Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decompositio...Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decomposition ratio of carbonate were investigated.The experimental result shows that the decomposition ratio of carbonate is 98.24%under the conditions of liquid-to-solid ratio of 5:1,Fe^(3+)concentration of 20 g/L,sulfuric acid concentration of 20 g/L,reaction temperature of 80 ℃ and reaction time of 2 h.Then,the slurry obtained from carbonate decomposition was put into the titanium autoclave for pressure oxidation leaching.Effects of liquid-to-solid ratio,temperature,time and oxygen partial pressure on sulfur oxidation ratio were studied during pressure oxidation.With the prolonged time,pyrite and arsenopyrite are oxidized to ferric subsulfate,hydrated ferric sulfate and jarosite,resulting in the increasing residue ratio.The residue ratio and the sulfur content in the residue can be decreased by ferric subsulfate dissolution.The oxidation ratio of the sulfur is 99.35% under the conditions of oxidation time of 4 h,temperature of 210 ℃,oxygen partial pressure of 0.8 MPa and stirring speed of 600 r/min.展开更多
GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon ...GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.展开更多
This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.
1 Scope :This standard specifies the classification, technical requirements, test methods, inspection rules, packing, marking, transportation, storage and quality certificate of alumina carbon refractory products fo...1 Scope :This standard specifies the classification, technical requirements, test methods, inspection rules, packing, marking, transportation, storage and quality certificate of alumina carbon refractory products for continuous casting.展开更多
In order to improve oxidation resistance and ther- mal shock resistance of Al2O3-C refractories, two groups of specimens were prepared with phenolic resin as binder, adding 0, 2 wt% , 4 wt% and 6 wt% commercial SiC or...In order to improve oxidation resistance and ther- mal shock resistance of Al2O3-C refractories, two groups of specimens were prepared with phenolic resin as binder, adding 0, 2 wt% , 4 wt% and 6 wt% commercial SiC or ZrO2-SiC composite powder synthesized from zircon respectively to Al2O3- C refractories, pressing at 200 MPa, drying fully at 250℃, and then carbon embedded firing at 1400℃ for 2 h. Oxidation resistance and thermal shock resistance were researched, phase composition was analyzed by XRD. The results showed that the oxidation of SiC in additives could protect carbon in specimens effectively and thus decreased the mass loss ratio and oxidation area, and improved the oxidation resistance of the specimen. Thermal shock resistance was improved owing to the micro crack toughening of ZrO2 and grain toughening of SiC. In this experiment, the specimens with 6 wt% ZrO2 -SiC composite powder or 6 wt% SiC powder had the best oxidation resistance and thermal shock resistance.展开更多
Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic car...Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic carbon(DOC)in submarine groundwater(well water and pore water)in salt marshes plays an important role in advective exchange between the salt marshes and coastal waters.However,the molecular characteristics of DOC in salt marsh groundwater are poorly understood because of the complex DOC structures and hydrodynamic process.In this study,fl uorescent components and refractory DOC(RDOC)in submarine groundwater from a salt marsh(Chongming Island,China)and adjacent coastal water were characterized by fl uorescence spectroscopy and nuclear magnetic resonance spectroscopy.The fl uorescent components identifi ed by parallel factor analysis indicated that humic-like substances dominated the chromophoric dissolved organic matter in the submarine groundwater.The chromophoric dissolved organic matter and dissolved organic matter in the submarine groundwater had non-conservative behaviors because of additions from terrestrial humic substances.The nuclear magnetic resonance spectra indicated that bioactive substances(carbohydrates)contributed only 13.2%-14.8%of the dissolved organic matter in the submarine groundwater but carboxyl-rich alicyclic molecules(CRAMs),the main components of RDOC,contributed 64.5%of the dissolved organic matter.Carbohydrates and CRAMs contributed 16.4%and 61.7%of the dissolved organic matter in the coastal water,similar to the contributions for submarine groundwater.The DOC concentration in submarine groundwater was 386±294μmol/L,which was signifi cantly higher than that in coastal water(91±19μmol/L).The high DOC concentrations and>60%relative RDOC content suggested that submarine groundwater may be an important source of RDOC to coastal seawater.This information will be helpful for estimating the climate eff ects of salt marsh blue carbon.展开更多
