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International Journal of Minerals,Metallurgy and Materials 2023年第12期30卷 2375-2385页

作者： Yiqi Zhou Sultan Mahmood dirk Lars Engelberg Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Metallurgy and Corrosion School of MaterialsThe University of ManchesterM139PLManchesterUK Materials Performance Centre The University of ManchesterM139PLManchesterUK

Bipolar electrochemistry is used to produce a linear potential gradient across a bipolar electrode(BPE),providing direct access to the anodic and cathodic reactions under a wide range of applied *** occurrence of pitting corrosion,crevice corrosion,and general corrosion on type 2205 duplex stainless steel(DSS 2205)BPE has been observed at room *** critical pit depth of 10-20μm with a55%-75% probability of pits developing into stable pits at potential from+0.9 to+1.2 V ***(open circuit potential)are *** pit nucleation sites are either within ferritic grains or at the interface between austenite and *** critical conditions for pitting and crevice corrosion are discussed with Epit(critical pitting potential)and Ecre(critical crevice potential)decreasing from 0.87 and 0.80 V *** after150 s of exposure to 0.84 and 0.76 V *** after 900 s of exposure,*** growth kinetics under different applied bipolar potentials and exposure times have been *** ferrite is shown to be more susceptible to general dissolution.

关键词： bipolar electrochemistry duplex stainless steel pitting corrosion pit growth factor crevice corrosion

Development of a Long-Term Operational Optimization Model for a Building Energy System Supplied by a Geothermal Field

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Journal of Thermal Science 2022年第5期31卷 1293-1301页

作者： KÜMPEL Alexander STOFFEL Phillip MÜLLER dirk RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor ClimateAachen 52074Germany

In order to reduce energy consumption and CO_(2) emissions in the building sector, more and more renewable energy sources are integrated into energy systems. Especially geothermal fields combined with heat pumps are able to supply buildings with heat and cold at low carbon emissions. However, using geothermal fields as heat and cold source influences the ground temperature. Consequently, the ground temperature can change dramatically over a building’s lifetime, leading to less efficient operation of the energy system. Therefore, a sustainable operation is required to ensure the long-term efficiency of geothermal fields. In this paper, we develop an optimization model to derive operating strategies for an efficient long-term operation of a building energy system coupled to a geothermal field. The investigated energy system is the main building of the *** Energy Research Center in Aachen, Germany, which includes a heat pump, two boilers, a combined heat, and power unit, a glycol cooler, and a geothermal field with 41 probes. For each component, we develop energy-based sub-models, which are connected to form the overall system. The geothermal field is modeled by using a g-functions approach as well as a simplified resistance-capacitance approach. To achieve short computing times and realize an optimization horizon of several years, the optimization problem is formulated as mixed-integer linear programming(MILP). The developed model is optimized regarding two different objectives: the minimization of energy costs and the minimization of long-term temperature changes in the ground. Conclusions for an efficient and sustainable operation of the field, especially for the cooling supply, can be derived from the optimization results. It is shown that a state of equilibrium should be aimed to achieve an energy-efficient operation, in which the temperature of the field is close to the initial ground temperature.

关键词： geothermal energy building energy systems operational optimization long-term operation

Plausibility in Early Stages of Architectural Design: A New Tool for High-Rise Residential Buildings

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Tsinghua Science and Technology 2009年第3期14卷 327-332页

作者： dirk Donath Danny Lobos Chair of Computer Science in Architecture Faculty of Architecture Bauhaus-UniversityWeimar 99423 Germany

This paper analyzes the problem of the design of envelopes for high-rise isolated residential buildings. The phenomenon of envelope creation appears in the early stages of the architectural design. Variables that influence the final shape and size of such envelopes are then identified. This paper presents the state-of-the-art tools for the current solutions at the commercial and academic/scientific level. The variables identified in this research are the client＇s needs, the urban code and architectural practice, and their specific components for the final creation of a new decision support system tool based on the building information modeling （BIM） software platform, to facilitate the work in the project development and drawing production stages. This tool generates several options for building envelopes according to the parameters required by the city Zoning Planning Commission. These options then lead to deliver reliable data and a geometry that can be analyzed in a timely fashion by the engineers, builders, architects, government, and clients in the early stages of the building＇s design. The results show that use of specific information and communication technologies （ICT） tools in the early stages of a building design helps reduce the working time, increases confidence in the generated solution, and contributes to the exploration of alternatives in a short period of time.

