In this paper, we apply a discrete Littlewood-Paley analysis to obtain Hardy spaces HP（Rn1× … ×Rnk） of arbitrary number of parameters characterized by discrete Littlewood-Paley square function and derive ...In this paper, we apply a discrete Littlewood-Paley analysis to obtain Hardy spaces HP（Rn1× … ×Rnk） of arbitrary number of parameters characterized by discrete Littlewood-Paley square function and derive the boundedness of singular integral operators onHP（Rn1× … ×Rnk） and fromHP（Rn1× … ×Rnk）toLP（Rn1× … ×Rnk）.展开更多
This paper aims to study a novel expansion discrete grey forecasting model, which could aggregate input information more effectively. In general, existing multi-factor grey forecasting models, such as one order and h ...This paper aims to study a novel expansion discrete grey forecasting model, which could aggregate input information more effectively. In general, existing multi-factor grey forecasting models, such as one order and h variables grey forecasting model （GM （1, h））, always aggregate the main system variable and independent variables in a linear form rather than a nonlinear form, while a nonlinear form could be used in more cases than the linear form. And the nonlinear form could aggregate collinear independent factors, which widely lie in many multi-factor forecasting problems. To overcome this problem, a new approach, named as the Solow residual method, is proposed to aggregate independent factors. And a new expansion model, feedback multi-factor discrete grey forecasting model based on the Solow residual method （abbreviated as FDGM （1, h））, is proposed accordingly. Then the feedback control equation and the parameters＇ solution of the FDGM （1, h） model are given. Finally, a real application is used to test the modelling accuracy of the FDGM （1, h） model. Results show that the FDGM （1, h） model is much better than the nonhomogeneous discrete grey forecasting model （NDGM） and the GM （1, h） model.展开更多
The possibility of creating zero CO2 emissions residential buildings due to life cycle energy use in the island of Crete, Greece has been examined. In a typical residential building located in Crete, Greece, its annua...The possibility of creating zero CO2 emissions residential buildings due to life cycle energy use in the island of Crete, Greece has been examined. In a typical residential building located in Crete, Greece, its annual operating energy has been appraised at 170 KWh/m2 and its embodied energy at 30 KWh/m2. Various locally available renewable energies including solar energy, solid biomass and low enthalpy geothermal energy with heat pumps have been considered for generating the required heat and offsetting the grid electricity used. Their technologies are mature, reliable and cost-effective. Offset of the annual grid electricity use in the building with solar-PV electricity is allowed according to the net metering regulation. For zero carbon emissions due to embodied energy of the building, generation of additional solar electricity injected into the grid is required. A mathematical model has been developed for sizing the required solar-PV system installed in the building in order to offset the grid electricity use. For a residential building in Crete, Greece with a covered area of 100 m2, the power of the additional solar-PV system has been estimated at 1.6 KWp and its cost at 2400 €. In the current work, it is indicated that the creation of a zero CO2 emissions residential building due to life cycle energy use in Crete, Greece does not have major difficulties and it could be achieved relatively easily.展开更多
A description and assessment of a small renewable energy community located in Crete, Greece is presented. The community included private residential and agricultural activities without any involvement of the public se...A description and assessment of a small renewable energy community located in Crete, Greece is presented. The community included private residential and agricultural activities without any involvement of the public sector. Small-scale decentralized energy systems were used. Solar energy and solid biomass which are locally available covered most of the heat and electricity requirements in the community. Renewable energy technologies used include solar thermal energy, solar-PV and solid biomass burning utilizing olive tree wood and olive kernel wood. These technologies are mature, reliable, well proven in Crete and cost-effective. Existing energy systems were generating 857,877 kWh per year covering 94.46% of the current energy requirements in the community, significantly reducing its emissions at 278,494 kg CO2 per year. The addition of a new solar-PV system with nominal power of 33.6 kWp could cover all the remaining electricity needs in the community, transforming it to a zero-CO2 emission community due to energy use. The total installation cost of the existing renewable energy systems in the community was estimated at 0.16€ per total kWh of thermal and electric energy generated annually and at 0.50€ per ton of CO2 emissions saved annually. Results indicated that the creation of the above-mentioned small local energy community is economically viable, environmental friendly and socially accepted. Therefore it could be replicated in other territories with similar availability of renewable energies, increasing their energy autonomy and sustainability.展开更多
