This study aims to investigate the mechanical and fatigue behavior of additively manufactured metallic materials. Several challenges associated with different metal additive manufacturing (AM) techniques (i.e. laser-powder bed fusion and direct laser deposition) have been addressed experimentally and numerically. Experiments have been carried out to study the effects of process inter-layer time interval – i.e. either building the samples one-at-a-time or multi-at-a-time (in-parallel) – on the microstructural features and mechanical properties of 316L stainless steel samples, fabricated via a direct laser deposition (DLD). Next, the effect of building orientation – i.e. the orientation in which AM parts are built – on microstructure, tensile, and fatigue behaviors of 17-4 PH stainless steel, fabricated via a laser-powder bed fusion (L-PBF) method was investigated. Afterwards, the effect of surface finishing – here, as-built versus machined – on uniaxial fatigue behavior and failure mechanisms of Inconel 718 fabricated via a laser-powder bed fusion technique was sought. The numerical studies, as part of this dissertation, aimed to model the mechanical behavior of AM materials, under monotonic and cyclic loading, based on the observations and findings from the experiments. Despite significant research efforts for optimizing process parameters, achieving a homogenous, defectree AM product – immediately after fabrication – has not yet been fully demonstrated. Thus, one solution for ensuring the adoption of AM materials for application should center on predicting the variations in mechanical behavior of AM parts based on their resultant microstructure. In this regard, an internal state variable (ISV) plasticity-damage model was employed to quantify the damage evolution in DLD 316L SS, under tensile loading, using the microstructural features associated with the manufacturing process. Finally, fatigue behavior of AM parts has been modeled based on the crack-growth concept. Using the FASTRAN code, the fatigue-life of L-PBF Inconel 718 was accurately calculated using the size and shape of process-induced voids in the material. In addition, the maximum valley depth of the surface profile was found to be an appropriate representative of the initial surface flaw for fatigue-life prediction of AM materials in an as-built surface condition.

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-10-24T11:35:35Z No. of bitstreams: 1 DIS_CARLOS_DAVID_GODWARD_COMPLETO.pdf: 1317478 bytes, checksum: b5114678f308871a52be8844a408fe66 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-10-24T11:35:49Z (GMT) No. of bitstreams: 1 DIS_CARLOS_DAVID_GODWARD_COMPLETO.pdf: 1317478 bytes, checksum: b5114678f308871a52be8844a408fe66 (MD5) / Made available in DSpace on 2017-10-24T11:36:01Z (GMT). No. of bitstreams: 1 DIS_CARLOS_DAVID_GODWARD_COMPLETO.pdf: 1317478 bytes, checksum: b5114678f308871a52be8844a408fe66 (MD5) Previous issue date: 2017-08-11 / Conditional Income Transfer Programs, Bolsa Fam?lia Program in Brazil, became an innovative instrument for reducing social inequality in many countries, specifically, in Latin America, where they were widely adopted. These programs have proven effective in several aspects such as reducing poverty and inequality, improving schooling rates, etc. An aspect that has remained unmentioned of these programs was their potential to encourage targeted workers of the program to migrate to the informal labour market in order to remain "invisible" to program managers and, thus, receive the benefits even when they do not qualify according to program standards. This study applies VECM (Vector Error Corrector Model) to show this issue may be occurring in the six Brazilian state capitals, included in the IBGE Monthly Employment Survey, from the creation of the program, in 2004, until March 2016. / Os Programas de Transfer?ncia de Renda Condicionada, Programa Bolsa Fam?lia no Brasil, foram uma forma inovadora de reduzir a desigualdade social em muitos pa?ses, principalmente da Am?rica Latina. Estes programas se mostraram eficientes em v?rios aspectos, como reduzir a pobreza, a desigualdade, melhorar ?ndices de escolaridade, etc. Mas, um aspecto pouco mencionado destes programas, ? o potencial de incentivar os trabalhadores - alvo do programa - a migrar para o mercado laboral informal, com o objetivo de ficarem ?invis?veis? aos gestores do programa e, assim, receberem os benef?cios, ainda que n?o se qualifiquem a eles, pelos n?veis de renda definidos pelo programa. Este trabalho utiliza o VECM (modelo Vector Corretor de Erros) para mostrar que este fato pode estar ocorrendo nas seis capitais do Brasil, que conformaram a Pesquisa Mensal de Emprego do IBGE, desde a cria??o do programa at? mar?o de 2016.

