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Curing Kinetics of Tannin and Lignin Biobased Adhesives Determined by DSC and ABES

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Journal of Renewable Materials 2022年第8期10卷 2117-2131页

作者： jaša Saražin Ida Poljanšek Antonio Pizzi MilanŠernek University of Ljubljana Biotechnical FacultyLjubljana1000Slovenia Universitéde Lorraine LERMAB-ENSTIB Epinal88000France

The curing process of two biobased adhesives:pine tanninhexamine(TH)and organosolv lignin non-isocyanate polyurethane(NIPU),suitable for interior nonstructural use,were compared with commercial urea-formaldehyde(UF)*** in chemical structure before and after the curing process were observed with Fouriertransform infrared spectroscopy(FTIR).The process of adhesive curing was monitored with differential scanning calorimetry(DSC)and the automated bonding evaluation system(ABES).Both DSC and ABES measurements confirmed UF as the fastest and NIPU as the slowest curing adhesive *** into account the ABES results,the optimal pressing parameters for the TH adhesive would be 4 min at 175℃,for the NIPU adhesive 7 min at 200℃and for the UF 1.5 min at 100℃.Strong linear correlation was observed between mechanical and chemical curing for the UF and NIPU adhesives,whereas lower correlation was observed for the TH *** all observed adhesives,the DSC measurements were underestimating the curing process determined by ABES in the first part and overestimating it at the *** underestimation was the most evident with the TH adhesive and the less with the UF *** comparing the uncured and cured FTIR spectra of all three types of adhesives,a drastic decrease in the characteristic band of-OH groups at 3330–3400 cm^(−1)and an increase in the signal intensity at 2920 cm^(−1)of aliphatic-CH2-groups were *** the UF adhesive,the C=O stretching frequency has shifted from 1632 cm^(−1)for uncured to three different bands at 1766,1701,and 1655 cm^(−1)for cured *** sharp band for phenolic alcohols at 1236 cm^(−1)of C–O stretch and hydroxyl O–H functional group at 1009 cm^(−1)and at 684 cm^(−1)of uncured TH adhesive diminished during curing,which indicates that a crosslinking reaction occurs via-OH *** peak of the C=O group of urethane bridges at 1697 cm^(−1)for uncured NIPU shifted to lower wavenumber at 1633 cm^(−1)for cured NIPU.

关键词： Biobased adhesives curing kinetics tannin lignin ABES DSC FTIR

Introducing a New Tool for Studying Unstable Systems

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International Journal of Automation and computing 2014年第6期11卷 580-587页

作者： Frantiek Gazdo Tomas Bata University in Zlín Faculty of Applied Informatics nam.T.G.Masaryka 5555760 01 Zlin Czech Republic

This paper presents the starting project of a web site focussed on unstable systems. It is a web-based database in a bilingual version(English/Czech), which can be used as an information database for models of unstable processes. The web site contains the mathematical models of such systems, including their simulation files together with basic information about the stability of dynamic systems. The paper outlines the motivation for the development of this database, presents its basic structure, and discusses several models from the site. The areas of prospective usage are also suggested together with the possible directions of further development of this project. The contribution ends with a case study using the database for control system analysis and design of the Amira inverted pendulum. The systematic polynomial approach is fruitfully utilised for the task together with some useful tools from the robust control theory.

关键词： Unstable systems stability modelling simulation database robust control polynomial approach

Calibration and uniqueness analysis of microparameters for DEM cohesive granular material

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International Journal of Mining Science and Technology 2022年第1期32卷 121-136页

作者： Songtao Ji Jurij Karlovšek School of Civil Engineering The University of QueenslandBrisbane 4067Australia

