171 research outputs found

    Predictive modelling of the granulation process using a systems-engineering approach

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    © 2016 Elsevier B.V.The granulation process is considered to be a crucial operation in many industrial applications. The modelling of the granulation process is, therefore, an important step towards controlling and optimizing the downstream processes, and ensuring optimal product quality. In this research paper, a new integrated network based on Artificial Intelligence (AI) is proposed to model a high shear granulation (HSG) process. Such a network consists of two phases: in the first phase the inputs and the target outputs are used to train a number of models, where the predicted outputs from this phase and the target are used to train another model in the second phase to lead to the final predicted output. Because of the complex nature of the granulation process, the error residual is exploited further in order to improve the model performance using a Gaussian mixture model (GMM). The overall proposed network successfully predicts the properties of the granules produced by HSG, and outperforms also other modelling frameworks in terms of modelling performance and generalization capability. In addition, the error modelling using the GMM leads to a significant improvement in prediction

    Material degradation in mooring chains for floating structures in deep waters

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    There is a dire need for an efficient, trustworthy, and financially feasible positioning technique for offshore large floating structures. Of all the methods of positioning the offshore structures, the mooring chains play a significant role. There is a need for explicit knowledge of the properties of mooring systems so that the design, operation, and analysis of large floating structures, particularly in deep water, should be reliable. Experts from the oil and gas industry have experienced actual corrosion loss rates data for mooring systems that they get are different from those allowed for in traditional design guidance and have long been a recognized challenge. The corrosion allowances from the codes are sometimes very conservative leading to an over design (thicker); this could be the other way round, in some cases. Recently, as long as corrosion has been tolerated with an 'allowance', thicker and heavier chains have been the only way to extend the life of these mooring chains. On the other hand, Corrosion rates can be unpredictable and vary greatly around the world due to the diverse marine environments. As a worst-case scenario, this results in significantly shortened chain lifespans and, at the very least, increased failure rates and integrity issues in the mooring systems. The findings of this study will result in a practical equation function from previous studies that can be used to estimate corrosion loss in deep water based on parameters that have a significant impact on the corrosion, such as temperature, and dissolved inorganic nitrogen (nitrates, nitrites, and ammonia) usually measured together as DIN concentration levels. Data may be unavailable in some regions, or finding them may be difficult, and using the allowances during design from the standards without considering the parameters may lead to inappropriate allowances, and as a result failure may occur. Thereafter, estimating the rest life of inservice degraded mooring chains is another issue and how can this be done through FEM analysis. Finally, although Cathodic Protection has long been a part of corrosion prevention strategies for offshore steel structures, the mooring lines have never been successfully protected in deep waters. Finding a method of protection to extend the lifetime of these degraded chains is another challenge. Following extensive research, a new sacrificial anode cathodic protection system technology has been found in recent years. Considering this method has guaranteed efficiency and a cathodic protection calculation has been made using these anode types

    Aeronautical engineering: A continuing bibliography with indexes (supplement 214)

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    This bibliography lists 422 reports, articles and other documents introduced into the NASA scientific and technical information system in May, l987

    Mass Production Processes

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    It is always hard to set manufacturing systems to produce large quantities of standardized parts. Controlling these mass production lines needs deep knowledge, hard experience, and the required related tools as well. The use of modern methods and techniques to produce a large quantity of products within productive manufacturing processes provides improvements in manufacturing costs and product quality. In order to serve these purposes, this book aims to reflect on the advanced manufacturing systems of different alloys in production with related components and automation technologies. Additionally, it focuses on mass production processes designed according to Industry 4.0 considering different kinds of quality and improvement works in mass production systems for high productive and sustainable manufacturing. This book may be interesting to researchers, industrial employees, or any other partners who work for better quality manufacturing at any stage of the mass production processes

    Biologization, Nanotechnology, Simulation: Proceedings of the 1st Joint PhD Conference on Material Science:: from 27.6.-1.7.2022 in Dresden/ Germany and Usti/Česká republika

