@article{RaffeisAdjeiKyeremehVroomenetal.2020, author = {Raffeis, Iris and Adjei-Kyeremeh, Frank and Vroomen, Uwe and Westhoff, Elmar and Bremen, Sebastian and Hohoi, Alexandru and B{\"u}hrig-Polaczek, Andreas}, title = {Qualification of a Ni-Cu alloy for the laser powder bed fusion process (LPBF): Its microstructure and mechanical properties}, series = {Applied Sciences}, volume = {10}, journal = {Applied Sciences}, number = {Art. 3401}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app10103401}, pages = {1 -- 15}, year = {2020}, abstract = {As researchers continue to seek the expansion of the material base for additive manufacturing, there is a need to focus attention on the Ni-Cu group of alloys which conventionally has wide industrial applications. In this work, the G-NiCu30Nb casting alloy, a variant of the Monel family of alloys with Nb and high Si content is, for the first time, processed via the laser powder bed fusion process (LPBF). Being novel to the LPBF processes, optimum LPBF parameters were determined, and hardness and tensile tests were performed in as-built conditions and after heat treatment at 1000 °C. Microstructures of the as-cast and the as-built condition were compared. Highly dense samples (99.8\% density) were achieved after varying hatch distance (80 µm and 140 µm) with scanning speed (550 mm/s-1500 mm/s). There was no significant difference in microhardness between varied hatch distance print sets. Microhardness of the as-built condition (247 HV0.2) exceeded the as-cast microhardness (179 HV0.2.). Tensile specimens built in vertical (V) and horizontal (H) orientations revealed degrees of anisotropy and were superior to conventionally reported figures. Post heat treatment increased ductility from 20\% to 31\% (V), as well as from 16\% to 25\% (H), while ultimate tensile strength (UTS) and yield strength (YS) were considerably reduced.}, language = {en} } @inproceedings{EggertWeber2023, author = {Eggert, Mathias and Weber, Jannik}, title = {What drives the purchase decision in Instagram stores?}, series = {ECIS 2023 Research Papers}, booktitle = {ECIS 2023 Research Papers}, pages = {17 Seiten}, year = {2023}, abstract = {The popularity of social media and particularly Instagram grows steadily. People use the different platforms to share pictures as well as videos and to communicate with friends. The potential of social media platforms is also being used for marketing purposes and for selling products. While for Facebook and other online social media platforms the purchase decision factors are investigated several times, Instagram stores remain mainly unattended so far. The present research work closes this gap and sheds light into decisive factors for purchasing products offered in Instagram stores. A theoretical research model, which contains selected constructs that are assumed to have a significant influence on Instagram user´s purchase intention, is developed. The hypotheses are evaluated by applying structural equation modelling on survey data containing 127 relevant participants. The results of the study reveal that 'trust', 'personal recommendation', and 'usability' significantly influences user's buying intention in Instagram stores.}, language = {en} } @inproceedings{StapenhorstGessnerWoerd2017, author = {Stapenhorst, Carolin and Geßner, Stephan and Woerd, Jan Dirk van der}, title = {ArchitecTours - a close look on structures around us}, series = {Proceedings of IASS Annual Symposia}, booktitle = {Proceedings of IASS Annual Symposia}, editor = {B{\"o}gle, Annette and Grohmann, Manfred}, publisher = {IASS}, address = {Madrid}, issn = {2518-6582}, pages = {9 Seiten}, year = {2017}, abstract = {Architects and civil engineers work together regularly during their professional days and are irreplaceable for each other. This co-operation is sometimes made more difficult by the differences in their disciplinary languages and approaches. Structures are evaluated by architects on the basis of criteria such as spatial impact and usability, while civil engineers analyze them more closely by their bearing and deformation properties, as well as by constructive aspects. This diversity of assessment criteria and approaches is often continued in both academic disciplines in the view on structures. Within the framework of the Exploratory Teaching Space (ETS), a funding program to improve teaching at RWTH Aachen University and to promote new teaching concepts, a project was carried out jointly by the Junior Professorship of Tool-Culture at the Faculty of Architecture and the Institute of Structural Concrete at the Faculty of Civil Engineering. The aim of the project is to present buildings in such a way that