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Methanol Synthesis with Steel Mill Gases: Performance Investigations in an On‐Site Technical Center
(2021)
Synthesis and Analysis of a Novel Linkage Mechanism with the Helical Motion of the End-Effector
(2020)
The decarbonization of for example the energy or heat sector leads to the transformation of distribution grids. The expansion of decentralized energy resources and the integration of new consumers due to sector coupling (e.g. heat pumps or electric vehicles) into low voltage grids increases the need for grid expansion and usage of flexibilities in the grid. A high observability of the current grid status is needed to perform these tasks efficiently and effectively. Therefore, there is a need to increase the observability of low voltage grids by installing measurement technologies (e.g. smart meters). Multiple different measurement technologies are available for low voltage grids which can vary in their benefit to observation quality and their installation costs. Therefore, Bayernwerk Netz GmbH and E.DIS AG in cooperation with E-Bridge Consulting GmbH and the Institute for High Voltage Equipment and Grids, Digitalization and Energy Economics (IAEW) investigated the effectiveness of different strategies for the smartification of low voltage grids. This paper presents the methodology used for the investigation and exemplary results focusing on the impact of intelligent cable distribution cabinets and smart meters on the quality of the state estimation.
Today, the use of renewable energies and recycling of climate-changing gases are increasingly important. In this context,coupling of methanation with small, decentralized CO2sources such as biogas plants provides one possibility. However,fluctuating availability of renewables for hydrogen production in combination with small storage volumes result in anenhanced demand for dynamic process operation. This leads to new research challenges with respect to the required cata-lysts and the overall process design. To draw reliable conclusions about the catalytic performance under dynamic processoperation, the mechanism of the methanation reaction as well as typical deactivation procedures of the catalyst appliedunder steady-state conditions have to be reviewed thoroughly.
In the context of using renewable energies and recycling climate-changing gases, methanation of CO2 provides one possibility. However, volatile availability of renewable energies for hydrogen production and fluctuating CO2streams from different sources lead to enhanced demand in investigating the influence of dynamic process operation on the catalyst performance, including detailed kinetic characterization. Reliable kinetic measurements require isothermal temperature control and absence of macrokinetic diffusion limitations. Both were investigated in this work while the determination of steady-state kinetic parameters is part of ongoing studies. Furthermore, a detailed analysis with respect to the long-term-stability of the nickel-based catalyst was performed
The impact of culture on entrepreneurship is a widely accepted phenomenon. Cultural factors influence entrepreneurship via different mechanisms on the macro-, meso-, and micro-level of a country. Building on existing research, we draw a clear link between national cultural dimensions and entrepreneurship, using a new model that arranges different cultural dimensions in groups based on their particular function: political, social, or individual (PSI-model) and that distinguishes between values and practices where relevant. The PSI-model provides a coherent theoretical framework on which different cultural dimensions and their impact on entrepreneurship can be analysed, allowing for particular attention to be drawn to social practices and social values. This paper contributes to a better understanding of the relationship between culture and entrepreneurship, providing empirical evidence of how specific cultural dimensions influence entrepreneurship. The findings are of relevance from a policy perspective and can be used to generate practical recommendations for national institutions interested in promoting entrepreneurship and entrepreneurial activities. The findings are also transferable to other fields related to national cultural dimensions such as level of innovation, investment, budgeting etc.
The links between innovativeness as a driver of economic performance, and the determinants of innovativeness have been investigated by management scholars and economists for decades, focusing mostly on “hard factors” as investment in research and development, or education. Focusing on a relatively neglected, but in times of globalization even more important aspect, the infuence of cultural characteristics on innovativeness, we apply diferent econometric models to test for links between cultural tightness and looseness on the one hand, and national innovativeness on the other hand. We fnd that cultural tightness—in the sense of homogenous and intolerant societies—has a negative link to national innovativeness, while cultural looseness—in the sense of tolerant and diverse societies—displays a positive link to national innovativeness.
In order to determine demand as precisely as possible, many businesses use several forecasting methods. The aim of forecasting is to determine future demand based on data from the past. The use of a specific method is not always easy and depends on a number of factors. To help prospective engineers find the most suitable forecasting method for a specific problem, a forecasting game was developed and then evaluated.
