Occupants of highly glazed buildings often suffer from thermal discomfort during the mid-seasons when no shadings are used in such buildings,especially when inertial heating systems are used.The present study is devot...Occupants of highly glazed buildings often suffer from thermal discomfort during the mid-seasons when no shadings are used in such buildings,especially when inertial heating systems are used.The present study is devoted to evaluating the impact of long solar beam exposure on the internal thermal discomfort in glazed spaces when heating is implemented through a floor system.A comprehensive experimental study is carried out using an experimental bi-climatic chamber which is fully monitored and controlled,allowing realistic simulations of the dynamic movement of the sun patch on a heated slab.The findings show that a period of discomfort as long as 8 h can occur,and persist far after the sunbeam exposure stops.During this period,the heating slab’s surface temperature,considered from an average point of view,can attain 34°C while the indoor temperature reaches 26°C.Simulations conducted using a previously developed model display a good fit with the measurements.展开更多
The feasibility of Plus Energy Building for a sample relevant case is investigated.After a literature review aimed to identify key aspects of this type of buildings,a preliminary evaluation of the thermal performance ...The feasibility of Plus Energy Building for a sample relevant case is investigated.After a literature review aimed to identify key aspects of this type of buildings,a preliminary evaluation of the thermal performance of a building constructed using conventional material is presented together with a parametric analysis of the impact of typical influential parameters.Solar domestic hot water(SDHW)and photovoltaic systems(PV)are considered in the study.Numerical simulations indicate that for the examined sample case(Beirut in Lebanon)the total annual energy need of conventional building is 87.1 kWh/y.m^(2).About 49%of energy savings can be achieved by improving the building envelope and installing energy efficient technologies.Moreover,about 90%of energy savings in domestic hot water production can be achieved by installing a SDHW system composed of two solar collectors connected in series.Finally,the addition of a grid connected PV array system can significantly mitigate the energy needs of the building leading to an annual excess of energy.展开更多
The thermal comfort of frail people has to be considered carefully,mainly because of the high thermal sensitivity of this population and the negative influences that unsatisfactory thermal conditions have on their hea...The thermal comfort of frail people has to be considered carefully,mainly because of the high thermal sensitivity of this population and the negative influences that unsatisfactory thermal conditions have on their health.Most existing thermal comfort works have been conducted under steady-state,uniform thermal environments,with far fewer being performed in dynamic and non-uniform thermal environments,and even less for frail people.This study aimed at assessing the thermal responses of frail people under transient and non-uniform thermal environments,using a thermal manikin and a climatic test cell.Thermal responses were investigated and discussed in both genders.The analysis of variance showed a significant difference in thermal comfort and thermal sensation between females and males over time,under hot exposure.Under cold exposure,results showed a significant difference in thermal sensation between females and males over time,but no significant difference was observed in term of thermal comfort.Analysis revealed also significant differences in the dynamic thermal sensation between the sexes under cold exposure,while results confirmed that there is no significant difference in the dynamic thermal sensation between sexes under hot exposure.展开更多
In the present work,selective laser melting(SLM)technology was utilized for manufacturing CX stainless steel samples under a series of laser parameters.The effect of laser linear energy density on the microstructure c...In the present work,selective laser melting(SLM)technology was utilized for manufacturing CX stainless steel samples under a series of laser parameters.The effect of laser linear energy density on the microstructure characteristics,phase distribution,crystallographic orientation and mechanical properties of these CX stainless steel samples were investigated theoretically and experimentally via scanning electron microscope(SEM),X-ray diffraction(XRD),electron backscatter diffraction(EBSD)and transmission electron microscope(TEM).Based on the systematic study,the SLM CX stainless steel sample with best surface roughness(Ra=4.05±1.8μm)and relative density(Rd=99.72%±0.22%)under the optimal linear density(η=245 J/m)can be obtained.SLM CX stainless steel was primarily constituted by a large number of fine martensite(α’phase)structures(i.e.,cell structures,cellular dendrites and blocky grains)and a small quantity of austenite(γphase)structures.The pre ferred crystallographic orientation(i.e.,<111>direction)can be determined in the XZ plane of the SLM CX sample.Furthermore,under the optimal linear energy density,the good combinations with the highest ultimate tensile strength(UTS=1068.0%±5.9%)and the best total elongation(TE=15.70%±0.26%)of the SLM CX sample can be attained.Dislocation strengthening dominates the strengthening mechanism of the SLM CX sample in as-built state.展开更多