Carbon nanotubes (CNTs) have been extensively studied over the last two decades since they possess excellent properties.CNTs have been considered as new promising reinforcements for carbon containing refractories (...Carbon nanotubes (CNTs) have been extensively studied over the last two decades since they possess excellent properties.CNTs have been considered as new promising reinforcements for carbon containing refractories (CCRs).Current research progress of the CNT-reinforced MgO-C and Al2O3-C refractories was summarized in this mini-review,and the CNT-reinforced CCRs possess remarkable mechanical properties and superior thermal shock resistance compared to CCRs without CNTs.展开更多
Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel (5 - 3 and 3 - 1 mm ) and fused magnesia (5 - 3 and 3 - 1 mm ) as coarse aggregates, respectively, ...Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel (5 - 3 and 3 - 1 mm ) and fused magnesia (5 - 3 and 3 - 1 mm ) as coarse aggregates, respectively, fused magnesia ( ≤1 mm) as fine aggregate, magnesia powder (≤ 0. 088 mm ) , flake graphite powder ( ≤0. 088 mm), metal Al powder ( 〈0. 074 mm) as matrix, and phenol resin as binder. After curing at 220 ℃ and coke-embedded firing at 1 500 ℃ , the apparent porosity, cold crushing strength, cold modulus of rupture, permanent linear change on heating, thermal shock resistance and slag resistance of the specimens were studied comparatively. The results indicate that: ( 1 ) after curing at 220 ℃ and coke-embedded firing at 1 500 ℃, the specimen with microporous magnesia-rich spinel replacing fused magnesia has lower bulk density and higher apparent porosity than the common low car- bon MgO - C specimen. After curing at 220 ℃, the specimen with microporous aggregate has lower strength than common low carbon MgO - C specimen, but after coke-embedded firing at 1 500℃, it has higher strength and lower permanent linear change on heating; (2) low carbon MgO - C specimen using microporous magnesia-rich spinel to replace fused magnesia aggregate has better thermal shock resistance but worse slag resistance.展开更多
Al2O3-C refractories are widely used as functional elements like nozzles, well blocks, sliding gate plates and stoppers in the continuous casting process of steel production. Application of silicon as a metallic agent...Al2O3-C refractories are widely used as functional elements like nozzles, well blocks, sliding gate plates and stoppers in the continuous casting process of steel production. Application of silicon as a metallic agent in Al2O3-C slide gate plate production is usual. In fact, a non-oxide bond can be generated due to the reaction between silicon and carbon under reducing atmosphere in the plate matrix. This non-oxide bond can enhance the mechanical strength and abrasion resistance. In order to improve the mechanical and thermo-mechanical properties, functional additives can be aimed to lower the sinte- ring temperature and tailor the microstructure. For this reason, the effect of a special solid state sintering aid addition on the microstructure and thermo-mechanical properties of Al2O3-C slide gate plates in the presence of Si as a metallic component has been investigated. Two types of specimens were pressed at 150 MPa, tempered at 200 ℃ and fired in coke bed at 1 400 ℃ , respectively. Physical ( BD and AP ) , mechanical ( CCS and MOR ) and thermo-mechanical ( HMOR ) properties were determined; in addition, phase composition was characterized by X-ray diffraction analysis ( XRD ) and microstructure of specimens was investigated by field emission scanning electron microscopy (FESEM). Results have shown that the addition of sintering aid increased the generation of cation vacancy in Al2O3 structure which enhanced the cation diffusion and densification process ; consequently, CCS, MOR and HMOR of specimens increased drasticallywhile bulk density and apparent porosity remained un- changed.展开更多
The oxidation behaviors of fused zirconium diboride and chemosynthetic zirconium diboride as well as morphology and composition of their oxidation products were researched by FESEM-EDS and XRD.The two kinds of zirconi...The oxidation behaviors of fused zirconium diboride and chemosynthetic zirconium diboride as well as morphology and composition of their oxidation products were researched by FESEM-EDS and XRD.The two kinds of zirconium diboride were heated at 700℃,900℃,1100℃and 1300℃for 3 h in air,respectively.The results show that Zr02 and B203(Ⅰ)are generated from the chemosynthetic zirconium diboride oxidized at 700℃for 3 h or the fused zirconium diboride oxidized at 800℃for 24 h;B203(Ⅰ)dissolves into water and then H3B03 crystallizes.展开更多