Made available in DSpace on 2016-04-04T18:33:15Z (GMT). No. of bitstreams: 1 Angelica Lima da Silva.pdf: 831395 bytes, checksum: 484b5337192fea58cecebc8007f8b27b (MD5) Previous issue date: 2014-02-11 / The receipt of the benefit of the Bolsa Familia Program (BFP), public policy of cash transfer from the federal government program to families in poverty and extreme poverty is linked to compliance with conditionalities on health and education. In education the minimum school attendance of 85 % for children between 6 and 15 years and 75 % for adolescents aged 16 to 17 years is required . According rationale explicit in legislation and official documents BFP, ensuring school attendance of children and young people in school would be a major break with the call for intergenerational transmission of poverty factor. This paper assumes the following questions: is attendance important factor to prevent the call intergenerational transmission of poverty? Does the fact that the child is in school with the help of the program ensures your education? This study examined the perceptions of mothers beneficiaries of the program regarding the requirement of attending school and prepared to understand according to their placements, the education of their children was related to participation in the BFP. Twenty semi-structured interviews with mothers of BFP beneficiaries were held in the southern region of Campinas/SP. The survey results indicate that for the beneficiary mothers BFP education of their children is not linked to the program because, according to them, the only requirement BFP with respect to school is school attendance and that they declare comply. As to the education of their children, mothers argue that it is necessary to promote a school that develops a quality education that will prepare them for the job market, so they will have opportunities to break away from poverty in the future and build a better life. / O recebimento do benef?cio do Programa Bolsa Fam?lia (PBF), pol?tica p?blica de transfer?ncia de renda do governo federal destinado a fam?lias em situa??o de pobreza e de extrema pobreza est? vinculado ao cumprimento de condicionalidades nas ?reas de sa?de e educa??o. Na ?rea da educa??o ? exigida a frequ?ncia escolar m?nima de 85% para as crian?as entre 6 e 15 anos e de 75% para adolescentes entre 16 e 17 anos. Segundo justificativa explicitada na legisla??o e documentos oficiais do PBF, a garantia da frequ?ncia escolar de crian?as e jovens na escola seria um fator importante para romper com a chamada transmiss?o intergeracional da pobreza. O presente trabalho parte das seguintes indaga??es: ser? a frequ?ncia escolar fator importante para impedir a chamada transmiss?o intergeracional da pobreza? Ser? que o fato da crian?a estar na escola com o aux?lio do programa garante a sua educa??o? Este estudo analisou as percep??es de m?es benefici?rias do programa a respeito da exig?ncia da frequ?ncia escolar e se disp?s a compreender de acordo com suas coloca??es, se a educa??o de seus filhos estava relacionada com a participa??o no PBF. Foram realizadas vinte entrevistas semiestruturadas com m?es benefici?rias do PBF na regi?o sul de Campinas/SP. Os resultados da pesquisa indicam que para as m?es benefici?rias do PBF a educa??o de seus filhos n?o est? vinculada ao programa, pois, segundo elas, a ?nica exig?ncia do PBF com rela??o ? escola ? a frequ?ncia escolar e isso elas declaram cumprir. J? com rela??o ? educa??o de seus filhos, as m?es argumentam que ? necess?rio promover uma escola que desenvolva um ensino de qualidade, que os prepare para o mercado de trabalho, assim eles ter?o possibilidades de romper com a pobreza no futuro e construir uma vida melhor.

Additive manufacturing can bring several advantages in tooling applications especially hot working tooling as high pressure die casting. Printing of conformal cooling channels can lead to improved cooling and faster solidification, which, in turn, can possibly result in better quality of the cast part. However, few studies on advantages of additive manufactured tools in high pressure die casting are published.The aim of this study was to investigate and quantify the effect of conformal cooling on microstructure and mechanical properties of high pressure die cast aluminum alloy. Two tools each consisting of two die inserts were produced with and without conformal channels using additive manufacturing. Both tools were used in die casting of aluminum alloy. Aluminum specimens were then characterized microstructurally in light optical microscope for secondary arm spacing measurements and subjected to tensile and hardness testing. Cooling behavior of different inserts was studied with a thermal camera and by monitoring the temperature change of cooling oil during casting. Surface roughness of die inserts was measured with profilometer before and after casting.Thermal imaging of temperature as a function of time and temperature change of oil during casting cycle indicated that conformal insert had faster cooling and lower temperature compared to conventional insert. However, thermal imaging of temperature after each shot in a certain point of time showed higher maximum and minimum temperature on conformal die surface but no significant difference in normalized temperature gradient compared to the conventional insert.The average secondary dendrite arm spacing values were fairly similar for samples from conventional and conformal inserts, while more specimens from conventional insert demonstrated coarser structure. Slower cooling in conventional insert could result in the coarser secondary dendrite arm spacing.Tensile strength and hardness testing revealed no significant difference in mechanical properties of the specimens cast in conventional and conformal die inserts. However, reduced deviations in hardness was observed for samples cast with conformal insert. This is in agreement with secondary dendrite arm spacing measurements indicating improved cooling with conformal insert.Surface roughness measurement showed small wear of the inserts. More castings are needed to observe a possible difference in wear between the conventional and conformal inserts.Small observed differences in cooling rate and secondary arm spacing did not result in evident difference in mechanical properties of the aluminum alloy but the variation in properties were reduced for samples cast with conformal cooling. Future work may include more accurate measurement of cooling behavior with a thermocouple printed into the die insert, casting of thicker specimen for porosity evaluation and fatigue testing and longer casting series to evaluate the influence of conformal cooling on tool wear.

