Background:B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific immunoglobulins.Exercise alters B cell counts and immunoglobulin l...Background:B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific immunoglobulins.Exercise alters B cell counts and immunoglobulin levels,but evidence-based conclusions on potential benefits for adaptive immunity are lacking.This systematic review assessed current literatures on the impact of acute exercise and exercise training on B cells,immunoglobulins,and markers of secretory immunity in human biofluids.Methods:According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines,MEDLINE,Web of Science,and Embase were searched on March 8,2023.Non-randomized controlled trials and crossover trials investigating the impact of acute exercise or exercise training on B cell counts and proportions,immunoglobulin levels,salivary flow rate,or secretory immunoglobulin A secretion rate were included.Quality and reporting of exercise training studies were assessed using the Tool for the Assessment of Study Quality and reporting in Exercise.Study characteristics,outcome measures,and statistically significant changes were summarized tabularly.Results:Of the 67 eligible studies,22 applied acute exercise and 45 applied exercise training.All included outcomes revealed significant alterations over time in acute exercise and exercise training context,but only a few investigations showed significant differences compared to control conditions.Secretory and plasma immunoglobulin A levels were most consistently increased in response to exercise training.Conclusion:B cell-related outcomes are altered by acute exercise and exercise training,but evidence-based conclusions cannot be drawn with high confidence due to the large heterogeneity in populations and exercise modalities.Well-designed trials with large sample sizes are needed to clarify how exercise shapes B cell-related immunity.展开更多
Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering.The latter is particularly true for slope stability assessment,where the effects of uncertainty ...Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering.The latter is particularly true for slope stability assessment,where the effects of uncertainty are synthesized in the so-called probability of failure.This probability quantifies the reliability of a slope and its numerical calculation is usually quite involved from a numerical viewpoint.In view of this issue,this paper proposes an approach for failure probability assessment based on Latinized partially stratified sampling and maximum entropy distribution with fractional moments.The spatial variability of geotechnical properties is represented by means of random fields and the Karhunen-Loève expansion.Then,failure probabilities are estimated employing maximum entropy distribution with fractional moments.The application of the proposed approach is examined with two examples:a case study of an undrained slope and a case study of a slope with cross-correlated random fields of strength parameters under a drained slope.The results show that the proposed approach has excellent accuracy and high efficiency,and it can be applied straightforwardly to similar geotechnical engineering problems.展开更多
Detection of liquid mixture of different volume ratio is very important in industrial purposes. The paper reports a sensing mechanism of binary liquid mixture for different volume fraction, based on the measurement of...Detection of liquid mixture of different volume ratio is very important in industrial purposes. The paper reports a sensing mechanism of binary liquid mixture for different volume fraction, based on the measurement of refractive index of the mixture. Here, a highly sensitive liquid filled core Photonic Crystal Fiber structure has been proposed to detect liquid mixture solution. Numerical investigation of the proposed structure is carried out by employing full vectorial Finite Element Method (FEM).展开更多
Background:The side effects of the FIFA 11+program on performance have not been generally reviewed.The objective of this study was to synthesize the literature on the effects of the 11+on players’performance.Methods:...Background:The side effects of the FIFA 11+program on performance have not been generally reviewed.The objective of this study was to synthesize the literature on the effects of the 11+on players’performance.Methods:Five online databases(PubMed,Scopus,ScienceDirect,Springer,and Google Scholar)were searched(from April 2006 to March 2022)using predefined keywords and sub-keywords.The potential references were primarily recorded through Endnote and imported to Covidence.Out of the 123 references screened by 2 blinded researchers through the software,59 full texts were assessed for eligibility,33 of which were ultimately included.The quality of the studies and the risk of bias were then assessed.Study ID,title,place,aim,design,start/end dates,population description,study criteria,statistical analysis,and outcomes were extracted.Results:Studies were conducted on male and female players aged 10-32 years old.The quality of the studies was moderate to high,and except for unclear bias for blinding outcome assessment,the risk of bias for all domains was low.Long-term application of the 11+improved most biomechanical measures and physiological responses except for lower extremity stability,ankle evertors time latency,ankle dorsiflexion,and proprioception.Conversely,the 11+showed acute negative effects on physical performance compared to dynamic warm-ups and non-significant effects on technical abilities.Conclusion:Mid-to-long-term implementation of the 11+improved the maj ority of biomechanical and a couple of physical measure s but showed no effects on technical skills.Precaution must be observed for using the 11+before competitions,as it could acutely decrease physical/technical performance.Given the contradictory nature of the literature,further studies should evaluate the short-to-mid-term effects of the 11+.Further studies are required to address ankle responses to the 11+intervention.展开更多
Partial discharge diagnosis is an important part of monitoring and diagnosing compo-nents of the power transmission system.Four different patch antenna structures for the detection of partial discharges are investigat...Partial discharge diagnosis is an important part of monitoring and diagnosing compo-nents of the power transmission system.Four different patch antenna structures for the detection of partial discharges are investigated.These patch antennas,which are realisable in a variety of geometric structures,are already the subject of research.They 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 antennas.However,it is important and required to examine different structures extensively at the same measurement setup and to compare their performance.To 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 antennas.They are exposed to the same conditions on a special and unique measurement setup.As 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 examined.To rate the structures,an evaluation scheme is created and a sensitivity matrix is generated.展开更多
