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Modelling erosion of a single rock block using a coupled CFD-DEM approach

Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2375-2387页

作者： Penghua Teng Fredrik johansson J.Gunnar I.Hellström Division of Fluid and Experimental Mechanics Department of Engineering Sciences and MathematicsLuleåUniversity of TechnologyLuleåSE-97187Sweden Division of Soil and Rock Mechanics KTH Royal Institute of TechnologyStockholmSE-10044Sweden

Rock block removal is the prevalent physical mechanism for rock erosion and could affect the stability of dam foundations and *** this,understanding of block removal is still inadequate because of the complex interactions among block characteristics,hydraulic forces,and erosive processes acting on the ***,based on a previously conducted physical experiment of erosion of a single rock block,the removal processes of two different protruding blocks are represented by a coupled computational fluid dynamics-discrete element model(CFD-DEM)approach under varied flow ***,the blocks could be rotated with respect to the flow direction to consider the effect of the discontinuity orientation on the block removal *** results visualize the entire block removal *** simulations reproduce the effects of the discontinuity orientation on the critical flow velocity inducing block incipient motion and the trajectory of the block motion observed in the physical *** numerical results present a similar tendency of the critical velocities at different discontinuity orientations but have slightly lower *** trajectory of the block in the simulations fits well with the experimental *** relationship between the dimensionless critical shear stress and discontinuity orientation observed from the simulations shows that the effect of block protrusion becomes more dominant on the block incipient motion with the increase of relative protrusion *** our knowledge,this present study is the first attempt to use the coupled finite volume method(FVM)-DEM approach for modelling the interaction behavior between the block and the flowing water so that the block removal process can be reproduced and analyzed.

关键词： Rock erosion Block removal Incipient motion Coupled CFD-DEM Critical shear stress

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Finite-time consensus protocols for multi-dimensional multi-agent systems

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Control Theory and Technology 2020年第4期18卷 419-430页

作者： Jieqiang Wei Bart Besselink Junfeng Wu Henrik Sandberg Karl H.johansson Ericsson Global AI Accelerator Torshamnsgatan 21StockholmSweden Bernoulli Institute for Mathematics Computer Science and Artificial IntelligenceUniversity of GroningenP.O.Box 4079700 GroningenAKThe Netherlands College of Control Science and Engineering Zhejiang University310027 HangzhouChina Division of Decision and Control Systems KTH Royal Institute of Technology10044 StockholmSweden

A fnite.-time consensus protocol is proposed for multi -dimensional multi- agent systems, using direction peserving signumcontrols. Flipp solutions and nonsmooh analysis tehniques are adopted to handle discontinuities. Suficient and ncessaryconditions are provided to guarantee infinte time convergence and boundedness of the solutions. It turns out that the numberof agents which have cotinuous contol law plays an ssenan role in fnite-tine conerence In adidio it is shown thatthe unit bals itoduced bylp, norms. where p ∈[1,∞] , are inariat for the closed lop.

关键词： Multi-agent systems Network consensus Finite time convergence Nonsmooth analysis

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Pefabloc- A sulfonyl fluoride serine protease inhibitor blocks induction of Diotericin in Drosoohila 1（2）mbn cells

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Insect Science 2012年第4期19卷 472-476页

作者： Karin C. johansson Kenneth Soderhall Maria I. Lind Department of Comparative Physiology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Insects protect themselves against microbial infection by an efficient innate immune system that is activated by recognition ofinvariant microbial surface molecules. In the fruit fly Drosophila melanogaster the presence of bacteria is associated with expression of antimicrobial peptides in host immune-competent tissues. Host receptors detect infection and relay the signal to mount the appropriate immune response. In Drosophila hemocyte- like l（2）mbn cells pre-infection treatment with Pefabloc, a commonly used serine protease inhibitor, induced two major effects： it blocked expression of the antibacterial peptide Diptericin in response to live Gram-negative bacteria and bacterial surface molecules （crude lipopolysaccharide contaminated by peptidoglycans） and it induced morphological changes.

