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Experimental qualification and sensitivity study of antipodal patch antenna structures for orientation independent detection of partial discharges

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High Voltage 2024年第3期9卷 674-684页

作者： kerstin Friebe Frank Jenau TU Dortmund University Institute of High Voltage EngineeringDortmundGermany

Partial discharge diagnosis is an important part of monitoring and diagnosing compo-nents of the power transmission *** different patch antenna structures for the detection of partial discharges are *** patch antennas,which are realisable in a variety of geometric structures,are already the subject of *** offer the advantage of contactless detection without intervention in the test object or the measuring circuit,and also offer the possibility of alignment independent detection compared to directional ***,it is important and required to examine different structures extensively at the same measurement setup and to compare their *** achieve this,four different configurations of patch antenna structures based on basic geometries all in antipodal design are realised:a logarithmic periodic structure,a Hilbert fractal structure and two tapered slot *** are exposed to the same conditions on a special and unique measurement *** the main aspect,the performance of orientation independent detection of partial discharges patch antennas with varying distance and rotation in relation to the partial discharge source as well as the operating bandwidth is *** rate the structures,an evaluation scheme is created and a sensitivity matrix is generated.

关键词： antenna patch structures

Localization of rare earth ions in an inhomogeneous magnetic field toward their magnetic separation

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Journal of Rare Earths 2022年第10期40卷 1598-1605页

作者： Barbara Fritzsche Zhe Lei Xuegeng Yang kerstin Eckert TU Dresden Institute of Process Engineering and Environmental Technology01062DresdenGermany Helmholtz-Zentrum Dresden-Rossendorf(HZDR) Institute of Fluid DynamicsBautzner Landstrasse 40001328DresdenGermany

Efficient extraction and recycling methods are an important issue for rare earth elements(REE). The significant differences in their magnetic moments make magnetic separation a promising step. Although the magnetic field gradient manipulation of ions seemed to be impossible, the robust enrichment of some paramagnetic RE ions was found in the vicinity of the magnet. The studies in recent years resolved the physical paradox of why, despite the Brownian motion of the ions, there is a reproducible enrichment of RE ions in magnetic field gradients. The existence of trigger process and energy barrier was ***, these studies usually used only high paramagnetic ions, e.g., Dy(Ⅲ) or Ho(Ⅲ). This work verifies the theory of the possible magnetic separation for 8 different rare earth ions, respectively. For this purpose, concentration distribution in rare earth chloride solutions were measured using a MachZehnder interferometer. The magnetic field was assured by a Halbach configuration to enhance the effect. The results show the classification of RE solutions into 2 classes: Class I contains the REs with low magnetic moment, whereas Class II includes the REs of high magnetic moment. Only the latter group shows the enrichment of ions in the vicinity of the magnet which encourages the implementation of magnetic separation into existing hydrometallurgical technology to enhance the selectivity of REE.

关键词： Magnetic separation Paramagnetic rare earth ions Enrichment Halbach array Interferometry Aqueous solution

Regulation of hepatic blood flow:The hepatic arterial buffer response revisited

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World Journal of Gastroenterology 2010年第48期16卷 6046-6057页

作者： Christian Eipel kerstin Abshagen Brigitte Vollmar Institute for Experimental Surgery Medical FacultyUniversity of Rostock

The interest in the liver dates back to ancient times when it was considered to be the seat of life processes. The liver is indeed essential to life,not only due to its complex functions in biosynthesis,metabolism and clearance,but also its dramatic role as the blood volume reservoir. Among parenchymal organs,blood flow to the liver is unique due to the dual supply from the portal vein and the hepatic artery. Knowledge of the mutual communication of both the hepatic artery and the portal vein is essential to understand hepatic physiology and pathophysiology. To distinguish the individual importance of each of these inflows in normal and abnormal states is still a challenging task and the subject of on-going research. A central mechanism that controls and allows constancy of hepatic blood flow is the hepatic arterial buffer response. The current paper reviews the relevance of this intimate hepatic blood flow regulatory system in health and disease. We exclusively focus on the endogenous interrelationship between the hepatic arterial and portal venous inflow circuits in liver resection and transplantation,as well as inflammatory and chronic liver diseases. We do not consider the hepatic microvascular anatomy,as this has been the subject of another recent review.