The erosion resistance of carbon containingrefractories for continuous casting to molten steel wasinvestigated by means of simulative erosion test and examining used refractories. Decarbonization and reaction between ...The erosion resistance of carbon containingrefractories for continuous casting to molten steel wasinvestigated by means of simulative erosion test and examining used refractories. Decarbonization and reaction between molten steel and decarbonization layer are main erosion process of carbon containingrefractories by molten steel. The reactions between molten steel and oxide in refractories determine thethickness of decarbonization layer. A dense layer formation on the working surface contacting withmolten steel during casting will suppress decarbonization and erosion process.展开更多
Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation.The lifetime of BC depends on atmospheric transport,aging and consequently on...Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation.The lifetime of BC depends on atmospheric transport,aging and consequently on wet scavenging processes(in-cloud and below-cloud scavenging).In this study,sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer(SP2)and a nebulizer.The results showed that the volume-weighted average(VWA)mass concentrations of refractory black carbon(rBC)in each rainfall event varied,ranging from 10.8 to 78.9μg/L.The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events.The geometric mean median mass-equivalent diameter(MMD)decreased under precipitation,indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging.A positive correlation(R2=0.73)between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process.Additionally,the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74%and 26%to wet scavenging,respectively.The scavenging ratio of rBC particles was estimated to be 0.06 on average.This study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.展开更多
Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon (WIRC) component of total suspended particulates (TSP), collected weekly during 2003, as well as from Oc...Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon (WIRC) component of total suspended particulates (TSP), collected weekly during 2003, as well as from October 2005 to May 2006 at the WMO-GAW Mt. Waliguan (WLG) site. The overall average WlRC mass concentration was (1183 ± 120)ng/m3 (n = 79), while seasonal averages were 2081 ± 1707 (spring), 454±205 (summer), 650 ±411 (autumn), and 1019 ± 703 (winter) ng/m3. Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer, although WIRC concentrations were typically higher, especially in winter and spring. The δ13C PDB value (-25.3 ± 0.8)%0 determined for WIRC suggests that its sources are C3 biomass or fossil fuel combustion. No seasonal change in δ13C PDB was evident. The average percent Modern Carbon (pMC) for 14C in WIRC for winter and spring was (67.2 ± 7.7)% (n = 29). Lower pMC values were associated with air masses trans- ported from the area east of WLG, while higher pMC values were associated with air masses from the Tibetan Plateau, southwest of WLG. Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event.展开更多
基金Project(51404296)supported by the Young Scientists Fund of National Natural Science Foundation of ChinaProject(134414)supported by the Postdoctoral Funded Program of Central South University,China
文摘Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decomposition ratio of carbonate were investigated.The experimental result shows that the decomposition ratio of carbonate is 98.24%under the conditions of liquid-to-solid ratio of 5:1,Fe^(3+)concentration of 20 g/L,sulfuric acid concentration of 20 g/L,reaction temperature of 80 ℃ and reaction time of 2 h.Then,the slurry obtained from carbonate decomposition was put into the titanium autoclave for pressure oxidation leaching.Effects of liquid-to-solid ratio,temperature,time and oxygen partial pressure on sulfur oxidation ratio were studied during pressure oxidation.With the prolonged time,pyrite and arsenopyrite are oxidized to ferric subsulfate,hydrated ferric sulfate and jarosite,resulting in the increasing residue ratio.The residue ratio and the sulfur content in the residue can be decreased by ferric subsulfate dissolution.The oxidation ratio of the sulfur is 99.35% under the conditions of oxidation time of 4 h,temperature of 210 ℃,oxygen partial pressure of 0.8 MPa and stirring speed of 600 r/min.
