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Consequences of the consistent exact solution of Einstein{Cartan equation on the time dependence of Hubble parameter are discussed. The torsion leads to a space and time-dependent expansion parameter which results into nontrivial windows of Hubble parameter between diverging behavior.
Only one window shows a period of decreasing followed by increasing time dependence. Provided a known cosmological constant and the present values of Hubble and deceleration parameter this
changing time can be given in the past as well as the ending time of the windows or universe. The comparison with the present experimental data allows to determine all parameters of the model.
Large-scale spatial periodic structures appear. From the metric with torsion outside matter, it is seen that torsion can feign dark matter.
Family firm performance through transformational CEO leadership and familiness-related team forces
(2024)
Purpose. The purpose of this study is to test the role of familiness-related team forces induced by the CEO of family firms. In particular, we report on the effects of the transformational leadership style of CEOs on their respective top-management team (TMT) and firm performance when viewed through a familiness lens.
Design/methodology/approach. Survey measures were taken from a snowballed
sample of 72 CEOs of German family firms as well as from 245 members of their TMTs. We tested the aggregated firm-level data with objective performance indicators of the firms they led.
Findings. Support was obtained for the three hypothesized team-force mediations and the four-path mediation model. The relationship between CEO’s transformational style and
high family-firm performance is found to be serially mediated by TMT cohesion, behavioral integration and efficacy. Together, these three types of collective forces are assumed to be the
familiness effect of a family-member CEO with a transformational leadership style.
Originality. With our model we quantitatively tested familiness-type forces vis-à-vis firm performance. Theoretical and practical implications of these findings are discussed.
Wastewater generation model to predict impacts of urine separation on wastewater treatment plants
(2024)
Wastewater treatment plants (WWTPs) are under increasing pressure to enhance resource efficiency and reduce emissions into water bodies. The separation of urine within the catchment area may be an alternative to mitigate the need for costly expansions of central WWTPs. While previous investigations assumed a spatially uniform implementation of urine separation across the catchment area, the present study focuses on an adapted stochastic wastewater generation model, which allows the simulation of various wastewater streams (e.g., urine) on a household level. This enables the non-uniform separation of urine across a catchment area. The model is part of a holistic modelling framework to determine the influence of targeted urine separation in catchments on the operation and emissions of central WWTPs, which will be briefly introduced. The wastewater generation model is validated through an extensive sampling and measurement series.
Results based on observed and simulated wastewater quantity and quality for a catchment area of 366 residents for two dry weather days indicate the suitability of the model for wastewater generation and transport modelling. Based on this, four scenarios for urine separation were defined. The results indicate a potential influence of spatial distribution on the peaks of total nitrogen and total phosphorus.
Potential and risks of water reuse in Brandenburg (Germany) – an interdisciplinary case study
(2024)
For Brandenburg, a region in Germany with increasing water shortage and drought events, water reuse can counteract competition scenarios between drinking water supply, agricultural irrigation, and industrial use. Centralized and decentralized sources for reclaimed water are found to potentially substitute 245 or 28% of irrigation water, respectively, in agriculture production in Brandenburg. For such a reuse scenario, the
fate of organic micropollutants is examined for diatrizoate (DZA) and carbamazepine (CBZ). Retention in local sandy soil and transfer into roots and leaves of arugula are analyzed in lysimeter studies and greenhouse pot experiments. Vertical transport was found for DZA and accumulation in or on arugula roots with a root concentration factor of 1,925+34% but a low bioconcentration factor due to intrinsic molecule properties. CBZ was not found to be mobile in the sandy soil but accumulates in arugula roots and leaves by factors of 70+7% and 155+12%, respectively. Further research on potential plant uptake and groundwater enrichment for more substances is highly recommended as well as tertiary wastewater treatment prior to water reuse.