In the education sector,blockchain is currently at the end of the peak of inflated expectations in Gartner’s Hype Cycle.Thus,it is crucial to understand whether this technology meets the expectations of Higher Educat...In the education sector,blockchain is currently at the end of the peak of inflated expectations in Gartner’s Hype Cycle.Thus,it is crucial to understand whether this technology meets the expectations of Higher Education Institutions(HEIs).We go on an expedition to identify blockchain application scenarios and its potential for HEI administration-the universities are digitalized to just 23.3%.Current information systems research addresses classifications of blockchain-based projects(application level)rather than their technical realization(protocol level).Thus,when evaluating blockchain application scenarios in HEI administration,we intensively consider the technical side of blockchain-based projects.We perform a threestep approach:(1)systematic literature review,(2)qualitative exploratory semi-structured interviews to sup-plement information on market-ready solutions,and(3)an evaluation of the potential of the blockchain-based projects identified,based on HEI administration requirements.We find that the leading blockchain application scenarios are credential verification and record-sharing.At the protocol level,we obtain equivocal results regarding the technical realization of projects,e.g.,their underlying blockchain types and storage models.At the application level,when discussing the potential of different projects,we find that most of them address adaptability,complexity decomposition,and cost reduction requirements between HEIs;interest diversity and stakeholder collaboration between HEIs and business actors;privacy and trust between HEIs and students.展开更多
This paper aims to give an insight into the development and evaluation of force controlled machining processes with a commercially available setup. We will focus on a deburring and a grinding scenario, representing th...This paper aims to give an insight into the development and evaluation of force controlled machining processes with a commercially available setup. We will focus on a deburring and a grinding scenario, representing the major applications in today’s robot machining. Whereas the deburring use-case implements a force dependent feed-rate control, the grinding use-case implements an orthogonal force (pressure) control. Both strategies will be evaluated and the influence of general machining and robot specific parameters will be discussed.展开更多
To better understand characteristics of seismic signals of tracked vehicles measured when passing a sensor line,we numerically modelled force-pulse responses of a layered soil that is similar in its seismic properties...To better understand characteristics of seismic signals of tracked vehicles measured when passing a sensor line,we numerically modelled force-pulse responses of a layered soil that is similar in its seismic properties to that found at the original measurement site.The vertical-force pulses from the road wheels rolling over the track elements are fitted to the measured ones.Single-pulse seismic waves vary with distance due to diff erent wave types,refl ections at layer boundaries,vehicle velocity and relative position of the left and right track elements.They are computed by a modelling program and superposed at sensor positions with the appropriate slant distance and time shift for each track element.These sum signals are in qualitative agreement with those from the original measurements.However,they are several magnitudes weaker and much smoother.Furthermore,higher frequencies are damped much less at larger distances.Due to the large variability of the sum signals,recognition of tracked-vehicle types exclusively through their seismic signals seems diffi cult.展开更多
MPW (magnetic pulse welding) is a solid state joining technology that allows for the generation of strong metallic bonds, even between dissimilar metals. Due to the absence of external heat, critical intermetallic p...MPW (magnetic pulse welding) is a solid state joining technology that allows for the generation of strong metallic bonds, even between dissimilar metals. Due to the absence of external heat, critical intermetallic phases can largely be avoided. In this process, Lorentz forces are utilized for the rapid acceleration of at least one of the two metallic joining partners leading to the controlled high velocity impact between them. The measurement of the collision conditions and their targeted manipulation are the key factors of a successful process development. Optical measuring techniques are preferred, since they are not influenced by the prevalent strong magnetic field in the vicinity of the working coil. In this paper, the characteristic high velocity impact flash during MPW was monitored and evaluated using phototransistors in order to measure the time of the impact. The results are in good accordance with the established PDV (photon Doppler velocimetry) and show a good repeatability. Furthermore, the collision front velocity was investigated using adapted part geometries within a series of tests. This velocity component is one of the key parameters in MPW; its value decreases along the weld zone. With the help of this newly introduced measurement tool, the magnetic pressure distribution or the joining geometry can be adjusted more effectively.展开更多
The chemical industry is nowadays predominantly using fossil raw materials,but the alternative use of bio-based resources is investigated to account for the foreseeable scarcity of fossil feedstocks.A main challenge o...The chemical industry is nowadays predominantly using fossil raw materials,but the alternative use of bio-based resources is investigated to account for the foreseeable scarcity of fossil feedstocks.A main challenge of using biobased feedstocks is the complexity of the impurity profile.For an economic production of bio-based chemicals,the use of intensified processes is inevitable and approaches are needed for the various process intensification techniques to identify their applicability to be used for the production of bio-based components.In the presented study,an approach is shown for the reactive distillation(RD) technology to identify the most critical bio-based impurities and their impact on the reactive distillation process.The investigated case-study is the production of n-butyl acrylate from acrylic acid and n-butanol.Among all initially identified impurities,the key impurities,having the biggest impact on the product purity in the reactive distillation process,are found.These impurities are then studied in more detail and an operating window depending on the impurity concentration is identified for the reactive distillation column.Furthermore,an integrated design of upstream and downstream processes is facilitated,as the presented results can be used in the development of the fermentation processes for the production of the bio-based reactants by decreasing the concentration of the critical impurities.展开更多