Implicit summation is a technique for the conversion of sums over intermediate states in multiphoton absorption and the high-order susceptibility in hydrogen into simple integrals.Here,we derive the equivalent techniq...Implicit summation is a technique for the conversion of sums over intermediate states in multiphoton absorption and the high-order susceptibility in hydrogen into simple integrals.Here,we derive the equivalent technique for hydrogenic impurities in multi-valley semiconductors.While the absorption has useful applications,it is primarily a loss process;conversely,the non-linear susceptibility is a crucial parameter for active photonic devices.For Si:P,we predict the hyperpolarizability ranges from χ^((3))/n_(3D)=2.9 to 580×10^(−38 )m^(5)/V^(2) depending on the frequency,even while avoiding resonance.Using samples of a reasonable density,n3D,and thickness,L,to produce thirdharmonic generation at 9 THz,a frequency that is difficult to produce with existing solid-state sources,we predict that χ^((3)) should exceed that of bulk InSb and χ^((3))L should exceed that of graphene and resonantly enhanced quantum wells.展开更多
This article exposes the beginnings of a new field which could be named as ＂plasmomechanics＂. Plasmomechanics comes from the convergence between mechanics and plasmonics. Here we discuss a relatively recent topic wh...This article exposes the beginnings of a new field which could be named as ＂plasmomechanics＂. Plasmomechanics comes from the convergence between mechanics and plasmonics. Here we discuss a relatively recent topic whose technolo- gical aim is the development of plasmonic strain sensors, The idea is based on the ability to deduce Au nanoparticles （NPs） distance distributions from polarized optical extinction spectroscopy which could thus give access to material strains. Variations of interparticle distances distributions can indeed lead to variations of plasmonic coupling and thus to material color change as shown here experimentally and numerically for random Au NP assemblies deposited onto elastomer films,展开更多
文摘Occupants of highly glazed buildings often suffer from thermal discomfort during the mid-seasons when no shadings are used in such buildings,especially when inertial heating systems are used.The present study is devoted to evaluating the impact of long solar beam exposure on the internal thermal discomfort in glazed spaces when heating is implemented through a floor system.A comprehensive experimental study is carried out using an experimental bi-climatic chamber which is fully monitored and controlled,allowing realistic simulations of the dynamic movement of the sun patch on a heated slab.The findings show that a period of discomfort as long as 8 h can occur,and persist far after the sunbeam exposure stops.During this period,the heating slab’s surface temperature,considered from an average point of view,can attain 34°C while the indoor temperature reaches 26°C.Simulations conducted using a previously developed model display a good fit with the measurements.
文摘The feasibility of Plus Energy Building for a sample relevant case is investigated.After a literature review aimed to identify key aspects of this type of buildings,a preliminary evaluation of the thermal performance of a building constructed using conventional material is presented together with a parametric analysis of the impact of typical influential parameters.Solar domestic hot water(SDHW)and photovoltaic systems(PV)are considered in the study.Numerical simulations indicate that for the examined sample case(Beirut in Lebanon)the total annual energy need of conventional building is 87.1 kWh/y.m^(2).About 49%of energy savings can be achieved by improving the building envelope and installing energy efficient technologies.Moreover,about 90%of energy savings in domestic hot water production can be achieved by installing a SDHW system composed of two solar collectors connected in series.Finally,the addition of a grid connected PV array system can significantly mitigate the energy needs of the building leading to an annual excess of energy.
基金This work was supported by the Regional Council of Champagne-Ardenne(CRCA),the European Fund for Economic and Regional Development(FEDER),for the Doctoral research program“Retcli”agreement number:CA0023755.
