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Two-dimensional numerical manifold method with multilayer covers

Science China(Technological Sciences) 2016年第4期59卷 515-530页

作者： LIU ZhiJun ZHENG Hong State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Key Laboratory of Urban Security and Disaster Engineering Ministry of Education Beijing University of Technology

In order to reach the best numerical properties with the numerical manifold method(NMM),uniform finite element meshes are always favorite while constructing mathematical covers,where all the elements are *** the presence of steep gradients or strong singularities,in principle,the locally-defined special functions can be added into the NMM space by means of the partition of unity,but they are not available to those complex problems with heterogeneity or nonlinearity,necessitating local refinement on uniform *** is believed to be one of the most important open issues in *** this study multilayer covers are proposed to solve this *** addition to the first layer cover which is the global cover and covers the whole problem domain,the second and higher layer covers with smaller elements,called local covers,are used to cover those local regions with steep gradients or strong *** global cover and the local covers have their own partition of unity,and they all participate in the approximation to the *** advantageous over the existing procedures,the proposed approach is easy to deal with any arbitrary-layer hanging nodes with no need to construct super-elements with variable number of edge nodes or introduce the Lagrange multipliers to enforce the continuity between small and big *** no limitation to cover layers,meanwhile,the creation of an even error distribution over the whole problem domain is significantly *** typical examples with steep gradients or strong singularities are analyzed to demonstrate the capacity of the proposed approach.

关键词： numerical manifold method finite element method covers hanging nodes structured local refinement short cracks

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GALOIS TRIPLE covers OF SURFACES

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Science China Mathematics 1991年第8期34卷 935-942页

作者：谈胜利 Department of Mathematics East China Normal University Shanghai 200062 PRC

The basic theory on Galois triple covers is developed in this paper. For Galois triplecovers, it is proved that the singularities can be resolved by a canonical method, and someformulas for the invariants are found.

关键词： surfaces triple covers invariants resolution of singularities.

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On　the　Structure　of　E-unitary　covers　for　an　Orthodox　Semigroup

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数学进展 1997年第2期 86-87页

ＯｎｔｈｅＳｔｒｕｃｔｕｒｅｏｆＥ┐ｕｎｉｔａｒｙＣｏｖｅｒｓｆｏｒａｎＯｒｔｈｏｄｏｘＳｅｍｉｇｒｏｕｐＧｕｏＸｉａｏｊｉａｎｇ＊（郭小江）（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＬａｎｚｈｏｕＵｎｉｖｅｒｓｉｔｙ，Ｌａｎｚｈ... 详细信息

ＯｎｔｈｅＳｔｒｕｃｔｕｒｅｏｆＥ┐ｕｎｉｔａｒｙＣｏｖｅｒｓｆｏｒａｎＯｒｔｈｏｄｏｘＳｅｍｉｇｒｏｕｐＧｕｏＸｉａｏｊｉａｎｇ＊（郭小江）（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＬａｎｚｈｏｕＵｎｉｖｅｒｓｉｔｙ，Ｌａｎｚｈｏｕ，Ｇａｎｓｕ，３００００）Ｃｏ...

关键词： an Orthodox Semigroup E-unitary On the covers

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Restoration of Folk Document covers from the Qing Dynasty to the Republic of China

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Paper And Biomaterials 2023年第3期8卷 66-74页

作者： Jiao Yao Fujiang Geng Huanhuan Wang Yunpei Lu Local Culture Research Institute Handan UniversityHandanHebei Province056005China College of Chemical Engineering and Materials Handan UniversityHandanHebei Province056005China Invoice Museum Hebei University of Economics and BusinessShijiazhuangHebei Province050061China

The covers of booklets and books in folk documents primarily serve to protect the *** to long-term storage limitations,a considerable number of book covers have suffered varying degrees of *** the principles of restoration,a comparative analysis and restoration of folk document covers were conducted,selecting four different types of carriers from the Taihang Mountain Documents,ranging from the Qing dynasty to the Republican *** carriers included hemp,mulberry bark,and machinemade paper,and cotton blue *** cover type was matched with an appropriate restoration paper,and different methods were employed during the restoration *** restoration,the previously damaged document covers can continue to fulfill their role in protecting the books,thereby extending the lifespan of these four folk documents.

关键词： restoration folk documents covers

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Farm-Scale Applicability of Three covers (Peat, Polystyrene Balls and Synthetic Sheet Roof) to Reduce Ammonia Emissions from Pig Slurry Storage

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Agricultural Sciences 2016年第6期7卷 396-406页

作者： Laurence Loyon Fabrice Guiziou Sylvie Picard Patricia Saint-Cast National Research Institute of Science and Technology for Environment and Agriculture (IRSTEA) UR OPAALE Rennes France University Bretagne Loire Rennes France

