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Plasmonic decay into hot electrons in silver

PROGRESS IN SURfACE SCIENCE 2023年第3期98卷

作者： Petek, Hrvoje Li, Andi Li, Xintong Tan, Shijing Reutzel, Marcel Univ Pittsburgh Dept Phys & Astron & IQ Initiat Pittsburgh PA 15260 USA Univ Sci & Technol China Hefei Natl Res Ctr Phys Sci Microscale Hefei 230026 Anhui Peoples R China Georg August Univ Gottingen Phys Inst 1 D-37077 Gottingen Germany

Light at optical frequencies interacting with a metal surface can excite interband quantum transitions, or intraband currents at frequencies approaching the PHz range. Momentum con-servation enables the interband excitation to occur in first order as a dipole transition, while intraband excitations involve second-order momentum scattering processes. The free electron response to optical fields can also be collective, causing the optical field to be screened by the multipole plasmon response. We describe the exitation of single crystal silver surfaces in the region where the dielectric response transits from negative to positive passing through the epsilon near zero (ENZ) condition. There, electrons can no longer screen the optical field, so that it penetrates as a collective charge density wave of the free electron plasma, in other words, as a bulk transverse or longitudinal plasmon field. We examine two-photon photoemission (2PP) signals from Ag(1 1 1), (100) and (110) surfaces through the ENZ region under conditions where intraband, and interband single particle, and bulk plasmon collective responses dominate. We are specifically interested in the bulk plasmon decay into plasmonic photoemission. Plasmonic decay into excitation of electrons from the fermi level, which we observe as a nonlinear 2PP process, has been established for the free electron and noble metals, but its significance to transduction of optical-to-electronic energy has not penetrated the plasmonics community. 2PP spectra show evidence for intraband hot electron generation, interband surface and bulk band excitation, and nonlinear bulk plasmon driven plasmonic single particle excitation. Because the intraband and plasmonic decay into hot electron distributions have been extensively considered in the literature, without reference to explicit experimental measurements, we discuss such processes in light of the directional anisotropy of the electronic structure of single crystalline silver. We note t

关键词： TR- m PP time resolved multiphoton photoemission (spectroscopy) AR- m PP angle resolved multiphoton photoemission (spectroscopy) LP localized plasmons 2 PP two-photon photoemission m PP multi-photon photoemission ( m =2–10) ENZ epsilon (dielectric constant) near zero SPP surface plasmon polariton SAM spin angular momentum OAM orbital angular momentum ITR-PEEM interferometric time-resolved photoemission electron microscopy SS Shockley surface state IP1 Image potential state ( n =1) L sp lower sp -band U sp upper sp -band E f fermi level E V vacuum level TS Tamm surface state ℏω L laser photon energy ITR- 2 PP interferometric time-resolved two photon photoemission fT fourier transform E f ( k || ) final state energy vs . parallel momentum (spectra) ω p bulk plasmon frequency

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Effective removal of methylene blue, a hazardous dye from industrial effluents using active carbon of *** plant

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INTERNATIONAL JOURNAL Of ENVIRONMENTAL SCIENCE AND TECHNOLOGY 2019年第12期16卷 7837-7848页

作者： Ravulapalli, S. Kunta, R. Koneru Lakshmaiah Educ Fdn Vaddeswaram Andhra Pradesh India

Activated carbon prepared from the barks of f. infectoria is investigated as an adsorbent for the extraction of methylene blue dye from industrial wastewater using batch methods of adsorption. Influence of different physicochemical parameters on the adsorptive removal of dye is investigated and the conditions are optimized. The maximum adsorption ability for the adsorbent is noticed as 151.6 mg/g. Surface morphology of the adsorbent is studied using field emission scanning electron microscope, fourier transform infrared spectroscopy and Brunauer-Emmett-Teller techniques. The adsorption mechanism is analyzed by various adsorption isotherms and kinetic models. Investigation of thermodynamic parameters reveals the endothermic and spontaneous nature of the extraction process. The spent adsorbent is regenerated and reused for the extraction and noted the adsorption capacity is marginally affected due to regeneration. The method is applied for purifying the dye-contaminated samples from the industrial effluents.

