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Estimating interaction between surface water and groundwater in a permafrost region of the northern Tibetan Plateau using heat tracing method

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Research in Cold and Arid Regions 2020年第2期12卷 71-82页

作者： TanGuang Gao Jie Liu TingJun Zhang ShiChang kang Chua.kun Liu ShuFa Wang mika Sillanpaa YuLan Zhang key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhouGansu 730000China Institute of Water Sciences College of EngineeringPeking UniversityBeijing 100871China State key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China Department of Civil and Environmental Engineering Florida International University Miami FL 33199USA

Understanding the interaction between groundwater and surface water in permafrost regions is essential to study flood frequencies and river water quality, especially in the high latitude/altitude basins. The application of heat tracing method,based on oscillating streambed temperature signals, is a promising geophysical method for identifying and quantifying the interaction between groundwater and surface water. Analytical analysis based on a one-dimensional convective-conductive heat transport equation combined with the fiber-optic distributed temperature sensing method was applied on a streambed of a mountainous permafrost region in the Yeniugou Basin, located in the upper Heihe River on the northern Tibetan Plateau. The results indicated that low connectivity existed between the stream and groundwater in permafrost *** interaction between surface water and groundwater increased with the thawing of the active layer. This study demonstrates that the heat tracing method can be applied to study surface water-groundwater interaction over temporal and spatial scales in permafrost regions.

关键词： surface water groundwater permafrost heat tracing method Tibetan Plateau

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Numerical Analysis of a Sliding Frictional Contact Problem with Normal Compliance and Unilateral Contact

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Open Journal of Modelling and Simulation 2021年第4期9卷 391-406页

作者： Yahyeh Souleiman mikaël Barboteu Mathematics and Computer Science Laboratory Campus Balbala University of Djibouti Balbala Djibouti Mathematics and Physics Laboratory University of Perpignan Perpignan France

This paper represents a continuation of [1] and [2]. Here, we consider the numerical analysis of a non-trivial frictional contact problem in a form of a system of evolution nonlinear partial differential equations. The model describes the equilibrium of a viscoelastic body in sliding contact with a moving foundation. The contact is modeled with a multivalued normal compliance condition with memory term restricted by a unilateral constraint and is associated with a sliding version of Coulomb’s law of dry friction. After a description of the model and some assumptions, we derive a variational formulation of the problem, which consists of a system coupling a variational inequality for the displacement field and a nonlinear equation for the stress field. Then, we introduce a fully discrete scheme for the numerical approximation of the sliding contact problem. Under certain solution regularity assumptions, we derive an optimal order error estimate and we provide numerical validation of this result by considering some numerical simulations in the study of a two-dimensional problem.

关键词： Viscoelastic Material Sliding Frictional Contact Normal Compliance Unilateral Constraint Memory Term Variational Approximation Finite Element Error Estimate Numerical Simulations

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Photoacoustic Imaging with a Line-Focus Laser Beam for Rapid Inspection and Tomographic Characterization of Simulated Surface and Undersurface Defects

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Open Journal of Acoustics 2013年第2期3卷 8-15页

作者： Tsutomu Hoshimiya mika Hatake-Yama Graduate School of Engineering Tohoku Gakuin University Tagajo Japan

A photoacoustic (PA) imaging apparatus using a laser line-focus beam (LFB) was designed to perform rapid inspection and photoacoustic tomographic (PAT) imaging of surface and undersurface defects. 2D-PAT imaging of surface and undersurface defects was demonstrated based on a formulation similar to the X-ray tomography. The obtained PAT images represented forward-projected PA signals collected along the LFB. The reconstructed images were in close agreement with those obtained from laser point-focus beam (PFB) PA imaging. We achieved rapid non-destructive inspection of a surface-simulated defect using a LFB. The reconstructed PA image of the undersurface defect was consistent with that obtained by a plane-thermal wave diffraction model.