关键词： cell morphology diptericin Drosophila IMD pathway immune response,proteinase inhibitor

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Uncertainty-aware molecular dynamics from Bayesian active learning for phase transformations and thermal transport in SiC

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npj Computational Materials 2023年第1期9卷 2000-2007页

作者： Yu Xie Jonathan Vandermause Senja Ramakers Nakib H.Protik Anders johansson Boris Kozinsky John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMAUSA Department of Physics Harvard UniversityCambridgeMAUSA Corporate Sector Research and Advance Engineering Robert Bosch GmbHRenningenUSA Interdisciplinary Centre for Advanced Materials Simulation Ruhr-Universität BochumBochumGermany Robert Bosch LLC Research and Technology CenterWatertownMAUSA

Machine learning interatomic force fields are promising for combining high computational efficiency and accuracy in modeling quantum interactions and simulating atomistic *** learning methods have been recently developed to train force fields efficiently and *** them,Bayesian active learning utilizes principled uncertainty quantification to make data acquisition *** this work,we present a general Bayesian active learning workflow,where the force field is constructed from a sparse Gaussian process regression model based on atomic cluster expansion *** circumvent the high computational cost of the sparse Gaussian process uncertainty calculation,we formulate a high-performance approximate mapping of the uncertainty and demonstrate a speedup of several orders of *** demonstrate the autonomous active learning workflow by training a Bayesian force field model for silicon carbide(SiC)polymorphs in only a few days of computer time and show that pressure-induced phase transformations are accurately *** resulting model exhibits close agreement with both ab initio calculations and experimental measurements,and outperforms existing empirical models on vibrational and thermal *** active learning workflow readily generalizes to a wide range of material systems and accelerates their computational understanding.

关键词： computer thermal utilize

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Using transient plane source sensor for determination of thermal properties of vacuum insulation panels

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Frontiers of Architectural Research 2012年第4期1卷 334-340页

作者： Par johansson Bijan Adl-Zarrabi Carl-Eric Hagentoft Department of Civil ond Environmentol Engineering Cholmers University of Technology Gothenburg SE-412 96 Sweden

The energy use in buildings has to be decreased to reach the targets and regulations in the European Union. One way of reducing the energy demand is to use vacuum insulation panels （VIP） in the buitding envelope. To make sure the declared thermal properties of the VlP are valid for the mounted panels, in situ measurements are needed. The transient plane source （TPS） method allows fast measurement of the thermal properties of a variety of materials. However, the large anisotropy of the VIP makes it hard to interpret the temperature increase in the TPS sensor. This paper presents a comparison between an analytical solution, numerical simulations and TPS measurements of polystyrene and polystyrene with aluminum film. Polystyrene and aluminum were used instead of VIP to increase the number of setups. The numerical simulation model was validated by comparing the simulated temperature increase with an analytical solution for the polystyrene sample. The simulated temperature increase in the polystyrene sample after 40 s was 7.8% higher than the TPS measurements. For the case with polystyrene with aluminum film, the deviation was 5.7%. Losses in the wires of the TPS sensor, uncertainties regarding the material parameters and surface resistances could explain the deviations.

关键词： Thermal properties Transient planesource Vacuum insulationpanel AnaLytical solution Numerical simulation Measurement

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Predefined-time distributed multiobjective optimization for network resource allocation

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Science China(Information Sciences) 2023年第7期66卷 58-72页

作者： Kunpeng ZHANG Lei XU Xinlei YI Zhengtao DING Karl H.johansson Tianyou CHAI Tao YANG State Key Laboratory of Synthetical Automation for Process Industries Northeastern University School of Electrical Engineering and Computer Science KTH Royal Institute of Technology School of Electrical and Electronic Engineering The University of Manchester

We consider the multiobjective optimization problem for the resource allocation of the multiagent network, where each agent contains multiple conflicting local objective functions. The goal is to find compromise solutions minimizing all local objective functions subject to resource constraints as much as possible, i.e., the Pareto optimums. To this end, we first reformulate the multiobjective optimization problem into one single-objective distributed optimization problem by using the weighted Lppreference index,where the weighting factors of all local objective functions are obtained from the optimization procedure so that the optimizer of the latter is the desired Pareto optimum of the former. Next, we propose novel predefined-time algorithms to solve the reformulated problem by time-based generators. We show that the reformulated problem is solved within a predefined time if the local objective functions are strongly convex and smooth. Moreover, the settling time can be arbitrarily preset since it does not depend on the initial values and designed parameters. Finally, numerical simulations are presented to illustrate the effectiveness of the proposed algorithms.

关键词： distributed optimization multiobjective optimization predefined-time algorithms time-based generators weighted ${L_p}$ preference index

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形状因子的实验现状（英文）

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中国科学技术大学学报 2016年第4期46卷 316-322页

作者： johansson Tord 乌普萨拉大学物理学和天文学系瑞典乌普萨拉75105

阐述了类空空间和类时空间基态重子电磁形状因子的实验现状及其展望,并进行了展望.

