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Winkler Support Model and Nonlinear Boundary Conditions Applied to 3D Elastic Contact Problem Using the Boundary Element Method

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Acta Mechanica Solida Sinica 2019年第2期32卷 230-248页

作者： J.Vallepuga-Espinosa Lidia Sanchez-Gonzalez ivan Ubero-Martinez Departamento de Tecnologia Minera Topografiay de EstructurasUniversidad de LeonCampus de Vegazana s/n24071 LeonSpain Departamento de Ingenierias Mecanica Informatica y AeroespacialUniversidad de LeonCampus de Vegazana s/n24071 LeonSpain

This work presents a numerical methodology for modeling the Winkler supports and nonlinear conditions by proposing new boundary conditions. For the boundary conditions of Winkler support model, the surface tractions and the displacements normal to the surface of the solid are unknown, but their relationship is known by means of the ballast coefficient, whereas for nonlinear boundary conditions, the displacements normal to the boundary of the solid are zero in the positive direction but are allowed in the negative direction. In those zones, detachments of nodes might appear, leading to a nonlinearity, because the number of nodes that remain fixed or of the detached ones (under tensile tractions) is unknown. The proposed methodology is applied to the 3D elastic receding contact problem using the boundary element method. The surface t r actions and the displacements of the common int erface bet ween the two solids in contac t under the influence of different supports are calculated as well as the boundary zone of the solid where the new boundary conditions are applied. The problem is solved by a double-iterative met hod, so in the final solut ion, t here are no t r act ions or pene trations between the two solids or at the boundary of the solid where the nonlinear boundary conditions are Simula ted. The effectiveness of the proposed method is verified by examples.

关键词： Boundary element method Elastic contact problem Winkler support model Nonlinear boundary conditions

Determination of Vertices and Edges in a Parametric Polytope to Analyze Root Indices of Robust Control Quality

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International Journal of Automation and computing 2019年第6期16卷 828-837页

作者： Sergey Gayvoronskiy Tatiana Ezangina ivan Khozhaev Viktor Kazmin School of Computer Science and Robotics National Research Tomsk Polytechnic University

The research deals with the methodology intended to root robust quality indices in the interval control system, the parameters of which are affinely included in the coefficients of a characteristic polynomial. To determine the root quality indices we propose to depict on the root plane not all edges of the interval parametric polytope(as the edge theorem says), but its particular vertex-edge route. In order to define this route we need to know the angle sequence at which the edge branches depart from any integrated pole on the allocation area. It is revealed that the edge branches can integrate into the route both fully or partially due to intersection with other branches. The conditions which determine the intersection of one-face edge images have been proven. It is shown that the root quality indices can be determined by its ends or by any other internal point depending on a type of edge branch. The conditions which allow determining the edge branch type have been identified. On the basis of these studies we developed the algorithm intended to construct a boundary vertex-edge route on the polytope with the interval parameters of the system. As an illustration of how the algorithm can be implemented, we determined and introduced the root indices reflecting the robust quality of the system used to stabilize the position of an underwater charging station for autonomous unmanned vehicles.

关键词： Robust control parametric uncertainty parametric polytope interval parameters system analysis

Device performance and light characteristics stability of quantum-dot-based white-light-emitting diodes

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Nano Research 2018年第3期11卷 1575-1588页

作者： Bruno Clasen Hames ivan Mora-Sero Rafael S. Sanchez Institute of Advanced Materials (INAM) Universitat Jaume 1 12071 Castello Spain

Advances in image quality in recent decades have made it necessary to develop new technologies for producing displays to meet remarkably stricter standards. The display market is governed mainly by liquid crystal display and light-emitting diode （LED） technology; however, it suffers from limitations that can be overcome by developing the next generation of electroluminescent displays. The introduction of colloidal quantum dots （QDs） as down-converters has enabled the production of displays with extremely high color purity and gamut. Therefore, colloidal nanocrystals are excellent candidates for the preparation of electroluminescent devices, which represent a straightforward approach to the development of unprecedented high-quality displays. We synthesized light-emitting QDs covering the entire visible spectrum with high fluorescence quantum yields and color purity, and produced high-brightness single-color LEDs with external quantum efficiencies of 0.39%, 1.04%, 2.10%, and 1.30% for red-, orange-, green-, and blue-emitting dots, respectively. Additional136 white LEDs were prepared by mixing QDs; they showed color temperatures of 5,300 K and color rendering indices exceeding 80%. Very importantly, we exhaustively characterized the LED performance, including the response time, stability, and evolution of the light characteristics, thus providing crucial information toward the development of high-quality electroluminescent displays.