The differential evolution(DE)algorithm was deployed to calibrate microparameters of the DEM cohesive granular material.4 macroparameters,namely,uniaxial compressive strength,direct tensile strength,Young’s modulus and Poisson’s ratio,can be calibrated to high *** best calibration accuracy could reach the sum of relative errors RE_(sum)<0.1%.Most calibrations can be achieved with RE_(sum)<5%within hours or RE_(sum)<1%within 2 *** on the calibrated results,microparameters uniqueness analysis was carried out to reveal the correlation between microparameters and the macroscopic mechanical behaviour of material:(1)microparameters effective modulus,tensile strength and normal-to-shear stiffness ratio control the elastic behaviour and stable crack growth,(2)microparameters cohesion and friction angles present a negative linear correlation that controls the axial strain and lateral strain prior to the peak stress,and(3)microparameters friction coefficient controls shear crack friction and slip mainly refers to the unstable crack *** of more macroparameters to regulate the material mechanical behaviour that is dominated by shear crack and slip motion is highlighted for future *** DE calibration method is expected to serve as an alternative method to calibrate the DEM cohesive granular material to its peak strength.

关键词： Discrete element method(DEM) Particle flow code(PFC) Differential evolution(DE) Parameter calibration Uniqueness analysis Post-peak behaviour

The Economic Demands on the Method of Founding a Passive Brick House on Foamed Glass Granulate

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Journal of Civil Engineering and Architecture 2024年第5期18卷 218-222页

作者： Marek jašek Faculty of Civil Engineering VSB-TU of OstravaOstrava 70800Czech Republic

The cost of acquisition of a passive house is a little higher than that of a conventional *** design of a passive house should include not only thermal protection and stability of the construction,but it must also take into account the price demands on each of the proposed structures and solution of *** paper deals with the financial comparison of the traditional method of a foundation on the foundation strips of plain concrete and the modern method of founding a passive house as brick construction on the reinforced concrete slab base with a compact subsoil layer of thermal insulation in the form of granules of foamed glass.

关键词： Passive house financial comparison granules of foamed glass

Stochastic many-body calculations of moiréstates in twisted bilayer graphene at high pressures

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npj Computational Materials 2022年第1期8卷 89-98页

作者： Mariya Romanova Vojtěch Vlček Department of Chemistry and Biochemistry University of CaliforniaSanta BarbaraCA93106-9510USA

We introduce three developments within the stochastic many-body perturbation theory:efficient evaluation of off-diagonal self-energy terms,construction of Dyson orbitals,and stochastic constrained random phase *** stochastic approaches readily handle systems with thousands of *** use them to explore the electronic states of twisted bilayer graphene(tBLG)characterized by giant unit cells and correlated electronic *** document the formation of electron localization under compression;weakly correlated states are merely shifted in *** demonstrate how to efficiently downfold the correlated subspace on a model Hamiltonian with a screened frequency-dependent two-body *** the 6°tBLG system,the onsite interactions are between 200 and 300 meV under *** Dyson orbitals exhibit spatial distribution similar to the mean-field single-particle *** pressure,the electron-electron interactions increase in the localized states;however,the dynamical screening does not fully balance the dominant bare Coulomb interaction.

关键词： interaction twisted stochastic

Characteristics of Underground Water Flow at Different Water Levels in Tianshengan Karst Area, Yunnan, China

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Acta Geologica Sinica(English Edition) 2010年第1期84卷 206-212页

作者： janja KOGOVek Karst Research Institute ZRC SAZU Titov trg 2 SI-6230 Postojna Slovenija