This paper is the result of an investigation of the flora and traditionalknowledge in the conception of Javaé indigenous people from the Txuirivillage located on Bananal Island, Brazil. The objective is to invest...This paper is the result of an investigation of the flora and traditionalknowledge in the conception of Javaé indigenous people from the Txuirivillage located on Bananal Island, Brazil. The objective is to investigatethe plants used by these indigenous people, their diverse uses and tounderstand how traditional knowledge is passed on to new generations.This is a qualitative, descriptive and interdisciplinary survey, whose datacollection strategies included the application of semi-structured questionnairesand collection of plants for cataloguing according to AngiospermPhylogeny Group or APG III (2009). We identified 26 plant species, usedfor various purposes such as medicinal use, food, construction, craft andcultural, which were deposited in the Herbarium of the Federal Universityof Tocantins. Roots, stem and leaf are the plant parts most used bythe community. The plants mentioned were most frequently found on thebanks of the Javaés River and in the backyard of the residences. Significanttraditional knowledge of these people about the plants are transmittedto new generations, through visual, orality and experimentation. Ethnobotanicalstudies strengthen research in ecopsychology while allowingresearch into the interactions between human populations and plants.展开更多
Additive manufacturing(AM)is widely used in the automotive industry and has been expanded to include aerospace,marine,and rail.High flexibility and the possibility of manufacturing complex parts in AM motivate the int...Additive manufacturing(AM)is widely used in the automotive industry and has been expanded to include aerospace,marine,and rail.High flexibility and the possibility of manufacturing complex parts in AM motivate the integration of additive manu-facturing with classical forming technologies,which can improve tooling concepts and reduce costs.This study presents three applications of this integration.First,the possibility of successful utilization of selective laser melting for manufacturing extrusion tools with complex cooling channels and paths for thermocouples is reported,leading to significantly reduced inner die temperatures during the extrusion process.Second,sheet lamination is integrated with laser metal deposition(LMD)to manufacture deep-drawing dies.Promising results are achieved in reducing the stair step effect,which is the main challenge in sheet lamination,by LMD and following post-processing such as milling,ball burnishing,and laser polishing.The new manufacturing route shows that LMD can economically and efficiently reduce the stair step effect and omit the hardening step from the conventional manufacturing process route.Finally,LMD is used to manufacture a hot stamping punch with improved surface roughness by ball burnishing and near-surface complex cooling channels.The experimental results show that the manufactured punch has lower temperatures during hot stamping compared with the conventionally manufactured punch.This study shows the successful integration of AM processes with classical forming processes.展开更多
To address the pressing energy and environmental challenges and accelerate the realization of the“Carbon Net Zero”concept,the role of Environmentally Benign Automotive Lightweighting is crucial.Among the various tec...To address the pressing energy and environmental challenges and accelerate the realization of the“Carbon Net Zero”concept,the role of Environmentally Benign Automotive Lightweighting is crucial.Among the various technologies available,automotive lightweighting technologies not only contribute to the“Carbon Net Zero”process,but also extend the range of electric and hybrid-powered vehicles.Moreover,the implementation of environmentally-friendly technologies greatly improves the safety and overall performance of automobiles.展开更多
Despite substantial evidence emphasizing the pleiotropic benefits of exercise for the prevention and treatment of various diseases,the underlying biological mechanisms have not been fully elucidated.Several exercise b...Despite substantial evidence emphasizing the pleiotropic benefits of exercise for the prevention and treatment of various diseases,the underlying biological mechanisms have not been fully elucidated.Several exercise benefits have been attributed to signaling molecules that are released in response to exercise by different tissues such as skeletal muscle,cardiac muscle,adipose,and liver tissue.These signaling molecules,which are collectively termed exerkines,form a heterogenous group of bioactive substances,mediating inter-organ crosstalk as well as structural and functional tissue adaption.Numerous scientific endeavors have focused on identifying and characterizing new biological mediators with such properties.Additionally,some investigations have focused on the molecular targets of exerkines and the cellular signaling cascades that trigger adaption processes.A detailed understanding of the tissue-specific downstream effects of exerkines is crucial to harness the health-related benefits mediated by exercise and improve targeted exercise programs in health and disease.Herein,we review the current in vivo evidence on exerkine-induced signal transduction across multiple target tissues and highlight the preventive and therapeutic value of exerkine signaling in various diseases.By emphasizing different aspects of exerkine research,we provide a comprehensive overview of(i)the molecular underpinnings of exerkine secretion,(ii)the receptor-dependent and receptor-independent signaling cascades mediating tissue adaption,and(iii)the clinical implications of these mechanisms in disease prevention and treatment.展开更多