关键词： colloidal quantum dots quantum dotlight-emitting diodes white light-emitting diode(LED) displays electroluminescence LED stability

Influence of Magnetic Field and Lighting during the Creation Process of Nanohybrid Semiconductor-Nematic Structures on Their Impedance and Photo Response

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Journal of Materials Science & Technology 2011年第11期27卷 973-978页

作者： Fedir Ivashchyshyn ivan Grygorchak Olena Sudakova Igor Bordun Miroslav Micov Lviv Polytechnic National University 12 Bandera Str. Lviv 79013 Ukraine

In this work, for the first time, photosensitive nanostructures with alternate semiconductor and magnetic oriented nematic molecular nanolayers were obtained. The established dependency on the ordering type of kinetic and optical properties is deserving attention. For the first time, the notion of ＇rotary＇ polaron in such structures is introduced and microscopic model is created, which explains band structure transformation. The model is well coordinated with experimental optical data, which, at the same time, indicate the prospects of application of materials obtained due to the intercalation engineering for photoenergetics.

关键词： Nanocomposites Heterostructures Intercalation Liquid crystals Impedancespectroscopy Photoelectromotive force

“To measure is to know”: how advances in image analysis are supporting neural repair strategies

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Neural Regeneration Research 2015年第7期10卷 1040-1042页

作者： Pascal Vallotton Robert Michail ivan Kapsa Digital Productivity Flagship CSIRO Locked Bag 17 North Ryde NSW Australia ARC Centre for Electromaterials Science University of Wollongong (IPRI) Fairy Meadow NSW Australia

Neuronal regeneration in the peripheral nervous system arises via a synergistic interplay of neurotrophic factors,integrins,cytoskeletal proteins,mechanical cues,cytokines,stem cells,glial cells and astrocytes.

关键词： To measure is to know how advances in image analysis are supporting neural repair strategies

Multi-criteria decision-making method for evaluation of investment in enhanced geothermal systems projects

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Energy and AI

Energy and AI 2024年第3期17卷 143-167页

作者： Sara Raos Josipa Hranić ivan Rajšl University of Zagreb Faculty of Electrical Engineering and Computing Unska 310000 ZagrebCroatia GE Vernova 58 Charles StreetCambridgeMassachusettsUSA

Deep geothermal energy presents large untapped renewable energy potential could significantly contribute to global energy needs. However, developing geothermal projects involves uncertainties regarding adequate geothermal brine extraction and huge costs related to preparation phases and consequently drilling and stimulation activities. Therefore, evaluating utilization alternatives of such projects is a complex decision-making problem effectively addressed using multi-criteria decision-making (MCDM) methods. This study introduces the MCDM method utilizing analytic hierarchy process (AHP) and weighted decision matrix (WDM) to assess different utilization alternatives (electricity generation, direct heat use and cogeneration). The AHP method determines the weight of each criterion and sub-criterion, while the WDM calculates the final project grade. Five criteria groups - technological, geological, economic, societal and environmental – comprising twenty-eight influencing factors were selected and used for the assessment of investment in Enhanced Geothermal Systems (EGS) projects. The AHP-WDM method was used by 38 experts from six categories: industry, educational institution, research and technology organization (RTO), small- and medium-sized enterprises (SME), local community and other. These diverse expert inputs aimed to capture varying perspectives and knowledge influence investment decisions in geothermal energy. The results were analysed accordingly. The results underscore the importance of incorporating different viewpoints to develop robust, credible, and effective investment strategies for EGS projects. Therefore, this method will contribute to more efficient EGS project development, enabling thus a greater penetration of the EGS into the market. Additionally, the proposed AHP-WDM method was implemented for a case study examining two locations. Locations were assessed and compared on scenario-based evaluation. The results confirmed the method's adequacy for a

关键词： Deep geothermal energy Enhanced geothermal systems(EGS) Multi-criteria decision-making(MCDM)method Analytic hierarchy process(AHP) Weighted decision matrix(WDM)

Semiotic Proposition for Understanding Semantics Within Construction Documents

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Tsinghua Science and Technology 2008年第S1期13卷 192-198页

作者： ivan Mutis Raja R. A. Issa Department of Construction Science Texas A & M University College Station School of Building Construction University of Florida

This research develops a methodology that helps actors in understanding information generated from multiple construction participants. It employs semiotic theory which approaches the interpreter’s understanding of the role of the representations used in construction documents to communicate meanings to other participants. This strategy is designed to aid the interpreters’ comprehension of the use of symbols. The symbols within the construction documents are forms of representations that take the form of a visual representation of a set of markers that describe a formal language, and of markers that are used to represent natural language as well as other possible representations, such as a collection of codes for indexing documents. Symbols are replaced by signs under the semiotics theory. The use of symbols as signs is this study’s recognition of the relationship between the interpreter and the material quality of symbols. The semiotic analysis is an examination of the compromise between the meanings of a representation per se and the concept associated with the understanding of such representation.