The mix proportions and strength ofplain concrete, top-and-hottoim layered steel fiber concrete and common steel fiber concrete are camparatively researched in this article. The influence of the quantity and plac...The mix proportions and strength ofplain concrete, top-and-hottoim layered steel fiber concrete and common steel fiber concrete are camparatively researched in this article. The influence of the quantity and place of steel fiber layer on the concrete's strength is systematically researched and the simulated analysis is made by computer.展开更多
The possibility of electrifying the transport sector in Crete, Greece has been investigated. Currently the conventional vehicles in Crete consume annually 316,872 tons of gasoline and diesel oil emitting 1,030,188 ton...The possibility of electrifying the transport sector in Crete, Greece has been investigated. Currently the conventional vehicles in Crete consume annually 316,872 tons of gasoline and diesel oil emitting 1,030,188 tons of CO2. Electrification of the transport sector in Crete will result in a decrease of imported fossil fuels use and a reduction of CO2 emissions. It will also increase the use of locally available renewable energies in electricity generation. If all the existing conventional vehicles in Crete were to be replaced by electric vehicles, the annual electricity requirements in their batteries would be 1,092,568 to 1,311,077 MWh depending on the type of battery. The energy demand of the electric cars could be covered with electricity generated by renewable energies including solar and wind energy which are abundant in the island. The batteries of the electric cars could be used as electricity storage devices facilitating the penetration of intermittent renewable energies, with distributed generation systems, into the smart electric grid of Crete. It has been estimated that the aggregated theoretical storage capacity of all the batteries would be 6.33 GWh and that the size of the solar-PV plants and wind energy systems, generating all the electricity required by electric vehicles, would be 728 to 874 MWp and 445 to 534 MW respectively.展开更多
An increase in energy efficiency and a reduction of carbon emissions in buildings are prerequisites for mitigating climate change. Public buildings should be energy-refurbished for minimizing their energy use, complyi...An increase in energy efficiency and a reduction of carbon emissions in buildings are prerequisites for mitigating climate change. Public buildings should be energy-refurbished for minimizing their energy use, complying with EU legislation and directives. The creation of net zero carbon emissions prisons in Crete, Greece with reference to the agricultural prison of Agia has been examined. The prison’s capacity is 178 offenders and the annual energy consumption has been estimated at 4000 KWh/prisoner. The use of a solar thermal system for hot water production and a solar-PV system for electricity generation has been proposed for generating the energy required in the prison. Two scenarios have been examined. In the first, the two solar energy systems would generate all the required energy in the prison, while in the second, the two solar energy systems would generate 50% of the annual required energy in the prison, and the rest would be produced by fossil fuels. A tree plantation, either with olive trees or with Eucalyptus trees, would be created for offsetting the carbon emissions due to fossil fuels used in the prison. The surface of the flat plate solar collectors in the solar thermal system has been estimated at 113.9 M<sup>2</sup> to 227.8 M<sup>2</sup> while its cost is at 34,170€ to 68,340€. The nominal power of the solar-PV system has been estimated at 151.9 KW<sub>p</sub> to 303.8 KW<sub>p</sub> while its cost is at 182,280€ to 364,560€. The area of the tree plantation sequestrating 50% of the current CO<sub>2</sub> emissions due to fossil fuels use in the prison has been estimated at 14.74 ha for olive trees and at 5.9 ha for Eucalyptus trees. The results indicated that the energy refurbishment in Agia’s agricultural prison in Crete, Greece, in order to zero its annual net carbon emissions, is feasible.展开更多