关键词： Hepatic blood flow Hepatic arterial buffer response Liver

Spatial distributions of tropical tree species in northern Vietnam under environmentally variable site conditions

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Journal of Forestry Research 2014年第2期25卷 257-268页

作者： Nguyen Hong Hai kerstin Wiegand Stephan Getzin Department of Ecosystem Modelling Faculty of Forest Sciences and Forest EcologyUniversity of Goettingen Faculty of Agricultural Techniques Hatay Community College UFZ Helmholtz Centre for Environmental Research–UFZ Department of Ecological Modeling

Ecological interactions of species and thus their spatial pat- terns may differ between homogeneous and heterogeneous forests. To account for this, techniques of point pattern analysis were implemented on mapped locations of tree individuals from two 1-ha tropicalforest plots in Vietnam. We analyzed the effect of environmental heterogeneity on tree distributions; spatial distribution patterns of dominant species; inter-specific associations; and conspecific associations between life stages. Our analyses showed that： environmental conditions were homo- geneous at plot 1 but heterogeneous at plot 2; in both plots, all six domi- nant species were aggregated at various scales up to 30 m, and tree spe- cies were aggregated at larger scales in the homogeneous site than in the heterogeneous site; attraction between pairs of species was remarkably higher at the homogeneous site while negative associations were more frequent in the heterogeneous site; some species, H. kurzii, T. ilicifolia （homogeneous plot） and D. sylvatica, S. wightianum （heterogeneous plot） showed a lack of early life-stage individuals near conspecific adults. Moreover, additional clustering of young individuals was independent from conspecific adults, except D. sylvatica in both sites. These findings are consistent with the Janzen-ConneU hypothesis. Overall, habitat het- erogeneity influences spatial patterns and inter-specific associations of the tree species and evidences of self-thinning are shown in most species.

关键词： environmental heterogeneity spatial point pattern analysis tropical evergreen forest northern Vietnam.

Plant Surfaces:Structures and Functions for Biomimetic Innovations

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Nano-Micro Letters 2017年第2期9卷 116-155页

作者： Wilhelm Barthlott Matthias Mail Bharat Bhushan kerstin Koch Nees Institute for Biodiversity of Plants Rheinische Friedrich-Wilhelms University of BonnVenusbergweg 2253115 BonnGermany Institute of Crop Science and Resource Conservation(INRES)–Horticultural Science Rheinische Friedrich-Wilhelms University of BonnAuf dem Hugel 653121 BonnGermany

An overview of plant surface structures and their evolution is presented. It combines surface chemistry and architecture with their functions and refers to possible biomimetic applications. Within some 3.5 billion years biological species evolved highly complex multifunctional surfaces for interacting with their environments: some 10 million living prototypes(i.e., estimated number of existing plants and animals) for engineers. The complexity of the hierarchical structures and their functionality in biological organisms surpasses all abiotic natural surfaces: even superhydrophobicity is restricted in nature to living organisms and was probably a key evolutionary step with the invasion of terrestrial habitats some 350–450 million years ago in plants and insects. Special attention should be paid to the fact that global environmental change implies a dramatic loss of species and with it the biological role models. Plants, the dominating group of organisms on our planet, are sessile organisms with large multifunctional surfaces and thus exhibit particular intriguing *** and superhydrophobicity are focal points in this work. We estimate that superhydrophobic plant leaves(e.g., grasses) comprise in total an area of around 250 million km^2, which is about 50% of the total surface of our planet. A survey of structures and functions based on own examinations of almost 20,000 species is provided, for further references we refer to Barthlott et al.(Philos. Trans. R. Soc. A 374: 20160191, 1). A basic difference exists between aquatic nonvascular and land-living vascular plants; the latter exhibit a particular intriguing surface chemistry and architecture. The diversity of features is described in detail according to their hierarchical structural order. The first underlying and essential feature is the polymer cuticle superimposed by epicuticular wax and the curvature of single cells up to complex multicellular structures. A descriptive terminology for t