In comparison to the established twin-screw machines,the application of a planetary roller granulator for continuous operation of melt granulation is a promising alternative based on the unique process concept.An init...In comparison to the established twin-screw machines,the application of a planetary roller granulator for continuous operation of melt granulation is a promising alternative based on the unique process concept.An initial study focused on the material transport during processing as a key driver for the overall performance.Hereby,the impact of direct process parameters on the residence time distribution was the main objective.These investigations are complemented in this study by considering the free processing volume,which is defined by the number of planetary spindles applied within a module.The impact on the processing conditions is evaluated with respect to the process setting in terms of feed rate and rotation speed.The results highlight the potential of altering the underlying transport function in planetary roller melt granulation(PRMG)via the investigated direct process and equipment parameters.The impact of the feed rate is lower in comparison,while a higher rotation speed as well as a higher free processing volume promote material mixing.Moreover,a normalization of the determined residence time distribution(RTD)model data was feasible with respect to the process settings and the number of applied planetary spindles in the processing zone.This demonstrates the key role of the free processing volume in the fundamental mechanisms of material transport and mixing during PRMG.展开更多
In the context of electromobility,ensuring the leak tightness of assemblies is of paramount importance,particularly in bat-tery housings.Current battery housings,often featuring base assemblies crafted from extruded a...In the context of electromobility,ensuring the leak tightness of assemblies is of paramount importance,particularly in bat-tery housings.Current battery housings,often featuring base assemblies crafted from extruded aluminum profiles,address the challenge of leak tightness at joints through methods like friction stir welding,a process known for its time and cost intensiveness.The aim of this study is to develop and implement a new type of extruded profile concept to produce tight base assemblies for battery housings by a longitudinal mechanical single stroke joining process.The geometry,the process and the properties of the aluminum profiles are investigated to get a joint that meets the tightness requirements and achieve high load-bearing capacities in agreement with the high homologation requirements set to vehicles with high-voltage systems.The joint is formed by means of a single stage press stroke,which eliminates the need for complex tool designs that are neces-sary for continuous joining(roll joining).Flat steel contact surfaces are used as joining tools.To evaluate the joint quality,force curves from the joining process are analyzed and the resulting joint geometries are assessed using micrographs.The resulting leak tightness of the linear joints is measured by a helium sniffer leak detector and the load-bearing capacities are investigated by shear lap and bending tests and fatigue strength test.The study also explores whether a difference in strength between the two joining partners has a positive effect on the joint properties.展开更多
This study focuses on a virtual synchronous machine(VSM) based on voltage source converters to mimic the behavior of synchronous machines(SMs) and improve the damping ratio of the power system. The VSM model is simpli...This study focuses on a virtual synchronous machine(VSM) based on voltage source converters to mimic the behavior of synchronous machines(SMs) and improve the damping ratio of the power system. The VSM model is simplified according to some assumptions(neglecting the speed variation and the stator transients) to allow for the possibility of dealing with low-frequency oscillation in large-scale systems with many VSMs. Furthermore, a virtual power system stabilizer(VPSS) structure is proposed and tuned using a method based on a linearized power system dynamic model. The linear and nonlinear analyses examine the stability of two modified versions of a 16-machine power system in which, in the first case, partial classical machines are replaced by VSMs, and in the second case, all SMs are replaced by VSMs. The simulation results of the case studies validate the efficiency of the proposed control strategy.展开更多
We extend the monolithic convex limiting(MCL)methodology to nodal discontinuous Galerkin spectral-element methods(DGSEMS).The use of Legendre-Gauss-Lobatto(LGL)quadrature endows collocated DGSEM space discretizations ...We extend the monolithic convex limiting(MCL)methodology to nodal discontinuous Galerkin spectral-element methods(DGSEMS).The use of Legendre-Gauss-Lobatto(LGL)quadrature endows collocated DGSEM space discretizations of nonlinear hyperbolic problems with properties that greatly simplify the design of invariant domain-preserving high-resolution schemes.Compared to many other continuous and discontinuous Galerkin method variants,a particular advantage of the LGL spectral operator is the availability of a natural decomposition into a compatible subcellflux discretization.Representing a highorder spatial semi-discretization in terms of intermediate states,we performflux limiting in a manner that keeps these states and the results of Runge-Kutta stages in convex invariant domains.In addition,local bounds may be imposed on scalar quantities of interest.In contrast to limiting approaches based on predictor-corrector algorithms,our MCL procedure for LGL-DGSEM yields nonlinearflux approximations that are independent of the time-step size and can be further modified to enforce entropy stability.To demonstrate the robustness of MCL/DGSEM schemes for the compressible Euler equations,we run simulations for challenging setups featuring strong shocks,steep density gradients,and vortex dominatedflows.展开更多
In multi-stage press hardening,the product properties are determined by the thermo-mechanical history during the sequence of heat treatment and forming steps.To measure these properties and finally to control them by ...In multi-stage press hardening,the product properties are determined by the thermo-mechanical history during the sequence of heat treatment and forming steps.To measure these properties and finally to control them by feedback,two soft sensors are developed in this work.The press hardening of 22MnB5 sheet material in a progressive die,where the material is first rapidly austenitized,then pre-cooled,stretch-formed,and finally die bent,serves as the framework for the development of these sensors.To provide feedback on the temporal and spatial temperature distribution,a soft sensor based on a model derived from the Dynamic mode decomposition(DMD)is presented.The model is extended to a parametric DMD and combined with a Kalman filter to estimate the temperature(-distribution)as a function of all process-relevant control vari-ables.The soft sensor can estimate the temperature distribution based on local thermocouple measurements with an error of less than 10°C during the process-relevant time steps.For the online prediction of the final microstructure,an artificial neural network(ANN)-based microstructure soft sensor is developed.As part of this,a transferable framework for deriving input parameters for the ANN based on the process route in multi-stage press hardening is presented,along with a method for developing a training database using a 1-element model implemented with LS-Dyna and utilizing the material model Mat248(PHS_BMW).The developed ANN-based microstructure soft sensor can predict the final microstructure for specific regions of the formed and hardened sheet in a time span of far less than 1 s with a maximum deviation of a phase fraction of 1.8%to a reference simulation.展开更多