Decrease of energy consumption in buildings and increase of the share of renewable energies in them are currently technologically and economically feasible and it is promoted by E.U. policies. After 2019, all the new ...Decrease of energy consumption in buildings and increase of the share of renewable energies in them are currently technologically and economically feasible and it is promoted by E.U. policies. After 2019, all the new public buildings in EU countries must be near zero energy buildings reducing their energy consumption and CO<sub>2</sub> emissions. Use of various renewable energies for heat and power generation in school buildings in Crete-Greece can result in zeroing their fossil fuels consumption and CO<sub>2</sub> emissions. Purpose of the current work is to investigate the possibilities of creating zero CO<sub>2</sub> emissions school buildings in Crete-Greece due to operational energy use in them. A methodology which allows the replacement of fossil fuels with renewable energies in school buildings is proposed. Solar energy, solid biomass and low enthalpy geothermal energy, which are abundant in Crete, can be used for that. School buildings in Greece consume significantly less energy, 68 KWh/m<sup>2</sup> year, and emit less CO<sub>2</sub>, 28 kgCO<sub>2</sub>/m<sup>2</sup> year, than the corresponding buildings in other countries. The installation cost of renewable energies systems in order to replace all fossil fuels used in school buildings in Crete-Greece and to zero their CO<sub>2</sub> consumption due to energy use in them has been estimated at 47.42 - 87.71 €/m<sup>2</sup>, which corresponds to 1.69 - 3.13 €/kg CO<sub>2</sub> saved.展开更多
Olive pomace plants process olive paste, a waste product of olive mills which produces crude olive kernel oil and olive kernel wood. Olive kernel wood has very good burning characteristics, high heat content, low cost...Olive pomace plants process olive paste, a waste product of olive mills which produces crude olive kernel oil and olive kernel wood. Olive kernel wood has very good burning characteristics, high heat content, low cost and it is used as a renewable solid fuel replacing liquid fuel and heating oil. Part of the produced olive kernel wood is consumed inside the factory for heat generation and the rest is sold to heat consumers. It has been estimated that a typical olive pomace plant located in Crete, Greece consumes 42.86% of the produced olive kernel wood for its own heat generation, while the remaining 57.14% is sold to various heat consumers. 99.1% of the energy used in these plants is consumed for heating and the rest, 0.9%, for lighting and the operation of various electric devices. Olive pomace plants utilize a renewable solid fuel, which is carbon neutral, for the production of thermal energy. Therefore their CO<sub>2</sub> emissions regarding energy utilization are due to electricity use. Installation of solar-PV panels in the plant could generate annually all the electricity needed for its operation. The current legal framework in Greece through net-metering allows the offsetting of grid electricity consumed in factories with PV electricity. The required capital cost of a solar-PV system installed in a typical olive pomace plant located in Crete, Greece in order to offset the grid electricity consumed annually has been estimated at 185,832€, the payback period of 5.33 years and the net present value at 555,671€. Since the plant could utilize only solid biomass for heat generation and could offset the grid electricity consumption with solar electricity, its total CO<sub>2</sub> emissions due to energy use would be zero contributing positively to climate stabilization.展开更多
为提高青贮玉米粉碎物料压缩致密过程仿真所需的准确性,构建青贮玉米粉碎物料离散元仿真模型。以青贮玉米粉碎物料为研究对象,利用EDEM软件中的Hertz-Mindlin with JKR接触模型进行离散元仿真模拟。将物理试验测定的青贮玉米粉碎物料的...为提高青贮玉米粉碎物料压缩致密过程仿真所需的准确性,构建青贮玉米粉碎物料离散元仿真模型。以青贮玉米粉碎物料为研究对象,利用EDEM软件中的Hertz-Mindlin with JKR接触模型进行离散元仿真模拟。将物理试验测定的青贮玉米粉碎物料的接触参数作为模拟参数,利用Plackett-Burman试验、最陡爬坡试验和Box-Behnken试验对相关参数进行优化。获得最优参数组合:青贮玉米粉碎物料与物料碰撞恢复系数0.29,青贮玉米粉碎物料与45号钢板碰撞恢复系数0.50、青贮玉米粉碎物料与45号钢板滚动摩擦因数0.25。通过仿真试验对最优参数组合进行验证,仿真堆积角与物理试验堆积角相对误差为0.66%。研究结果表明,标定的参数可靠性高,可为青贮玉米粉碎物料的离散元仿真提供理论参考。展开更多
Among the environmental threats,the intensification of natural hazards,such as soil erosion may threaten the integrity and value of cultural heritage sites.In this framework,the present study’s main objective was to ...Among the environmental threats,the intensification of natural hazards,such as soil erosion may threaten the integrity and value of cultural heritage sites.In this framework,the present study’s main objective was to identify archaeological sites susceptible by soil erosion,taking the case study of Chania prefecture in Crete Island.Remotely sensed and other available geospatial datasets were analyzed in a GIS-based empirical model,namely Unit Stream Power Erosion and Deposition(USPED),to estimate the average annual soil loss and deposition rates due to waterinduced erosion in the study area.The resultant erosion map was then intersected with the locations and surrounding zones of the known archaeological sites for identifying the sites and the portions of their vicinity being at risk.The results revealed that Chania prefecture and its cultural heritage are significantly affected by both soil loss and deposition processes.Between the two processes,soil loss was found to be more intensive,influencing a larger part of the prefecture(especially to the west)as well as a higher amount of archaeological sites.The extreme and high soil loss classes were also detected to cover the most considerable portion of the sites’surrounding area.The identification of the archaeological sites being most exposed to soil erosion hazard can constitute a basis for cultural heritage managers in order to take preventive preserva-tion measures and develop specific risk mitigation strategies.展开更多