关键词： Bionics Superhydrophobicity Hierarchical structuring Lotus effect Salvinia effect Evolution

Improving Complex Problem-Solving in Emergency Response: A Study of the Fire and Rescue Service in Sweden

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International Journal of Disaster Risk Science 2024年第6期15卷 867-878页

作者： Lotta Vylund Joel Jacobsson Tove Frykmer kerstin Eriksson Division of Safety and Transport RISE Research Institutes of Sweden Greater Gothenburg Fire and Rescue Service Southern?lvsborg's Rescue Service Association Division of Fire Safety Engineering Lund University Division of Risk Management and Societal Safety Lund University Division of Built Environment RISE Research Institutes of Sweden

This study explored how the Swedish Fire and Rescue Service identifies problems and implements necessary actions during complex problem-solving in emergencies, aiming to increase our understanding of this process. Primary and secondary data from large-scale fire events were analyzed, including semistructured interviews and incident reports. The concept of “possibility space” is applied to identify factors aff ecting complex problem-solving. This refers to the scope of action available at a specific point in time for a particular operation. The study identified eight factors, including problem identification,incident development, capability, collaboration, management, legal framework, logistics, and time available, that could either decrease or increase the scope of action. The findings contribute to an increased understanding of complex problem-solving in real-world environments and suggest that the possibility space could be a valuable tool for practitioners in enhancing problem-solving during emergency response.

关键词： Emergency response Fire and Rescue Service Possibility space Problem space Problem-solving Sweden

Gender-specific associations between coronary heart disease and other chronic diseases: cross-sectional evaluation of national survey data from adult residents of Germany

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Journal of Geriatric Cardiology 2019年第9期16卷 663-670,I0002-I0005页

作者： Marie-Isabel K Murray kerstin Bode Peter Whittaker Department of Cardiology University Hospital Frankfurt am Main Frankfurt Germany Department of Electrophysiology Heart Center Leipzig Leipzig Germany Cardiovascular Research Institute and Department of Emergency Medicine Wayne State University Detroit MI USA

Background Combinations of coronary heart disease(CHD) and other chronic conditions complicate clinical management and increase healthcare costs. The aim of this study was to evaluate gender-specific relationships between CHD and other comorbidities. Methods We analyzed data from the German Health Interview and Examination Survey(DEGS1), a national survey of 8152 adults aged 18-79 years. Female and male participants with self-reported CHD were compared for 23 chronic medical conditions. Regression models were applied to determine potential associations between CHD and these 23 conditions. Results The prevalence of CHD was 9%(547 participants): 34%(185) were female CHD participants and 66%(362) male. In women, CHD was associated with hypertension(OR = 3.28(1.81-5.9)), lipid disorders(OR = 2.40(1.50-3.83)), diabetes mellitus(OR = 2.08(1.24-3.50)), kidney disease(OR = 2.66(1.101-6.99)), thyroid disease(OR = 1.81(1.18-2.79)), gout/high uric acid levels(OR = 2.08(1.22-3.56)) and osteoporosis(OR = 1.69(1.01-2.84)). In men, CHD patients were more likely to have hypertension(OR = 2.80(1.94-4.04)), diabetes mellitus(OR = 1.87(1.29-2.71)), lipid disorder(OR = 1.82(1.34-2.47)), and chronic kidney disease(OR = 3.28(1.81-5.9)). Conclusion Our analysis revealed two sets of chronic conditions associated with CHD. The first set occurred in both women and men, and comprised known risk factors: hypertension, lipid disorders, kidney disease, and diabetes mellitus. The second set appeared unique to women: thyroid disease, osteoporosis, and gout/high uric acid. Identification of shared and unique gender-related associations between CHD and other conditions provides potential to tailor screening, preventive, and therapeutic options.

