire, des modèles sont proposés pour analyser les données d’impédance obtenues à Ecorr. Dans le cas de 70Cu-30Ni, la boucle HF illustre principalement le transfert de charge anodique (diamètre égal à Rta) ; alors que la boucle BF est liée au transport de matière anodique et au blocage partiel de la surface par CuCl. Dans le cas du laiton, la seule boucle expérimentale illustre à la fois le transfert de charge anodique et le transport de matière anodique. Le comportement électrochimique et la composition chimique de surface de l’alliage 70Cu-30Ni sont similaires dans ASW et dans FNSW statiques, du fait de la faible concentration en biomolécules dans FNSW. En comparaison de l’alliage 70Cu-30Ni dans ASW statique sans biomolécules, pour lequel une couche duplex épaisse (couche externe de Cu2O redéposé et couche interne de nickel oxydé) est montrée, la présence de BSA conduit à une couche mixte d’oxydes de Cu et de Ni d’épaisseur plus faible ; les résultats montrent aussi un ralentissement de la réaction anodique et un faible effet d’inhibition de la corrosion en présence de BSA. Sous circulation et agitation, une couche mixte d’oxydes de Cu et de Ni, de très faible épaisseur, est obtenue. Pour les deux alliages dans FNSW, le courant de corrosion icorr estimé à partir de Rta est indépendant de la vitesse de rotation de l’électrode tournante, du fait de la compensation des effets du potentiel et du transport de matière. Pour 70Cu-30Ni dans FNSW statique, la réaction anodique est ralentie à pH acide (effet cinétique). Pour le laiton, un effet d’inhibition de la corrosion est montré à pH acide, et plus le pH est acide, plus la réaction anodique est lente. Pour 70Cu-30Ni, l’épaisseur de la couche d'oxyde augmente avec la diminution du pH, dans le cas du laiton il est indépendante du pH. La composition chimique de la couche d'oxyde semble avoir un effet sur la quantité de protéines adsorbées et l'épaisseur équivalente calculée de la couche organique est très faible (quelques Å pour 70Cu-30Ni et 1 Å pour laiton). / This thesis was carried out in the frame of the BIOCOR ITN European project, in close collaboration with the industrial partner RSE S.p.A. (Italy). Copper alloys commonly used in cooling systems of power plants may be affected by biocorrosion induced by biofilm formation. The main objective of this work was to study the corrosion behavior of 70Cu-30Ni alloy and aluminum brass in seawater environments, under real industrial conditions (field experiments) and in laboratory. The influence of different parameters, such as the solution (filtered natural seawater (FNSW) vs artificial seawater (ASW)), the concentration of biomolecules (biomolecules naturally present in seawater vs a model protein, the bovine serum albumin (BSA)), hydrodynamics (static conditions, under flow and stirring, rotating ring electrode (RRE)) and pH (8.0, 6.0 and 3.7), was evaluated. In field, the overall corrosion behavior and antifouling treatments were monitored using electrochemical (corrosion potential Ecorr vs time, LPR), gravimetric (weight losses) and genetic techniques. In lab, electrochemical measurements (Ecorr vs time, polarization curves, EIS), performed during the very first steps of oxide layers formation (1 h immersion time), were combined to surface analysis by XPS and ToF-SIMS. From field experiments, microbiological and molecular analysis of biofilms formed on both copper alloys in natural seawater indicates the presence of Marinobacter, Alteromonas and Pseudomonas bacterial species. From lab experiments, models are proposed to analyze impedance data obtained at Ecorr. In the case of 70Cu-30Ni, the HF loop illustrates mainly the anodic charge transfer (diameter equal to Rta); whereas the LF loop is related to the anodic mass transport and partial blocking effect by CuCl. In the case of Al brass, the single experimental loop illustrates both anodic charge transfer and anodic mass transport. Similar electrochemical behavior and surface chemical composition of 70Cu-30Ni alloy are obtained in static ASW and FNSW, due to the low biomolecule concentration in FNSW. Compared to 70Cu-30Ni in static ASW without biomolecules, for which a thick duplex oxide layer (outer redeposited Cu2O layer and inner oxidized nickel layer) is shown, the presence of BSA leads to a mixed Cu and Ni oxide layer with a lower thickness; the results also show a slow-down of the anodic reaction and a small corrosion inhibition effect in the presence of BSA. Under flow and stirring, a very thin mixed Cu and Ni oxide layer is obtained. For both alloys in FNSW, the corrosion current icorr estimated from Rta is independent of the rotation speed of the RRE, due to compensated potential and mass transport effects. For 70Cu-30Ni in static FNSW, the anodic reaction is slown down at acidic pH (kinetic effect). For Al brass, there is a corrosion inhibition effect at acidic pH, and the more acidic the pH, the slower the anodic reaction. In the case of 70Cu-30Ni alloy, the oxide layer thickness increases with decreasing pH, whereas for Al brass it is independent of the pH. The chemical composition of the oxide layer seems to have an effect on the amount of adsorbed proteins and the calculated organic layer equivalent thickness is very low (few Å for 70Cu-30Ni and 1 Å for Al brass).
184