the differences in perception between architects and civil engineers are reduced and the common understanding is promoted. The project develops a database, which contains a collection of striking buildings from Aachen and the surrounding area. The buildings are categorized according to terms that come from both disciplinary areas. The collection can be freely explored or crossed through learning trails. The medium of film plays a special role in presenting the buildings. The buildings are assigned to different categories of load bearing structures as linear, planar and spatial structures, and further to different types of material, functional programs and spatial characteristics. Since the buildings are located in the direct vicinity of Aachen, they can be visited by the students. This makes them more sensitive to their environment. Intrinsic motivation, as well as implicit learning is encouraged. The paper will provide a detailed report of the project, its implementation, the feedback of the students and the plans for further development.}, language = {en} } @book{Stapenhorst2016, author = {Stapenhorst, Carolin}, title = {Concept : a dialogic instrument in architectural design}, publisher = {Jovis}, address = {Berlin}, isbn = {978-3-86859-364-8}, pages = {207 Seiten}, year = {2016}, abstract = {Concept - this is a key term in architectural discourse. However, all too often it is used imprecisely or merely for marketing purposes. What is a concept actually? This publication moves between design theory and design practice and follows the history of the definition of concept in architecture, leading to the formulation of a specifically instrumental and operative definition. It bases concept in architecture on its strategic potential in design decision-making processes. In the changing profession of the designing architect, decisions are increasingly made in multidisciplinary groups. Concept can serve as a dialogic instrument in the process, making it possible to process heterogeneous information from a range of spheres of knowledge. The effective presentation of selected information becomes a relevant interface in the design process, which has a significant influence on the quality of the design.}, language = {en} } @inproceedings{YanStreseChwallek2018, author = {Yan, Zexiong and Strese, Steffen and Chwallek, Constanze}, title = {Explorer CEOs: The effect of CEO career variety on large firms' relative exploration orientation}, series = {G-Forum Jahreskonferenz 2018}, booktitle = {G-Forum Jahreskonferenz 2018}, pages = {42 Seiten}, year = {2018}, abstract = {Prior studies demonstrate that firms need to make smart trade-off decisions between exploration and exploitation activities in order to increase performance. Chief executive officers (CEOs) are principal decision makers of a firm's strategic posture. In this study, we theorize and empirically examine how relative exploration orientation of large publicly listed firms varies based on the career variety of their CEOs - that is, how diverse the professional experiences of executives were prior to them becoming CEOs. We further argue that the heterogeneity and structure of the top management team moderates the impact of CEO career variety on firms' relative exploration orientation. Based on multisource secondary data for 318 S\&P 500 firms from 2005 to 2015, we find that CEO career variety is positively associated with relative exploration orientation. Interestingly, CEOs with high career varieties appear to be less effective in pursuing exploration, when they work with highly heterogeneous and structurally interdependent top management teams.}, language = {en} } @inproceedings{HunsdiekChwallek2019, author = {Hunsdiek, Niklas J.A. and Chwallek, Constanze}, title = {External venturing activities and the influence of the chief technology officer}, series = {G-Forum Jahreskonferenz 2019}, booktitle = {G-Forum Jahreskonferenz 2019}, pages = {6 Seiten}, year = {2019}, language = {en} } @inproceedings{MaurerMiskiwAcostaetal.2023, author = {Maurer, Florian and Miskiw, Kim K. and Acosta, Rebeca Ramirez and Harder, Nick and Sander, Volker and Lehnhoff, Sebastian}, title = {Market abstraction of energy markets and policies - application in an agent-based modeling toolbox}, series = {EI.A 2023: Energy Informatics}, booktitle = {EI.A 2023: Energy Informatics}, editor = {Jorgensen, Bo Norregaard and Pereira da Silva, Luiz Carlos and Ma, Zheng}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-48651-7 (Print)}, doi = {10.1007/978-3-031-48652-4_10}, pages = {139 -- 157}, year = {2023}, abstract = {In light of emerging challenges in energy systems, markets are prone to changing dynamics and market