Covering the slurry pit has been shown to be one of the best ways to reduce ammonia emissions (NH3) during manure management. Yet, few studies have been conducted at farm scale. We studied the feasibility of three cover materials (peat, polystyrene balls and synthetic sheet roof) to reduce ammonia (NH3) emissions during on-farm storage of pig slurry. The impact on greenhouse gas emissions, methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) of covering the slurry pit was also evaluated. Simultaneous field experiments were carried out using two similar pits at a farm with peat and polystyrene ball covers, which allowed direct comparison of the feasibility of the two covers to reduce gas emissions (measured using the dynamic chamber technique). Emissions from the third option (using a synthetic sheet roof) were estimated by measuring the concentrations in the headspace under the cover and the air leakage from the cover with a tracer gas (CO2). Results showed that the polystyrene balls cover reduced emissions of NH3 during storage by up to 80% whatever the season, but increased potential greenhouse gas emissions by 20% in summer. No consistent reduction was achieved with the peat cover even though some individual results seemed to indicate up to 25% reduction in ammonia emissions;moreover, there was a 30% increase in CH4 and CO2 emissions during the storage period. The use of a synthetic sheet roof enabled up to 90% reduction in NH3, CH4 and CO2 emissions whatever the season.

关键词： Ammonia Slurry covers Farm-Scale Measurement Pig

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Use of Evapotranspiration (ET) Landfill covers to Reduce Methane Emissions from Municipal Solid Waste Landfills

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Journal of Water Resource and Protection 2015年第13期7卷 1087-1097页

作者： Tarek Abichou Tarek Kormi Cheng Wang Haykel Melaouhia Terry Johnson Stephen Dwyer Department of Civil Engineering Florida State University Tallahassee FL USA Ecole Nationale d’ Ingenieurs de Gabes Department de Genie Civil Gabes Tunisia LASMAP Ecole Polytechnique de Tunisie University of Carthage Tunisia Argonne National Laboratory Chicago IL USA. Waste Management Minneapolis MN USA. Dwyer Engineering Albuquerque NM USA

Solid waste landfills need to have final covers to 1) reduce the infiltration of rainfall into the waste mass and 2) reduce surface greenhouse gas emissions. Most regulations require that such final covers include hydraulic barriers, such as compacted clays with or without geomembrane. Significant research has been undertaken to allow the use of evapotranspiration-based covers (often termed: Evapotranspiration (ET) Cover, Water Balance covers, or Phyto covers) as an alternative to the barrier concept covers. ET covers are designed so that they have the capacity to store water by the soil and also have plants or vegetation to remove the stored water. In ET covers, plant roots can enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil. Therefore, biological methane oxidation (a natural process in landfill soils) can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This paper summarizes a study to investigate the capacity of an ET cover to reduce surface greenhouse gas emissions when implemented on a solid waste landfill. This study consisted of using a numerical model to estimate methane emission and oxidation through an ET cover under average climatic conditions in Bennignton, Nebraska, USA. Different simulations were performed using different methane loading flux (5 to 200 gm-2·d-1) as the bottom boundary. For all simulations, surface emissions were the lowest during the growing season and during warmer days of the year. Percent oxidation is the highest during the growing season and during warmer days. The lowest modeled surface emissions were always obtained during the growing season. Finally, correlations between percent oxidation and methane loading into simulated ET covers were proposed to estimate methane emissions and methane oxidation in ET covers.

关键词： Evapotranspiration covers Methane Oxidation Landfills Greenhouse Gas Emissions

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UNESCO post about local manhole covers onwebsite

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Changjiang Weekly 2022年第19期 M0001-M0001页

An article highlighting a series of manhole covers in Wuhan was posted on May 2 on the website of the UNESco Creative Cities Network,demonstrating the city's cultural features and strength in design.

关键词： website UNESCO covers

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Album recording Wuhan's painted manhole covers

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Changjiang Weekly 2023年第2期 6-6页

作者： Deng Xiaolong 不详

For more than 10 years,*** has been taking photos of manhole covers that havepictures on *** has found over 100 in the streets and alleys of Wuhan and has finally organized many of them into a ***,he posted a"Wuhan ma... 详细信息

关键词： recording finally covers

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Use of Evapotranspiration (ET) Landfill covers to Reduce Methane Emissions from Municipal Solid Waste Landfills

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Journal of Water Resource and Protection（水资源与保护） 2015年第13期 1087-1097页

作者： Tarek Abichou Tarek Kormi Cheng Wang Haykel Melaouhia Terry Johnson Stephen Dwyer

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Relative (n, k) -Weak Cotorsion Modules

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ALGEBRA COLLOQUIUM 2024年第3期31卷 481-498页

作者： Amini, Mostafa Amzil, Houda Bennis, Driss Payame Noor Univ Fac Sci Dept Math Tehran Iran Chouaib Doukkali Univ Fac Sci El Jadida Dept Math El Jadida Morocco Mohammed V Univ Rabat Fac Sci Dept Math Rabat Morocco

Let R be a ring and n, k be two non-negative integers. As an extension of several known notions, we introduce and study (n, k)-weak cotorsion modules using the class of right R-modules with n-weak flat dimensions at m... 详细信息

关键词： (n, k)-weak cotorsion module n-weak injective module n-weak flat module n-super finitely presented module covers ENVELOPES RINGS

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