The paper describes the design and the evaluation of the forecasting game. In order to provide an overview of existing forecasting methods, the first part of the paper examined the mathematical fundamentals of eight different forecasting methods and outlined the requirements for their application.
The second part of the paper describes the creation of a forecasting game in which prospective engineers can learn how to determine the appropriate forecasting method for specific scenarios. In total, five scenarios covering the three different demand patterns (linear/stationary, trend and seasonal) as well as the forecast quality methods were developed and can be played through. For each scenario, the player has to choose the most appropriate forecasting method for a specific problem based on a self-created task description. To make the game as realistic as possible, a fictional company with a background story was designed.
The last part was about the evaluation of the forecasting game. For the evaluation, a student survey to gather the opinions of the students was conducted. The results of the student survey show an overall positive evaluation of the simulation game by the students. However, the test also showed that the game takes a certain amount of time. Since only 15 of the approximately 30 students who tested the game participated in the evaluation, the results are not significant.
This paper explores the tensions in team creativity. The tensions in team creativity are based on a tension between originality and effectiveness in the standard definition of creativity. To display the tensions in team creativity, the value square (“Wertequadrat”) developed by Schulz von Thun (1998) is used which balances a value with its countervalue. The author identifies tensions for cohesion, consensus and conformity. Cohesion is described as a tension between team diversity and team safety, consensus as a tension between constructive controversy and participatory decision-making and conformity as a tension between support for innovation and task orientation. Finally, the connection of individual and team creativity is described as an interplay between solitary and interactive components.
There is a popular saying in German: Innovation is when the market shouts “Hooray!”. Thus, a new idea is only as good as its diffusion into the addressed social system. The question is what affects the adoption or rejection of a new idea. Carsten Deckert shares his experience on the main innovation resistances and on ways to increase the acceptance of new ideas. He talks about which perceived attributes of innovations are conducive to the rate of adoption of an innovation and which are characteristics of failed innovations.
The definition of individual creativity is based on a tension between novelty on the one side and usefulness respectively appropriateness on the other side. The paper explores how this tension pervades the stage and componential theories of creativity. To achieve this, the so called value square (“Wertequadrat”) developed by Helwig (1967) and Schulz von Thun (1998)is used which balances a value with its countervalue to analyze creativity. The author identifies tensions of action and inaction, expertise and mindfulness, precision and ambiguity as well as immersion and detachment permeating the creative process and the components of creativity. As a conclusion a morphological box for creativity is presented which allows one to show which combination of characteristics of the tensions support different stages of creativity. Furthermore implications for development and time management are discussed.
The standard definition of creativity is based on a tension between originality and effectiveness. Borrowing from the wave-particle duality in physics one could say that there is an originality-effectiveness duality at work for creativity. The paper explores how this tension pervades Amabile's (1997) componential theory of organizational creativity with the components organizational motivation, management practices (including work assignment and work control) and resources. As a method the so called value square (" Wertequadrat ") developed by Helwig (1967) and Schulz von Thun (1998) is used which balances a value with its countervalue. The author identifies a tension of corporate tradition and corporate change for organizational motivation, a tension of skills and challenges for work assignment, a tension of management by control and management by loss of control for work control as well as a tension of organizational efficiency and organizational slack for resources. Additionally different implications of these tensions for the resistance of a company to creativity, for an organizational climate conducive to creativity as well as for resource allocation in creative endeavours are discussed.
The task of the Center for Language Research is to provide content-based English language instruction for students of computer science and engineering. As such, we find ourselves at the confluence of many of the streams currently running through the English Language Teaching profession, including English for Science and Technology (EST), English for Academic Purposes (EAP), English for Specific Purposes (ESP), Computer-assisted language learning (CALL), content-based instruction, and multimedia applications in foreign language pedagogy. This paper describes our initial attempts to construct a number of World Wide Web pages where students will be able to study EST, EAP, and computer science topics on their own in a multimedia environment.