关键词： Imaging Photoacoustic Tomography Line-Focus Beam

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Development of the Bioenergy as a Part of Renewable Energy in the Nordic Countries: A Comparative Analysis

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Journal of Sustainable Bioenergy Systems 2020年第3期10卷 92-112页

作者： Tapio Ranta mika Laihanen Antti karhunen School of Energy Systems Lappeenranta-Lahti University of Technology Mikkeli Finland

A comparative assessment of the bioenergy and renewable energy situation in the Nordic countries, Finland, Sweden, Denma.k and Norway, was conducted in this study. What factors have contributed to the current high use of renewable energy and especially bioenergy in the Nordic countries? What are the sources of renewable energy and where renewable energy is being used? The development of renewable energy use is described by time series and compared to the overall development of the EU. All of the Nordic countries have high renewable energy consumption and have already met the target for gross final energy consumption according to the Europe 2020 strategy while the EU is behind the 20% target. In total, 53.1 Mtoe renewable energy was used in the Nordic countries in 2018, which was 51% of the final energy consumption, 103.3 Mtoe. Bioenergy accounts for approximately half of renewable energy, 25.8 Mtoe, and is anticipated to develop further. Especially in Norway and Sweden the share of renewable energy was high (73% and 55%) compared to Finland and Denma.k (41% and 36%). Norway is famous for hydropower (81% share of Renewable Energy Sources (RES) in 2018) and Denma.k for wind power production (20%), while Finland utilizes a lot of biomass for co-generation and heating (79%), followed by Denma.k (64%) and Sweden (55%) in 2018. At EU level, bioenergy plays even a higher role than in Nordic countries in renewable energy production (56%) in 2017 and is anticipated to continue to grow in all end-use sectors such as heating and cooling, electricity generation and transport, in the 2020s.

关键词： Bioenergy Renewable Energy Ma.kets Policies

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Schedule for Reducing the Use of Peat and the Possibilities of Replacing It with Forest Chips in Energy Production in Finland

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Journal of Sustainable Bioenergy Systems 2022年第4期12卷 99-115页

作者： Tapio Ranta Antti karhunen mika Laihanen School of Energy Systems Lappeenranta-Lahti University of Technology (LUT) Lappeenranta Finland

Between 2018 and 2020, an average of 15 TWh of energy peat was consumed in Finland. Energy peat is used in 260 boilers in Finland, which produce district heat and heat and steam for industry, as well as electricity as cogeneration (CHP) in connection with district heating and industrial heat production. Peat accounts for 3% - 5% of the energy sources used in Finland, but its importance has been greater in terms of security of supply. With current use in accordance with the 2018-2020 average, the emissions from peat are almost 6 Mt CO2 per year in Finland, which is 15% of emissions from the energy sector. In this study, the technical limitations related to peat burning, economic limitations related to the availability of biomass, and socio-economic limitations related to the regional economy are reviewed. By 2040, the technical minimum use of peat will fall to 2 TWh. The techno-economical potential may be even lower, but due to socio-economic objectives, peat production will not be completely ceased. The reduction in the minimum share assumes that old peat boilers are replaced with new biomass boilers or are alternatively replaced by other forms of heat production. Based on the biomass reserves, the current use of peat can be completely replaced by forest chips, but regional challenges may occur along the coast and in southern Finland. It is unlikely that the current demand for all peat will be fully replaced by biomass when part of CHP production is replaced by heat production alone and combustion with waste heat sources.

关键词： Biomass Supply Ma.ket Economics Heat Combined Heat and Power Generation (CHP)

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Comparative Study on Three-directional Changes in Shift Length of a Two-dimensional Gauze Ma.k for Preventing Hay Fever with Different Mouth Movements 17th

Comparative Study on Three-directional Changes in Shift Leng...

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第十七届国际工效学大会暨中国人类工效学会成立20周年庆祝大会

作者： mika Morishima Gifu City Women’s College

The objective of this study is to propose ways to improve the performance of hay fever *** conducted in previous studies have revealed that the ma.ks currently available adsorb a considerable amount of ***,the effectiveness of these ma.ks once they are actually worn has not been *** study investigates the issues related to the inhalation of pollen through the gap between the ma.k and the *** order to provide a solution for the abovementioned problems,I measured the shift length of the ma.k and face in real time by observing a subject wearing a two-dimensional gauze ma.k for hay fever.