关键词：重子质子中子超子电磁形状因子

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Immune checkpoint therapy for pancreatic cancer

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World Journal of Gastroenterology 2016年第43期22卷 9457-9476页

作者： Henrik johansson Roland Andersson Monika Bauden Sarah Hammes Stefan Holdenrieder Daniel Ansari Department of Surgery Clinical Sciences Lund Lund University and Sk?ne University Hospital Institute of Laboratory Medicine German Heart Center at the Technical University Munich

Novel treatment modalities are necessary for pancreatic cancer. Immunotherapy with immune checkpoint inhibition has shown effect in other solid tumors, and could have a place in pancreatic cancer treatment. Most available clinical studies on immune checkpoint inhibitors for pancreatic cancer are not yet completed and are still recruiting patients. Among the completed trials, there have been findings of a preliminary nature such as delayed disease progression and enhanced overall survival after treatment with immune checkpoint inhibitors in mono- or combination therapy. However, due to small sample sizes, major results are not yet identifiable. The present article provides a clinical overview of immune checkpoint inhibition in pancreatic cancer. Pub Med, Clinical *** and American Society of Clinical Oncology's meeting abstracts were systematically searched for relevant clinical studies. Four articles, five abstracts and 25 clinical trials were identified and analyzed in detail.

关键词： Pancreatic cancer Immune checkpoint inhibitors Clinical trials

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Characterization of TGFβ-specific CD4+T cells through the modulation of TGFβexpression in malignant myeloid cells

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Cellular & Molecular Immunology 2021年第11期18卷 2575-2577页

作者： Rasmus Erik johansson Mortensen Morten Orebo Holmström Mads Hald Andersen National Center for Cancer Immune Therapy Department of OncologyCopenhagen University HospitalHerlevDenmark Institute for Immunology and Microbiology Copenhagen UniversityCopenhagenDenmark

Transforming growth factor beta(TGFβ)is a pleiotropic cytokine with functions related to angiogenesis,tumor suppression,and immune tolerance[1].TGFβis involved in tumor immune escape and is a target for cancer immune therapy[1].We have reported that healthy donors and cancer patients harbor CD8^(+)cytotoxic T lymphocytes(CTLs)that are specific to TGFβ-derived epitopes and that these CD8^(+)CTLs kill malignant myeloid cells in a TGFβ-dependent manner[2].

关键词： TGFβ malignant myeloid

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Volatile Organic Compound Emissions when Drying Wood Particles at High Dewpoints

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Chinese Journal of Chemical Engineering 2004年第6期12卷 767-772页

作者： Inge johansson Tobias Karlsson Roland Wimmerstedt S.E.P. Scandinavian Energy Project AB Bror Nilssons g. 16 SE-417 55 Goteborg SwedenThurne Teknik AB Heliosvagen 1 b SE-120 30 STOCKHOLM SwedenChemical Engineering Lund University P.O. Box 124 SE-221 00 LUND Sweden

Emission of volatile organic compounds (VOCs) during drying of wood particles for particleboard manufacture, or for production of refined biofuels, is a potential environmental problem. The aim of this work is to study the emissions of VOCs during drying, and the influence on the emissions by different drying *** experiments have mainly been done in a batch fluidized bed dryer, but measurements have also been done in a, pilot scale, continuous fluidized bed dryer. The parameters studied are air flow rate through the bed, air temperature, air dewpoint, and bed height. Since the present trend in biofuels and particle drying is towards very high dewpoints during drying, some measurements have been made at dewpoints up to 95℃, corresponding to a water content of 3.2 kg water per kilogram dry air. The emissions have been measured in two different ways,online during drying with a flame ionization detector and through wood analyses of the terpene content in the wood particles before and after drying. Substantial work has been made in developing the latter method as well as developing the drying equipment to be able to produce a wide range of conditions of the drying medium. It was shown that the VOCs emitted, during wood particle drying, mainly consist of terpenes. The behavior of the emissions was typical, at first contact with the drying gas a sharp peak in the release rate was detected. After that,the release rate stabilizes and declines slowly to a point where the material temperature increases and results in a second small peak in the release rate. Typically 80%-90% of the initial terpene content in the material was emitted during drying to low moisture content and it is not possible to significantly influence this release by changing the drying conditions. Up to 50% of the emitted terpenes are released during a very short period after contact with the drying medium. This fact could be utilized by employing a 2-step drying process. The fact that the VOC con

关键词： drying biofuels particleboard volatile organic compound high dewpoints

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