This dissertation, written for the course Master of European Social Policy Analysis – National University of Ireland Maynooth - , shows the context or so-called framework within which the medical social work service in two different welfare states: Ireland and Germany operates. This means the societal context as a whole, the health system in general (macro-level) and the hospital setting (mezzo-level) in particular. The idea of this publication is to give a short overview of the historic development of medical social work (micro-level) in Ireland and Germany and some background information about what medical social work is. The time frame examined starts from the 1980s up to present. The main questions to be answered are: What are the interdependencies between the macro-, mezzo- and micro-level? Have changes in the health system in general and the hospitals in particular influenced medical social work and if so how? What are the similarities and differences in the two countries?
Spatial precision and recall indices to assess the performance of instance segmentation algorithms
(2022)
Through constant technical progress, multi-user virtual reality is transforming towards a social activity that is no longer only used by remote users, but also in large-scale location-based experiences. We evaluate the usage of realtime-tracked avatars in co-located business-oriented applications in a "guide-user-scenario" in comparison to audio only instructions. The present study examined the effect of an avatar-guide on the user-related factors of Spatial Presence, Social Presence, User Experience and Task Load in order to propose design guidelines for co-located collaborative immersive virtual environments. Therefore, an application was developed and a user study with 40 participants was conducted in order to compare both guiding techniques of a realtime-tracked avatar guide and a non-visualised guide with otherwise constant conditions. Results reveal that the avatar-guide enhanced and stimulated communicative processes while facilitating interaction possibilities and creating a higher sense of mental immersion for users. Furthermore, the avatar-guide appeared to make the storyline more engaging and exciting while helping users adapt to the medium of virtual reality. Even though no assertion could be made concerning the Task Load factor, the avatar-guide achieved a higher subjective value on User Experience. Due to the results, avatars can be considered valuable social elements in the design of future co-located collaborative virtual environments.
The German banking system and the global financial crisis: causes, developments and policy responses
(2009)
Germany’s banking sector has been severely hit by the global financial crisis. In a German context as of February, 2009, this paper reviews briefly the structure of the banking industry, quantifies effects of the crisis on banks and surveys responses of economic policy. It is argued that policy design needs to enhance transparency and enforce the liability principle. In addition, economic policy should not eclipse principles of competition policy.
Magneto-hydrothermal triple-convection in a W-shaped porous cavity containing oxytactic bacteria
(2022)
Bioconvective heat and mass transport phenomena have recently been the subject of interest in diverse fields of applications pertaining to the motion of fluids and their thermophysical properties. The transport processes in a system involving triple convective phenomena, irregular geometry, and boundary conditions constitute a complex phenomenon. This work aims to explore the mixed thermo-bioconvection of magnetically susceptible fluid containing copper nanoparticles and oxytactic bacteria in a novel W-shaped porous cavity. The buoyant convention is generated due to the isothermal heating at the wavy bottom wall, whereas the mixed convection is induced due to the shearing motion of the top-cooled sliding wall. Furthermore, the bioconvection is induced due to the manifestation of oxytactic bacteria or organisms. The inclined sidewalls are insulated. The geometry is packed with water based Cu nanoparticle mixed porous structure, which is subjected to a magnetizing field acted horizontally. The complex transport equations are transformed into nondimensional forms, which are then computed using the finite volume-based developed code. The coupled triple-convective flow physics are explored for a wide range of involved controlling parameters, which could provide helpful insight to the system designer for its proper operation. The shape of geometry can be considered one of the important parameters to control the heat and mass transport phenomena. In general, the influence of amplitude (δ) is more compared to the waviness number (m) of the undulations. The magnitude of heat (Nu) and mass (Sh) transfer rate for the W-shaped cavity is high compared to conventional square and trapezoidal-shaped cavities. The output of the analysis could be very helpful for the designer for modeling devices operating on nanotechnology-based bioconvection, microbial fuel cells, and others.