文摘The thermal comfort of frail people has to be considered carefully,mainly because of the high thermal sensitivity of this population and the negative influences that unsatisfactory thermal conditions have on their health.Most existing thermal comfort works have been conducted under steady-state,uniform thermal environments,with far fewer being performed in dynamic and non-uniform thermal environments,and even less for frail people.This study aimed at assessing the thermal responses of frail people under transient and non-uniform thermal environments,using a thermal manikin and a climatic test cell.Thermal responses were investigated and discussed in both genders.The analysis of variance showed a significant difference in thermal comfort and thermal sensation between females and males over time,under hot exposure.Under cold exposure,results showed a significant difference in thermal sensation between females and males over time,but no significant difference was observed in term of thermal comfort.Analysis revealed also significant differences in the dynamic thermal sensation between the sexes under cold exposure,while results confirmed that there is no significant difference in the dynamic thermal sensation between sexes under hot exposure.
基金supported financially by the Sciences Platform Environment and Capacity Building Projects of GDAS(No.2019GDASYL-0502006)the Key R&D Program of Guangdong Province(No.2020B090923002)+3 种基金the Guangdong Academy of Science Projects(No.2021GDASYL-20210102005)the Guangdong Province Science and Technology Plan Projects(No.2020A1515011096)the Guangzhou Project of Science&Technology(Nos.202007020008 and 201807010030)the support from the Program of CSC(No.201801810106)。
文摘In the present work,selective laser melting(SLM)technology was utilized for manufacturing CX stainless steel samples under a series of laser parameters.The effect of laser linear energy density on the microstructure characteristics,phase distribution,crystallographic orientation and mechanical properties of these CX stainless steel samples were investigated theoretically and experimentally via scanning electron microscope(SEM),X-ray diffraction(XRD),electron backscatter diffraction(EBSD)and transmission electron microscope(TEM).Based on the systematic study,the SLM CX stainless steel sample with best surface roughness(Ra=4.05±1.8μm)and relative density(Rd=99.72%±0.22%)under the optimal linear density(η=245 J/m)can be obtained.SLM CX stainless steel was primarily constituted by a large number of fine martensite(α’phase)structures(i.e.,cell structures,cellular dendrites and blocky grains)and a small quantity of austenite(γphase)structures.The pre ferred crystallographic orientation(i.e.,<111>direction)can be determined in the XZ plane of the SLM CX sample.Furthermore,under the optimal linear energy density,the good combinations with the highest ultimate tensile strength(UTS=1068.0%±5.9%)and the best total elongation(TE=15.70%±0.26%)of the SLM CX sample can be attained.Dislocation strengthening dominates the strengthening mechanism of the SLM CX sample in as-built state.
基金financial support from the UK Engineering and Physical Sciences Research Council[ADDRFSS,Grant No.EP/M009564/1]EPSRC strategic equipment grant no.EP/L02263X/1.
文摘Implicit summation is a technique for the conversion of sums over intermediate states in multiphoton absorption and the high-order susceptibility in hydrogen into simple integrals.Here,we derive the equivalent technique for hydrogenic impurities in multi-valley semiconductors.While the absorption has useful applications,it is primarily a loss process;conversely,the non-linear susceptibility is a crucial parameter for active photonic devices.For Si:P,we predict the hyperpolarizability ranges from χ^((3))/n_(3D)=2.9 to 580×10^(−38 )m^(5)/V^(2) depending on the frequency,even while avoiding resonance.Using samples of a reasonable density,n3D,and thickness,L,to produce thirdharmonic generation at 9 THz,a frequency that is difficult to produce with existing solid-state sources,we predict that χ^((3)) should exceed that of bulk InSb and χ^((3))L should exceed that of graphene and resonantly enhanced quantum wells.
文摘This article exposes the beginnings of a new field which could be named as ＂plasmomechanics＂. Plasmomechanics comes from the convergence between mechanics and plasmonics. Here we discuss a relatively recent topic whose technolo- gical aim is the development of plasmonic strain sensors, The idea is based on the ability to deduce Au nanoparticles （NPs） distance distributions from polarized optical extinction spectroscopy which could thus give access to material strains. Variations of interparticle distances distributions can indeed lead to variations of plasmonic coupling and thus to material color change as shown here experimentally and numerically for random Au NP assemblies deposited onto elastomer films,
