Environmental impacts of using various sources of energy in heating a family house with 180 m2 of floor surface were compared by means of the SimaPro computer programme and attached to its databases, describing the en...Environmental impacts of using various sources of energy in heating a family house with 180 m2 of floor surface were compared by means of the SimaPro computer programme and attached to its databases, describing the environmental impacts of using typical materials and technologies. The set of compared heat energy sources comprised nine different sources. After normalisation （which meant recalculating the impacts into their proportions to the average impact of the kind, experienced by an average European in a year）, weighting （which meant attaching arbitrary weights to three aggregate impact categories according to a methodology Eco-indicator 99 E/E） and summation of the weighted results expressed in so-called ecopoints, the coal combustion furnace turned out to have the greatest impact. It was followed by an electric stove and an oil burning furnace. The wood burning furnace and the heat pump had the smallest impact, almost equal in size. Results indicate that in case of renewable energy carriers like wood, straw and pellets, the total environmental hazard factor in 70% and more is derived from the respiratory harmful inorganic emissions. Extending the analysis by a LC assessment of equipment （boilers and pumps） might change the order of technologies.展开更多
Located in the cold and very cold semiarid steppe climate zone, North Dakota boasts not only long cold winters but also hot summers, which significantly increases the energy consumption of buildings. In fact, North Da...Located in the cold and very cold semiarid steppe climate zone, North Dakota boasts not only long cold winters but also hot summers, which significantly increases the energy consumption of buildings. In fact, North Dakota has the highest energy consumption per capita in residential buildings （101 MM Btu in 2013）, and its energy consumption per capita in commercial buildings ranks the second （l 18 MM Btu in 2013） in the nation. When humans spend a long time indoors to escape the inclement weather, their health will be more susceptible to the indoor environment. In addition, North Dakota has the 3rd least number of green buildings certified by LEED （Leadership in Energy and Environmental Design） in the nation. This paper aims to investigate the status quo of buildings with respect to energy, health and sustainability in North Dakota, and attempts to propose strategies regarding research and higher education to rectify the current issues. These strategies include but not limited to forming the architectural engineering program, a comprehensive and interdisciplinary program in buildings.展开更多
The performance of DFIG-based wind generation systems that interconnected to solid networks is well understood and prevalent in Europe and North America. However, the application of these renewable generating stations...The performance of DFIG-based wind generation systems that interconnected to solid networks is well understood and prevalent in Europe and North America. However, the application of these renewable generating stations to weak network has been examined in very limited occasions. Weak networks have a range of limitations from system capacities to CFCT restrictions which would need to be well understood prior to wind energy integration. Of particular interest would be how much wind generation could be integrated into a weak network prior to increasing voltage and frequency stability issues brought about by penetration issues. This paper introduces a simple and practical approach based on the equal area criteria to investigate the stability of weak networks. Simulation results that are presented to show the proposed approach is a viable preliminary assessment tool to determine system stability on weak networks with wind power penetration.展开更多
Photocatalytic hydrogen production is considered a promising approach to generating clean sustainable energy.However,the conventional co-catalyst(e.g.,Pt)used in photocatalytic hydrogen production is high-cost and dif...Photocatalytic hydrogen production is considered a promising approach to generating clean sustainable energy.However,the conventional co-catalyst(e.g.,Pt)used in photocatalytic hydrogen production is high-cost and difficult to obtain.Here,we designed and prepared a ternary nanocomposite MXene@Au@Cd S,which can be used in the field of efficient and excellent photocatalytic hydrogen production.The MXene@Au@Cd S has a hydrogen production rate of 17,070.43μmol g^-1h^-1(tested for 2 h),which is 1.85 times that of pure Cd S nanomaterials.The improved hydrogen production performance of the MXene@Au@Cd S is attributed to:(i)MXene provides more active adsorption sites and reaction centers for Au and Cd S nanoparticles;(ii)the synergistic effect of Au’s strong surface plasmon resonance expands the optical response range of Cd S.Therefore,this work solves the problem of the solid connection between the surface functional groups of photocatalyst,and achieves rapid interface charge transfer and long-term stability during the hydrogen production.展开更多
Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong l...Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong laser. The radiation pressure acceleration mechanism plays an important role on the studied problem. For the ions near the plasma mirror, i.e. electrons layer, the dependence of ions energy on their charge-mass ratio is derived theoretically. It is found that the larger the charge-mass ratio is, the higher the accelerated ions energy gets. For those ions far away from the layer, the dependence of energy and energy spread on ions charge-mass ratio are also obtained by numerical performance. It exhibits that, as ions charge-mass ratio increases, not only the accelerated ions energy but also the energy spread will become large.展开更多
文摘Environmental impacts of using various sources of energy in heating a family house with 180 m2 of floor surface were compared by means of the SimaPro computer programme and attached to its databases, describing the environmental impacts of using typical materials and technologies. The set of compared heat energy sources comprised nine different sources. After normalisation （which meant recalculating the impacts into their proportions to the average impact of the kind, experienced by an average European in a year）, weighting （which meant attaching arbitrary weights to three aggregate impact categories according to a methodology Eco-indicator 99 E/E） and summation of the weighted results expressed in so-called ecopoints, the coal combustion furnace turned out to have the greatest impact. It was followed by an electric stove and an oil burning furnace. The wood burning furnace and the heat pump had the smallest impact, almost equal in size. Results indicate that in case of renewable energy carriers like wood, straw and pellets, the total environmental hazard factor in 70% and more is derived from the respiratory harmful inorganic emissions. Extending the analysis by a LC assessment of equipment （boilers and pumps） might change the order of technologies.