关键词： Active carbon f infectoria plant Methylene blue dye Adsorption Regeneration Adsorbent

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Pinching in Steel Rack Joints: Numerical Modelling and Effects on Structural Response

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INTERNATIONAL JOURNAL Of STEEL STRUCTURES 2019年第1期19卷 131-146页

作者： Gusella, federico Orlando, Maurizio Spinelli, Paolo Univ Florence Dept Civil & Environm Engn Via S Marta 3 I-50139 Florence Italy

The structural behaviour of beam-to-column joints plays a key role in the seismic response of frame structures. Regarding to steel storage pallet racks, experimental tests have highlighted that the hysteresis loop of their joints is characterized by the pinching, with the consequence of a reduction of the dissipated hysteretic energy and load carrying capacity. In this paper the authors propose a simplified numerical pinching model capable to simulate the mechanical response of beam-to-column joints under cyclic loads. To develop and check this model, several comparisons are performed with both literature data and experimental results of laboratory tests. The proposed model is characterised by three links placed in parallel: two composed links describe the non-linear bending moment-rotation curve of the joint, and a linear elastic link transfers the axial and shear force from the beam to the column. The model is appropriate for predicting the down-aisle seismic response of rack systems and it can be easily implemented in commercial software packages, commonly used for non-linear seismic vulnerability analyses. Moreover, features of the model can be estimated from a few structural data and it does not require to perform expensive cyclic experimental tests. for a deeper understanding of the effects of pinching in the seismic response and to highlight the potentiality of the proposed model a case-study example is also considered. The case-study concerns a rack system, whose beam-to-column joints are modelled using two numerical approaches which differ in the deterioration of the rotational stiffness of joints. Non-linear dynamic analyses, with simulated ground acceleration time-histories, have been carried.

关键词： Beam-to-column joints f E numerical models Steel rack systems Seismic vulnerability analysis Pinching effects

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Study of thermodynamic properties of SrThf6(s) in Srf2-Thf4 system using solid state electrochemical cell method

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JOURNAL Of SOLID STATE ELECTROCHEMISTRY 2019年第11期23卷 3067-3074页

作者： Mukherjee, Sumanta Dash, S. Bhabha Atom Res Ctr Div Fuel Chem Mumbai 400085 Maharashtra India Bhabha Atom Res Ctr HBNI Mumbai 400085 Maharashtra India

The fission product strontium (Sr), after generation in the reactor due to fission of U-233, might exist as Srf2 in the molten fluoride medium of molten salt reactor (MSR) using fluoride carrier salts. The high temperature interactions between the strontium fluoride (Srf2) with the fertile fuel component and thorium fluoride (Thf4) leads to form single ternary compound SrThf6(s). The Gibbs energy of formation is the driving force for formation of any compound. In the present study, standard molar Gibbs energy of formation SrThf6(s) has been determined using an e.m.f. technique using Caf2(s) as solid electrolyte. Using the experimental thermodynamic data, to study the stability domain of SrThf6(s), the chemical potential diagram of Sr-Th-f-O system and ternary phase diagram of Sr-Th-f-2 system have been calculated.

关键词： MSR SrThf6(s) E M f Phase diagram Potential diagram

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Hydrothermal carbonization of plastic waste: A review of its potential in alternative energy applications

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fuel Communications 2024年 18卷

作者： Clovis Awah Che Philippe M. Heynderickx Center for Environmental and Energy Research (CEER) Engineering of Materials via Catalysis and Characterization Ghent University Global Campus 119-5 Songdo Munhwa-ro Yeonsu-gu Incheon 406-840 Republic of Korea Department of Green Chemistry and Technology Faculty of Bioscience Engineering Ghent University Coupure Links 653 B-9000 Ghent Belgium

The significant rise in plastic consumption and waste generation, coupled with the urgent need for sustainable energy solutions, has led to innovative research seeking to convert plastic waste into valuable resources. This review focuses on the application of hydrothermal carbonization as a promising technique for transforming plastic waste into valuable products. It highlights the suitability of hydrothermal carbonization for plastic waste conversion, and presents recent reports showing promising results, prospects, and a range of potential hydrochar applications, including solid recovered fuels, catalysts, direct carbon fuel cells and supercapacitors. This review further presents the challenges in utilizing plastic hydrochar across different applications, which include feedstock variability, contamination, scalability, material properties, and environmental considerations. The need for optimized synthesis methods, stable performance, and long-term sustainability is also emphasized. The critical evaluation of the applications of hydrothermal carbonization can contribute to advancing sustainable waste management and renewable energy production.

