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Numerical study on waste polyethylene pyrolysis driven by self-sustaining smoldering

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Science China(Technological Sciences) 2024年第2期67卷 627-638页

作者： PAN RuMing WU YiBo GUENE LOUGOU Bachirou SHUAI Yong dEBENEST Gérald School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China institut de Mecanique des Fluides de Toulouse(IMFT)-Universite de Toulouse CNRS-INPT-UPSToulouse 31400France

Polyethylene is the type of waste plastic that accounts for the most significant proportion of municipal solid *** polyethylene can be valorized via pyrolysis and produce value-added oil,gas,and *** the other hand,self-sustaining smoldering is an emerging technical means to deal with sand/soil contaminated by organic *** high-temperature heat generated by smoldering can be used as a heat source for pyrolyzing waste ***,this study investigates numerically the pyrolysis of waste polyethylene driven by self-sustaining smoldering.A novel 4-step lumped kinetic model is proposed for simulating the pyrolysis of waste *** results indicate that the operating parameters can determine the pyrolysis product yields by regulating the pyrolysis temperature and the volatile residence *** that higher temperatures and longer residence times favor the generation of shorter-chain pyrolysis products because of the intensified volatiles’secondary *** can be concluded that a high interface-wall heat transfer coefficient(400 W m^(-2)K^(-1)),a low PE content(0.20),a high char concentration(2.4%),and a moderate air velocity(0.040 m s^(-1))are beneficial to oil *** some extent,this study may broaden the boundaries for the application of self-sustained smoldering-driven pyrolysis.

关键词： self-sustained smoldering waste polyethylene thermal decomposition oil production waste valorization

Mg(OH)_2 Nanorods Synthesized by A Facile Hydrothermal Method in the Presence of CTAB

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Nano-Micro Letters 2011年第3期3卷 153-159页

作者： Hassouna dhaouadi Hedia Chaabane Fathi Touati "Laboratoire des Matriaux Utiles" institut national de Recherche et d’Analyse Physico-chimique Ple technologique de Sidi-Thabet "Laboratoire de Microbiologie" institut national de Recherche et d’Analyse Physico-chimique Ple technologique de Sidi-Thabet

Magnesium hydroxide(Mg(OH)_2) nanorods were synthesized by a simple and facile hydrothermal method in the presence of cetyltetramethylammonium bromide(CTAB) as a surfactant. Nanorods of magnesium oxide Mg O were also induced by thermal decomposition of Mg(OH)_2 nanorods at 700. By using disk diffusion technique, the Mg(OH)_2 nanorods were found to exhibit higher antibacterial efficiency against several tested bacterial strains.

关键词： Nanorods Morphology Hydrothermal synthesis

Minimal Legendrian surfaces in the tangent sphere bundle of ■

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Science China Mathematics 2024年

作者： Mingyan Li Guofang Wang School of Mathematical Sciences Ocean University of China Mathematisches institut Albert-Ludwigs-Universit?t Freiburg

In this paper, we study minimal Legendrian surfaces Σ immersed in the tangent sphere bundle T1■3. We classify（1） totally geodesic Legendrian surfaces,（2） closed minimal Legendrian surfaces of genus smaller than or equal to 1 and complete minimal Legendrian surfaces with the non-negative Gauss curvature,and（3） complete stable minimal Legendrian surfaces.

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A Review on Technologies for the Use of CO2 as a Working Fluid in Refrigeration and Power Cycles

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Energy and Power Engineering 2024年第6期16卷 217-256页

作者： Orelien T. Boupda Hyacinthe d. Tessemo Isidore B. Nkounda Fongang Francklin G. Nyami Frederic Lontsi Thomas djiako Laboratory of Energy Higher National Polytechnic School of Douala University of Douala Douala Cameroon institut Ucac-Icam Douala Cameroon department of Energy and Mechanical Engineering ISTA-IUG University of Ngaoundere Ngaoundere Cameroon

The use of carbon dioxide as a working fluid has been the subject of extensive studies in recent years, particularly in the field of refrigeration where it is at the heart of research to replace CFC and HCFC. Its thermodynamic properties make it a fluid of choice in the efficient use of energy at low and medium temperatures in engine cycles. However, the performance of transcritical CO2 cycles weakens under high temperature and pressure conditions, especially in refrigeration systems;On the other hand, this disadvantage becomes rather interesting in engine cycles where CO2 can be used as an alternative to the organic working fluid in small and medium-sized electrical systems for low quality or waste heat sources. In order to improve the performance of systems operating with CO2 in the field of refrigeration and electricity production, research has made it possible to develop several concepts, of which this article deals with a review of the state of the art, followed by analyzes in-depth and critical of the various developments to the most recent modifications in these fields. detailed discussions on the performance and technical characteristics of the different evolutions are also highlighted as well as the factors affecting the overall performance of the systems studied. Finally, perspectives on the future development of the use of CO2 in these different cycles are presented.