关键词： Chronic diseases Comorbidities Gender Heart disease Risk factors Survey data

BLE beacon-based floor detection for mobile robots in a multi-floor automation laboratory

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Transportation Safety and Environment 2024年第2期6卷 114-121页

作者： Haiping Wu Hui Liu Thomas Roddelkopf kerstin Thurow Institute of Artificial Intelligence&Robotics(IAIR) Key Laboratory of Traffic Safety on Track of Ministry of EducationSchool of Traffic and Transportation EngineeringCentral South UniversityChangshaHunan 410075China Center of Life Science Automation(celisca) 18119 Rostoc kGerman y Institute of Automation(IAT) University Rostock18119 RostockGermany

As an important task of multi-floor localization,floor detection has elicited great *** infrastructures like Wi-Fi and Bluetooth Low Energy(BLE)play important roles in floor ***,most floor detection research tends to focus on data modelling but pays little attention to the data collection system,which is the basis of wireless infrastructure-based floor *** fact,the floor detection task can be greatly simplified with proper data collection system *** this paper,a floor detection solution is developed in a multi-floor life science automation lab.A data collection system consisting of BLE beacons,a receiver node and an Internet of Things(IoT)cloud is *** features of the BLE beacon under different settings are evaluated in detail.A mean filter is designed to deal with the fluctuation of the received signal strength indicator data.A simple floor detection method without a training process was implemented and evaluated in more than 100 floor detection *** time delay and floor detection accuracy under different settings are ***,floor detection is evaluated on the H20 multi-floor transportation *** sensor nodes are installed on the robot at different *** floor detection performance with different installation heights is *** experimental results indicate that the proposed floor detection method provides floor detection accuracy of 0.9877 to 1 with a time delay of 5s.

关键词： BLE beacon floor detection multi-floor automation transportation robot

Hepatitis C virus reinfection after liver transplant: New chances and new challenges in the era of direct-acting antiviral agents

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World Journal of Hepatology 2015年第3期7卷 532-538页

作者： kerstin Herzer Guido Gerken Department of Gastroenterology and Hepatology University Hospital Essen Department of General Visceral and Transp-lantation Surgery University Hospital Essen

The first interferon-free regimens have been approved for the treatment of patients with chronic hepatitis C virus(HCV). In the liver transplant(LT) setting, these regimens are expected to have an important effect, because graft loss due to HCV recurrence is a serious problem after LT. The response to the hitherto conventional treatment with pegylated interferon and ribavirin is poor. The significantly better responserates achieved with boceprevir-based and telaprevirbased triple therapy have led to better graft and patient survival rates, but severe drug interactions with immunosuppressants limit the feasibility of this therapy for LT patients. With the approval of sofosbuvir in January 2014, of simeprevir in May 2014, and of daclatasvir in August 2014, three antiviral agents are now available and promise to be applicable without relevant adverse effects or negative interactions with immunosuppressants. Thus, 2014 marks the beginning of a new era of treatment options for HCV recurrence after LT. Although safety and efficacy studies of several interferon-free regimens for patients with HCV recurrence after LT have achieved good preliminary results, reports of clinical experiences with LT patients are scarce. The lack of randomized studies, the small number of enrolled and carefully selected patients, and the heterogeneity of these studies make the results questionable. Real-life experiences are eagerly awaited so that clinicians can estimate the usefulness and the pitfalls of these new regimens. Additionally, the high costs of these agents may limit their accessibility for many patients. The aim of this review is to summarize the current experience with and the expectations of the new direct-acting antiviral agents for LT patients.

关键词： Hepatitis C virus Liver transplant Interferon Sofosbuvir Simeprevir Daclatasvir