关键词： Hydrothermal carbonization Plastic waste to energy Plastic hydrochar Sustainability ABS Acrylonitrile butadiene styrene C flammability index CHf Critical heat flux CI Combustion characteristic index DCfC Direct carbon fuel cell D i Ignition index D f Burnout index EG Ethylene glycol GHG Greenhouse gas HEVs Hybrid Electric Vehicles H f Index of intensity HGI Hardgrove grindability index HIPS High impact polystyrene HTC Hydrothermal carbonization HTL Hydrothermal liquefaction HTG Hydrothermal gasification IPA Isopropyl alcohol NiO-SDC Nickel Oxide and Samarium-Doped Ceria NRf National Research foundation OECD The Organization for Economic Co-operation and Development PC Polycarbonate P c Critical pressure PE Polyethylene PEMfC Proton exchange membrane fuel cells PET Polyethylene Terephthalate PP Polypropylene PS Polystyrene PVC Polyvinyl Chloride S Combustion performance index SRf Solid recovered fuel T c Critical temperature T f Burnout temperature T i Ignition temperature T p Peak temperature TG-DTG Thermogravimetry-derivative thermogravimetry TPA Terephthalic acid

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Simulation of Low Velocity Impact on CfRP Aerospace Structures: Simplified Approaches, Numerical and Experimental Results

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APPLIED COMPOSITE MATERIALS 2019年第3期26卷 835-856页

作者： Prentzias, V. Tsamasphyros, G. J. Natl Tech Univ Athens Strength Mat Lab 5 Iroon Polytech GR-15773 Athens Greece

This paper presents a study of low velocity impact on unidirectional composite specimens, a plate and an aerospace stiffened panel following the building block approach. Simplified approaches for a quick estimation of impact behavior description are used to define the impact dynamic response and the existence of delamination at coupon level, while numerical analysis models using ABAQUS/Explicit software and experimental results are described in detail and compared at all levels. Significant effort was made in the use of different types of elements and damage models for matrix cracking, fiber breakage and cohesive elements for delamination between plies of composite. The results obtained show that simplified approaches give an effective initial understanding of the impact response helping the interpretation of numerical and experimental results. In addition, the comparison of different methods of simulation demonstrated that continuum shell elements with induced cohesive elements present the most accurate results regarding the impact force, contact duration, energy absorption and damage extension.

关键词： A Low velocity impact B Explicit finite element analysis C Interlaminar damage D Intralaminar damage E Aerospace CfRP panels f Building block approach

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Reinterpreting Dependency Schemes: Soundness Meets Incompleteness in DQBf

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JOURNAL Of AUTOMATED REASONING 2019年第3期63卷 597-623页

作者： Beyersdorff, Olaf Blinkhorn, Joshua Chew, Leroy Schmidt, Renate Suda, Martin Univ Leeds Sch Comp Leeds W Yorkshire England Univ Manchester Sch Comp Sci Manchester Lancs England Vienna Univ Technol Inst Informat Syst Vienna Austria

Dependency quantified Boolean formulas (DQBf) and QBf dependency schemes have been treated separately in the literature, even though both treatments extend QBf by replacing the linear order of the quantifier prefix with a partial order. We propose to merge the two, by reinterpreting a dependency scheme as a mapping from QBf into DQBf. Our approach offers a fresh insight on the nature of soundness in proof systems for QBf with dependency schemes, in which a natural property called 'full exhibition' is central. We apply our approach to QBf proof systems from two distinct paradigms, termed 'universal reduction' and 'universal expansion'. We show that full exhibition is sufficient (but not necessary) for soundness in universal reduction systems for QBf with dependency schemes, whereas for expansion systems the same property characterises soundness exactly. We prove our results by investigating DQBf proof systems, and then employing our reinterpretation of dependency schemes. finally, we show that the reflexive resolution path dependency scheme is fully exhibited, thereby proving a conjecture of Slivovsky.