Additive manufacturing (AM) has the potential to overtake the conventional production of pipe systems of stainless steel grade 316L intended for bioprocessing applications by utilising powder bed fusion laser beam (PBF-LB) technologies. However, challenges such as high surface roughness need to be overcome and corrosion properties improved to meet industry standards. This can be done by applying surface post-treatments to the printed parts. Therefore, the first aim of this thesis was to investigate the ability of different post-treatments of PBF-LB 316L samples, including tumbling, electropolishing, chemical milling, Hirtisation®, and DryLyte®, to reduce the surface roughness. One set of samples was left untreated, as-built set, and used as reference. The second aim was to try to correlate the surface roughness with the corrosion properties of the various post-treated samples. Analytical techniques used included needle profilometry, light optical microscopy (LOM), critical pitting temperature (CPT), cyclic potentiodynamic polarisation (CPDP) and immersion in 1M NaCl and 1M NaOH for two different durations for each solution. While some results were expected, others were surprising. Even though tumbled samples resulted in the lowest surface roughness, the results for immersion and CPDP curves tests indicated the lowest corrosion resistance compared to the other post-treatments. On the other hand, electropolishing resulted in the lowest surface roughness reduction among the post-treated samples. However, these samples had comparatively high corrosion resistance in the CPT and CPDP tests. The DryLyte® samples were tested using two DryLyte® medias where one of them resulted in the second lowest surface roughness and showed highest corrosion resistance in all three corrosion tests even though the process parameters are still to be developed. The results for samples post-treated by Hirtisation® and chemical milling were inconsistent and need further investigations. The reference as-built set showed high corrosion resistance in its untreated state, indicating post-treatments having minor impact on its performance from a corrosion perspective. / Additiv tillverkning (AM) har möjlighet att konkurrera ut konventionell produktion av rörsystem i rostfritt stål typ 316L avsett för bioprocessapplikationer genom att använda pulverbäddsinfusionslaserstråleteknik (PBF-LB). För tekniken kvarstår dock utmaningar för att uppfylla branschstandarder då tillverkningen medför material med hög ytråhet och sämre korrosionsegenskaper än traditionella metoder. Detta kan åstadkommas genom olika typer av efterbearbetning av de printade ytorna. Ett syfte med denna studie var att utvärdera hur olika typer av efterbehandling av PBF-LB 316L (trumling, elektropolering, kemisk etsning, Hirtisation® och DryLyte®) påverkar ytråheten. Som referensmaterial användes obearbetade printade ytor. Studiens andra huvudmål var att undersöka möjligheten för korrelation mellan ytråhet efter behandling och korrosionsegenskaperna. Analyser gjordes med hjälp av nålprofilometri, ljusoptisk mikroskopi (LOM), bestämning av kritisk gropfrätningstemperatur (CPT), framtagning av cykliska potentiodynamiska polarisationskurvor (CPDP) samt nedsänkning i 1M NaCl och 1M NaOH under två olika tidsperioder per lösning. Resultaten var delvis väntade och delvis överraskande. Trots att de trumlade proverna resulterade i lägst ytråhet, visade de elektrokemiska studierna (CPDP) i de olika lösningarna på att lägre korrosionsbeständighet jämfört med övriga efterbehandlingar. Å andra sidan resulterade elektropolering resulterade i den lägsta minskningen i ytråhet bland de efterbehandlade proverna. Dessa prover visade dock på en jämförelsevis hög korrosionsbeständighet i både CPT och CPDP testerna. DryLyte®-proverna studerades med två olika DryLyte®-medier, varav en av dem gav näst lägst ytråhet samt visade högst korrosionsbeständighet i samtliga korrosionstester trots att processparametrarna inte ännu är optimerade för denna nya teknik. Resultaten för prover som efterbehandlats med Hirtisation® och kemisk etsning var tvetydiga och behöver studeras vidare. De obehandlade referensproverna indikerade hög korrosionsbeständighet, vilket tyder på att efterbehandlingar hade minimal påverkan ur ett korrosionsperspektiv.

