Approach for Increasing the Resource Efficiency for the Production Process of Titanium Structural Components

Titanium structural components for the aircraft industry are usually manufactured from ingots of primary material. The process chain for the fabrication of these components consists of the production of titanium sponge, the melting process, the forging process and the milling process. High chip removal rates from up to 95% due to the milling process and a high energy demand in producing the titanium sponge of about 85% of the overall energy consumption characterize the process chain. This obviously leads to a high optimization potential under monetary and energetic aspects. Recycling titanium chips for the ingot production could help to dramatically improve the overall production process in terms of ecological aspects. However, process-induced contaminations of the chips prevent the use of high amounts of these in the melting procedure. Macroscopic impurities like residues of cooling lubricant can be removed in a complex cleaning process. Yet, contaminations like oxidization cannot be eliminated, hence only a small amount of titanium chips is usable in the melting process to achieve the required purity of the titanium alloy. This paper describes a novel method to decrease the energy consumption in fabricating titanium products. By reducing process-induced contaminations, the amount of titanium chips usable in the melting process can be significantly increased and consequently the necessary quantity of titanium sponge reduced. The described method contains the investigation of relevant influencing factors like the impact of tool and cooling concept on chip quality or manufacturing costs. The research of cause-effect relationships identifies the trade-off between ecological and economic targets. A mathematical description of this relationship is implemented within a simulation environment to find an optimum between ecological and economic targets. The paper describes this approach with samples of the titanium alloy Ti6Al4 V.BMWi/03ET1174

Costructed Wetlands. A biological alternative wastewater treatments and its role in the new circular economy

The climate changes, the natural resources depletion, the population number increase are alarm bells for the future that must push the humanity to turn on more sustainable use of the natural resources, particularly the water. The water management must shift towards solutions acted to protect, safeguard, and sustainably use the available water resources. A new water scheme must be implemented, in which the waste paradigm must be overtaken and substituted with resource-oriented one. The Thesis aims to present the Constructed Wetland (CW) technology, an attractive green solution for wastewater treatment that nowadays is consolidated as a efficient and valid Natural Based alternative to the conventional systems. The different typologies of CWs are exposed as well as their advantages, disadvantages, and applications. The removal pollutant processes (biological, physical, and chemical processes) occurred within, are deeply analysed and the choice of the suitable vegetation species depending on the wastewater characteristic discussed. Furthermore, I give a brief overview on the European and Italian regulations before explaining in details the design (preliminary and empirical) methods. The treatment goodness and effectiveness are discussed and commented with helping of working applications. Finally, the future role of the CWs systems in circular economy approach is clarified and an overview on the water management scheme modification (from waste paradigm to resource-oriented concept) is provided. The potential applications of CWs within this new scheme are outlined and an in-depth study on recreative applications of CW (Natural Swimming Pools technology) are presented

Probabilistic structural mechanics research for parallel processing computers

Aerospace structures and spacecraft are a complex assemblage of structural components that are subjected to a variety of complex, cyclic, and transient loading conditions. Significant modeling uncertainties are present in these structures, in addition to the inherent randomness of material properties and loads. To properly account for these uncertainties in evaluating and assessing the reliability of these components and structures, probabilistic structural mechanics (PSM) procedures must be used. Much research has focused on basic theory development and the development of approximate analytic solution methods in random vibrations and structural reliability. Practical application of PSM methods was hampered by their computationally intense nature. Solution of PSM problems requires repeated analyses of structures that are often large, and exhibit nonlinear and/or dynamic response behavior. These methods are all inherently parallel and ideally suited to implementation on parallel processing computers. New hardware architectures and innovative control software and solution methodologies are needed to make solution of large scale PSM problems practical

Impact of operation strategies of large scale battery systems on distribution grid planning in Germany

Due to the increasing penetration of fluctuating distributed generation electrical grids require reinforcement, in order to secure a grid operation in accordance with given technical specifications. This grid reinforcement often leads to over-dimensioning of the distribution grids. Therefore, traditional and recent advances in distribution grid planning are analysed and possible alternative applications with large scale battery storage systems are reviewed. The review starts with an examination of possible revenue streams along the value chain of the German electricity market. The resulting operation strategies of the two most promising business cases are discussed in detail, and a project overview in which these strategies are applied is presented. Finally, the impact of the operation strategies are assessed with regard to distribution grid planning.Postprint (author's final draft