Three tracing tests from the same injection point executed at low, medium, and high water levels in the karst aquifer near Tianshengan village, Lunan Stone Forest, Yunnan Province, China, have revealed the basic properties of underground water flow. They showed the general directions of water flows; tracer concentrations were observed at six successive points allowing for the calculation of apparent dominant flow velocities at these sections towards the Dalongtan karst spring. For the high water level, the discharge between single sections was between two and 10 times greater than that at low water level. For the medium water level, the flow velocity at different sections was between 1.4 and 3.7 times faster than that at low water level; and for high water level, it was between 1.3 and 2.7 times faster than that at medium water level. The fastest water flow appeared at the first section （23 cm/s at medium water level）; and the slowest （0.6 cm/s at low water level） appeared where water flow must cross the Tianshengan fault （north-south direction）, and later, a layer of 20-30 m thickness of quartz sandstone and shale clay-stones. It was also possible to calculate the recovery of the tracer for point 4, Dakenyan, where discharge was measured. At the medium water level, 50% of the injected tracer was detected a half-day after its first appearance and at low water level after more than 3 days. The previously published research illustrates the transport velocities of possible contaminants and their solubilities in water at different hydrological conditions.

关键词： karst tracing test underground water flow Lunan Yunnan China

Electrochemical studies of Meldola blue-modified bilayer lipid membranes

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Chinese Science Bulletin 1997年第3期42卷 203-207页

作者： Ding, L Wang, ek CHINESE ACAD SCI CHANGCHUN INST APPL CHEMELECTROANALYT CHEM LABCHANGCHUN 130022PEOPLES R CHINA

BILAYER lipid membranes (BLM) have been extensively regarded as a basic structure that forms the matrix of biological membranes. The properties of BLM may be altered by incorporation and modification and can be employed to study many membrane processes. Especially biosensors and bi-molecular electronic devices made by BLM have a wide application. Many kinds of organic dyes are known as biological stains and often used in biology, physiology, pharmacology and medicine. In general, coloring and staining processes involve adsorp-

关键词： Meldola blue bilayer lipid membranes (BLM) electrochemistry.

STM image of tungstosilicic acid molecular layer on highly oriented pyrolytic graphite

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Chinese Journal of Chemistry 1995年第6期13卷 493-496页

作者： Zhang, BL Wang, ek CHINESE ACAD SCI CHANGCHUN INST APPL CHEMELECTROANALYT CHEM LABCHANGCHUN 130022JILINPEOPLES R CHINA

Molecular layer of tungstosilicic acid (H4SiW12O40) deposited on freshly-cleaved highly oriented pyrolytic graphite (HOPG) was observed by scanning tunneling microscopy (STM) in air at room temperature. The molecular dimension (11.5 Angstrom) of H4SiW12O40 measured by STM is consistent with known crystallographic parameter. We also imaged the boundary of H4SiW12O40 molecular layer on HOPG showing that molecular layer of H4SiW12O40 was formed. It has been proved that individual tungstosilicic acid species is imaged. The probable reason for the formation of the molecular layer is also discussed.

关键词： tungstosilicic acid HOPG STM

Analytical study of subcritical crack growth under mode I loading to estimate the roof durability in underground excavation

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International Journal of Mining Science and Technology 2022年第2期32卷 375-385页

作者： Songtao Ji Zeng Wang Jurij Karlovšek Geotechnical Engineering Centre School of Civil EngineeringThe University of QueenslandBrisbane 4067Australia China Coal Technology&Engineering Group Nanjing Design&Research Institute Co. Ltd.Nanjing 210031China

The long-term stability of the roof is particularly important in designing underground rock *** estimate the durability of roof strata in underground excavation,a computation scheme of subcritical crack growth is proposed in this *** adopting the proposed method,the potential collapse location of strata is derivable in accordance with a static model,the durability of roof strata can be estimated,a dynamic time step control strategy is achieved to balance the accuracy and speed of computing,and the initial crack size of rock can be *** addition to the above,a mechanical model of underground excavation with non-uniformly distributed loads and partially yielded foundation is presented as the prototypical case.A set of case studies is carried out that showcase a power correlation between applied stress and roof *** allowable applied tensile stress for a 100-year life cycle is about 76%of the tensile *** using the proposed subcritical crack growth computation scheme,the roof stability in an underground excavation can be identified not only from the spatial view but also from the temporal perspective.

关键词： Roof durability Analytical model Subcritical crack growth Stress intensity factor Initial crack size Dynamic time step