A new FAGE setup has recently been built at the University of Lille,France.It permits the quantification of OH and HO 2 in the atmosphere with a detection limit of 3×10 5 molecules/（cm 3 ·min） for OH and 1...A new FAGE setup has recently been built at the University of Lille,France.It permits the quantification of OH and HO 2 in the atmosphere with a detection limit of 3×10 5 molecules/（cm 3 ·min） for OH and 1×10 6 molecules/（cm 3 ·min） for HO 2.Its coupling to a photolysis cell enables the measurement of the total reactivity of the hydroxyl radical in ambient air and kinetic studies in laboratory.Two configurations have been considered：one with the photolysis cell at 90° to the FAGE nozzle,the other on line with the FAGE nozzle.The two configurations have been tested and validated by measuring the well known rate constants of OH with CH 4,C 3 H 8 and CO.The advantages and drawbacks of each configuration have been evaluated.The ＂on line＂ configuration limits losses and permits measurements over a larger reactivity range but is affected by OH formation from the laser beam striking the FAGE nozzle,thus limiting the ability to carry out energy dependence studies which can,in contrast,be successfully performed in the 90° configuration.展开更多
The Atlantic Meridional Overturning Circulation(AMOC)is part of the great ocean“conveyor belt”that circulates heat around the globe.Since the early 2000s,ocean sensors have started to monitor the AMOC,but the measur...The Atlantic Meridional Overturning Circulation(AMOC)is part of the great ocean“conveyor belt”that circulates heat around the globe.Since the early 2000s,ocean sensors have started to monitor the AMOC,but the measurements are still far from accurate and the time window does not permit the separation of short term variability from a longer term trend.Other works have claimed that global warming is slowing down the AMOC,based on models and proxies of temperatures.Some other observations demonstrate a stable circulation of the oceans.By using tide gauge data complementing recent satellite and ocean sensor observations,the stability of the AMOC is shown to go back to 1860.It is concluded that no available information has the due accuracy and time coverage to show a clear trend outside the inter-annual and multi-decadal variability in the direction of increasing or decreasing strength over the last decades.展开更多
Experimental studies on full-scale straw-bale walls have demonstrated the adequacy of straw-bale wall systems for resisting lateral loads from wind or seismic actions.Critical to the performance of the wall system is ...Experimental studies on full-scale straw-bale walls have demonstrated the adequacy of straw-bale wall systems for resisting lateral loads from wind or seismic actions.Critical to the performance of the wall system is the anchorage of mesh reinforcement to the bottom plate and to the roof bearing assembly or top plate.Reported in this paper are the results of experiments examining mesh strength,anchorage strength,and failure mode for a variety of reinforcement meshes(steel,plastic,and hemp)and anchorage details.Because of the potential for new wood preservative pressure treatments to cause corrosion,stainless steel staples driven pneumatically into pressure-treated sill plates were tested in addition to electro-galvanized staples driven pneumatically into untreated sill plates and a heavier gauge staple driven manually into an untreated sill plate.Recommended anchorage details are identified,considering not only the test results but also the many other factors that must be considered in developing reliable,economical,and constructible details.展开更多
基金supported by the Nord-Pas de Calais region in the frame of the IRENI research program,by the French Research Ministry,by the European Fund for Regional Economic Development (FEDER)the EU for financial support through project MEST-CT-2005-020659the French Government for financial aid through an EIFFEL scholarship
文摘A new FAGE setup has recently been built at the University of Lille,France.It permits the quantification of OH and HO 2 in the atmosphere with a detection limit of 3×10 5 molecules/（cm 3 ·min） for OH and 1×10 6 molecules/（cm 3 ·min） for HO 2.Its coupling to a photolysis cell enables the measurement of the total reactivity of the hydroxyl radical in ambient air and kinetic studies in laboratory.Two configurations have been considered：one with the photolysis cell at 90° to the FAGE nozzle,the other on line with the FAGE nozzle.The two configurations have been tested and validated by measuring the well known rate constants of OH with CH 4,C 3 H 8 and CO.The advantages and drawbacks of each configuration have been evaluated.The ＂on line＂ configuration limits losses and permits measurements over a larger reactivity range but is affected by OH formation from the laser beam striking the FAGE nozzle,thus limiting the ability to carry out energy dependence studies which can,in contrast,be successfully performed in the 90° configuration.
文摘The Atlantic Meridional Overturning Circulation(AMOC)is part of the great ocean“conveyor belt”that circulates heat around the globe.Since the early 2000s,ocean sensors have started to monitor the AMOC,but the measurements are still far from accurate and the time window does not permit the separation of short term variability from a longer term trend.Other works have claimed that global warming is slowing down the AMOC,based on models and proxies of temperatures.Some other observations demonstrate a stable circulation of the oceans.By using tide gauge data complementing recent satellite and ocean sensor observations,the stability of the AMOC is shown to go back to 1860.It is concluded that no available information has the due accuracy and time coverage to show a clear trend outside the inter-annual and multi-decadal variability in the direction of increasing or decreasing strength over the last decades.
文摘Experimental studies on full-scale straw-bale walls have demonstrated the adequacy of straw-bale wall systems for resisting lateral loads from wind or seismic actions.Critical to the performance of the wall system is the anchorage of mesh reinforcement to the bottom plate and to the roof bearing assembly or top plate.Reported in this paper are the results of experiments examining mesh strength,anchorage strength,and failure mode for a variety of reinforcement meshes(steel,plastic,and hemp)and anchorage details.Because of the potential for new wood preservative pressure treatments to cause corrosion,stainless steel staples driven pneumatically into pressure-treated sill plates were tested in addition to electro-galvanized staples driven pneumatically into untreated sill plates and a heavier gauge staple driven manually into an untreated sill plate.Recommended anchorage details are identified,considering not only the test results but also the many other factors that must be considered in developing reliable,economical,and constructible details.