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    Materials scientists from Ústí nad Labem and Dresden met in June of 2022 for the first joint PhD Conference on Material Science, with the special focus on biologization, nanotechnology and simulation. The conference aimed to encourage interdisciplinary exchange between Čzech and German research institutes and promote transnational cooperation on an international level along the Saxon- Čzech border. Due to the restrictions caused by the corona pandemic, several attempts were necessary before the conference, which was first planned in 2020, could finally take place for the first time in 2022. The conference could take place in presence, which was seen as a big plus by all participants, especially as it was the first meeting in this German - Čzech context for most of the participants. The attending scientists (about 60) met at the Institute of Material Science of TU Dresden in Germany for the first half of the week before the conference moved to the faculties of Science and Environment of the Jan Evangelista Purkyně University UJEP in Ústí nad Labem in Čzechia. The organized activities ranged from scientific presentations of current PhD projects and research topics, lab tours in the participating institutions, come-together events such as a guided tour at the dye collection of the TU Dresden and a hiking trip to Bohemian Switzerland. The conference was funded by INTERREG VA Saxony - Čzech Republic - a cooperation programme of the Elbe/Labe region. All participants - PhD students, scientists and staff members of the participating institutions - enjoyed this opportunity to build individual and new contacts, exchange information on current research topics and methods, find starting points for future collaborations between the different research areas and institutions and also discuss the similarities and differences between the German and Čzech research landscape. The purpose of this brochure is to present the institutions with their special topics and laboratories and to present current research topics - on the base of the presented PhD projects.:1 Introduction 2 1.1 Committees 5 2 Presentation of the participating institutes and chairs 5 2.1 Jan Evangelista Purkyně University in Ústí nad Labem 6 2.1.1 Faculty of Science 6 2.1.2 Faculty of Environment 12 2.2 Technische Universität Dresden 17 2.2.1 Institute of Material Science 17 2.3 Fraunhofer Institute for Ceramic Technologies and Systems IKTS 19 2.3.1 Department Bio- and Nanotechnology at IKTS 19 2.4 Institute for Complex Materials, Leibniz-IFW Dresden 21 2.5 TRANS³Net 22 3 Presentation of the PhD topics 23 3.1 Topic: BIOLOGIZATION 23 3.1.1 Ludovico Andrea Alberta: Exploring the effect of Cu additions on the mechanical behaviour of β-TiNb biomaterials 23 3.1.2 Franziska Alt: Formation of a microenvironment for directed differentiation of stem cells in a perfusion bioreactor 25 3.1.3 Dmitry Belyaev: Circular microfluidic systems for electro-chemical continuous monitoring of bio-chemicals in emulsion droplets 27 3.1.4 Constantin Ißleib: Dynamic osteoimmunological crosstalk in a bone replacement context 28 3.1.5 Adela Jagerová: Surface Modification by High-Energy Heavy-Ion Irradiation in Various Crystalline ZnO Facets 29 3.1.6 Nils Kaube: Bioinspired development of artificial enamel via in-situ nano-mineralization 30 3.1.7 Michaela Kocholata: Isolation and characterization of plant derived nanovesicles 30 3.1.8 Zuzana Nejedlá: Dendrimers as Drug Delivery System 31 3.1.9 Jacub Perner: Effect of cold plasma treatment of Poppy and Proso Millet seeds in plasma downer 32 3.1.10 Marina Roshchina: Development of new bacteria-killing coatings on beta-Ti-Nb alloy based on functional oxide nanotubular (ONT) layers 33 3.1.11 Muhammad Saqib: Algorithms and fluid-dynamic experimental platform for in vitro degradation studies of implant materials 34 3.1.12 Jacub Tolasz: Interaction of pollutants on nanoceria 35 3.1.13 Zuzana Žmudová: 3D spheroid culture for in vitro testing of nanoparticles 35 3.2 Topic: METROLOGY 37 3.2.1 Katrien Boonen: The potential of dendrochemistry and dendroecology in pollution research 37 3.2.2 Ivan Lopez Carasco: Development of immobilization protocols for Tro6 and Tro4 aptamers to be used in electrochemical biosensor 38 3.2.3 Jacub Hoskovec: Functionalized electrospun materials for selectvie capture of selected gases 39 3.2.4 Dominic Pilnaj: Applications of gas sensors for air-quality monitoring and identification of volatile organic compounds by GC-HRMS 39 3.2.5 Michaela Průšová: Prostat, Glioblastoma and Mammary carcinoma cells derived exosomes: Their isolation, characterization and loading with doxorubicin 40 3.2.6 Kateřina Přibylová: Preparation of nanostructured surfaces for CO2 Detection, Capture and Utilization 41 3.2.7 Michal Syrový: Chemical modification of PAN – based nanofibrous membranes prepared by electrospinning and their properties for CO2 capture potential 42 3.3 Topic: GEOLOGICAL/MATERIALS 43 3.3.1 Sabine Apelt: Using biomimicry to design anti-ice surfaces for air-water heat pumps 43 3.3.2 Jan Dočkal: Molecular dynamics of interfacial solution structure of alkali-halide electrolytes at graphens electrodes 47 3.3.3 Tereza Dušková: Metal complexes with polyfluorinated NHCs 48 3.3.4 Kristína Fiantoková: Obtaining of the active mass from the spent Li-Ion batteries 48 3.3.5 Stephanie Ihmann: Engineering of bio-based Building and Construction Materials 49 3.3.6 Sara Jalali: Degradable bone substitute materials with load-bearing properties - Fiber-strengthened silica 50 3.3.7 Pavel Kaule: Preparation of heteroborane derivatives for thin film deposition by the covalent bond formation 53 3.3.8 M. Kozakovic: The effect of primary and secondary flows on the homogenization process in a vertical bladed mixer 53 3.3.9 Pavlína Matysová: Molecular Simulation of Salt Hydrates 54 3.3.10 Viktorie Neubertová: Surface functionalization of Ti3C2T MXene for MRI contrast agent 55 3.3.11 Robert Ato Newton: Fuel characteristics of Miscanthus x giganteus biomass produced at the marginal and slightly contaminated by trace elements soils 55 3.3.12 Martin Otto: Bioresorbable Fe-based alloys processed via laser powder bed fusion 56 3.3.13 Petr Panuška: A millifluidic chip for cultivation of fish embryos and toxicity testing fabricated by 3D printing technology 59 3.3.14 David Poustka: Unlocking mass production of photocrosslinked chitosan nanofibers 60 3.3.15 Eliška Rezlerová: Adsorption and Diffusion of Short Hydrocarbons and Carbon Dioxide in Shale Organic Matter: Insights from Molecular Simulations 60 3.3.16 Stefan Weitz: Investigating the material hardness of mollusks shells in dry and wet states by microindentation 6