关键词： length of shift Gauzes Hay fever Pollen

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The Role of Bioenergy in Achieving the Carbon Neutrality Target in Finland by 2035—A Case Study of Student Surveyed at University in Finland

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Journal of Sustainable Bioenergy Systems 2021年第2期11卷 61-81页

作者： Tapio Ranta mika Laihanen Antti karhunen Lappeenranta-Lahti University of Technology LUT School of Energy Systems Lappeenranta Finland

The largest share of renewable energy in Finland comes from bioenergy. In 2019, bioenergy accounted for 82% (416 PJ, 116 TWh) of renewable energy in Finland. This study assesses the potential for increasing bioenergy in energy production by 2035 and what role it will play in achieving the carbon neutrality target in Finland. The role of different energy sources in the energy system was examined using existing scenarios developed for The National Long-Term Strategy. Two alternative low-emission scenarios have been developed to last until 2050 to meet the 2035 carbon neutrality target. In 2035, the amount of bioenergy has risen to 520 - 550 PJ (144 - 153 TWh), which is about 70% of renewable energy consumption. This means, that the bioenergy resource has been fully deployed and the relative share of bioenergy in renewables has decreased slightly. The study also included a survey to university students to map out how likely a carbon neutrality target is to be considered by 2035. University students were unsure of achieving the carbon neutrality target by 2035. The schedule was considered challenging especially in the transport sector. Bioenergy was also seen as still playing an important role, especially in heat production. Achieving significant emission reductions will require significant electrification

关键词： Bioenergy Renewable Energies CO2 Reduction Strategies Policies Education

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Regional Energy Balance and Its Implementation to South karelia

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Journal of Sustainable Bioenergy Systems 2011年第1期1卷 1-7页

作者： mika Laihanen Antti karhunen Tapio Ranta Lappeenranta University of Technology Lappeenranta Finland

All EU countries have targets for increasing the use of renewable energy at a national level. However this effort should become concrete at regional and local levels where investments on bioenergy are made. This study introduces a systematical and universally applicable method for constructing regional energy balance. This study focuses on the method how to combine specific regional primary energy sources with their end uses. The primary energy sources include different fuels and the net import of electricity. The energy end uses are heat, electricity and losses. The concept of the regional energy balance was illustrated through a case of South karelia. The total use of primary energy in South karelia was 25.2 TWh (or 91 PJ) in 2010 and the share of renewable energy sources was 65%. The regional energy balance analysis can be utilized as a guideline for strategically planning and allocating regional energy sources for example, increasing the use of renewable energy sources. It can provide local decision makers and shareholders about the current status of energy supply, convincing them to take proper actions and consider producing energy at a local and regional level.

关键词： Regional Energy Balance Energy Production Energy Consumption Renewable Energy

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Supply and Demand of a Forest Biomass in Application to the Region of South-East Finland

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Smart Grid and Renewable Energy 2012年第1期3卷 34-42页

作者： Antti karhunen mika Laihanen Tapio Ranta LUT Energy-Bioenergy Technology Lappeenranta University of Technology Lappeenranta Finland.

In Finland it is estimated that forest biomass will be the main source of bioenergy when meeting the national target: 38% renewable from total energy consumption by 2020. This target must become concrete for regional and local level participators of a forest industry and actions should take place in large combined heat and power generation (CHP) plants, district heating plants and independent heating systems. In energy production replacing fossil fuels with renewa-ble energy is reasonable in many cases. However, there are usually doubts about the availability and security of supply of forest biomass. The aim of this study is to introduce a systematical method for analyzing the availability and demand of forest biomass in regional and local level. This study introduces an objective method for analyzing local possibilities on where and how much the use of forest biomass could be increased. By replacing use of fossil fuels with renewable and domestic energy sources carbon dioxide (CO2) emissions and dependency on imported fossil fuels can be reduced. Utilization of biomass creates also local employment on energy sector.

关键词： Forest Biomass Energy Production Energy Consumption

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Implementation of National Renewable Energy Obligations at the Regional Level

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Journal of Sustainable Bioenergy Systems 2019年第4期9卷 155-168页

作者： mika Laihanen Antti karhunen Tapio Ranta LUT University LUT School of Energy Systems Lappeenranta Finland

The aim of the paper described here was to clarify the potential of decreasing the use of fossil fuels regionally. According to Finnish national obligations, the use of oil and other fossil fuels should be minimised by 2030. The study combines the regional consumption of primary energy sources with national obligations introduced in the national climate and energy strategy. This set up a basis when evaluating the regional state of future energy supply for 2030. The paper utilises the region of South Savo as a case study. In the region, the consumption of renewable energy sources is already above the national average, but it can be increased further by 2030. Wood fuels and especially forest biomass have regionally a major role. Local and national targets, support schemes and willingness to invest play key roles when increasing the use of renewable energy sources in the future.

关键词： Regional Biomass Forest Residues Renewable Energy

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