Supply chains often match the supply of labour to uncertain demand by using precarious workprecarious workers. This increases flexibility and lowers costs for the supply chain by shifting risk to the workers and costs to society. Supply chains are maximizing profits, often literally, on the backs of their workers by creating serious negative externalities for society. We address this issue using a powerpower perspective because powerpower is asymmetrically oriented against workers in many supply chain contexts. This allows us to identify examples of how to reverse this trend and shift powerpower back to workers. The goal is to get to where stakeholders understand the costs and limited benefits of precarity, where we can separate the notion of flexibility from low costs, and where through a combination of incentives, policy, social norms of ethical behaviour, and consumer action, we can get to a better place than where we are now.
An important, often overlooked group of workers that HR managers have trouble reaching are those intentionally disconnected from personal digital devices. That is, workers in manufacturing facilities, distribution centers, secure areas, or locations where employers ban workers from bringing their own devices. We explore the engagement problem for these intentionally disconnected workers. We outline a disruptive HR strategy in these work contexts. We then focus on implementation, testing a simple digital platform prototype that can serve as an entry for existing, disruptive HR management engagement tools (e.g. chatbots, HR analytics) in these settings. Our exploratory findings suggest engagement is a problem for these workers and these simple tools can be an effective strategy to help HR managers improve engagement. We conclude that simple digital solutions aimed at engaging this underserved segment of the workforce can have disruptive yet positive effects for workers, HR managers and shareholders.
When simulating and optimizing urban energy systems, the focus is usually on minimizing financial costs or greenhouse gas (GHG) emissions. As energy systems transition towards a growing share of renewable energy sources and technological complexity, environmental impacts that affect more than just GHG emissions, such as resource extractions, water and land use impacts or impacts on human health, are becoming increasingly relevant.
To address this gap, this thesis introduces an automated coupling procedure for energy system modeling (ESM) and life cycle assessment (LCA). The implementation includes general recommendations and a practical coupling of the Open Energy Modelling Framework (oemof) based Spreadsheet Energy System Model Generator (SESMG) with a suitable LCA software.
The LCA procedure involves goal and scope definition, inventory analysis, impact assessment, and interpretation. To adapt these steps to different energy system models, the LCA should be attributional, process-based and territorial. Further, the openLCA software by Green-Delta serves as a suitable soft-linking tool. The main challenge of the coupling procedure is the inventory analysis. Data collection faces limitations, reasoned by the commercialization and high maintenance efforts in open-source databases. After evaluating free databases, the Prozessorientierte Basisdaten für Umweltmanagement-Instrumente (ProBas) database of the Umweltbundesamt emerged as the most suitable choice for the coupling. However, also this database lacks traceability of datasets or compatibility with a comprehensive impact assessment.
A generalized framework for the LCA application of energy systems was developed. The framework is based on an ex-post LCA assessment that considers the combination of the two approaches within every step of the procedure. Main considerations of this framework include automatic calculations of the inventory analysis and the impact assessment for different energy technologies, as well as calculations summed up for all technologies of energy system scenarios. Further, technology mapping and data harmonization are essential considerations for the automatic coupling and double counting of impacts needs to be avoided.
Subsequently, the framework is realized with the adaption of the SESMG. Its database-independent realization allows compatibility with different databases in openLCA. For the selected ProBas database, the tool can be used with different available energy technologies. The use of unit processes is encouraged for data harmonization. Result interpretation of the LCA (in general or with the SESMG) should not solely focus on the absolute values of the impact categories, but rather on the comparative strengths among scenarios and technologies.
The successful application to a reference single-family building using the ProBas database revealed varied environmental impacts, in relation with a higher reduction in GHG emissions, with an increase of 11 % in terrestrial acidification impacts in the emission-optimized scenario. These findings emphasize a more comprehensive perspective on environmental impacts and provide a valuable validation of the developed methodology.
Future research should include the improvement of data harmonization, the inclusion of more datasets for a more customized analysis of energy systems and more applications. The coupled approach offers a promising avenue for gaining deeper insights into optimizing urban energy systems.
This study investigates the role of individual differences in channel choice and switching behavior in a multichannel environment using latent class analysis on data from 1512 customers. Psychographic variables from five domains (risk attitudes, cognitive ability, motivation, personality, and decision-making style) serve as covariates for multichannel customer behavior. We identify six segments that differ significantly on six psychographic variables (readiness to take risks, need for cognition, autotelic and instrumental need for touch, and rational and intuitive decision-making styles). The results advance the theory-building of multichannel customer behavior and present insights for proactively managing customer journeys of distinct segments.
