Brandenburg University of Technology Cottbus - Senftenberg
Recent publications
Using two laboratory-scale conceptual fluid dynamic models of the mid-latitude atmospheric circulation we investigate the statistical properties of pointwise temperature signals obtained in long experiment runs. We explore how the average “equator-to-pole” temperature contrast influences the range and the jump distribution of extreme temperature fluctuations, the ratio of the frequencies of rapid cooling and warming events, and the persistence of “weather” in the set-ups. We find simple combinations of the control parameters—temperature gradient, rotation rate and geometric dimensions–which appear to determine certain scaling properties of these statistics, shedding light on the underlying dynamics of the Rossby wave-related elements of the mid-latitude weather variability.
Programmable Logic Controllers (PLCs) are indispensable in Critical Infrastructures (CIs) and Industrial Control Systems (ICSs). The increasing demand for enhanced cost-effectiveness and production efficiency has driven automation manufacturers to integrate PLC based applications and systems with external networks, such as Internet. Unfortunately, this connectivity has exposed systems to potential malicious attacks from motivated adversaries. Addressing this pressing issue necessitates a comprehensive summary of ongoing research related to PLCs and their related systems. This summary should classify these systems based on disclosed vulnerabilities, potential threats, and proposed security solutions, catering to both scientists and industrial engineers. While several recent surveys have reviewed and discussed PLC security and related topics, they often fell short of covering all essential aspects comprehensively. Furthermore, prior surveys tended to focus on analyzing vulnerabilities at the system level, overlooking the vulnerabilities specific to PLCs themselves. Consequently, their findings failed to effectively secure current operational systems or propose improved solutions for future PLC designs. In this paper, we bridge this research gap by providing a detailed review of all aspects concerning the security of PLCs and related systems. This includes vulnerabilities, potential attacks, security solutions including digital forensics. We aim to offer a precise analysis, addressing the shortcomings of previous studies. Finally, we conclude the paper by presenting our recommendations tailored for PLC manufacturers, researchers and engineers. We hope that these recommendations will contribute to the development of more secure PLCs in the future.
Zusammenfassung Die digitale Transformation findet im Gesundheitswesen statt und erfordert eine um digitale Kompetenzen erweiterte berufliche Qualifikation. Einige Fakultäten haben hierfür erste Curricula implementiert. Für den primärärztlich orientierten Brandenburgischen Modellstudiengang Medizin (BMM) wird ein angepasstes Curriculum unter Berücksichtigung der Bedarfe des Lehrpraxennetzwerks des BMM entwickelt. Hierzu wurden die Lehrpraxen mittels Fragebogenstudie befragt, welche digitalen Technologien in der Patient*innenbehandlung genutzt bzw. künftig eingesetzt werden und um welche Kompetenzen die ärztliche Ausbildung ergänzt werden sollte. Es zeigte sich, dass digitale Themen und Technologien mehrheitlich bekannt waren, die Einbindung über gesetzliche Anforderungen jedoch in Konkurrenz zu zeitlichen und monetären Ressourcen stand. Zudem zeigten sich Unsicherheiten in Bezug auf den Umgang mit digitalen Medien, hierbei insbesondere beim Hintergrundwissen zu rechtlichen und technologischen Aspekten des Datenschutzes. Aber auch die Relevanz des direkten Kontakts zwischen Ärzt*innen und Patient*innen wurde besonders betont. Die Einbindung der Lehrpraxen stellt die Grundlage dafür dar, bedarfsorientierte Curricula für die Aus‑, Fort- und Weiterbildung zu entwickeln. Es zeigte sich, dass hier vor allem die zentralen Leitmotive Datenschutz sowie Arzt-Patienten-Beziehung berücksichtigt werden sollten, um das Potenzial der Digitalisierung im Gesundheitswesen für die Patient*innenversorgung bestmöglich zu nutzen. Ziel sollte es sein, die digitalen Technologien als sinnvolle Ergänzung zu den ärztlichen Kernkompetenzen zu integrieren, damit dem medizinischen Personal mehr Zeit für wertschöpfende Tätigkeiten bleibt und die Patient*innen wiederum eine verbesserte Erfahrung und damit Zufriedenheit erleben.
