Thermo-mechanical Forming of Al–Mg–Si Alloys: Modeling and Experiments

In an ongoing quest to realize lighter vehicles with improved fuel efficiency, deformation characteristics of the material AA 6016 is investigated. In the first part of this study, material behavior of Al–Mg–Si sheet alloy is investigated under different process (temperature and strain rate) and loading (uniaxial and biaxial) conditions experimentally. Later, warm cylindrical cup deep drawing experiments were performed to study the effect of various parameters on warm forming processes, such as the effect of punch velocity, holding time, temper and temperature on force-displacement response. The plastic anisotropy of the material which can be directly reflected by the earing behavior of the drawn cups has also been studied. Finite element simulations can be a powerful tool for the design of warm forming processes and tooling. Their accuracy will depend on the availability of material models that are capable of describing the influence of temperature and strain rate on the flow stresses. The physically based Nes model is used to describe the influence of temperature and strain rate and the Vegter yield criterion is used to describe the plastic anisotropy of the sheet. Experimental drawing test data are used to validate the modeling approaches

Effect of temperature on anisotropy in forming simulations of aluminum alloys

A combined experimental and numerical study of the effect of temperature on anisotropy in warm forming of AA 6016-T4 aluminum was performed. The anisotropy coefficients of the Vegter yield function were calculated from crystal plasticity models with an adequate combination of extra slip systems. Curve fitting was used to fit the anisotropy coefficients calculated at discrete temperatures. This temperature dependent constitutive model was successfully applied to the coupled thermo-mechanical analysis of deep drawing of aluminum sheet and results were compared with experiments

Thermo-mechanical forming of Al-Mg-Si Sheet

In warm forming of aluminum sheet, the temperature and strain rates vary considerably. In simulations, the material\ud model must be capable to predict stresses within this wide range. Here, the physically based Nes model is used to describe\ud the behavior of AA6061-T4 sheet material under warm forming conditions. A significant change of earing behavior is\ud found between room temperature and 250 ºC. Crystal plasticity calculations showed a reasonable correspondence of\ud changing r-values if extra slip systems are considered at high temperatures. Satisfactory results are obtained for simulation\ud of tensile tests and cylindrical deep drawing

Tesla Inc. : an equity valuation

The purpose of this dissertation is to determine the value of one Tesla, Inc. share as of 31 December 2018. An analysis of the automotive and energy generation and storage industry is presented, together with a detailed analysis of Tesla’s business and financial performance. For Tesla’s valuation purposes, the financial items are forecasted for a period of 10 years, i.e. from 2018 to 2027. In order to determine Tesla’s value, it is used the DCF approach, with the WACC as the discount rate. Additionally, the multiples method is also prepared as a complementary valuation to DCF. Based on the DCF approach, the achieved Tesla’s price target is $229.95, with a downside of 27.62$317.69, on 31 December 2018. Therefore, it is considered that Tesla is overvalued. In addition, a sensitivity analysis was completed to variations on WACC, terminal growth rate and total operating costs. Finally, the estimated Tesla’s share price is compared to the valuation done by J.P.Morgan, which recommended price target is $216 on 31 December 2018. To conclude, both valuations yield to a sell recommendation.O objetivo da presente dissertação é determinar o valor de uma ação da Tesla, Inc. a 31 de dezembro de 2018. É apresentada uma análise da indústria automóvel, produção e armazenamento de energia, juntamente com uma análise detalhada do negócio e do desempenho financeiro da Tesla. Para fins de avaliação da Tesla, são efetuadas previsões das contas financeiras para um período 10 anos, i.e., de 2018 a 2027. Por forma a determinar o valor da Tesla é usado o método DCF com WACC como a taxa de desconto. Adicionalmente, também é usado o método dos múltiplos, como um método de avaliação complementar do DCF. Com base no modelo DCF, o preço target estimado da Tesla é$229.95, o qual representa um valor de 27.62% abaixo do preço de mercado da ação $317.69, a 31 de dezembro de 2018. Neste sentido, considera-se que a Tesla está sobrevalorizada. Adicionalmente, uma análise de sensibilidade é efetuada relativamente às variações na taxa WACC, na taxa de crescimento a longo prazo e nos custos operacionais. Por fim, o preço estimado da Tesla é comparado com a avaliação feita pela J.P.Morgan, que recomendou um preço target de$216 a 31 de dezembro de 2018. Concluindo, ambas as avaliações recomendam uma decisão de venda