Flexibility in energy systems can support the operation of the electricity grid by providing active and reactive power to avoid voltage limit violations or congestion.Active distribution networks can provide this flex...Flexibility in energy systems can support the operation of the electricity grid by providing active and reactive power to avoid voltage limit violations or congestion.Active distribution networks can provide this flexibility by implementing systems to control distributed generators,storage or loads.Additionally,power flow controlling devices can be used to implement operational flexibility in the energy system.This paper presents concepts for planning and forecasting of flexibility,monitoring of energy systems and control of flexibility from active distribution networks(ADNs)to enable the use of flexibility in future power systems.展开更多
文摘Background:B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific immunoglobulins.Exercise alters B cell counts and immunoglobulin levels,but evidence-based conclusions on potential benefits for adaptive immunity are lacking.This systematic review assessed current literatures on the impact of acute exercise and exercise training on B cells,immunoglobulins,and markers of secretory immunity in human biofluids.Methods:According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines,MEDLINE,Web of Science,and Embase were searched on March 8,2023.Non-randomized controlled trials and crossover trials investigating the impact of acute exercise or exercise training on B cell counts and proportions,immunoglobulin levels,salivary flow rate,or secretory immunoglobulin A secretion rate were included.Quality and reporting of exercise training studies were assessed using the Tool for the Assessment of Study Quality and reporting in Exercise.Study characteristics,outcome measures,and statistically significant changes were summarized tabularly.Results:Of the 67 eligible studies,22 applied acute exercise and 45 applied exercise training.All included outcomes revealed significant alterations over time in acute exercise and exercise training context,but only a few investigations showed significant differences compared to control conditions.Secretory and plasma immunoglobulin A levels were most consistently increased in response to exercise training.Conclusion:B cell-related outcomes are altered by acute exercise and exercise training,but evidence-based conclusions cannot be drawn with high confidence due to the large heterogeneity in populations and exercise modalities.Well-designed trials with large sample sizes are needed to clarify how exercise shapes B cell-related immunity.
基金funding support from the China Scholarship Council(CSC).
文摘Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering.The latter is particularly true for slope stability assessment,where the effects of uncertainty are synthesized in the so-called probability of failure.This probability quantifies the reliability of a slope and its numerical calculation is usually quite involved from a numerical viewpoint.In view of this issue,this paper proposes an approach for failure probability assessment based on Latinized partially stratified sampling and maximum entropy distribution with fractional moments.The spatial variability of geotechnical properties is represented by means of random fields and the Karhunen-Loève expansion.Then,failure probabilities are estimated employing maximum entropy distribution with fractional moments.The application of the proposed approach is examined with two examples:a case study of an undrained slope and a case study of a slope with cross-correlated random fields of strength parameters under a drained slope.The results show that the proposed approach has excellent accuracy and high efficiency,and it can be applied straightforwardly to similar geotechnical engineering problems.
文摘Detection of liquid mixture of different volume ratio is very important in industrial purposes. The paper reports a sensing mechanism of binary liquid mixture for different volume fraction, based on the measurement of refractive index of the mixture. Here, a highly sensitive liquid filled core Photonic Crystal Fiber structure has been proposed to detect liquid mixture solution. Numerical investigation of the proposed structure is carried out by employing full vectorial Finite Element Method (FEM).
文摘Background:The side effects of the FIFA 11+program on performance have not been generally reviewed.The objective of this study was to synthesize the literature on the effects of the 11+on players’performance.Methods:Five online databases(PubMed,Scopus,ScienceDirect,Springer,and Google Scholar)were searched(from April 2006 to March 2022)using predefined keywords and sub-keywords.The potential references were primarily recorded through Endnote and imported to Covidence.Out of the 123 references screened by 2 blinded researchers through the software,59 full texts were assessed for eligibility,33 of which were ultimately included.The quality of the studies and the risk of bias were then assessed.Study ID,title,place,aim,design,start/end dates,population description,study criteria,statistical analysis,and outcomes were extracted.Results:Studies were conducted on male and female players aged 10-32 years old.The quality of the studies was moderate to high,and except for unclear bias for blinding outcome assessment,the risk of bias for all domains was low.Long-term application of the 11+improved most biomechanical measures and physiological responses except for lower extremity stability,ankle evertors time latency,ankle dorsiflexion,and proprioception.Conversely,the 11+showed acute negative effects on physical performance compared to dynamic warm-ups and non-significant effects on technical abilities.Conclusion:Mid-to-long-term implementation of the 11+improved the maj ority of biomechanical and a couple of physical measure s but showed no effects on technical skills.Precaution must be observed for using the 11+before competitions,as it could acutely decrease physical/technical performance.Given the contradictory nature of the literature,further studies should evaluate the short-to-mid-term effects of the 11+.Further studies are required to address ankle responses to the 11+intervention.