Approche passive pour la modélisation, la simulation et l'étude d'un banc de test robotisé pour les instruments de type cuivre / Passive approach for the modelling, the simulation and the study of a robotised test bench for brass instruments

Lopes, Nicolas 15 June 2016 (has links)
Cette thèse s'inscrit dans le contexte de la robotique, de l'automatique et de l'acoustique musicale. Elle propose une étude d'un banc de test robotisé pour le jeu des cuivres et se décompose selon trois volets: la modélisation passive du système, sa simulation et son développement. La modélisation utilise le formalisme passif des systèmes hamiltoniens à ports. Les principaux éléments du système sont: l'alimentation en air pour le souffle, l'excitateur (composé de deux lèvres et d'un jet d'air) et un résonateur acoustique. Un nouveau modèle de jet d'air généré entre les lèvres est proposé. Ce modèle a pour but de restituer un bilan de puissance plus proche de la réalité physique que les modèles couramment utilisés. Pour la simulation à passivité garantie, la méthode du gradient discret est présentée. Elle ne garantit pas l'existence et l'unicité d'une solution et est limitée au second ordre de consistance numérique. De plus, son exécution nécessite des algorithmes d'optimisations non linéaires. Pour pallier ces limitations, une méthode à plusieurs étapes de type Runge-Kutta double et basée sur un changement de variable est proposée. Des résultats de simulations sont interprétés et comparés à ceux issus d'un modèle classique de la littérature. Le banc de test, ainsi que les développements techniques sont présentés. Ils permettent la mise au point d'expériences de cartographies répétables pouvant être utilisées pour caractériser différents instruments de musique. Enfin, des résultats numériques et expérimentaux sont comparés afin de mettre en avant les défauts et les qualités du modèle proposé. / This thesis is to be seen against the robotic, the automatic, and the musical acoustic backgrounds. It provides a study of a robotized test bench for brass instruments and is divided into three parts: the passive modelling of the system, its simulation and its development. The modelling uses a passive formalism, namely, the ports-Hamiltonian systems. The main parts of the complete system are: an air supply for the breath, an acoustic exciter (composed of a couple of artificial lip and an air jet) and an acoustic resonator. A new model for the air jet generated between the lips is proposed. This model aims at providing a power balance, which is closer to the real system than other commonly used models. The discrete gradient method is presented to perform passive simulations. It does not generally guaranty the existence and uniqueness of a solution and is limited to the second order of numerical consistency. Moreover, its execution needs nonlinear optimisation algorithms. To compensate for these limitations, a multi-stage method of double Runge-Kutta type and based on a change of variable is proposed. Results from simulations are interpreted and compared to those coming from a Bernoulli type model. Finally, the test bench and the technical developments are presented. They enable the performance of repeatable cartographies experiments which can be used to characterise music instruments. Finally, experimental and numerical results are compared in order to highlight the defaults and the qualities of the proposed model.
185

Exploring the Private Music Studio: Problems Faced by Teachers in Attempting to Quantify the Success of Teaching Theory in Private Lessons through One Method as Opposed to Another

McKnight, Michael 08 1900 (has links)
I present strategies and methods for teaching fundamentals of music theory in the context of the private music studio through a variety of techniques and research. Beginning with a background in educational psychology, examples of behaviorist and cognitive teaching models are presented, and how each applies to teaching music is explained. Two detailed examples of actual lessons are presented, coupled with musical examples, to describe both the process and the concepts that can be presented. A qualitative experiment based upon the learning styles of three music students and the effect of different teaching styles when teaching the same concept is presented and discussed in detail.
186

Modern Forms of an Ancient Art: A Selection of Contemporary Fanfares for Multiple Trumpets Demonstrating Evolutionary Processes in the Fanfare Form

Florek, Paul J. 05 1900 (has links)
The pieces discussed throughout this dissertation provide evidence of the evolution of the fanfare and the ability of the fanfare, as a form, to accept modern compositional techniques. While Britten’s Fanfare for St. Edmundsbury maintains the harmonic series, it does so by choice rather than by the necessity in earlier music played by the baroque trumpet. Stravinsky’s Fanfare from Agon applies set theory, modal harmonies, and open chords to blend modern techniques with medieval sounds. Satie’s Sonnerie makes use of counterpoint and a rather unusual, new characteristic for fanfares, soft dynamics. Ginastera’s Fanfare for Four Trumpets in C utilizes atonality and jazz harmonies while Stravinsky’s Fanfare for a New Theatre strictly coheres to twelve-tone serialism. McTee’s Fanfare for Trumpets applies half-step dissonance and ostinato patterns while Tower’s Fanfare for the Uncommon Woman demonstrates a multi-section work with chromaticism and tritones. By applying modern compositional techniques to an older, abstract form, composers have maintained the original aesthetic while allowing for fanfares to be used as concert music. This document adds to the limited body of scholarly writing on modern fanfares.
187