The dimensional variation analysis of complex mechanical systems

Dimensional variation analysis (DVA) is a computer based simulation process used to identify potential assembly process issues due the effects of component part and assembly variation during manufacture. The sponsoring company has over a number of years developed a DVA process to simulate the variation behaviour of a wide range of static mechanical systems. This project considers whether the current DVA process used by the sponsoring company is suitable for the simulation of complex kinematic systems. The project, which consists of three case studies, identifies several issues that became apparent with the current DVA process when applied to three types of complex kinematic systems. The project goes on to develop solutions to the issues raised in the case studies in the form of new or enhanced methods of information acquisition, simulation modelling and the interpretation and presentation of the simulation output Development of these methods has enabled the sponsoring company to expand the range of system types that can be successfully simulated and significantly enhances the information flow between the DVA process and the wider product development process

Measuring Corporate Social Responsibility in tourism: Development and validation of an efficient measurement scale in the hospitality industry.

ABSTRAC: This article aims at developing an efficient measurement scale for corporate social responsibility in the tourism industry, given the contextual character that is recognized in the practice of this construct. Indicators were generated on the basis of a literature review and qualitative research. To assess the reliability and validity, first- and second-order confirmatory factor analysis were carried out. Results show a multidimensional structure of this construct—including economic, social, and environmental issues. This study contributes to the advancement of knowledge in the field of social responsibility through its practical application regarding concepts of sustainable development which have mainly been theoretical