When skeletal fractures are too extensive for fixation with plates and screws, autografts are the most used technique for treating this. Within the biomedical field the interest in biodegradable implants made from additive manufacturing have increased. Magnesium alloys has also gained interest because of its favorable mechanical properties.. The objective of this project is to report on new knowledge, possibilities and limitations of powder bed fusion-laser beam (PBF-LB) printed magnesium-based alloys for biomedical applications, specifically the mechanical properties of WE43. Before the practical work was carried through, a gathering of literature from scientific papers was put together to a background with information regarding Magnesium, additive manufacturing, microscopic observation methods and mechanical testing.  The practical elements were divided into 4 different categories: printing, sample preparation for observation and testing, microscopic observation, and mechanical testing. All the collected data was observed and discussed, and lastly compiled in to a result with microscopic images, stress-strain curves and data tables. It was discovered that the mechanical properties differed between the two build orientations. The specimen most appropriate for load bearing implants was the horizontal build direction. The differences between 67° and 90° scan strategy were that the 90° scan strategy with horizontal build orientation showed the lowest Young´s modulus which is favorable, whereas the 67° scan strategy showed higher tensile strength and ductility which also is favorable. Thereby no conclusion could be drawn on whether a 67° or 90° scan strategy was preferable. The conclusion was made that a horizontal build orientation had the most optimal mechanical properties, and that more research needs to be conducted on this topic before it can be used for biomedical applications.

Magister Scientiae - MSc (Chemistry) / Blending polymers together offers researchers the ability to create novel materials that have a combination of desired properties of the individual polymers for a variety of functions as well as improving specific properties. The behaviour of the resulting blended polymer or blend is determined by the interactions between the two polymers. The resultant synergy from blending an intrinsically conducting polymer like polyaniline (PANI), is that it possesses the electrical, electronic, magnetic and optical properties of a metal while retaining the poor mechanical properties, solubility and processibility commonly associated with a conventional polymer. Aromatic polyamic acid has outstanding thermal, mechanical, electrical, and solvent resistance properties that can overcome the poor mechanical properties and instability of the conventional conducting polymers, such as polyaniline.