Applicability of Aeroacoustic Scaling Laws of Leading Edge Serrations for Rotating Applications
(2020)
CFX 11.0 is a Computational Fluid Dynamics (CFD) program for simulating the behavior of systems involving fluid flow, heat transfer, and other related physical processes. It works by solving the equations of fluid flow (in a special form) over a region of interest, with specified (known) conditions on the boundary of that region. This tool is used here to analyse the straw cutter which is used to comminute the straw which is left standing in the field after stripper header has stripped the grains from the crops. Stripper Header is a new technique different to conventional harvester machines and it is still under development and testing. It works on the principle in which grains are first stripped off from the head of the standing crop which helps in much reduced intake freeing up the separation systems to handle a larger volume of grains. But with this, the new problem of the disposal of the long, uncut straw left after stripping of grains arose. So a straw cutter is used after the stripper header stage in this Combine Harvester, where the rotor is equipped with pressed steel blades and rotates towards the crop, i.e., it cuts and lifts the straw over the top. This technique is environment friendly because previously farmers would have to burn the long, uncut straw standing in the fields while in this case mulched straw can be used for min-till systems. This rotor based straw cutting machine is analysed here which helps us in increasing power efficiency and comminution rate and quality of cut straw particles. Here fluid flow simulation has been preferred over particle simulation: - CFX 10.0 tool is not very effective for particle simulation techniques and computation time is increased considerably. - It’s very hard to realize particle simulation in CFX 10.0 because we have to define size and properties of each particle and besides this wall conditions would have to be defined differently for every boundary. - Besides this, it’s hard to realize cutting effect with straw particles in CFX 10.0 which otherwise would be comminuted in real life conditions. - The results obtained from fluid simulation are validated using experimental results and found to be nearly the same which clearly contradicts any need of performing particle simulation.
Computational investigation of hemodynamics in hardshell venous reservoirs: A comparative study
(2019)
Extracorporeal circulation using heart‐lung‐machines is associated with a profound activation of corpuscular and plasmatic components of circulating blood, which can also lead to deleterious events such as systemic inflammatory response and hemolysis. Individual components used to install the extracorporeal circulation have an impact on the level of activation, most predominantly membrane oxygenators and hardshell venous reservoirs as used in extracorporeal systems. The blood flows in two different hardshell reservoirs are computationally investigated. A special emphasis is placed on the prediction of an onset of transition and turbulence generation. Reynolds‐averaged numerical simulations (RANS) based on a transitional turbulence model, as well as large eddy simulations (LES) are applied to achieve an accurate prediction. In the LES analysis, the non‐Newtonian behavior of the blood is considered via the Carreau model. Blood damage potential is quantified applying the Modified Index of Hemolysis (MIH) based on the predicted flow fields. The results indicate that the flows in both reservoirs remain predominantly laminar. For one of the reservoirs, considerable turbulence generation is observed near the exit site, caused by the specific design for the connection with the drainage tube. This difference causes the MIH of this reservoir to be nearly twice as large as compared to the alternative design. However, a substantial improvement of these performance criteria can be expected by a local geometry modification.
A swirling pulverized coal flame is computationally investigated. A Eulerian–Lagrangian formulation is used to describe the two-phase flow. Turbulence is modelled within a RANS (Reynolds averaged numerical simulation) framework. Four turbulence viscosity- (TV) based models, namely the standard k-ε model, realizable k-ε model, renormalization group theory k-ε model, and the shear stress transport k-ω model are used. In addition, a Reynolds stress transport model (RSM) is employed. The models are assessed by comparing the predicted velocity fields with the measurements of other authors. In terms of overall average values, the agreement of the predictions to the measurements is observed to be within the range 20–40%. A better performance of the RSM compared to the TV models is observed, with a nearly twice as better overall agreement to the experiments, particularly for the swirl velocity. In the second part of the investigation, the resolution of the discrete particle phase in modelling the turbulent particle dispersion (TPD) and particle size distribution (SD) is investigated. Using the discrete random walk model for the TPD, it is shown that even five random walks are sufficient for an accuracy that is quite high, with a less than 1% mean deviation from the solution obtained by thirty random walks. The approximation of the measured SD is determined by a continuous Rosin–Rammler distribution function, and inaccuracies that can occur in its subsequent discretization are demonstrated and discussed. An investigation on the resolution of the SD by discrete particle size classes (SC) indicates that 12 SC are required for an accuracy with a less than 1% mean deviation from the solution with 18 SC. Although these numbers may not necessarily be claimed to be sufficiently universal, they may serve as guidance, at least for SD with similar characteristics
The settling velocities of helminth eggs of three types, namely Ascaris suum (ASC), Trichuris suis (TRI), and Oesophagostomum spp. (OES), in clean tap water are computationally determined by means of computational fluid dynamics, using the general-purpose CFD software ANSYS Fluent 18.0. The previous measurements of other authors are taken as the basis for the problem formulation and validation, whereby the latter is performed by comparing the predicted sink velocities with those measured in an Owen tube. To enable a computational treatment, the measured shapes of the eggs are parametrized by idealizing them in terms of elementary geometric forms. As the egg shapes show a variation within each class, “mean” shapes are considered. The sink velocities are obtained through the computationally obtained drag coefficients. The latter are defined by means of steady-state calculations. Predicted sink velocities are compared with the measured ones. It is observed that the calculated values show a better agreement with the measurements, for ASC and TRI, compared to the theoretical sink values delivered by the Stokes theory. However, the observed agreement is still found not to be very satisfactory, indicating the role of further parameters, such as the uncertainties in the characterization of egg shapes or flocculation effects even in clean tap water.