文摘Partial discharge diagnosis is an important part of monitoring and diagnosing compo-nents of the power transmission system.Four different patch antenna structures for the detection of partial discharges are investigated.These patch antennas,which are realisable in a variety of geometric structures,are already the subject of research.They 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 antennas.However,it is important and required to examine different structures extensively at the same measurement setup and to compare their performance.To 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 antennas.They are exposed to the same conditions on a special and unique measurement setup.As 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 examined.To rate the structures,an evaluation scheme is created and a sensitivity matrix is generated.
基金funded by the German Federal Ministry of Education and Research under the funding code 534800.The responsibility for the content of this publication lies with the authors.
文摘In the education sector,blockchain is currently at the end of the peak of inflated expectations in Gartner’s Hype Cycle.Thus,it is crucial to understand whether this technology meets the expectations of Higher Education Institutions(HEIs).We go on an expedition to identify blockchain application scenarios and its potential for HEI administration-the universities are digitalized to just 23.3%.Current information systems research addresses classifications of blockchain-based projects(application level)rather than their technical realization(protocol level).Thus,when evaluating blockchain application scenarios in HEI administration,we intensively consider the technical side of blockchain-based projects.We perform a threestep approach:(1)systematic literature review,(2)qualitative exploratory semi-structured interviews to sup-plement information on market-ready solutions,and(3)an evaluation of the potential of the blockchain-based projects identified,based on HEI administration requirements.We find that the leading blockchain application scenarios are credential verification and record-sharing.At the protocol level,we obtain equivocal results regarding the technical realization of projects,e.g.,their underlying blockchain types and storage models.At the application level,when discussing the potential of different projects,we find that most of them address adaptability,complexity decomposition,and cost reduction requirements between HEIs;interest diversity and stakeholder collaboration between HEIs and business actors;privacy and trust between HEIs and students.
文摘This paper aims to give an insight into the development and evaluation of force controlled machining processes with a commercially available setup. We will focus on a deburring and a grinding scenario, representing the major applications in today’s robot machining. Whereas the deburring use-case implements a force dependent feed-rate control, the grinding use-case implements an orthogonal force (pressure) control. Both strategies will be evaluated and the influence of general machining and robot specific parameters will be discussed.
文摘To better understand characteristics of seismic signals of tracked vehicles measured when passing a sensor line,we numerically modelled force-pulse responses of a layered soil that is similar in its seismic properties to that found at the original measurement site.The vertical-force pulses from the road wheels rolling over the track elements are fitted to the measured ones.Single-pulse seismic waves vary with distance due to diff erent wave types,refl ections at layer boundaries,vehicle velocity and relative position of the left and right track elements.They are computed by a modelling program and superposed at sensor positions with the appropriate slant distance and time shift for each track element.These sum signals are in qualitative agreement with those from the original measurements.However,they are several magnitudes weaker and much smoother.Furthermore,higher frequencies are damped much less at larger distances.Due to the large variability of the sum signals,recognition of tracked-vehicle types exclusively through their seismic signals seems diffi cult.
文摘MPW (magnetic pulse welding) is a solid state joining technology that allows for the generation of strong metallic bonds, even between dissimilar metals. Due to the absence of external heat, critical intermetallic phases can largely be avoided. In this process, Lorentz forces are utilized for the rapid acceleration of at least one of the two metallic joining partners leading to the controlled high velocity impact between them. The measurement of the collision conditions and their targeted manipulation are the key factors of a successful process development. Optical measuring techniques are preferred, since they are not influenced by the prevalent strong magnetic field in the vicinity of the working coil. In this paper, the characteristic high velocity impact flash during MPW was monitored and evaluated using phototransistors in order to measure the time of the impact. The results are in good accordance with the established PDV (photon Doppler velocimetry) and show a good repeatability. Furthermore, the collision front velocity was investigated using adapted part geometries within a series of tests. This velocity component is one of the key parameters in MPW; its value decreases along the weld zone. With the help of this newly introduced measurement tool, the magnetic pressure distribution or the joining geometry can be adjusted more effectively.
基金funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no.241718,Eurobioref
文摘The chemical industry is nowadays predominantly using fossil raw materials,but the alternative use of bio-based resources is investigated to account for the foreseeable scarcity of fossil feedstocks.A main challenge of using biobased feedstocks is the complexity of the impurity profile.For an economic production of bio-based chemicals,the use of intensified processes is inevitable and approaches are needed for the various process intensification techniques to identify their applicability to be used for the production of bio-based components.In the presented study,an approach is shown for the reactive distillation(RD) technology to identify the most critical bio-based impurities and their impact on the reactive distillation process.The investigated case-study is the production of n-butyl acrylate from acrylic acid and n-butanol.Among all initially identified impurities,the key impurities,having the biggest impact on the product purity in the reactive distillation process,are found.These impurities are then studied in more detail and an operating window depending on the impurity concentration is identified for the reactive distillation column.Furthermore,an integrated design of upstream and downstream processes is facilitated,as the presented results can be used in the development of the fermentation processes for the production of the bio-based reactants by decreasing the concentration of the critical impurities.