1. The consequences of land-use change for savanna biodiversity remain undocumented in most regions of tropical Asia. One such region is western Maharashtra, India, where old-growth savannas occupy a broad rainfall gradient and are increasingly rare due to agricultural conversion and afforestation. 2. To understand the consequences of land-use change, we sampled herbaceous plant communities of old-growth savannas and three alternative land-use types: tree plantations, tillage agriculture and agricultural fallows (n = 15 sites per type). Study sites spanned 457 to 1954 mm of mean annual precipitation-corresponding to the typical rainfall range of mesic savannas globally. 3. Across the rainfall gradient, we found consistent declines in old-growth savanna plant communities due to land-use change. Local-scale native species richness dropped from a mean of 12 species/m 2 in old-growth savannas to 8, 6 and 3 species/m 2 in tree plantations, fallows and tillage agriculture, respectively. Cover of native plants declined from a mean of 49% in old-growth savannas to 27% in both tree plantations and fallows, and 4% in tillage agriculture. Reduced native cover coincided with increased cover of invasive species in tree plantations (18%), fallows (18%) and tillage agriculture (3%). 4. In analyses of community composition, tillage agriculture was most dissimilar to old-growth savannas, while tree plantations and fallows showed intermediate dis-similarity. These compositional changes were driven partly by the loss of characteristic savanna species: 65 species recorded in old-growth savannas were absent in other land uses. Indicator analysis revealed 21 old-growth species, comprised mostly of native savanna specialists. Indicators of tree plantations (nine species) and fallows (13 species) were both invasive and native species, while the two indicators of tillage agriculture were invasive. As reflective of declines in savanna communities, mean native perennial graminoid cover of 27% in old-growth savan-nas dropped to 9%, 7%, and 0.1% in tree plantations, fallows and tillage agriculture , respectively. 5. Synthesis. Agricultural conversion and afforestation of old-growth savannas in India destroys and degrades herbaceous plant communities that do not spontaneously recover on fallowed land. Efforts to conserve India's native biodiversity should encompass the country's widespread savanna biome and seek to limit conversion of irreplaceable old-growth savannas.
This paper investigates the changes in time use, working conditions and subjective time wealth during the COVID-19 pandemic in Germany. Our analysis draws on panel data collected before and during the first lockdown among 786 employees. It employs a recently developed scale on time wealth which has been suggested as a comprehensive measure to capture the subjective experience of time. We provide separate analyses according to gender and essential occupation. First-difference regressions are applied to examine how changes in time use and changes in working conditions during the lockdown affected subjective time wealth. Our results show a general growth in time wealth during the lock-down which is, among other factors, driven by a decline in work hours and an increase in sleep duration. We also find positive effects on time wealth from decreased time pressure at work, more autonomy in organising one's working day, and an improved reconciliation of work and private life. This study contributes to existing research by identifying key aspects how to improve time wealth among employees.