关键词： Quantified Boolean formulas DQBf Dependency schemes f 2 2 Nonnumerical algorithms and problems

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Mapping the ‘business of development’: the geography of UK for-profit development contractors

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finance and Space 2024年第1期1卷

作者： Olivia Taylor Paul Gilbert a Department of Geography University of Sussex Brighton UK b Department of International Development University of Sussex Brighton UK

ABSTRACTThis financial visualisation (finVis) shows the geographical distribution of the UK’s top for-profit development contractors. Using a novel database, we map the location and value of 915 contracts awarded to UK-based private sector contractors by the UK’s foreign, Commonwealth and Development Office (formerly the Department for International Development). It shows the geography of firms capturing aid finance, concentrated in London and the southeast of England. It contributes to understanding ‘aid contractor assemblages’ (cf. Roberts, S. M. 2014. Development Capital: USAID and the Rise of Development *** of The Association of American Geographers,104(5), 1030–1051), and the knowledge economies and networks of firms which have become increasingly powerful in shaping a market around the ‘business of development’.

关键词： Aid-funded business development contractors development finance for-profit firms foreign Commonwealth and Development Office United Kingdom f35 f3 f H57 H5 H R10 R1 R

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Numerical Simulation of Damage on Cementitious Sprayed fire-Resistive Materials Applied on Steel Plates

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fIRE TECHNOLOGY 2019年第5期55卷 1877-1910页

作者： Zografopoulou, Kalliopi Mistakidis, Euripidis Univ Thessaly Lab Struct Anal & Design Dept Civil Engn Volos Greece

Cementitious Sprayed fire Resistive Materials (SfRMs) are extensively employed for the fire protection of steel structural members due to their cost-effective fire proofing capabilities. They are susceptible, however, to brittle failure, cracking and spalling when the underlying structural member is subjected to mechanical deformations. A numerical method combining the smeared crack model and the discrete crack concept in a finite Element mesh splitting scheme, is proposed for the simulation of the damage occurring in the body of the material, leading to a more realistic modeling of the material spalling, which, in conjunction with the loss of interface bond between the SfRM and steel, allows individual pieces of the SfRM coating to detach from steel, leaving it exposed to thermal actions. The proposed method is implemented in a series of numerical models, simulating steel plates bearing 20 mm or 30 mm SfRM coating, which are submitted to constant bending moment, axial tension or axial compression. The numerical results of the failure mechanisms of the SfRM coatings, regarding the failure of the interface bond and the formation of transverse cracks, are in good agreement with the reported observations of the corresponding experimental tests found in the literature. A subsequent numerical thermal analysis of three damaged configurations of the SfRM coated plate, missing 10% to 60.5% of the SfRM coating, submitted to ISO-834 thermal load, indicated that the critical yield stress of the plate due to the temperature rise, is reached 38% to 76% faster in comparison to the undamaged state. The proposed method can be a very effective tool in the assessment and prediction of SfRM damage, as it could be applied on any structural configuration, allowing the further study of the parameters space.

关键词： SfRM Damage fire protection Cracking f E M

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High-pressure pyrolysis and oxidation of DME and DME/CH4

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COMBUSTION AND fLAME 2019年 205卷 80-92页

作者： Hashemi, Hamid Christensen, Jakob M. Glarborg, Peter Tech Univ Denmark DTU Chem Engn DK-2800 Lyngby Denmark

The pyrolysis and oxidation of dimethyl ether (DME) and its mixture with methane were investigated at high pressure (50 and 100 bar) and intermediate temperature (450-900 K). Mixtures highly diluted in nitrogen with different fuel-air equivalence ratios (Phi = infinity, 20, 1, 0.06) were studied in a laminar flow reactor. At 50 bar, the DME pyrolysis started at 825 K and the major products were CH4, CH2O, and CO. for the DME oxidation at 50 bar, the onset temperature of reaction was 525 K, independent of fuel-air equivalence ratio. The DME oxidation was characterized by a negative temperature coefficient (NTC) zone which was found sensitive to changes in the mixture stoichiometry but always occurring at temperatures of 575-625 K. The oxidation of methane doped by DME was studied in the flow reactor at 100 bar. The fuel-air equivalence ratio (Phi) was varied from 0.06 to 20, and the DME to CH4 ratio changed over 1.8-3.6%. Addition of DME had a considerable promoting effect on methane ignition as the onset of reaction shifted to lower temperatures by 25-150 K. A detailed chemical kinetic model was developed by adding a DME reaction subset to a model developed in previous high-pressure work. The model was evaluated against the present data as well as data from literature. Additional work is required to reconcile experimental and theoretical work on reactions on the CH3 OCH2OO PES with ignition delay measurements in the NTC region for DME. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

关键词： Dimethyl ether (DME) Methane Oxidation High pressure Reaction mechanism f Intermediate temperatures f

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