文摘In this paper, we apply a discrete Littlewood-Paley analysis to obtain Hardy spaces HP（Rn1× … ×Rnk） of arbitrary number of parameters characterized by discrete Littlewood-Paley square function and derive the boundedness of singular integral operators onHP（Rn1× … ×Rnk） and fromHP（Rn1× … ×Rnk）toLP（Rn1× … ×Rnk）.
基金supported by the National Natural Science Foundation of China(7117111370901041)
文摘This paper aims to study a novel expansion discrete grey forecasting model, which could aggregate input information more effectively. In general, existing multi-factor grey forecasting models, such as one order and h variables grey forecasting model （GM （1, h））, always aggregate the main system variable and independent variables in a linear form rather than a nonlinear form, while a nonlinear form could be used in more cases than the linear form. And the nonlinear form could aggregate collinear independent factors, which widely lie in many multi-factor forecasting problems. To overcome this problem, a new approach, named as the Solow residual method, is proposed to aggregate independent factors. And a new expansion model, feedback multi-factor discrete grey forecasting model based on the Solow residual method （abbreviated as FDGM （1, h））, is proposed accordingly. Then the feedback control equation and the parameters＇ solution of the FDGM （1, h） model are given. Finally, a real application is used to test the modelling accuracy of the FDGM （1, h） model. Results show that the FDGM （1, h） model is much better than the nonhomogeneous discrete grey forecasting model （NDGM） and the GM （1, h） model.
文摘The possibility of creating zero CO2 emissions residential buildings due to life cycle energy use in the island of Crete, Greece has been examined. In a typical residential building located in Crete, Greece, its annual operating energy has been appraised at 170 KWh/m2 and its embodied energy at 30 KWh/m2. Various locally available renewable energies including solar energy, solid biomass and low enthalpy geothermal energy with heat pumps have been considered for generating the required heat and offsetting the grid electricity used. Their technologies are mature, reliable and cost-effective. Offset of the annual grid electricity use in the building with solar-PV electricity is allowed according to the net metering regulation. For zero carbon emissions due to embodied energy of the building, generation of additional solar electricity injected into the grid is required. A mathematical model has been developed for sizing the required solar-PV system installed in the building in order to offset the grid electricity use. For a residential building in Crete, Greece with a covered area of 100 m2, the power of the additional solar-PV system has been estimated at 1.6 KWp and its cost at 2400 €. In the current work, it is indicated that the creation of a zero CO2 emissions residential building due to life cycle energy use in Crete, Greece does not have major difficulties and it could be achieved relatively easily.
文摘A description and assessment of a small renewable energy community located in Crete, Greece is presented. The community included private residential and agricultural activities without any involvement of the public sector. Small-scale decentralized energy systems were used. Solar energy and solid biomass which are locally available covered most of the heat and electricity requirements in the community. Renewable energy technologies used include solar thermal energy, solar-PV and solid biomass burning utilizing olive tree wood and olive kernel wood. These technologies are mature, reliable, well proven in Crete and cost-effective. Existing energy systems were generating 857,877 kWh per year covering 94.46% of the current energy requirements in the community, significantly reducing its emissions at 278,494 kg CO2 per year. The addition of a new solar-PV system with nominal power of 33.6 kWp could cover all the remaining electricity needs in the community, transforming it to a zero-CO2 emission community due to energy use. The total installation cost of the existing renewable energy systems in the community was estimated at 0.16€ per total kWh of thermal and electric energy generated annually and at 0.50€ per ton of CO2 emissions saved annually. Results indicated that the creation of the above-mentioned small local energy community is economically viable, environmental friendly and socially accepted. Therefore it could be replicated in other territories with similar availability of renewable energies, increasing their energy autonomy and sustainability.