    Bibliography of Lewis Research Center technical publications announced in 1986

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    This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1986. All the publications were announced in the 1986 issues of Scientific and Technical Aerospace Reports (STAR) and/or International Aerospace Abstracts (IAA). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

    Metodologias para projeto mecânico ótimo de estruturas espaciais obtidas por fabrico aditivo

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    Additive Layer Manufacturing (ALM) is growing rapidly due to the unprecedented design freedom. Thus, the structures' complexity can be drastically increased without significant raises in costs. However, the economic viability of ALM is strongly dependent on the full exploration of the referred design freedom. In fact, the ALM is only cost-effective in highly customized parts. Moreover, the mechanical behavior of materials processed via ALM is an ongoing challenge due to defects, uncertainties in material characterization, and verification methods. Thus, the goal of the present work is the development of a robust methodology for the mechanical optimum design of metallic space structures obtained from additive manufacturing. Thus, two main tasks were established. The first task is related to the mechanical characterization of a Ti6Al4V alloy, processed via Selective Laser Melting (SLM). Therefore, an experimental testing campaign of Ti6Al4V samples is presented using homogeneous macroscopic testing (tensile, compression, density, hardness, and fatigue) and microscopic testing (defects detection via microcomputed tomography). These samples show better static properties than the other counterparts, obtained by traditional manufacturing processes. However, the repeatability of the SLM samples is still a challenge (particularly in its fatigue behavior) and more testing is needed. Furthermore, these campaigns are expensive and, consequently, more information per test is required. With the development of full-field measurement methods, material model calibration strategies call upon the use of heterogeneous testing specimens. In the scope of this work, an indirect TO methodology is presented, being capable of designing a wide range of different heterogeneous specimens. Then, a stress states performance indicator is also presented to help the selection of the most promising geometry. The second task is related to the definition of the engineering cycle for ALM structures in its mains phases: (i) design for ALM, (ii) bridging between Topology Optimization (TO) and ALM, (iii) process simulation and structural verification, and (iv) manufacturing. Concerning the first phase, ALM provides great geometric freedom however, there are some design limitations. Therefore, a systematic design methodology is presented, being based on a topology optimization algorithm capable of incorporating the main ALM design limitations (minimum member size and overhang angle). Furthermore, the non-trivial task of bridging between TO and the final smooth geometry is also studied (second phase). The referred task uses a Laplacian smoothing algorithm, which is based on the new concept of mutable diffusion. This new concept shows better properties than the classic algorithms, giving promising results. Furthermore, a new volume constraint is presented, which exhibits a less detrimental impact on the chosen structural indicators. Regarding the remaining phases, these were analyzed via industrial case studies. For instance, process simulation can provide crucial insight into the optimum manufacturing direction and might dictate the difference between success and failure upon manufacturing. The impact of this Ph.D. is related with some improvements in (i) the characterization of ALM-produced materials as well as the geometry of the specimens used for their characterization; and in (ii) the engineering cycle of ALM structures, allowing higher efficiency in the structural solutions for the space industry with lower costs.O uso do fabrico aditivo por camadas está a crescer a um elevado ritmo devido À elevada liberdade de projeto de estruturas. Assim, a