关键词： semiotics construction representation semantic forms ontology categories

EUS mini probes in diagnosis of cystic dystrophy of duodenal wall in heterotopic pancreas:A case report

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World Journal of Gastroenterology 2004年第17期10卷 2609-2612页

作者： ivan Jovanovic Srbislav Knezevic Miodrag Krstic Marjan Micev Clinic of Gastroenterology and Hepatology Institute of Digestive DiseasesBelgradeSerbia and Montenegro First Surgical Clinic BelgradeSerbia and Montenegro Clinical Center of Serbia BelgradeInstitute for Medical ResearchBelgradeSerbia and Montenegro

Cystic dystrophy of the duodenal wall is a rare condition characterized by the development of cysts in heterotopic pancreatic tissue localized in the duodenal wall.A 38-year- old man was admitted to the hospital for abdominal pain and vomiting after food *** diagnosis of acute pancreatitis was initially *** ultrasound examination revealed thickening of the second portion of duodenal wall within which,small cysts(diameter,less than 1 cm)were present in the vicinity of pancreatic head. The head of pancreas appeared enlarged(63 mm×42 mm) and *** endoscopy and barium X-ray series were performed revealing a severe circumferential deformation,as well as 4 cm long stenosis of the second portion of the *** examination revealed multiple cysts located in an enlarged,thickened duodenal wall with moderate to strong post-contrast *** suspected that patient had cystic dystrophy of duodenal wall developed in the heterotopic pancreas and diagnosis was confirmed by endoscopic ultrasound(EUS).Endoscopic ultrasound(EUS)revealed circular stenosis from the duodenal bulb onwards.A twenty megahertz mini-prope examination further showed diffuse(intramural)infiltration of duodenal wall limited to the submucosa and muscularis propria of the second portion of duodenum with multiple microcysts within the thickened mucosa and *** was successfully surgically treated and pancreatoduodenectomy was *** pathological examination confirmed a diagnosis of cystic dystrophy of a heterotopic pancreas. Endoscopic ultrasonography features allow preoperative diagnosis of cystic dystrophy of a heterotopic pancreas in duodenal wall,with intralumina120 MHz mini probe sonography being more efficient in cases of luminal stenosis.

关键词： Pancreas Adult Choristoma Cysts Duodenal Diseases Humans Male

Engineering of immunoinstructive extracellular matrices for enhanced osteoinductivity

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Bioactive Materials 2023年第6期24卷 174-184页

作者： Andrés García-García Sébastien Pigeot ivan Martin Department of Biomedicine University Hospital BaselUniversity of Basel4031BaselSwitzerland Department of Biomedical Engineering University of Basel4123AllschwillSwitzerland

The increasing recognition of the contribution of the immune system to activate and prime regeneration implies that tissue engineering strategies and biomaterials design should target regulation of early immunological *** previously proposed the cell-based engineering and devitalization of extracellular matrices(ECMs)as a strategy to generate implant materials delivering custom-defined ***,in the context of bone regeneration,we aimed at enhancing the osteoinductivity of such ECMs by enriching their immunomodulatory factors *** with IL1βa cell line overexpressing BMP-2 enabled engineering of ECMs preserving osteoinductive signals and containing larger amounts of angiogenic(VEGF)and pro-inflammatory molecules(IL6,IL8 and MCP1).Upon implantation,these IL1β-induced materials enhanced processes typical of the inflammatory phase(e.g.,vascular invasion,osteoclast recruitment and differentiation),leading to‘regenerative’events(e.g.,M2 macrophage polarization)and ultimately resulting in faster and more efficient bone *** results bear relevance towards the manufacturing of potent off-the-shelf osteoinductive materials and outline the broader paradigm of engineering immunoinstructive implants to enhance tissue regeneration.

关键词： Immunomodulation Bone tissue engineering Inflammation Hypertrophic cartilage matrices Osteoinduction