design. Simulation models are commonly used to understand the changing dynamics of future electricity markets. However, existing market models were often created with specific use cases in mind, which limits their flexibility and usability. This can impose challenges for using a single model to compare different market designs. This paper introduces a new method of defining market designs for energy market simulations. The proposed concept makes it easy to incorporate different market designs into electricity market models by using relevant parameters derived from analyzing existing simulation tools, morphological categorization and ontologies. These parameters are then used to derive a market abstraction and integrate it into an agent-based simulation framework, allowing for a unified analysis of diverse market designs. Furthermore, we showcase the usability of integrating new types of long-term contracts and over-the-counter trading. To validate this approach, two case studies are demonstrated: a pay-as-clear market and a pay-as-bid long-term market. These examples demonstrate the capabilities of the proposed framework.}, language = {en} } @inproceedings{ReisgenSchleserScheiketal.2011, author = {Reisgen, Uwe and Schleser, Markus and Scheik, Sven and Michaeli, Walter and Gr{\"o}nlund, Oliver and Neuß, Andreas and Wunderle, Johannes and Poprawe, Reinhart and R{\"o}sner, A. and Bobzin, Kirsten and Schl{\"a}fer, Thomas and Theiß, Sebastian and Kutschmann, Pia and Haberstroh, Edmund and Flock, Dustin and B{\"u}hrig-Polaczek, Andreas and Jakob, M.}, title = {Novel process chains for the production of plastics/metal-hybrids}, series = {17th International Conference on Concurrent Enterprising (ICE 2011) : Aachen, Germany, 20 - 22 June 2011}, booktitle = {17th International Conference on Concurrent Enterprising (ICE 2011) : Aachen, Germany, 20 - 22 June 2011}, editor = {Thoben, Klaus-Dieter}, publisher = {IEEE}, address = {Piscataway, NJ}, organization = {Forschungsinstitut f{\"u}r Rationalisierung ; International Conference on Concurrent Enterprising <17, 2011, Aachen>}, isbn = {978-1-457-70772-8 ; 978-3-943024-05-0}, pages = {596 -- 604}, year = {2011}, language = {en} } @inproceedings{NowackRoethBuehrigPolaczeketal.2008, author = {Nowack, N. and R{\"o}th, Thilo and B{\"u}hrig-Polaczek, Andreas and Klaus, G.}, title = {Advanced Sheet Metal Components Reinforced by Light Metal Cast Structures}, series = {Aluminium alloys : their physical and mechanical properties ; [proceedings of the 11th International Conference on Aluminium Alloys, 22 - 26 Sept. 2008, Aachen, Germany ; ICAA 11]}, booktitle = {Aluminium alloys : their physical and mechanical properties ; [proceedings of the 11th International Conference on Aluminium Alloys, 22 - 26 Sept. 2008, Aachen, Germany ; ICAA 11]}, number = {2}, editor = {Hirsch, J{\"u}rgen}, isbn = {978-3-527-32367-8}, pages = {2374 -- 2381}, year = {2008}, language = {en} } @inproceedings{MaurerNitschKochemsetal.2024, author = {Maurer, Florian and Nitsch, Felix and Kochems, Johannes and Schimeczek, Christoph and Sander, Volker and Lehnhoff, Sebastian}, title = {Know your tools - a comparison of two open agent-based energy market models}, series = {2024 20th International Conference on the European Energy Market (EEM)}, booktitle = {2024 20th International Conference on the European Energy Market (EEM)}, publisher = {IEEE}, address = {New York, NY}, doi = {10.1109/EEM60825.2024.10609021}, pages = {8 Seiten}, year = {2024}, abstract = {Due to the transition to renewable energies, electricity markets need to be made fit for purpose. To enable the comparison of different energy market designs, modeling tools covering market actors and their heterogeneous behavior are needed. Agent-based models are ideally suited for this task. Such models can be used to simulate and analyze changes to market design or market mechanisms and their impact on market dynamics. In this paper, we conduct an evaluation and comparison of two actively developed open-source energy market simulation models. The two models, namely AMIRIS and ASSUME, are both designed to simulate future energy markets using an agent-based approach. The assessment encompasses modelling features and techniques, model performance, as well as a comparison of model results, which can serve as a blueprint for future comparative studies of simulation models. The main comparison dataset includes data of Germany in 2019 and simulates the Day-Ahead market and participating actors as individual agents. Both models are comparable close to the benchmark dataset with a MAE between 5.6 and 6.4 €/MWh while also modeling the actual dispatch realistically.}, language = {en} }