The late immersion of multi-touch sensitive displays enables the use of tangibles on multi-touch screens. There a several wide spread and/or sophisticated solutions to fulfill this need but they seem to have some flaws. One popular system at the time of writing is an overlay frame that can be placed on a normal display with the corresponding size. The frame creates a grid with infrared light emitting diodes. The disruption of this grid can be detected and messages with the positions are sent via usb to a connected computer. This system is quite robust in matters of ambient light insensitivity and also fast to calibrate. Unfortunately it is not created with the recognition of tangibles in mind and printed patterns can not be resolved. This article summarizes an attempt to create fiducials that are recognized by an infrared multi-touch frame as fingers. Those false fingers are checked by a software for known patterns. Once a known pattern (= fiducial) has been recognized its position and orientation are send with the finger positions towards the interactive software. The usability is tested with an example application where tangibles and finger touches are used in combination.
Reconciling work and family life is one of the main issues of welfare state policies in the fields of childcare and long-term care. On that account, policy and research are focused almost exclusively on women – often on the reconciliation of work and childbearing – and social policy at the state level. In our study, we concentrate on men who reconcile gainful employment with elderly care, and we include the company level – a level of analysis often neglected in traditional theoretical approaches and typologies of comparative welfare state research. In Germany, during the last decade, the share of sons who are responsible for taking care of their elderly relatives has remarkably increased. In our qualitative research, we carried out comparative case studies in eleven German companies. We conducted around 60 interviews with male employees caring for an elderly relative, as well as with members of the works councils and human resources departments in different kinds of companies. We analysed which familial, social, professional, legal as well as occupational resources are central for these men, how they cope with reconciling work and care, and which gaps in the welfare system they identify. Interestingly, the overwhelming majority of the caring sons claim not to have problems in reconciling work and care, although they spend significant time on caring. In this paper we try to explain this pattern by looking at their typical care arrangements. We found that while women tend to organise employment around care, men rather seem to organise care around their employment. Given the feminist critique of the “adult worker model” this is an interesting result and needs theoretical reflection. Do men have the solution to the care-blindness of the “adult worker model” without falling into the “cold modern model of care”? Which resources are mainly used in “adult worker care arrangements”? Where are the limits of the approach?
Music-related decision-making encompasses a wide range of behaviours including those associated with listening choices, composition and performance, and decisions involving music education and therapy. Although research programmes in psychology and economics have contributed to an improved understanding of music-related behaviour, historically, these disciplines have been unconnected. Recently, however, researchers have begun to bridge this gap by employing tools from behavioural economics. This article contributes to the literature by providing a discussion about the benefits of using behavioural economics in music-decision research. We achieve this in two ways. First, through a systematic review, we identify the current state of the literature within four key areas of behavioural economics-heuristics and biases, social decision-making, behavioural time preferences, and dual-process theory. Second, taking findings of the literature as a starting point, we demonstrate how behavioural economics can inform future research. Based on this, we propose the Behavioural Economics of Music (BEM), an integrated research programme that aims to break new ground by stimulating interdisciplinary research in the intersection between music, psychology, and economics.