Toward a notation for modeling value driver trees: Classification development and research agenda
(2024)
In-depth analysis of customer journeys to broaden the understanding of customer behaviors and expectations in order to improve the customer experience is considered highly relevant in modern business practices. Recent studies predominantly focus on retrospective analysis of customer data, whereas more forward-directed concepts, namely predictions, are rarely addressed. Additionally, the integration of robotic process automation (RPA) to potentially increase the efficiency of customer journey analysis is not discussed in the current field of research. To fill this research gap, this paper introduces “customer journey mining”. Process mining techniques are applied to leverage digital customer data for accurate prediction of customer movements through individual journeys, creating valuable insights for improving the customer experience. Striving for improved efficiency, the potential interplay of RPA and customer journey mining is examined accordingly. The research methodology followed is based on a design science research process. An initially defined customer journey mining artifact is operationalized through an illustrative case study. This operationalization is achieved by analyzing a log file of an online travel agency functioning as an orientation for researchers and practitioners while also evaluating the initially defined framework. The data is used to train seven distinct prediction models to forecast the touchpoint a customer is most likely to visit next. Gradient-boosted trees yield the highest prediction accuracy with 43.1%. The findings further indicate technical suitability for RPA implementation, while financial viability is unlikely.
Against the setting of an increasing need for innovation and low margins, companies in the logistics
sector are facing highly competitive pressure. One field with high potential for optimization lies within
damage quotas. The use of big data analytics or data mining represents a promising approach to face
this challenge. However, within supply chain management, data mining is hardly being researched on
regarding damage quotas and thus not being utilized to its full possible extend. At the current time it
seems to predominantly be used for route and utilization optimization while the analysis of delivery
damages is hardly considered.
The aim of this research is therefore to showcase an initial approach for data mining in logistics to predict
delivery damage probabilities and to validate this by means of a multiple case study research. To create
a sound basis for evaluation, the groundwork is laid out based on CRISP-DM by the analysis of reference
data (German road-cargo market).
As a central result it is noted that data mining can systematically be used to help reducing the damages
by forecasting the probabilities of damages occurring during transport in dependence of different factors.
The approach can be utilized across different markets as long as sufficient data tracking delivery
damages is being collected within a company. Challenges arise in the field of air- and sea-freight.
The urge for personalisation and the rise of technological advancements
in the 21st century is pushing for more innovative marketing strategies. As such, this dissertation examines the impact of personality-tailored
campaigns (PTC) and how it affects purchasing decisions among
Generation Z, focusing on theoretical and practical implications.
A conceptual framework for the process of personality-tailored marketing has been developed to provide tangible value for businesses of
various industries in particular the fragrance, smartphone, and food
industry.
This working paper addresses the effectiveness of compliance management systems (CMS). The objective is to answer the question whether CMS are effective, and to consider the limits of compliance. For this purpose, the highly legalistic topic is considered in the context of business ethics and behavioural economic foundations. The review of effectiveness is based on the seven basic components set out in the Assurance Standard of the Institut der Wirtschaftsprüfer in Deutschland e. V. [Institute of Public Auditors in Germany, Incorporated Association] (IDW AssS 980).
To answer this question, reference is made to the three levels of business ethics and to selected behavioural economics concepts. For example, performance pressure, peer pressure and variable compensation schemes encourage opportunistic behaviour. It is argued that corporate compliance depends significantly on the behaviour of single individuals and their environment. Especially in the context of economic activity and competition, compliance cannot be equated to morality and ethics, or be expected as a matter of course. On the whole, the interdisciplinary consideration of corporate compliance demonstrates a natural limit whenever ethical and moral standards are contrary to economic interests.
A novel approach for ventilation systems is a periodically varying supply air flow rate, the so-called unsteady mode of operation. So far, useful effects of this unsteady operating mode have been observed, but the effect mechanisms are still unknown. In this manuscript, simulations using the recently proposed k-ω-ζ - f model implemented in a sensitized RANS computational framework for a cuboid room with swirl diffusers are compared and validated with PIV measurements.