Design and Manufacture of a mini-turbojet

The development and production of small engines with a jet propulsion system is, relatively recent, taking into account that this type of gas turbine started to be studied and developed many years before the first construction of these small turbojets. However, with the time evolving, the gas turbines turned out to be a greater challenge, becoming more and more difficult to develop and improve. The gas turbine requires an intense study of the several areas related to its functioning, demanding additional knowledge and skill to improve a small detail. Although the detail could be small, the effect on overall performance would be considerable. Until recent times, these small engines were developed without a significant role in the aviation industry, being only used for model jet engines. Even though, in the account of the science evolution, these engines are being studied and prepared to integrate Unmanned Aerial Vehicles, UAV’s, as their propulsion system [1]. This dissertation consists on the development of a turbojet, in a small-scale, respecting the dimensions of the two, previously obtained, components, the compressor, and turbine, from the model turbo IHI RHB31 VZ21. To understand how to execute a design with suitable dimensions, the study of every present component in a turbojet was carried out, in parallel with the fundamental areas, regarding the functioning of a turbojet, such as thermodynamic cycles. At the end of a general study of the turbojet, the author proceeded to the design phase, in which the dimensioning process starts based on the information contained in the various sources of information, found at the bibliography. The dimensioning was carried through by the use of a scale factor. This scale factor was obtained by the compressor’s diameters ratio. In brief, in the Mr.Thomas Kamps’ book, the author advises the novice to divide his compressor diameter by the compressor used for Mr.Kamps’s engine. The diameters ratio, or the scale factor, was applied to the remaining components, produced by Mr.Thomas Kamps,in order to attain the measures for this gas turbine, respecting the recommended. The dimensions of the compressor shroud, inlet flange, diffuser, shaft, shaft housing, combustion chamber, fuel distribution ring, nozzle guide vanes, exhaust nozzle and, the last, outer casing were obtained. The next step was the design process of the referred components, in regard to the observed designs, found in the studied literature, using the three-dimensional design software CATIA V5R18. The design is an empiric process, which reveals itself as extremely difficult to consider one design as absolute. The manufacturing process of the turbojet was executed, at the time, the design process had been concluded. The following action was to acquire the necessary material for the production of the pieces, essentially, aluminum and stainless steel. The aluminum used was cast aluminum, being, then, worked to acquire the requested shape concerning the established design. The majority of the components were manufactured with stainless steel sheets, in which, the pieces were cut, according to their dimensions and shape, in-plane geometry. The chapter describing the manufacture process, as well as, the design process, is explained to allow a future reproduction of the work completed or adaptation for a different compressor/turbine set. Unfortunately, the fabrication of the diffuser and compressor shroud was not possible, since it had extremely small dimensions to be produced in the 5-axis vertical machining center. Moreover, the welding applied to the manufactured pieces was not executed with the required quality, even having increased the material thickness to facilitate the process, as it is explained in chapter 4.3. Therefore, one of the main objectives was not accomplished due to the insufficient means that disabled the manufacture of the jet engine’s parts.O desenvolvimento e produção de pequenos motores a propulsão jato é relativamente recente, tendo em conta que, este tipo de turbina a gás começou a ser estudado e desenvolvido muito antes. No entanto, com a evolução dos tempos, as turbinas a gás foram-se tornando um desafio cada vez mais dificil de as desenvolver e melhorar. Este tipo de motor requere um estudo intenso das várias áreas relacionadas com o seu funcionamento, exigindo cada vez mais conhecimentos e perícia, para que um pequeno detalhe seja melhorado. Apesar de o detalhe poder ser pequeno, o efeito no desempenho geral é considerável. Até tempos recentes, estes pequenos motores foram desenvolvidos sem um papel significativo na indústria aeronáutica, apenas sendo utilizados para aeromodelos. Contudo, à conta da evolução na ciência, estes motores começam a ser estudados e preparados para integrarem Veículos Aéreos Não Tripulados, UAV, como o seu sistema de propulsão [1]. Este projeto consiste no desenvolvimento de um turbojato, respeitando as dimensões de dois componentes previamente obtidos, o compressor e a turbina, do turbo modelo IHI RHB31 VZ21. Para perceber como se executa o design com o dimensionamento adequado, o estudo de todo componente presente num turbojato foi prosseguido, em paralelo com as áreas fundamentais relativas ao funcionamento do turbojato, por exemplo, ciclos termodinâmicos. No final de um estudo geral do turbojato, o autor prosseguiu para a fase de design, na qual o processo de dimensionamento começa com base na informação contida nas várias fontes de informação, encontradas na bibliografia. O dimensionamento foi realizado pelo o uso de um fator de escala. Este fator de escala foi obtido por uma razão de diâmetros de compressores. Sucintamente, no livro do Sr.Thomas Kamps, o autor aconselha o novato a dividir o tamanho do seu compressor pelo do compressor utilizado para o motor do Sr.Thomas Kamps. A razão de diâmetros, ou fator de escala, foi aplicada nos restantes componentes, produzidos pelo Sr.Thomas Kamps, permitindo chegar às medidas para esta turbina a gás, respeitando o recomendado. As dimensões da cobertura do compressor, flange de entrada, difusor, veio, túnel de acoplamento do veio, câmara de combustão, anel de distribuição do combustível, bocal anterior à turbina com pás guias para o escoamento, bocal dos gases de escape e, por último, o invólucro externo, foram obtidas. O próximo passo foi o processo de design dos componentes referidos, em relação aos designs observados na literatura estudada, utilizando o software de três dimensões CATIA V5R18. O design é um processo empírico, que se torna extremamente difícil de considerar um design como absoluto. O processo de fabrico do turbojato foi realizado, aquando, o processo de design ter sido concluído. A próxima ação foi obter os materias necessários para a produção das peças, essencialmente, alumínio e aço inox. O alumínio usado foi alumínio fundido, sendo, depois, maquinado para adquirir as formas exigidas relativas ao desgin estabelecido. A maioria dos componentes foram produzidos com folhas de chapa de aço inox, na qual as peças foram cortadas, de acordo com as suas dimensões e forma, em geometria plana. O capítulo que descreve o processo de manufatura, assim como, o processo de design, é explicado para permitir uma futura reprodução do trabalho completado ou adaptação para um conjunto compressor/turbina diferente. Infelizmente, a fabricação do difusor e cobertura do compressor não foi possível, sendo que tinham dimensões extremamente pequenas para serem produzidas numa fresadora vertical de comando numérico de cinco eixos. Para além disso, a soldadura aplicada nas peças produzidas não foi executada com a qualidade exigida, mesmo tendo-se aumentado a espessura das peças para facilitar o processo, como foi explicado no capítulo 4.3. Portanto, um dos objetivos não foi atingido devido aos meios insuficientes que impediram a fabricação das partes do motor a jato