文摘GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.
文摘This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.
文摘1 Scope :This standard specifies the classification, technical requirements, test methods, inspection rules, packing, marking, transportation, storage and quality certificate of alumina carbon refractory products for continuous casting.
文摘In order to improve oxidation resistance and ther- mal shock resistance of Al2O3-C refractories, two groups of specimens were prepared with phenolic resin as binder, adding 0, 2 wt% , 4 wt% and 6 wt% commercial SiC or ZrO2-SiC composite powder synthesized from zircon respectively to Al2O3- C refractories, pressing at 200 MPa, drying fully at 250℃, and then carbon embedded firing at 1400℃ for 2 h. Oxidation resistance and thermal shock resistance were researched, phase composition was analyzed by XRD. The results showed that the oxidation of SiC in additives could protect carbon in specimens effectively and thus decreased the mass loss ratio and oxidation area, and improved the oxidation resistance of the specimen. Thermal shock resistance was improved owing to the micro crack toughening of ZrO2 and grain toughening of SiC. In this experiment, the specimens with 6 wt% ZrO2 -SiC composite powder or 6 wt% SiC powder had the best oxidation resistance and thermal shock resistance.
基金Supported by the Natural Science Foundation of Shanghai(No.19ZR1415300)the Zhejiang Provincial Natural Science Foundation of China(No.LQ21D060005)the China Postdoctoral Science Foundation(No.2020M681931)。
文摘Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic carbon(DOC)in submarine groundwater(well water and pore water)in salt marshes plays an important role in advective exchange between the salt marshes and coastal waters.However,the molecular characteristics of DOC in salt marsh groundwater are poorly understood because of the complex DOC structures and hydrodynamic process.In this study,fl uorescent components and refractory DOC(RDOC)in submarine groundwater from a salt marsh(Chongming Island,China)and adjacent coastal water were characterized by fl uorescence spectroscopy and nuclear magnetic resonance spectroscopy.The fl uorescent components identifi ed by parallel factor analysis indicated that humic-like substances dominated the chromophoric dissolved organic matter in the submarine groundwater.The chromophoric dissolved organic matter and dissolved organic matter in the submarine groundwater had non-conservative behaviors because of additions from terrestrial humic substances.The nuclear magnetic resonance spectra indicated that bioactive substances(carbohydrates)contributed only 13.2%-14.8%of the dissolved organic matter in the submarine groundwater but carboxyl-rich alicyclic molecules(CRAMs),the main components of RDOC,contributed 64.5%of the dissolved organic matter.Carbohydrates and CRAMs contributed 16.4%and 61.7%of the dissolved organic matter in the coastal water,similar to the contributions for submarine groundwater.The DOC concentration in submarine groundwater was 386±294μmol/L,which was signifi cantly higher than that in coastal water(91±19μmol/L).The high DOC concentrations and>60%relative RDOC content suggested that submarine groundwater may be an important source of RDOC to coastal seawater.This information will be helpful for estimating the climate eff ects of salt marsh blue carbon.
基金financially supported by the National Natural Science Foundation of China ( General program,51272188, 51472184 and 51472185 )the Natural Science Foundation of Hubei Province,China ( Contract No. 2013CFA086 )Foreign Cooperation Projects in Science and Technology of Hubei Province,China ( Contract No. 2013BHE002)
文摘Carbon nanotubes (CNTs) have been extensively studied over the last two decades since they possess excellent properties.CNTs have been considered as new promising reinforcements for carbon containing refractories (CCRs).Current research progress of the CNT-reinforced MgO-C and Al2O3-C refractories was summarized in this mini-review,and the CNT-reinforced CCRs possess remarkable mechanical properties and superior thermal shock resistance compared to CCRs without CNTs.