In the field of catalysis, dry reforming, that is, methane reforming with , is in the focus due to growing environmental concerns about oil depletion and global warming with a desire to produce synthesis gas. However, this process can lead to the formation of carbon, which can cause catalyst deactivation, especially at industrial conditions. Nevertheless, the key to develop a more coke‐resistant catalyst is a better comprehension of the reforming process at a molecular level. Regardless of all the investigations available in literature, the detailed path for the conversion of methane to syngas and carbon remains a controversial issue. Another problem in setting up a reaction mechanism is the difficulty to define the thermodynamic data for intermediate surface species and this leads to the development of thermodynamic consistent surface reaction mechanisms in literature where the thermodynamic data are not used to calculate the rate coefficients of the reverse reactions. Rather the Arrhenius parameters for the forward as well as backward reactions are explicitly given in the reaction mechanism to establish thermodynamic equilibrium. In this investigation, a kinetically consistent detailed surface reaction mechanism is developed which consists of 26 reversible reactions with the help of a one‐dimensional model, LOGEcat. Our previous work constructs the basis of the present investigation. Further, a detailed sensitivity analysis of reversible reactions and reaction pathways is performed to understand the mechanism better. The mechanism is validated for dry reforming of methane over nickel catalyst, however, it can also be used for other processes, such as, steam reforming and partial oxidation. The mechanism is tested by comparing the simulation results with the literature experiments and simulations in a wide range of temperature. The new developed kinetically consistent surface reaction mechanism is able to accurately express the dry reforming of methane over the nickel catalyst for complete range of temperature and also provide a useful insight into the key rate determining steps.
Turbulent mixing is an omnipresent phenomenon that constantly affects our everyday life and plays an important role in a variety of industrial applications. The simulation of turbulent mixing poses great challenges, since the full resolution of all relevant length and time scales is associated with an immense computational effort. This limitation can be overcome by only resolving the large‐scale effects and completely model the sub‐grid scales. The development of an accurate sub‐grid mixing model is therefore a key challenge to capture all interactions in the sub‐grid scales. At this place, the hierarchical parcel‐swapping (HiPS) model formulated by A.R. Kerstein [J. Stat. Phys. 153, 142–161 (2013)] represents a computationally efficient and scale‐resolving turbulent mixing model. HiPS mimics the effects of turbulence on time‐evolving, diffusive scalar fields. In HiPS, the diffusive scalar fields or a state space is interpreted as a binary tree structure, which is an alternative approach compared to the most common mixing models. Every level of the tree represents a specific length and time scale, which is based on turbulence inertial range scaling. The state variables are only located at the base of the tree and are treated as fluid parcels. The effects of turbulent advection are represented by stochastic swaps of sub‐trees at rates determined by turbulent time scales associated with the sub‐trees. The mixing only takes places between adjacent fluid parcels and at rates consistent with the prevailing diffusion time scales. In this work, the HiPS model formulation for the simulation of passive scalar mixing is detailed first. Preliminary results for the mean square displacement, passive scalar probability density function (PDF) and scalar dissipation rate are given and reveal the strengths of the HiPS model considering the reduced order and computational efficiency. These model investigations are an important step of further HiPS advancements. The integrated auxiliary binary tree structure allows HiPS to satisfy a large number of criteria for a good mixing model. From this point of view, HiPS is an attractive candidate for modeling the mixing in transported PDF methods.
Direct-band-gap Germanium-Tin alloys (Ge1-xSnx) with high carrier mobilities are promising materials for nano- and optoelectronics. The concentration of open volume defects in the alloy, such as Sn and Ge vacancies, influences the final device performance. In this article, we present an evaluation of the point defects in molecular-beam-epitaxy (MBE)- grown Ge1-xSnx films treated by post-growth nanosecond-range pulsed laser melting (PLM). Doppler broadening – variable energy positron annihilation spectroscopy (DB-VEPAS) and variable energy positron annihilation lifetime spectroscopy (VE-PALS) are used to investigate the defect nanostructure in the Ge1-xSnx films exposed to increasing laser energy density. The experimental results, supported with ATomic SUPerposition (ATSUP) calculations, evidence that after PLM, the average size of the open volume defects increases, which represents a raise in concentration of vacancy agglomerations, but the overall defect density is reduced as a function of the PLM fluence. At the same time, a finger print of dislocations and Ge vacancies decorated by Sn is emerging from the positron annihilation spectroscopy (PAS) analysis. Moreover, it is shown that the PLM reduces the strain in the layer, while dislocations are responsible for trapping of Sn and formation of small Sn-rich-clusters.