文摘This paper is the result of an investigation of the flora and traditionalknowledge in the conception of Javaé indigenous people from the Txuirivillage located on Bananal Island, Brazil. The objective is to investigatethe plants used by these indigenous people, their diverse uses and tounderstand how traditional knowledge is passed on to new generations.This is a qualitative, descriptive and interdisciplinary survey, whose datacollection strategies included the application of semi-structured questionnairesand collection of plants for cataloguing according to AngiospermPhylogeny Group or APG III (2009). We identified 26 plant species, usedfor various purposes such as medicinal use, food, construction, craft andcultural, which were deposited in the Herbarium of the Federal Universityof Tocantins. Roots, stem and leaf are the plant parts most used bythe community. The plants mentioned were most frequently found on thebanks of the Javaés River and in the backyard of the residences. Significanttraditional knowledge of these people about the plants are transmittedto new generations, through visual, orality and experimentation. Ethnobotanicalstudies strengthen research in ecopsychology while allowingresearch into the interactions between human populations and plants.
基金was carried out within the projects 198180216,426515407 and 417202720 funded by the German Research Foundation(DFG).
文摘Additive manufacturing(AM)is widely used in the automotive industry and has been expanded to include aerospace,marine,and rail.High flexibility and the possibility of manufacturing complex parts in AM motivate the integration of additive manu-facturing with classical forming technologies,which can improve tooling concepts and reduce costs.This study presents three applications of this integration.First,the possibility of successful utilization of selective laser melting for manufacturing extrusion tools with complex cooling channels and paths for thermocouples is reported,leading to significantly reduced inner die temperatures during the extrusion process.Second,sheet lamination is integrated with laser metal deposition(LMD)to manufacture deep-drawing dies.Promising results are achieved in reducing the stair step effect,which is the main challenge in sheet lamination,by LMD and following post-processing such as milling,ball burnishing,and laser polishing.The new manufacturing route shows that LMD can economically and efficiently reduce the stair step effect and omit the hardening step from the conventional manufacturing process route.Finally,LMD is used to manufacture a hot stamping punch with improved surface roughness by ball burnishing and near-surface complex cooling channels.The experimental results show that the manufactured punch has lower temperatures during hot stamping compared with the conventionally manufactured punch.This study shows the successful integration of AM processes with classical forming processes.
文摘To address the pressing energy and environmental challenges and accelerate the realization of the“Carbon Net Zero”concept,the role of Environmentally Benign Automotive Lightweighting is crucial.Among the various technologies available,automotive lightweighting technologies not only contribute to the“Carbon Net Zero”process,but also extend the range of electric and hybrid-powered vehicles.Moreover,the implementation of environmentally-friendly technologies greatly improves the safety and overall performance of automobiles.
基金support by the Open Access Publication Funds/transformative agreements of the University of Gottingen and NiedersachsenOPEN。
文摘Despite substantial evidence emphasizing the pleiotropic benefits of exercise for the prevention and treatment of various diseases,the underlying biological mechanisms have not been fully elucidated.Several exercise benefits have been attributed to signaling molecules that are released in response to exercise by different tissues such as skeletal muscle,cardiac muscle,adipose,and liver tissue.These signaling molecules,which are collectively termed exerkines,form a heterogenous group of bioactive substances,mediating inter-organ crosstalk as well as structural and functional tissue adaption.Numerous scientific endeavors have focused on identifying and characterizing new biological mediators with such properties.Additionally,some investigations have focused on the molecular targets of exerkines and the cellular signaling cascades that trigger adaption processes.A detailed understanding of the tissue-specific downstream effects of exerkines is crucial to harness the health-related benefits mediated by exercise and improve targeted exercise programs in health and disease.Herein,we review the current in vivo evidence on exerkine-induced signal transduction across multiple target tissues and highlight the preventive and therapeutic value of exerkine signaling in various diseases.By emphasizing different aspects of exerkine research,we provide a comprehensive overview of(i)the molecular underpinnings of exerkine secretion,(ii)the receptor-dependent and receptor-independent signaling cascades mediating tissue adaption,and(iii)the clinical implications of these mechanisms in disease prevention and treatment.
文摘In comparison to the established twin-screw machines,the application of a planetary roller granulator for continuous operation of melt granulation is a promising alternative based on the unique process concept.An initial study focused on the material transport during processing as a key driver for the overall performance.Hereby,the impact of direct process parameters on the residence time distribution was the main objective.These investigations are complemented in this study by considering the free processing volume,which is defined by the number of planetary spindles applied within a module.The impact on the processing conditions is evaluated with respect to the process setting in terms of feed rate and rotation speed.The results highlight the potential of altering the underlying transport function in planetary roller melt granulation(PRMG)via the investigated direct process and equipment parameters.The impact of the feed rate is lower in comparison,while a higher rotation speed as well as a higher free processing volume promote material mixing.Moreover,a normalization of the determined residence time distribution(RTD)model data was feasible with respect to the process settings and the number of applied planetary spindles in the processing zone.This demonstrates the key role of the free processing volume in the fundamental mechanisms of material transport and mixing during PRMG.