关键词： Refrigeration Cycle Power Cycle System Performance Transcritical CO2 Cycles Working Fluid

Anomalous negative magnetoresistance in quantum dot Josephson junctions with Kondo correlations

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 3-13页

作者： Mingtang deng Chunlin Yu Guangyao Huang Rosa López Philippe Caroff Sepideh Ghalamestani Gloria Platero Hongqi Xu institute for Quantum Information&State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China NanoLund and division of Solid State Physics Lund UniversityLund S-22100Sweden China Greatwall Quantum Laboratory Changsha 410006China institut de Física Interdisciplinària i de Sistemes Complexos IFISC Palma de Mallorca E-07122Spain instituto de Ciencia de Materiales de Madrid Madrid 28049Spain Beijing Key Laboratory of Quantum devices Key Laboratory for the Physics and Chemistry of Nanodevicesand Department of ElectronicsPeking UniversityBeijing 100871China Beijing Academy of Quantum Information Sciences Beijing 100193China Hefei national Laboratory Hefei 230088China

The interplay between superconductivity and the Kondo effect has stimulated significant interest in condensed matter *** compete when their critical temperatures are close and can give rise to a quantum phase transition that can mimic Majorana zero ***,we have fabricated and measured Al-InSb nanowire quantum dot-Al *** the Kondo regime,a supercurrent-induced zero-bias conductance peak *** zero-bias peak shows an anomalous negative magnetoresistance(NMR)at weak magnetic *** attribute this anomalous NMR to quasiparticle trapping at vortices in the superconductor leads as a weak magnetic field is *** trapping effect lowers the quasiparticle-caused dissipation and thus enhances the Josephson *** work connects the vortex physics and the supercurrent tunneling in Kondo regimes and can help further understand the physics of Josephson quantum dot system.

关键词： quantum dot Kondo correlation InSb nanowire quasiparticle trapping

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Numerical Blow-up for a Nonlinear Heat Equation

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Acta Mathematica Sinica,English Series 2011年第5期27卷 845-862页

作者： Firmin K. N'GOHISSE Theodore K. BONI Universite d'Abobo-Adjame UFR-SFA Departement de Mathematiques et Informatique 01 BP 1003 Abidjan 01 Cdte d'Ivoire institut national Polytechnique Houphouet-Boigny de Yamoussoukro BP 1093 Yamoussoukro Cote d'Ivoire

This paper concerns the study of the numerical approximation for the following initialboundary value problem{ut-uzx=f（u）,t∈（0,1）,t∈（0,T） u（0,t）=0,t∈（0,1）,t∈（0,T） u（x,0）=u0（x）,x∈（0,1）where f（s） is a positive, increasing, C1 convex function for the nonnegative values of s, f（0）〉0, f∞ds/f（s）〈∞, u0∈C1（[0, 1]）, u0（0） = 0, u＇0（1）=0. We find some conditions under which the solution of a semidiscrete form of the above problem blows up in a finite time and estimate its semidiserete blow-up time. We also prove the convergence of the semidiscrete blow-up time to the theoretical one. A similar study has been also undertaken for a discrete form of the above problem. Finally, we give some numerical results to illustrate our analysis.

关键词： Semidiscretization blow-up numerical blow-up time nonlinear heat equations

Rubik's cube as in-situ programmable matter and a reconfigurable mechanical metamaterial

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Science China Technological Sciences 2024年

作者： ZHU ShaoWei CHEN Huan YANG XiaoQiang TAN Li JIN Shuai CHEN LiMing LIU Tao TAN XiaoJun WANG LianChao WANG Bing MUAMER Kadic College of Aerospace Engineering Chongqing University State Key Laboratory of Coal Mine disaster dynamics and Control Chongqing University School of Civil Aviation Northwestern Polytechnical University national Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of Technology institut FEMTO-ST CNRS UMR 6174 University Bourgogne