Mechanical and forming properties of AA6xxx sheet from room to warm temperatures

The influence of temperature on the mechanical behaviour of the heat treatable Aluminium alloy EN AW-6061 has been investigated with a series of tensile tests. It is found that temperature has an effect on both the storage of dislocations and dynamic recovery. The results have been used to fit the dislocation based Nes work-hardening model. Simulations show that the model captures properly the dependence of yield stress and work-hardening rate with temperature and temper. The work-hardening model has been implemented into the Dieka FEM to simulate the warm deep drawing of cylindrical cups. Comparison of the simulated and experimental punch force and cup thickness reveals a good correspondence and validates the proposed modelling approach

Chinese companies conquering the world: A descriptive analysis of the rapid rise of Chinese acquisitions

In this article, we study the global acquisition trends of Chinese companies. We look at the countries and sectors they are investing in and the factors driving those investments. We consider the inflexion points and the changes before and after the Global Financial Crisis. The focus of the paper is the evolution of mergers and acquisitions (M&A), but we also consider greenfield investments and overall outward foreign direct investments. To that end, we use longitudinal data from three sources: the United Nations Conference on Trade and Development (UNCTAD), the Standard & Poor’s Capital IQ, and Financial Times fDi Markets. We note that M&A activity was key for the rapid growth and the fast internationalization pace of Chinese companies. While M&A is the entry mode of choice for Chinese firms to approach the developed world (Europe and the U.S.), greenfields are more common for expansion in Asia and Africa. The paper also provides comparisons with data from other emerging markets and the U.S

Stepping Stones

Les occasions de surprendre deux poètes en pleine conversation sont assez rares pour éveiller la curiosité du lecteur, mais lorsque cette conversation témoigne d’une relation suivie et sincère, la démarche suscite un intérêt encore plus grand. L’ouvrage que propose Dennis O’Driscoll est le fruit de six années d’échanges verbaux et épistolaires avec Seamus Heaney. Il se place dès l’introduction sous le signe de l’originalité en affichant sa volonté de se démarquer des biographies classiques. I..

Queratoacantoma Subungueal: Uma Variante Rara do Queratoacantoma

Sungungual keratoacanthoma is a rare and more aggressive variant of keratoacanthoma. The authors present a case of a 49-year-old male with a one year history of a growing exophytic nodule on the nail bed of the left first toe. Physical examination revealed a two centimeters large exofitic nodule with a verrucous hyperkeratotic central area on the nail bed. A plain radiograph showed a cup-shaped lytic defect in the underlying distal phalanx. Histopathologic analysis revealed a large crater-like squamoproliferative lesion, connected to the epidermis and consisting of lobules and nests of glassy epithelium with numerous dyskeratotic cells, very little degree of cytological atypia and low mitotic activity. Lymphovascular, perineural or bone invasion were not found. Immunohistochemistry with p53 and Ki67 showed exclusive focal basal staining. The diagnosis of subungual keratoacanthoma was made. The main differential diagnosis, both clinical and histological, is with squamous cell carcinoma. It is important to consider this entity to avoid unnecessary diagnostic delays and mutilating treatments.O queratoacantoma subungueal é uma variante rara do queratoacantoma, caracterizada por um comportamento mais agressivo. Os autores apresentam o caso de um homem de 49 anos que recorre à consulta por nódulo exofítico duro localizado no leito ungueal do primeiro dedo do pé esquerdo, com cerca de 2 cm de diâmetro, hiperqueratósico, amarelado, com 1 ano de evolução. A radiografia óssea mostrava osteólise parcial da falange distal do respetivo dedo. O exame histopatológico revelou uma proliferação epitelial conectada com a epiderme com padrão crateriforme, constituída por lóbulos de queratinócitos de citoplasma amplo, vítreo, com presença de muitas células disqueratósicas, escassa atipia citológica e pouca atividade mitótica. Ausência de invasão linfovascular, perineural ou óssea. Marcação imunohistoquímica p53 e Ki67 exclusivamente focal ao nível da camada basal. Foi feito o diagnóstico de queratoacantoma subungueal. O principal diagnóstico diferencial, tanto clínico como histológico, é com o carcinoma espinocelular. É importante considerar esta entidade para evitar atrasos diagnósticos e tratamentos mutilantes desnecessários