关键词： constraint based design parametric programming urban modeling optimization architectural design

Efficient Dynamic Floor Field Methods for Microscopic Pedestrian Crowd Simulations

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Communications in Computational Physics 2014年第6期16卷 264-286页

作者： dirk Hartmann Peter Hasel Siemens AG Corporate Technology80200 MunichGermany

Floor field methods are one of the most popular medium-scale navigation concepts in microscopic pedestrian *** introduced dynamic floor field methods have significantly increased the realism of such simulations,*** of spatio-temporal patterns of pedestrian densities in simulations with real world *** methods update floor fields continuously taking other pedestrians into *** implies that computational times are mainly determined by the calculation of floor *** this work,we propose a new computational approach for the construction of dynamic floor *** approach is based on the one hand on adaptive grid concepts and on the other hand on a directed calculation of floor fields,*** calculation is restricted to the domain of *** both techniques the computational complexity can be reduced by a factor of 10 as demonstrated by several realistic *** on-line simulations,a requirement of many applications,are possible for moderate realistic scenarios.

关键词： Pedestrian dynamics cellular automata adaptive grids floor field methods fast marching method navigation.

Highly Sensitive Ultrathin Flexible Thermoplastic Polyurethane/Carbon Black Fibrous Film Strain Sensor with Adjustable Scaffold Networks

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Nano-Micro Letters 2021年第4期13卷 159-177页

作者： Xin Wang Xianhu Liu dirk W.Schubert Institute of Polymer Materials Friedrich-Alexander-University Erlangen-NurembergMartensstr.791058 ErlangenGermany National Engineering Research Center for Advanced Polymer Processing Technology Zhengzhou UniversityZhengzhou 450002People’s Republic of China Bavarian Polymer Institute Dr.Mack‑Strasse 7790762 FürthGermany

In recently years,high-performance wearable strain sensors have attracted great attention in academic and ***,a conductive polymer composite of electrospun thermoplastic polyurethane(TPU)fibrous film matrix-embedded carbon black(CB)particles with adjustable scaffold network was fabricated for high-sensitive strain *** work indicated the influence of stereoscopic scaffold network structure built under various rotating speeds of collection device in electrospinning process on the electrical response of TPU/CB strain *** structure makes the sensor exhibit combined characters of high sensitivity under stretching strain(gauge factor of 8962.7 at 155%strain),fast response time(60 ms),outstanding stability and durability(>10,000 cycles)and a widely workable stretching range(0–160%).This high-performance,wearable,flexible strain sensor has a broad vision of application such as intelligent terminals,electrical skins,voice measurement and human motion ***,a theoretical approach was used to analyze mechanical property and a model based on tunneling theory was modified to describe the relative change of resistance upon the applied ***,two equations based from this model were first proposed and offered an effective but simple approach to analyze the change of number of conductive paths and distance of adjacent conductive particles.

关键词： Strain sensor Electrospinning Electronic skin Fitting model

Cloud-Based Optimal Control of Individual Borehole Heat Exchangers in a Geothermal Field

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Journal of Thermal Science 2022年第5期31卷 1253-1265页

作者： STOFFEL Phillip KÜMPEL Alexander MÜLLER dirk RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor Climate52074 AachenGermany

Integrating renewable energy sources is a crucial component in reducing CO_(2) emissions in the building sector. In particular, shallow geothermal energy is expected to play a significant role in the regenerative energy supply of buildings. An effective control strategy for the geothermal field is crucial to reduce the overall energy consumption. This paper analyzes the benefits of controlling an existing field’s individual borehole heat exchangers(BHE) using nonlinear model predictive control(NMPC) and moving horizon estimation. The considered geothermal field consists of 41 BHEs and is used for heating and cooling. Each BHE is equipped with temperature sensors for in-and outflow and has individually controllable valves, while a central hydraulic pump feeds all BHEs. The sensor measurements are accessed through a cloud platform, enabling also set point writing for the pump speed and the valve positions. To control the BHEs individually, we propose a two-stage process. In the calibration stage, a moving horizon estimator estimates the actual borehole and ground temperatures for each BHE. In the second stage, first, a nonlinear model predictive controller optimizes the number of active BHEs necessary to meet the buildings’ energy demand. With the estimated ground temperatures as a basis, it is determined which BHEs shall be(de)-activated. The active BHEs are fed with a fixed volume flow of 24 L/min to ensure turbulent heat transfer. To reduce the power usage of the pumps, an optimal control problem based on a simple hydraulic model of the geothermal field is used. The methodology is analyzed through simulations first and then validated experimentally. The results show that half or more of the BHEs could be deactivated most of the time, leading to 67% savings in electricity consumption by the hydraulic pump. The experimental validation confirms the high energy saving potential of the proposed methodology, reducing the consumption of electrical energy by 71%. Additiona

关键词： geothermal energy moving horizon estimation model predictive control operation optimization optimal control

An Efficient Calculation of Photonic Crystal Band Structures Using Taylor Expansions

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Communications in Computational Physics 2014年第10期16卷 1355-1388页

作者： dirk Klindworth Kersten Schmidt Research Center MATHEON TU BerlinDepartment of MathematicsStraße des 17.Juni 13610623 BerlinGermany.