文摘The mix proportions and strength ofplain concrete, top-and-hottoim layered steel fiber concrete and common steel fiber concrete are camparatively researched in this article. The influence of the quantity and place of steel fiber layer on the concrete's strength is systematically researched and the simulated analysis is made by computer.
文摘The possibility of electrifying the transport sector in Crete, Greece has been investigated. Currently the conventional vehicles in Crete consume annually 316,872 tons of gasoline and diesel oil emitting 1,030,188 tons of CO2. Electrification of the transport sector in Crete will result in a decrease of imported fossil fuels use and a reduction of CO2 emissions. It will also increase the use of locally available renewable energies in electricity generation. If all the existing conventional vehicles in Crete were to be replaced by electric vehicles, the annual electricity requirements in their batteries would be 1,092,568 to 1,311,077 MWh depending on the type of battery. The energy demand of the electric cars could be covered with electricity generated by renewable energies including solar and wind energy which are abundant in the island. The batteries of the electric cars could be used as electricity storage devices facilitating the penetration of intermittent renewable energies, with distributed generation systems, into the smart electric grid of Crete. It has been estimated that the aggregated theoretical storage capacity of all the batteries would be 6.33 GWh and that the size of the solar-PV plants and wind energy systems, generating all the electricity required by electric vehicles, would be 728 to 874 MWp and 445 to 534 MW respectively.
文摘An increase in energy efficiency and a reduction of carbon emissions in buildings are prerequisites for mitigating climate change. Public buildings should be energy-refurbished for minimizing their energy use, complying with EU legislation and directives. The creation of net zero carbon emissions prisons in Crete, Greece with reference to the agricultural prison of Agia has been examined. The prison’s capacity is 178 offenders and the annual energy consumption has been estimated at 4000 KWh/prisoner. The use of a solar thermal system for hot water production and a solar-PV system for electricity generation has been proposed for generating the energy required in the prison. Two scenarios have been examined. In the first, the two solar energy systems would generate all the required energy in the prison, while in the second, the two solar energy systems would generate 50% of the annual required energy in the prison, and the rest would be produced by fossil fuels. A tree plantation, either with olive trees or with Eucalyptus trees, would be created for offsetting the carbon emissions due to fossil fuels used in the prison. The surface of the flat plate solar collectors in the solar thermal system has been estimated at 113.9 M<sup>2</sup> to 227.8 M<sup>2</sup> while its cost is at 34,170€ to 68,340€. The nominal power of the solar-PV system has been estimated at 151.9 KW<sub>p</sub> to 303.8 KW<sub>p</sub> while its cost is at 182,280€ to 364,560€. The area of the tree plantation sequestrating 50% of the current CO<sub>2</sub> emissions due to fossil fuels use in the prison has been estimated at 14.74 ha for olive trees and at 5.9 ha for Eucalyptus trees. The results indicated that the energy refurbishment in Agia’s agricultural prison in Crete, Greece, in order to zero its annual net carbon emissions, is feasible.
文摘Decrease of energy consumption in buildings and increase of the share of renewable energies in them are currently technologically and economically feasible and it is promoted by E.U. policies. After 2019, all the new public buildings in EU countries must be near zero energy buildings reducing their energy consumption and CO<sub>2</sub> emissions. Use of various renewable energies for heat and power generation in school buildings in Crete-Greece can result in zeroing their fossil fuels consumption and CO<sub>2</sub> emissions. Purpose of the current work is to investigate the possibilities of creating zero CO<sub>2</sub> emissions school buildings in Crete-Greece due to operational energy use in them. A methodology which allows the replacement of fossil fuels with renewable energies in school buildings is proposed. Solar energy, solid biomass and low enthalpy geothermal energy, which are abundant in Crete, can be used for that. School buildings in Greece consume significantly less energy, 68 KWh/m<sup>2</sup> year, and emit less CO<sub>2</sub>, 28 kgCO<sub>2</sub>/m<sup>2</sup> year, than the corresponding buildings in other countries. The installation cost of renewable energies systems in order to replace all fossil fuels used in school buildings in Crete-Greece and to zero their CO<sub>2</sub> consumption due to energy use in them has been estimated at 47.42 - 87.71 €/m<sup>2</sup>, which corresponds to 1.69 - 3.13 €/kg CO<sub>2</sub> saved.