Made available in DSpace on 2015-03-13T17:10:29Z (GMT). No. of bitstreams: 1 TasiaMCV.pdf: 4510768 bytes, checksum: 5760c24f1a1891feb804206e63b0d9f6 (MD5) Previous issue date: 2008-09-26 / The question of evaluating the fight against poverty in a given society is very complex task, considering the range of factors that permeate, such as education, culture and economy itself. Come hence the relevance of the theme and its constant presence in discussions on the fruits of public policies, institutional structure and economic development which are the guiding elements of this work, and noted that seeks to highlight the social demographics and most important, the most significant trends and issues pertaining to her. The assessment was initially made in all the municipalities of Rio Grande do Norte doing a verticalilza??o to the municipalities Caic?, Pau dos Ferros, Ipueira and Taboleiro Grande. Highlighting the role of a social policy through government programs, such as the Bolsa Familia Program (PBF), which creates the possibility of changes in the socio demographic profile given the importance that the action of this public policy has in shaping the regional economic reality As well as social programs and actions of the government here reported that generate mobility of people and new social demands, such as rural retirements, the benefit of continuing provision (BPC), the Program for the Eradication of Child Labor (PETI) that put on the market of population living on the margins of various forms of consumption. Accordingly, the socio economic profile of the state shows a significant improvement in their social indicators, vital education and redistribution of income, due to the significant improvement in life expectancy in the fall of school drop-out rate and the drop in indicators of Proportion Poor and destitute of the state. Where the fall in the proportion of poor and indigent is strongly associated with an increase in income, from social programs. With this transfer and redistribution of income can be gauged that occurs a strengthening of local economies and an engagement of families with the conditionalities of social programs and PETI Bolsa Familia. Our research concludes that simply raising the rents caused by transfers, presents relevant impacts on the education of young people in beneficiary families. There is no doubt that the programs of transfer income, no facing the social field, representing a mechanism to decrease the most perverse ills of poverty, social and economic inequality that is hungry. For a significant portion of the Brazilian population living below the poverty line, programs for the transfer of income are expressed directly in improving the material conditions of life and indirectly in improving self-esteem of women and all family members receiving encouraging yet the integration family. Experiments have shown that improvements in health and nutrition can be obtained through the implementation of adequate social policies like the programs of transfer income, while social inclusion and economic does not become full / A quest?o da avalia??o do combate ? pobreza de uma determinada sociedade ? tarefa bastante complexa, considerando-se a gama de fatores que a permeiam, tais como a educa??o, a cultura e a economia, propriamente dita. Vem da? a relev?ncia do tema, bem como sua constante presen?a nos debates sobre os frutos das pol?ticas p?blicas, da estrutura institucional e do desenvolvimento econ?mico que s?o os elementos norteadores deste trabalho, que busca constatar e destacar os dados demogr?ficos e sociais mais importantes, as tend?ncias mais marcantes e as quest?es inerentes a ela. A avalia??o inicialmente foi feita em todos os munic?pios do Rio Grande do Norte fazendo uma verticalilza??o para os munic?pios de Caic?, Pau dos Ferros, Ipueira e Taboleiro Grande. Destacando o papel de uma pol?tica social atrav?s de programas governamentais, como ? o caso do Programa Bolsa Fam?lia (PBF), que cria a possibilidade de mudan?as no perfil s?cio demogr?fico dado a import?ncia que a a??o desta pol?tica p?blica tem na conforma??o da realidade econ?mica regional, bem como os programas e a??es sociais do governo aqui relatados que geram mobilidades de pessoas e novas demandas sociais, como ? o caso das Aposentadorias Rurais, do Benef?cio de Presta??o Continuada (BPC), do Programa de Erradica??o do Trabalho Infantil (PETI) que colocam no mercado contingentes populacionais que vivem ? margem de diversas formas de consumo. Nestes termos, o perfil s?cio econ?mico do estado mostra uma significativa melhoria em seus indicadores sociais, vitais de educa??o e redistribui??o de renda, haja vista a significativa melhora na Esperan?a de Vida, na queda da Taxa de Abandono Escolar e na queda dos indicadores de Propor??o de Pobres e Indigentes no Estado. Onde a queda na propor??o de pobres e indigentes est? fortemente associada ao aumento de renda, proveniente de programas sociais. Com esta transfer?ncia e redistribui??o de renda pode se aferir que ocorre um fortalecimento das economias locais e um engajamento das fam?lias com as condicionalidades dos programas sociais PETI e Bolsa Fam?lia. A nossa pesquisa conclui que a simples eleva??o das rendas causadas pelas transfer?ncias, apresenta impactos relevantes sobre a escolariza??o dos jovens nas fam?lias benefici?rias. N?o h? d?vida de que os programas de transfer?ncia de renda, voltados para qualquer campo social, representam um mecanismo de diminui??o das mazelas mais perversas da pobreza, da iniq?idade social e econ?mica que ? a fome. Para uma expressiva parcela da popula??o brasileira que vive abaixo da linha da pobreza, os programas de transfer?ncia de renda se expressam diretamente na melhoria das condi??es materiais de vida e indiretamente na melhoria da auto-estima da mulher e de todos os membros da fam?lia benefici?ria promovendo ainda a integra??o familiar. As experi?ncias t?m mostrado que as melhorias nas condi??es de sa?de e nutri??o podem ser obtidas por meio da implementa??o de pol?ticas sociais adequadas a exemplo dos programas de transfer?ncia de renda, enquanto a inclus?o social e econ?mica n?o se torna plena / 2020-01-01

This project was conducted as a case study at Öhlins Racing AB, a manufacturer of suspension systems for automotive applications. Öhlins usually manufacture their components by traditional methods such as forging, casting, and machining. The project aimed to investigate how applicable Additive Manufacturing (AM) is to manufacture products for suspension systems to add value to suspension system components. For this, a proof of concept was designed and manufactured. The thesis was conducted at Öhlins in Upplands Väsby via the consultant firm Combitech.  A product catalog was searched, screened, and one part was selected. The selected part was used as a benchmark when a new part was designed for AM, using methods including Topology Optimization (TO) and Design for Additive Manufacturing (DfAM). Product requirements for the chosen part were to reduce weight, add functions, or add value in other ways.  Methods used throughout the project were based on traditional product development and DfAM, and consisted of three steps: Product Screening, Concept Development, and Part Design. The re-designed part is ready to be manufactured in titanium by L-PBF at Amexci in Karlskoga.  The thesis result shows that at least one of Öhlin's components in their product portfolio is suitable to be chosen, re-designed, and manufactured by AM. It is also shown that value can be added to the product by increased performance, in this case mainly by weight reduction. The finished product is a fork bottom, designed with hollow structures, and is ready to print by L-PBF in a titanium alloy.

No description available.