In this paper we present an efficient algorithm for the calculation of photonic crystal band structures and band structures of photonic crystal *** method relies on the fact that the dispersion curves of the band structure are smooth functions of the quasi-momentum in the one-dimensional Brillouin *** show the derivation and computation of the group velocity,the group velocity dispersion,and any higher derivative of the dispersion *** derivatives are then employed in a Taylor expansion of the dispersion *** control the error of the Taylor expansion with the help of a residual estimate and introduce an adaptive scheme for the selection of nodes in the one-dimensional Brillouin zone at which we solve the underlying eigenvalue problem and compute the derivatives of the dispersion *** proposed algorithm is not only advantageous as it decreases the computational effort to compute the band structure but also because it allows for the identification of crossings and anti-crossings of dispersion curves,*** identification is not possible with the standard approach of solving the underlying eigenvalue problem at a discrete set of values of the quasi-momentum without taking the mode parity into account.

关键词： Photonic crystals band structure calculation group velocity Taylor expansion adaptivity

In search of optimal building behavior models for model predictive control in the context of flexibility

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Building Simulation 2024年第1期17卷 71-91页

作者： Arash Erfani Tohid Jafarinejad Staf Roels dirk Saelens KU Leuven Department of Civil EngineeringBuilding Physics and Sustainable Design SectionKasteelpark Arenberg 40 Bus 24473001 HeverleeBelgium EnergyVille Thor Park 8310Genk 3600Belgium

Model predictive control(MPC)is an advanced control *** has been deployed to harness the energy flexibility of a *** requires a dynamic model of the building to achieve such an ***,developing a suitable predictive model is the main challenge in MPC implementation forflexibility *** studyfocuses on the application of key performance indicators(KPls)to evaluate the suitability of MPC models via feature *** this end,multiple models were developed for two houses.A feature selection method was developed to select an appropriate feature space to train the *** predictive models were then quantified based on one-step ahead prediction error(OSPE),a standard KPI used in multiple studies,and a less-often KPl:multi-step ahead prediction error(MSPE).An MPC workflow was designed where different models can serve as the predictive *** showed that MSPE better demonstrates the performance of predictive models used for flexibility *** revealed that up to 57% of the flexibility potential and 48% of energy use reduction are not exploited if MSPE is not minimized while developing a predictive model.

关键词： building flexibility model predictive control for building building behaviour identification smart home

Current Developments in Cognitive Linguistics

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外国语 2008年第3期31卷 2-19页

作者： dirk Geeraerts University of Leuven Belgium

After 30 years of theoretical development,we need to address the question whether the internal evolution of Cognitive Linguistics can be synthesized:what are the fundamental underlying trends in Cognitive Linguistics,and how do they shape the current developments within Cognitive Linguistics This paper argues that Cognitive Linguistics is essentially characterized by a gradual recontextualization of the ***,the development of 20th century grammar is characterized by a succession of a decontextualizing and a recontextualizing ***,the various stages in the development of Cognitive Linguistics involve the gradual recovery of the various types of context that were discarded by generative *** involve the experiential and embodied context of meaning in natural language,the pragmatic context of actual language usage,and the social and cultural context of language as a shared code.

关键词：语言学外语教学方法发展现状

Migration to Intermediate XML for Electronic Data (MIXED)

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现代图书情报技术 2008年第1期 21-32页

作者： dirk ROORDA Data Archiving and Networked Services (DANS) NL

MIXED is a digital preservation project. It uses a strategy of converting data to intermediate XML. In this paper we position this strategy with respect to the well-known emulation and migration strategies. Then we detail the MIXED strategy and explain why it is an optimized, economical way of migration. Finally, we describe how DANS is implementing a software tool that can perform the migrations needed for this strategy.

关键词：电子数据数字资源长期保存迁移文件格式软件开发 XML MIXED 图书馆