Exploring performance related anxiety in brass players

Van Staden, Jacobus M.C. January 2016 (has links)
Music performance anxiety (MPA) is primarily described as stage fright concerning musicians and performers and affects orchestral and professional musicians severely (Brugués, 2009; Plummer, 2007). As a result, literature on MPA focuses extensively on how it affects professional and adolescent musicians, but limited resources emphasise how it affects brass instrumentalists. The aim of the study is to investigate the occurrence and experience of MPA in brass players. Further, it aims to explore prominent symptoms in this population and what coping strategies are most effective against MPA. Ten brass (five French horn, three trumpet and two trombone) players, of whom eight are professional and two semi-professional musicians, with varying performance experience, participated in this study. The study uses a qualitative research approach and falls into the interpretive paradigm. A multiple case study design was followed. The data were collected through semi-structured interviews, probing each participant’s reported experiences and coping strategies. MPA inhibits a brass player’s musical performance in areas such as musical expression, technical proficiency, physical endurance, tone quality and enjoyment. The results suggest that most of the participants experienced MPA since childhood, regardless of the starting age, and experiences of this condition varied over time throughout adulthood. The symptoms of MPA manifests physiologically (shaking, dry mouth, increased heart rate, sweating), behaviourally (muscle tension, shaking, dry lips), and cognitively (negative thought processes). First-time experiences of a musically demanding task such exams and Eisteddfods, with intimidating audiences, impacted early signs of severe MPA symptoms such as shaking and had a blunting effect on performance quality. Increased task difficulty, limited performance opportunities, auditions, recitals, and orchestral environments, which exposed the player’s performing ability under pressure, had a profound influence on recent experiences of MPA. These situations evoked multiple symptoms such as dry mouth, accelerated heartbeat, shortness of breath, negative thoughts/feelings and self-doubt. Symptoms such as a dry mouth, accelerated heartbeat, shortness of breath, and shaking affects a brass player’s musical performance severely, since it inhibits tone quality and influences musical spontaneity. Therefore, these symptoms affect technical proficiency among brass players negatively since performing these instruments are physically demanding. The results also showed that teachers gave useful advice concerning performing a brass instrument under pressure. The advice was useful among the participants’ lived experiences of MPA, particularly regarding early-experienced symptoms. The experiences of MPA in high demanding performance settings resulted in a better understanding of the situation over time, and led to the reported coping strategies against MPA, which enhanced optimal performance and reduced symptoms. The study concludes that MPA adversely affects brass instrumentalists, particularly the physiological manifestation of the condition. More research is needed to identify symptoms unique to this instrument group and the most effective coping strategies. / Mini Dissertation (MMus)--University of Pretoria, 2016. / Music / MMus / Unrestricted
188

Fractus I for Trumpet in C and Electronic Sound: A Critical Examination of the Compositional Process

Fieldsteel, Eli Mulvey 05 1900 (has links)
Fractus I is a composition for trumpet in C and live electronic sound. The electronics were primarily created using SuperCollider, an environment and programming language for real time audio synthesis. This project investigates SuperCollider's pattern and task functionality as a means of supporting and enriching the compositional process. Fractus I develops several different code architectures in order to randomize as well as synchronize various musical elements. The piece exploits SuperCollider as both an audio synthesis tool and a performance conduit. Additionally, the nature of SuperCollider's patterns and tasks influences the form and content of the composition. The project underscores SuperCollider as a powerful, versatile and open-ended tool for musical composition and examines future directions and improvements.
189

An Argument in Favor of the Saxhorn Basse (French Tuba) in the Modern Symphony Orchestra

Kleinsteuber, Carl 05 1900 (has links)
The French tuba was a much-needed addition to the brasswind musical instrument family, adding depth, projection and a unique color to French orchestral literature. Its ancestors the serpent and ophicleide both lacked the tonal stability and sonic power to adequately present the bass wind role in a robust orchestra. Through the efforts of its developer and patent-holder Adolphe Sax, the French tuba made converts among players and composers, effectively creating its own niche in music history. Musical tastes change however, and the French tuba has been largely supplanted by tubists using instruments twice its size. Since French composers composed specifically with the distinct timbre of the French tuba in mind, this unique and characteristic musical entity deserves a resurgence in performances of French orchestral repertoire.
190

Corrosion behavior of lead-free and dezincification resistant brass alloys in tap water / Korrosionsbeteende hos blyfria och avzinkningsbeständiga mässingslegeringar i kranvatten