complexidade das estruturas pode ser aumentada significativamente sem incrementos significativos nos custos. Todavia, a viabilidade económica do fabrico aditivo por camadas é fortemente dependente de uma exploração inteligente da liberdade de projeto estrutural. Na verdade, o fabrico aditivo por camadas só é rentável em peças de elevada complexidade e valor acrescentado. Adicionalmente, o comportamento mecânico de materiais processados através do fabrico aditivo por camadas é ainda um desafio por resolver devido à existência de defeitos, incertezas na caracterização de materiais e nos seus métodos de velicação. Deste modo, o objetivo deste trabalho é o desenvolvimento de uma metodologia robusta que permita o projeto mecânico ótimo de estruturas obtidas por fabrico aditivo para a indústria espacial. Para isso, foram estabelecidas duas tarefas principais. A primeira tarefa está relacionada com a caracterização mecânica da liga Ti6Al4V, processada através da fusão seletiva a laser. Portanto, foi realizado uma campanha de testes experimentais com provetes da liga Ti6Al4V composta por testes macroscópicos homogéneos (tração, compressão, densidade, dureza e fadiga) e testes microscópicos (deteção de defeitos usando uma análise com recurso à tomografia microcomputorizada). Foi verificado que estas amostras exibem melhor propriedades estáticas que amostras idênticas produzidas através de processos tradicionais. Contudo, a sua repetibilidade ainda é um desafio (particularmente o comportamento à fadiga), sendo necessário mais testes. Adicionalmente, estas campanhas experimentais são onerosas e, consequentemente, é crítico obter mais informação por cada teste realizado. Dado o desenvolvimento dos métodos de medição full-field, as estratégias de calibração de modelos de material propiciam o uso de provetes heterogéneos em testes mecânicos. No ^âmbito deste trabalho apresenta-se uma metodologia de otimização topológica indireta capaz de projetar uma grande variedade de provetes heterógenos. Posteriormente apresenta-se um indicador de desempenho baseado na quantidade de estados de tensão para selecionar o provete mais promissor. A segunda tarefa está relacionada com a definição do ciclo de engenharia para o fabrico aditivo por camadas de estruturas metálicas nas suas fases principais: (i) projeto para fabrico aditivo por camadas, (ii) transição entre a otimização topológica e o fabrico aditivo por camadas, (iii) simulação do seu processo de fabrico e sua verificação estrutural e (iv) fabrico. Relativamente à primeira fase, o fabrico aditivo por camadas proporciona uma grande liberdade geométrica, contudo existe limitações ao design. Portanto é apresentada uma metodologia de projeto sistemática, baseada num algoritmo de otimização topológica capaz de incorporar as principais limitações de projeto do fabrico aditivo por camadas tais como a espessura mínima e ângulo do material sem suporte. Adicionalmente, a tarefa complexa de efetuar a transição entre os resultados da otimização topológica e uma geometria final suave também é objeto de estudo. A tarefa anteriormente referida baseia-se na suavização Laplaciana que por sua vez se baseia no novo conceito de difusão mutável. Este novo conceito apresenta melhores e mais promissores resultados que os algoritmos clássicos. Adicionalmente, é apresentado uma nova restrição de volume que proporciona um menor impacto nos indicadores estruturais escolhidos. Relativamente às restantes fases, estas são analisadas através de casos de estudo industriais. A título exemplar, a simulação do processo de fabrico pode fornecer informações crucias para a escolha da direção de fabrico que, por sua vez, pode ditar a diferença entre o sucesso ou o insucesso durante o fabrico. O impacto deste trabalho está relacionado com melhorias na (i) caracterização de materiais produzidos através de fabrico aditivo por camadas assim como nas geometrias de provetes usados durante a sua caracterização e no (ii) ciclo de projeto em engenharia de estruturas obtidas através do fabrico aditivo por camadas, permitindo soluções estruturais com maior eficiência e menor custo para indústria espacial.Programa Doutoral em Engenharia Mecânic
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