As part of the 4th industrial revolution, programmable mechanical metamaterials exhibit great application potential in flexible robotics, vibration control, and impact protection. However, maintaining a programmed state without sustaining the external stimulus is often challenging and leads to additional energy consumption. Inspired by Rubik's cube, we design and study an insitu programmable and distribution-reconfigurable mechanical metamaterial(IPdR-MM). A matrix model is developed to model IPdR-MMs and describe their morphological transitions. Based on this model, the reinforcement learning method is employed to find the pathways for morphological transitions. We find that IPdR-MMs have controllable stiffness across several orders of magnitude and a wide range of adjustable anisotropies through morphology transformation. Additionally, because of the independence of the directions of morphology transformation and bearing, IPdR-MMs exhibit good stability in bearing and can readily achieve high stiffness. The Rubik's cube-inspired design concept is also instructive for other deformable structures and metamaterials, and the current version of the proposal should be sufficiently illustrative to attract and broaden interdisciplinary interests.

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Production of the X(4014)as the Spin-2 Partner of X(3872)in e^(+)e^(-)Collisions

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Chinese Physics Letters 2024年第3期41卷 30-36页

作者： Pan-Pan Shi Vadim Baru Feng-Kun Guo Christoph Hanhart Alexey Nefediev CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China departamento de F′ısica Te′orica and IFIC Centro Mixto Universidad de Valencia-CSIC Institutos de Investigaci′on de PaternaAptdo.2208546071 ValenciaSpain institut fur Theoretische Physik II Ruhr-Universitat BochumD-44780 BochumGermany Peng Huanwu Collaborative Center for Research and Education Beihang UniversityBeijing 100191China institute for Advanced Simulation Institut fur Kernphysik and Julich Center for Hadron PhysicsForschungszentrum JulichD-52425 JulichGermany Jozef Stefan institute Jamova 391000LjubljanaSlovenia CeFEMA Center of Physics and Engineering of Advanced MaterialsInstituto Superior T′ecnicoAvenida Rovisco Pais 11049-001 LisboaPortugal

In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion *** the hadronic molecule picture,this new structure can be associatedwith the shallow isoscalar d*d* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872)with the quantum numbers J^(PC)=2^(++)conventionally named X_(2).

关键词： process X(3872) Collisions

Temporal and Spatial dynamics of Vaccine-derived Poliovirus (VdPV) in democratic Republic of Congo from 2018 to 2023

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Open Journal of Epidemiology 2024年第3期14卷 459-470页

作者： Jean Blaise Yobo Iyala Comlan Cyriaque degbey N’Kpingou Nadakou Ounoussa Tapha Eveline Soclo Moise Gimiko Fabrice Mawa Chaltin Ambanga Riziki Yogolelo désiré Ekanga Jean Claude Onema institut Rgional de Sant Publique (IRSP) Universit Abomey-Calavi (UAC) Ouidah Bnin Programme Elargi de Vaccination (PEV) Kinshasa Congo institut One Health Pour lAfrique (INOHA) Universit de Kinshasa Kinshasa Congo Comit des Oprations dUrgence POLIO (COUP) Kinshasa Congo institut national des Recherches Biomdicales (INRB) Kinshasa Congo Ministre de la Sant Publique Hygine et Prvention Kinshasa Congo

Background: The democratic Republic of Congo (dRC) has been facing outbreaks of VdPV since 2017. These wild poliovirus variants are responsible for poliomyelitis, which is in the process of eradication.. In the following lines, we try to show the evolution of VdPV cases across the country in order to understand their chronological dynamics and seasonal influence. Methods: We conducted a cross-sectional study of of VdPV notified in the dRC from 2018 to 2023. Maps of the spatial dynamics of VdPV cases were produced from attack rates with QGIS® (3.22.8). As for temporal dynamics, time series were decomposed and presented in the form of graphs showing the chronological evolution of VdPV cases and their seasonal trend, using R.4.0 software package. Results: A total of 1196 Cases of VdPV types 1, 2 and 3 were recorded in the biological confirmation databases of the INRB and the Expanded Program of Immunization during the study period across25 provinces. The eastern part of the country reporting the most cases. The general trend is upwards, with a peak in 2022 of 527 cases, whereas in 2021 there was a notable drop of 31 cases. Analysis of the temporal breakdown suggests a seasonal pattern, with peaks between the months of September and december, considered being rainy periods in some provinces. Conclusion: during the 6 years of our study (2018 - 2023) almost all the Health Zones were hit by VdPV epidemics. The eastern part was the most impacted. The seasonal component is well marked suggesting a rise in detection in the rainy season and during pivotal periods of climate change.

关键词： Temporal Spatial dynamic Poliovirus Vaccine