Brunei Darussalam is a small country located in Southeast Asia, divided into four administrative regions, the districts of Brunei-Muara, Tutong, Kuala Belait, and Temburong. The country has enormous natural and water resources. Rainfall is an essential phenomenon in Brunei Darussalam. Brunei’s saline seawater and significant rivers play an important role in protecting the natural landscapes and developing and fertilizing the apartment lands. Tutong District is located in the country’s middle and shows proximity to the South China Sea to the west. The Tutong River basin carries water from the Rambai region to the South China Sea, with a tidal distance upstream covering the Tutong catchment area. The monsoon rains and extreme rainfall resulting from climate change will likely cause challenges in managing increased river flow, causing flooding in the Tutong District floodplain. Floods or flash floods are the most common natural disasters that frequently affect Brunei Darussalam and the low-lying flood-prone areas of Tutong District. The trend of wet days in Brunei is increasing, which can be seen from rainfall data and flooding conditions in four districts in Brunei. Tutong District has experienced several floods over the past two decades. In 2014 alone, over 115 cases of flooding and 105 landslides were reported. This study examines the trends and patterns of flooding and flash floods in Tutong District. The impact of climate change in the affected areas in Tutong District is mapped. The study will seek alternative environmental solutions to develop sustainable flood mitigation strategies for sustainable natural hazards measures and management in Brunei Darussalam.
Background Hip and knee osteoarthritis is common and leads to pain, stiffness, and disability. Clinical practice guidelines provide recommendations based on the best available evidence to assist health care professionals and patients in clinical decision-making. However, several studies have reported a gap between guideline recommendations and clinical practice in physiotherapy. Improved implementation strategies and the removal of existing barriers may facilitate the transfer of evidence into clinical practice and contribute to optimized quality of care. Objective This paper presents the protocol for a study that aims to describe the current physiotherapy practice in patients with hip and knee osteoarthritis and to investigate physiotherapists’ adherence to clinical practice guidelines, to identify and specify barriers to and facilitators of guideline use and implementation, and to develop and pilot test a theory-based tailored implementation intervention aiming to increase guideline use in osteoarthritis care. Methods The research project is divided into 4 parts. During the first part, we will conduct a nationwide web-based survey among German physiotherapists to evaluate the current management of hip and knee osteoarthritis and to evaluate whether treatment aligns with guideline recommendations. Subsequently, semistructured interviews will be conducted to specify barriers to and facilitators of guideline use and implementation among physiotherapists (part 2). On the basis of these findings, in part 3, we will develop a theory-driven implementation intervention based on the Theoretical Domains Framework and the Behavior Change Wheel, which will be evaluated in a controlled pilot study in terms of effectiveness, feasibility, and acceptability (part 4). Results Data collection of the web-based survey among German physiotherapists (part 1) was completed in December 2021. The semistructured interviews (part 2) were conducted between January and September 2023. Recruitment of physiotherapy practices to participate in the development of the implementation intervention is expected to start in January 2024. Conclusions This research project aims to develop a theory-driven implementation intervention to facilitate the transfer of evidence from hip and knee osteoarthritis guidelines in physiotherapy practice. We hypothesize that successful implementation will lead to increased guideline adherence in physiotherapists, which in turn will improve the quality of care. The results from our project will provide valuable knowledge concerning the development process and effectiveness of tailored implementation interventions. International Registered Report Identifier (IRRID) DERR1-10.2196/47834
There are scarce studies on bystanders' responses to racist hate speech. The present study was rooted in the general aggression model to examine the direct and indirect associations between witnessing racist hate speech and bystanders’ active defending behaviors. Moreover, we examined if these associations varied as a function of the immigration background of bystanders. The sample included 3,225 7th, 8th, and 9th graders (51.7% girls, 37.2% with an immigrant background) from 40 schools in Switzerland and Germany. A multilevel mediation path model revealed that witnessing racist hate speech negatively predicted bystanders’ active defending. It also had indirect associations with bystanders’ active defending via low levels of empathy. Finally, associations were not observed in students with an immigrant background. The findings regarding the potential contribution of these results to preventing hate speech in school are discussed.