文摘Olive pomace plants process olive paste, a waste product of olive mills which produces crude olive kernel oil and olive kernel wood. Olive kernel wood has very good burning characteristics, high heat content, low cost and it is used as a renewable solid fuel replacing liquid fuel and heating oil. Part of the produced olive kernel wood is consumed inside the factory for heat generation and the rest is sold to heat consumers. It has been estimated that a typical olive pomace plant located in Crete, Greece consumes 42.86% of the produced olive kernel wood for its own heat generation, while the remaining 57.14% is sold to various heat consumers. 99.1% of the energy used in these plants is consumed for heating and the rest, 0.9%, for lighting and the operation of various electric devices. Olive pomace plants utilize a renewable solid fuel, which is carbon neutral, for the production of thermal energy. Therefore their CO<sub>2</sub> emissions regarding energy utilization are due to electricity use. Installation of solar-PV panels in the plant could generate annually all the electricity needed for its operation. The current legal framework in Greece through net-metering allows the offsetting of grid electricity consumed in factories with PV electricity. The required capital cost of a solar-PV system installed in a typical olive pomace plant located in Crete, Greece in order to offset the grid electricity consumed annually has been estimated at 185,832€, the payback period of 5.33 years and the net present value at 555,671€. Since the plant could utilize only solid biomass for heat generation and could offset the grid electricity consumption with solar electricity, its total CO<sub>2</sub> emissions due to energy use would be zero contributing positively to climate stabilization.
文摘为提高青贮玉米粉碎物料压缩致密过程仿真所需的准确性,构建青贮玉米粉碎物料离散元仿真模型。以青贮玉米粉碎物料为研究对象,利用EDEM软件中的Hertz-Mindlin with JKR接触模型进行离散元仿真模拟。将物理试验测定的青贮玉米粉碎物料的接触参数作为模拟参数,利用Plackett-Burman试验、最陡爬坡试验和Box-Behnken试验对相关参数进行优化。获得最优参数组合:青贮玉米粉碎物料与物料碰撞恢复系数0.29,青贮玉米粉碎物料与45号钢板碰撞恢复系数0.50、青贮玉米粉碎物料与45号钢板滚动摩擦因数0.25。通过仿真试验对最优参数组合进行验证,仿真堆积角与物理试验堆积角相对误差为0.66%。研究结果表明,标定的参数可靠性高,可为青贮玉米粉碎物料的离散元仿真提供理论参考。
基金supported by the Hellenic Foundation for Research and Innovation(HFRI)of General Secretariat for Research and Technology(GSRT)under Grant No 651.
文摘Among the environmental threats,the intensification of natural hazards,such as soil erosion may threaten the integrity and value of cultural heritage sites.In this framework,the present study’s main objective was to identify archaeological sites susceptible by soil erosion,taking the case study of Chania prefecture in Crete Island.Remotely sensed and other available geospatial datasets were analyzed in a GIS-based empirical model,namely Unit Stream Power Erosion and Deposition(USPED),to estimate the average annual soil loss and deposition rates due to waterinduced erosion in the study area.The resultant erosion map was then intersected with the locations and surrounding zones of the known archaeological sites for identifying the sites and the portions of their vicinity being at risk.The results revealed that Chania prefecture and its cultural heritage are significantly affected by both soil loss and deposition processes.Between the two processes,soil loss was found to be more intensive,influencing a larger part of the prefecture(especially to the west)as well as a higher amount of archaeological sites.The extreme and high soil loss classes were also detected to cover the most considerable portion of the sites’surrounding area.The identification of the archaeological sites being most exposed to soil erosion hazard can constitute a basis for cultural heritage managers in order to take preventive preserva-tion measures and develop specific risk mitigation strategies.