文摘In the context of electromobility,ensuring the leak tightness of assemblies is of paramount importance,particularly in bat-tery housings.Current battery housings,often featuring base assemblies crafted from extruded aluminum profiles,address the challenge of leak tightness at joints through methods like friction stir welding,a process known for its time and cost intensiveness.The aim of this study is to develop and implement a new type of extruded profile concept to produce tight base assemblies for battery housings by a longitudinal mechanical single stroke joining process.The geometry,the process and the properties of the aluminum profiles are investigated to get a joint that meets the tightness requirements and achieve high load-bearing capacities in agreement with the high homologation requirements set to vehicles with high-voltage systems.The joint is formed by means of a single stage press stroke,which eliminates the need for complex tool designs that are neces-sary for continuous joining(roll joining).Flat steel contact surfaces are used as joining tools.To evaluate the joint quality,force curves from the joining process are analyzed and the resulting joint geometries are assessed using micrographs.The resulting leak tightness of the linear joints is measured by a helium sniffer leak detector and the load-bearing capacities are investigated by shear lap and bending tests and fatigue strength test.The study also explores whether a difference in strength between the two joining partners has a positive effect on the joint properties.
文摘This study focuses on a virtual synchronous machine(VSM) based on voltage source converters to mimic the behavior of synchronous machines(SMs) and improve the damping ratio of the power system. The VSM model is simplified according to some assumptions(neglecting the speed variation and the stator transients) to allow for the possibility of dealing with low-frequency oscillation in large-scale systems with many VSMs. Furthermore, a virtual power system stabilizer(VPSS) structure is proposed and tuned using a method based on a linearized power system dynamic model. The linear and nonlinear analyses examine the stability of two modified versions of a 16-machine power system in which, in the first case, partial classical machines are replaced by VSMs, and in the second case, all SMs are replaced by VSMs. The simulation results of the case studies validate the efficiency of the proposed control strategy.
文摘We extend the monolithic convex limiting(MCL)methodology to nodal discontinuous Galerkin spectral-element methods(DGSEMS).The use of Legendre-Gauss-Lobatto(LGL)quadrature endows collocated DGSEM space discretizations of nonlinear hyperbolic problems with properties that greatly simplify the design of invariant domain-preserving high-resolution schemes.Compared to many other continuous and discontinuous Galerkin method variants,a particular advantage of the LGL spectral operator is the availability of a natural decomposition into a compatible subcellflux discretization.Representing a highorder spatial semi-discretization in terms of intermediate states,we performflux limiting in a manner that keeps these states and the results of Runge-Kutta stages in convex invariant domains.In addition,local bounds may be imposed on scalar quantities of interest.In contrast to limiting approaches based on predictor-corrector algorithms,our MCL procedure for LGL-DGSEM yields nonlinearflux approximations that are independent of the time-step size and can be further modified to enforce entropy stability.To demonstrate the robustness of MCL/DGSEM schemes for the compressible Euler equations,we run simulations for challenging setups featuring strong shocks,steep density gradients,and vortex dominatedflows.
基金support of project 424334660 in the Collaborative Research Centre SPP2183“Property-controlled forming processes”(German:Eigenschaftsgeregelte Umformprozesse).
文摘In multi-stage press hardening,the product properties are determined by the thermo-mechanical history during the sequence of heat treatment and forming steps.To measure these properties and finally to control them by feedback,two soft sensors are developed in this work.The press hardening of 22MnB5 sheet material in a progressive die,where the material is first rapidly austenitized,then pre-cooled,stretch-formed,and finally die bent,serves as the framework for the development of these sensors.To provide feedback on the temporal and spatial temperature distribution,a soft sensor based on a model derived from the Dynamic mode decomposition(DMD)is presented.The model is extended to a parametric DMD and combined with a Kalman filter to estimate the temperature(-distribution)as a function of all process-relevant control vari-ables.The soft sensor can estimate the temperature distribution based on local thermocouple measurements with an error of less than 10°C during the process-relevant time steps.For the online prediction of the final microstructure,an artificial neural network(ANN)-based microstructure soft sensor is developed.As part of this,a transferable framework for deriving input parameters for the ANN based on the process route in multi-stage press hardening is presented,along with a method for developing a training database using a 1-element model implemented with LS-Dyna and utilizing the material model Mat248(PHS_BMW).The developed ANN-based microstructure soft sensor can predict the final microstructure for specific regions of the formed and hardened sheet in a time span of far less than 1 s with a maximum deviation of a phase fraction of 1.8%to a reference simulation.
基金This work was supported in part by the National Natural Science Foundation of China(NSFC)under Grant 51520105011in part by the 111 project of China under Grant B17016,in part by China Scholarship Council(No.201706130143)within the incentive scheme Showcase Intelligent Energy-Digital Agenda for the energy transition(SINTEG)under Grant 03SIN227 as well as the IDEAL project under Grand 03ET7557A provided by the Federal Ministry for Economic Affairs and Energy.
文摘Flexibility in energy systems can support the operation of the electricity grid by providing active and reactive power to avoid voltage limit violations or congestion.Active distribution networks can provide this flexibility by implementing systems to control distributed generators,storage or loads.Additionally,power flow controlling devices can be used to implement operational flexibility in the energy system.This paper presents concepts for planning and forecasting of flexibility,monitoring of energy systems and control of flexibility from active distribution networks(ADNs)to enable the use of flexibility in future power systems.