Alexis, naza January 2021 (has links)
Avzinkningshärdiga och blyfria mässingslegeringar används i stor utsträckning för att ersätta blyinnehållande mässingslegeringar som används för dricksvattensapplikationer. På grund av det begränsade antalet korrosionsstudier av dessa legeringar är syftet med denna studie att belysa hur vattensammansättning, temperatur och exponeringstid kan påverka legeringarnas korrosionsegenskaper. Tre avzinkningshärdiga mässingslegeringar studerades i kranvatten; två blyfria mässingslegeringar (CW511L och CW724R) och en blyinnehållande mässingslegering (CW602N) som betraktades som ett referensmaterial. En kombination av elektrokemiska, mikroskopiska och ytanalystekniker användes för att utforska korrosionstyp, mekanismer samt korrosionshastighet. Även om samtliga legeringar visade godkända egenskaper i avzinkningstestet enligt ISO 6509-1:2014 var målet att bedöma deras korrosionsbeteende i kranvatten. Vattenkemin justerades för att undersöka effekten av pH, kloridkoncentration och alkalinitet hos de tre mässingslegeringarna under kortvarig exponeringstid (24 timmar). Vattnets korrosivitet varierade beroende på mässingslegeringens sammansättning. Det visade sig att CW511L var känsligare för höga kloridkoncentrationer (44.7 mg/L) och hög alkalinitet (310 mg/L) än för lågt pH (6.9). Det motsatta observerades dock för både CW724R och CW602N. Testvattnets aggressivitet påverkades också av temperaturen när den ökades från 22 °C till 50 °C under exponering i 24 timmar. Medan ingen tydlig avzinkning upptäcktes observerades en kombination av både allmän och lokal korrosion i varierande utsträckning mellan de olika legeringarna. Initieringen av det lokala korrosionsangreppet varierade både med testvattnets kemi och med legeringssammansättningen. Medan CW724R och CW602N bägge uppvisade hög känslighet för lokal korrosion i vattnet med högst pH (8.2), var CW511L mer känslig i det vatten med lågt pH (6.9) vid 50 °C. Effekten av exponeringstid undersöktes i vattnet med högst pH (8.2) för de tre mässingslegeringarna upp till 72 dagar. Korrosionshastigheten baserad på viktminskning visade en förväntad hög korrosionshastighet som minskade med kontinuerlig exponeringstid, vilket ledde till en låg korrosionshastighet för alla tre mässingslegeringarna efter 72 dagar. De blyfria mässingslegeringar uppvisade ur detta perspektiv goda korrosionsegenskaper som är konkurrenskraftiga med mässing som innehåller bly. / Dezincification resistant (DZR) and lead-free brass alloys continue to be widely applied replacing lead containing brasses in the drinking water sector. Due to the limited number of corrosion studies of these alloys in tap water, the present thesis was initiated with the aim to understand how the water type, its temperature and exposure duration can affect the corrosion behavior. Three DZR brass alloys were studied in order to evaluate their corrosion behavior in tap water of varying characteristics. The alloys included were two lead-free brasses (CW511L and CW724R) and a leaded brass alloy (CW602N) considered as a reference material. A combination of electrochemical, microscopic and surface analytical techniques were adopted to explore the corrosion form, mechanisms and corrosion rate. While these alloys passed the dezincification test as per ISO 6509-1:2014, the aim was to assess their corrosion performance in tap water. The influence of water chemistry parameters including pH, chloride concentration and alkalinity on the corrosion resistance of the three DZR alloys was investigated in short-term exposures (24 h). Depending on the brass alloy, the corrosivity of the test waters varied. The results show grade CW511L to be more sensitive in tap water of higher chloride concentration (44.7 mg/L) and alkalinity (310 mg/L) compared with low pH (6.9). However, opposite results were obtained for both CW724R and CW602N. The corrosivity of the test water was also affected by the temperature when increased from 22°C to 50°C during 24 h of immersion. While no dezincification features were observed on the surfaces, a combination of general and localized corrosion was observed to a largely variable extent between the alloys. The extent of initiation of localized corrosion varied with test water and alloy composition. While CW724R and CW602N showed similar high susceptibility to localized corrosion in the alkaline (pH 8.2) tap water, CW511L was more prone to pitting corrosion in tap water of low pH (6.9). The effect of exposure duration was explored in the alkaline test water for the three brasses up to 72 days. Corrosion rates based on weight loss showed an expected initial high corrosion rate which declined with continuous immersion, leading to low and similar corrosion rates for all three brass alloys after 72 days. Thus, at given test conditions, the lead-free brasses showed good corrosion behavior being competitive to the performance of lead containing brass. Therefore, lead-free brass alloys are good candidates to substitute lead-containing brasses in tap water applications.

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