Non-state sustainability initiatives, such as eco-certification and voluntary sustainability standards, are eco-friendly, market-driven, and privately managed initiatives that garner support from concerned stakeholders in the blue economy. Consequently, these initiatives play pivotal roles in enhancing resource sustainability within the seafood sector. However, despite their importance, the intricacies of how non-state seafood sustainability schemes operate within the blue economy remain unclear. Therefore, this study examines the interactions of these non-state actors within institutional, social, and ecological contexts to improve common resource management. This study is based on a comprehensive review of secondary data from the literature to delineate its scope. In recent years, there has been an increase in non-state initiatives advocating for sustainable fisheries and the sustainable use of natural blue resources. These initiatives claimed to exhibit established institutional, social, and ecological synergies, yet the foundational principles guiding them remain underexplored. It is essential to note that addressing the long-term sustainability issues in the socioeconomic-ecological systems requires the resilience shift of non-state initiatives. Thus, non-state institutions must strengthen their resilience management capabilities by collaborating with other actors, networks, and institutions to promote sustainable development. This collaboration fosters societal understanding of these resilience factors, which are portrayed in this study. Finally, effective resource management necessitates a delicate balance between economic considerations and environmental preservation, supporting the sustainability of common resources. It is imperative to deepen our understanding of the interplay between the socioeconomic and ecological facets of these systems to ensure that our environmental laws serve as the proper framework for effective resource regulation and management.
The main focus of this work is to investigate the impact of varying milling times (2 to 18 h) on the structural and mechanical properties of the developed Ti-Nb-Mo alloy. The morphology, phase composition, microstructure, and mechanical behavior of milled and sintered Ti-25Nb-25Mo alloy samples were characterized systematically using x-ray diffraction, scanning electron microscope, optical microscope, and Vicker microhardness. It was noted that the quantity of the β-Ti phase increased as the milling time increased. After 12 h of milling, the synthesized alloys exhibited a spherical morphology and texture with homogeneous distribution. The milled alloys' structural evolution and morphological changes were found to be dependent on their milling duration. Morphological analysis revealed that the crystallite size and mean pore size decreased when the milling duration increased, reaching minimum values of 51 nm and < 1 μm, after 12 and 18 h respectively. As the milling time increased, the grain size decreased, resulting in an increase in density, microhardness, and elastic modulus. Ti-25Nb-25Mo will presents good anti-wear ability and higher resistance to plastic deformation due to enhanced mechanical characteristics (H/E, and H³/E²). Hence, the developed Ti-25Nb-25Mo alloys with reduced elastic modulus and desirable mechanical properties were found to be a promising option for biomedical applications.
Cancer sonodynamic therapy (SDT) is the therapeutic strategy of a high-frequency ultrasound (US) combined with a special sonosensitizer that becomes cytotoxic upon US exposure. The growing number of newly discovered sonosensitizers and custom US in vitro treatment solutions push the SDT field into a need for systemic studies and reproducible in vitro experimental set-ups. In the current research, we aimed to compare two of the most used and suitable SDT in vitro set-ups—“sealed well” and “transducer in well”—in one systematic study. We assessed US pressure, intensity, and temperature distribution in wells under US irradiation. Treatment efficacy was evaluated for both set-ups towards cancer cell lines of different origins, treated with two promising sonosensitizer candidates—carbon nanoparticle C60 fullerene (C60) and herbal alkaloid berberine. C60 was found to exhibit higher sonotoxicity toward cancer cells than berberine. The higher efficacy of sonodynamic treatment with a “transducer in well” set-up than a “sealed well” set-up underlined its promising application for SDT in vitro studies. The “transducer in well” set-up is recommended for in vitro US treatment investigations based on its US-field homogeneity and pronounced cellular effects. Moreover, SDT with C60 and berberine could be exploited as a promising combinative approach for cancer treatment.