文摘Located in the cold and very cold semiarid steppe climate zone, North Dakota boasts not only long cold winters but also hot summers, which significantly increases the energy consumption of buildings. In fact, North Dakota has the highest energy consumption per capita in residential buildings （101 MM Btu in 2013）, and its energy consumption per capita in commercial buildings ranks the second （l 18 MM Btu in 2013） in the nation. When humans spend a long time indoors to escape the inclement weather, their health will be more susceptible to the indoor environment. In addition, North Dakota has the 3rd least number of green buildings certified by LEED （Leadership in Energy and Environmental Design） in the nation. This paper aims to investigate the status quo of buildings with respect to energy, health and sustainability in North Dakota, and attempts to propose strategies regarding research and higher education to rectify the current issues. These strategies include but not limited to forming the architectural engineering program, a comprehensive and interdisciplinary program in buildings.
文摘The performance of DFIG-based wind generation systems that interconnected to solid networks is well understood and prevalent in Europe and North America. However, the application of these renewable generating stations to weak network has been examined in very limited occasions. Weak networks have a range of limitations from system capacities to CFCT restrictions which would need to be well understood prior to wind energy integration. Of particular interest would be how much wind generation could be integrated into a weak network prior to increasing voltage and frequency stability issues brought about by penetration issues. This paper introduces a simple and practical approach based on the equal area criteria to investigate the stability of weak networks. Simulation results that are presented to show the proposed approach is a viable preliminary assessment tool to determine system stability on weak networks with wind power penetration.
基金supported by the National Natural Science Foundation of China(21872119)the Talent Engineering Training Funding Project of Hebei Province(A201905004)the Research Program of the College Science and Technology of Hebei Province(ZD2018091)。
文摘Photocatalytic hydrogen production is considered a promising approach to generating clean sustainable energy.However,the conventional co-catalyst(e.g.,Pt)used in photocatalytic hydrogen production is high-cost and difficult to obtain.Here,we designed and prepared a ternary nanocomposite MXene@Au@Cd S,which can be used in the field of efficient and excellent photocatalytic hydrogen production.The MXene@Au@Cd S has a hydrogen production rate of 17,070.43μmol g^-1h^-1(tested for 2 h),which is 1.85 times that of pure Cd S nanomaterials.The improved hydrogen production performance of the MXene@Au@Cd S is attributed to:(i)MXene provides more active adsorption sites and reaction centers for Au and Cd S nanoparticles;(ii)the synergistic effect of Au’s strong surface plasmon resonance expands the optical response range of Cd S.Therefore,this work solves the problem of the solid connection between the surface functional groups of photocatalyst,and achieves rapid interface charge transfer and long-term stability during the hydrogen production.
基金Supported by the National Natural Science Foundation of China (NNSFC) under Grant Nos. 11175023 and 10834008partially by the Fundamental Research Funds for the Central Universities (FRFCU)
文摘Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong laser. The radiation pressure acceleration mechanism plays an important role on the studied problem. For the ions near the plasma mirror, i.e. electrons layer, the dependence of ions energy on their charge-mass ratio is derived theoretically. It is found that the larger the charge-mass ratio is, the higher the accelerated ions energy gets. For those ions far away from the layer, the dependence of energy and energy spread on ions charge-mass ratio are also obtained by numerical performance. It exhibits that, as ions charge-mass ratio increases, not only the accelerated ions energy but also the energy spread will become large.