This article explores educational media pedagogies that are predominantly non-digital, but nonetheless timely and influential. Design Thinking, Making, and Serious Play are three distinct yet interrelated approaches to problem-solving, resilience and innovation that have gained increased traction in education over the past decade. We explore the similarities and differences between these playful, experiental pedagogies and provide an overview of how these approaches can be integrated effectively into education settings. Finally, we provide transferable examples, including evaluation results, from a weeklong workshop series at Muenster University of Applied Sciences conducted in Spring 2022. The article serves as a theoretically informed practical guide for educators and practitioners seeking to select, implement and evaluate playful pedagogies. It contributes to the understanding of underlying principles, characteristics, potential impact and limitations.
Stormwater tree pits with storage elements enable the irrigation of urban trees and can potentially act as decentralized rainwater retention basins. This paper mainly focuses on analyzing this potential. Field tests were conducted to investigate the irrigation behavior and the storage effect of a storm water tree pit system using Perl hoses as irrigation elements over a period of two years.
The rainfall, storage volumes, and soil moisture within the employed planting pit were measured.
With the help of system modeling, the retention ability of the storm water tree pit system was analyzed. The available storage volume was sufficient to irrigate trees for several days. During the measurement period, about 15% of the inflowing rainwater was fed to the root zone of the tree. With practical storage volumes of 200 to 300 m3/ha, a remarkable amount of water from heavy rainfall could be completely stored, thus significantly reducing the risk of flooding. The retention effect and irrigation behavior largely depend on the soil conditions and the technical possibilities of the equipment supplying the root area (in this case, Perl hoses). Further investigations are required to determine the influence on the growth conditions of trees and optimize of the system for discharge into the root zone.
The extended quasiparticle picture is adapted to non-Fermi systems by suggesting a Pad´e approximation which interpolates between the known small scattering-rate expansion and the deviation from the Fermi energy. The first two energy-weighted sum rules are shown to be fulfilled independent of the interpolating function for any selfenergy. For various models of one-dimensional Fermions scattering with impurities the quality of the Pad´e approximation for the spectral function is demonstrated and the reduced density matrix or momentum distribution is reproduced not possessing a jump at the Fermi energy. Though the two-fold expansion is necessary to realize the spectral function and reduced density, the extended quasiparticle approximation itself is sufficient for the description of transport properties due to cancellation of divergent terms under integration.
The T-matrix approximation leads to the delay time as the time two particles spend in a correlated state. This contributes to the reduced density matrix and to an additional part in the conductivity which is presented at zero and finite temperatures. Besides a localization at certain impurity concentrations, the conductivity shows a maximum at small temperatures interpreted as onset of superconducting behaviour triggered by impurities. The Tan contact reveals the same universal behaviour as known from electron-electron scattering.
The Educational Journal of Renewable Energy Short Reviews (EduJRESR, formally published as ‘EGU Journal of Renewable Energy Short Reviews’) is a teaching project rather than a regular scientific journal.
To publish in this journal, it is a premise to take part in the master course wind power, hydro power and biomass usage at the department of Energy, Building Services and Environmental Engineering of the Münster University of Applied Sciences.
Students receive an equivalent of 2.5 credit points (European Credit Transfer and Accumulation System – ECTS) for their engagement in the course and for publishing a short review article of at most 3 000 words in this periodical. The publication process closely mimics the typical publication procedure of a regular journal.
The peer-review process, however, is conducted within the group of course-participants.
Although being just an exercise, we think that publishing the outcome of this course in a citable manner is not only promoting the motivation of our students, but may also be a helpful source of introductory information for researchers and practitioners in the field of renewable energies. We encourage students to write their articles in English, but this is not mandatory. The reader will thus find a few articles in German language.
To further encourage students practicing English writing, perfect grammar is not part of the assessment.