Due to the open-cast mining activities, a large area in the Lusatian region in eastern Germany was left unproductive. Robinia psedoacacia L. was planted within different ages in that large area as a short rotation coppice for woody biomass cultivation as well as to increase soil nutrients by increasing plant phosphorous (P) availability, accumulating organic matter input and biological nitrogen fixation. In this experiment, soil chemical analysis has been done to investigate the improvement and status of P in the mining soil depending on the ages of plantation (16, 17, 18 and 27 years old) of Robinia psedoacacia L. The results show a higher P sorption in the oldest site, and the average P sorption capacity (PSC) obtained in the oldest site was 21.0 mmol Kg , which was 3-4 times higher than the youngest site. However, all the values were very low compared to the optimum plant growth level, and low P desorption indicates a low level of plant-available P in the soil. The lower sorption properties with the small amount of oxalate iron (Fe ) and oxalate aluminium (Al ) indicate the general P deficiency in the soil. However, a comparison from a previous study on the same experimental areas shows that not much improvement has occurred in soil P, and the change in soil P dynamics is very low. Nevertheless, the improvement of the values with increasing ages of Robinia psedoacacia L. indicates that further improvement may be expected in soil nutrients with time.
Strategic resilience is the capacity of organizations to proactively transform and renew through innovation to minimize the effects of unknown future crises. In this context, we know that cooperation plays an essential role as an external innovation strategy, and cooperation projects with start-ups related to innovation are one specific way to implement strategic change. However, research does not provide deeper insights into the process, outcomes, and success conditions of such projects. To help fill this research gap, we use the cases of two established firms using cooperation projects with start-ups related to innovation to enhance their strategic resilience. Based on an in-depth empirical investigation, we developed a framework that describes the specifics of those cooperation projects along their course (i.e., before cooperation, entry-phase into cooperation, during cooperation, and after cooperation) and resulting direct and indirect resilience benefits for the established firms. Thereby, the relationship quality (i.e., balance between formal and informal procedures, improvisation mindset, and appreciation and prioritization) turned out to be a central condition for resilience to emerge from those projects. Our framework illustrates how strategic resilience can arise from cooperation projects with start-ups related to innovation and which factors are particularly important in this context. It thus can be used as a guideline for the successful implementation of strategic resilience in practice as well as a basis for future research on the role of cooperation in strategic resilience.
Energy-efficient, low-voltage, and low-power millimeter-wave (mm-wave) radars are gaining increasing attention for battery-powered commercial applications. In this article, the design of a low-power V -band radar sensor based on a transceiver (TRX) front-end chip using 1.5 V supply in an advanced SiGe BiCMOS technology with 300 GHz $\textit{f}\textsubscript{T}$ and 500 GHz $\textit{f}\textsubscript{max}$ is presented. The monostatic front-end chip utilizes low-voltage low-power circuit-level design techniques to achieve measured 9-dBm transmitter (TX) output power and 27-dB receiver (RX) gain with a simulated 3.8-dB noise figure (NF) consuming a total of only 72 mW in continuous mode. The TRX chip is used to build a radar sensor, which is experimentally verified in an anechoic chamber. The low-power sensor achieves a 46-dB dynamic range and a ranging precision better than 3.4 $\mu$ m measured with a static target at 1 m. Phase measurements using the low-power radar in the continuous-wave (CW) mode demonstrate that submillimeter movements can be tracked, and notably main vital parameters of a human can be determined accurately. Experimental results show that the performance of the proposed low-power TRX front-end chip is very competitive with designs in modern CMOS technologies.
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4,031 members
Jens Mittelbach
  • University Library
Herwig Winkler
  • Chair of Production and Operations Management
Christoph Hinz
  • Lehrstuhl Hydrologie
Jörg Acker
  • Department of Physical Chemistry
Platz der Deutschen Einheit 1, 03046, Cottbus, Brandenburg, Germany
Head of institution
Prof. Dr. Christiane Hipp
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