We especially thank our students for working with LATEX on Overleaf, although LATEX is new to some of them. In this way, the editorial workload was reduced to a minimum. We also thank our students for sharing their work under the creative commons attribution licence (CC-BY). We appreciate their contribution to scientific information, being available to every person of the world, almost without barriers. We also thank the corresponding authors and publishers of the cited work, for granting permission.
Wind energy plays a major role among renewable
energies. Its expansion is therefore important in order
to achieve the climate targets. Repowering is an
important element in the expansion of wind energy.
On the one hand, it offers a solution for many wind
turbines in Germany that are no longer subsidised due
to their age. On the other hand, modern turbines are
significantly more powerful and enable more efficient
land utilisation. This article provides an overview of
the most important aspects of onshore repowering.
There is a lot to consider when repowering wind turbines.
The legal situation for repowering aims to
be improved through simplified authorisation procedures.
Even though efforts are being made by the
government, there is still room for improvement. The
repowering potential is also dependent on the various
distance regulations to residential buildings in
the federal states. These regulations might also be
improved in the future. Another aspect is the remuneration,
which is now closer to market developments
due to the market premium model. It is also subject
to greater competition as a result of the tendering
process. At the same time, interest rates and turbine
prices have risen, which creates economic challenges
for the operators of future wind farms. Last but not
least, repowering also depends on public acceptance.
This is also to be regulated by law in the future.
As Germany aims to increase its utilization of wind
power, the potential threat to bird populations due
to this expansion is a controversial issue. This paper
aims to collect data on the magnitude of bird strikes
on wind turbines, review existing protective measures
and explore innovative solutions. After a thorough
examination of the literature, it was concluded that
although the impact on bird populations is significant,
it may be overemphasized in popular debates. This
statement is not final as further research is necessary
to assess the impact of bird strikes and explore new
solutions. Comprehensive studies on this specific topic
in Germany are limited, which makes a thorough evaluation
challenging. While there are measures in place
to protect species that may be negatively impacted, it
is possible that these measures will not be adequate
for all of them. While several innovative methods
are under examination, progress in testing and implementation
is slow. Lastly, an information problem
was identified. Since the topic is highly politicized
and polarizing, it is crucial to provide the public with
accessible and reliable information on the discussed
themes. This is currently not the case due to a lack
of data and missing information campaigns.
The upscaling of wind turbines has been increasing in
recent years and will continue to play a significant role
in the future, as it allows for the reduction of electricity
generation costs. Various challenges arise when it
comes to upscaling. This article summarizes the technical
challenges associated with upscaling wind turbines
and presenting their problem-solving approaches
and research trends based on other reviews. It was
found that the most frequently cited challenges are
related to individual components, such as rotor blades,
drive train, generator, tower, and noise impact.
For rotor blades, the challenges are increased flexibility,
more aeroelastic vibrations, increased wear,
interferences with radar and transportation difficulties.
Proposed solutions include the use of carbon-fiber
blades, prebending, novel paints, and for transportation,
segmented rotor blades and on-site manufacturing.
In the gearbox, torque increases, leading to
higher weight and susceptibility to errors. As a result,
the trend is moving towards gearless systems with
permanent magnet synchronous generators. Transportation
is the major issue with towers, which can
be resolved with on-site manufacturing. In terms of
noise emission, reducing aerodynamic noise plays the
most significant role.
This paper outlines the three main areas relevant
to dismantling: the rotor blades, hub and nacelle,
the tower and the foundation. The paper discusses
the dismantling procedures, including the removal of
the top structure, the tower and the foundation, and
evaluates various methods of dismantling the tower,
such as modular dismantling, collapse blasting, folding
blasting, wrecking ball demolition and hydraulic
ram demolition. The assessment of these methods
in practice and the potential challenges and considerations
for future dismantling, particularly as wind
turbine heights increase, are also addressed.
This review paper provides an initial overview of the
state of the art of common corrosion protection methods
for offshore wind turbines. The functions of the
individual corrosion protection methods and their
interaction are explained. In addition, the specific corrosion
protection of different zones and components
of an offshore wind turbine will be discussed. Finally,
some information is given on current and possible
future developments in this subject area.