文摘Two types of low carbon MgO - C refractories with 6% graphite were prepared using microporous magnesiarich spinel (5 - 3 and 3 - 1 mm ) and fused magnesia (5 - 3 and 3 - 1 mm ) as coarse aggregates, respectively, fused magnesia ( ≤1 mm) as fine aggregate, magnesia powder (≤ 0. 088 mm ) , flake graphite powder ( ≤0. 088 mm), metal Al powder ( 〈0. 074 mm) as matrix, and phenol resin as binder. After curing at 220 ℃ and coke-embedded firing at 1 500 ℃ , the apparent porosity, cold crushing strength, cold modulus of rupture, permanent linear change on heating, thermal shock resistance and slag resistance of the specimens were studied comparatively. The results indicate that: ( 1 ) after curing at 220 ℃ and coke-embedded firing at 1 500 ℃, the specimen with microporous magnesia-rich spinel replacing fused magnesia has lower bulk density and higher apparent porosity than the common low car- bon MgO - C specimen. After curing at 220 ℃, the specimen with microporous aggregate has lower strength than common low carbon MgO - C specimen, but after coke-embedded firing at 1 500℃, it has higher strength and lower permanent linear change on heating; (2) low carbon MgO - C specimen using microporous magnesia-rich spinel to replace fused magnesia aggregate has better thermal shock resistance but worse slag resistance.
文摘Al2O3-C refractories are widely used as functional elements like nozzles, well blocks, sliding gate plates and stoppers in the continuous casting process of steel production. Application of silicon as a metallic agent in Al2O3-C slide gate plate production is usual. In fact, a non-oxide bond can be generated due to the reaction between silicon and carbon under reducing atmosphere in the plate matrix. This non-oxide bond can enhance the mechanical strength and abrasion resistance. In order to improve the mechanical and thermo-mechanical properties, functional additives can be aimed to lower the sinte- ring temperature and tailor the microstructure. For this reason, the effect of a special solid state sintering aid addition on the microstructure and thermo-mechanical properties of Al2O3-C slide gate plates in the presence of Si as a metallic component has been investigated. Two types of specimens were pressed at 150 MPa, tempered at 200 ℃ and fired in coke bed at 1 400 ℃ , respectively. Physical ( BD and AP ) , mechanical ( CCS and MOR ) and thermo-mechanical ( HMOR ) properties were determined; in addition, phase composition was characterized by X-ray diffraction analysis ( XRD ) and microstructure of specimens was investigated by field emission scanning electron microscopy (FESEM). Results have shown that the addition of sintering aid increased the generation of cation vacancy in Al2O3 structure which enhanced the cation diffusion and densification process ; consequently, CCS, MOR and HMOR of specimens increased drasticallywhile bulk density and apparent porosity remained un- changed.
文摘The oxidation behaviors of fused zirconium diboride and chemosynthetic zirconium diboride as well as morphology and composition of their oxidation products were researched by FESEM-EDS and XRD.The two kinds of zirconium diboride were heated at 700℃,900℃,1100℃and 1300℃for 3 h in air,respectively.The results show that Zr02 and B203(Ⅰ)are generated from the chemosynthetic zirconium diboride oxidized at 700℃for 3 h or the fused zirconium diboride oxidized at 800℃for 24 h;B203(Ⅰ)dissolves into water and then H3B03 crystallizes.
文摘The erosion resistance of carbon containingrefractories for continuous casting to molten steel wasinvestigated by means of simulative erosion test and examining used refractories. Decarbonization and reaction between molten steel and decarbonization layer are main erosion process of carbon containingrefractories by molten steel. The reactions between molten steel and oxide in refractories determine thethickness of decarbonization layer. A dense layer formation on the working surface contacting withmolten steel during casting will suppress decarbonization and erosion process.
基金supported by the National Natural Science Foundation of China(No.41877314).
文摘Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation.The lifetime of BC depends on atmospheric transport,aging and consequently on wet scavenging processes(in-cloud and below-cloud scavenging).In this study,sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer(SP2)and a nebulizer.The results showed that the volume-weighted average(VWA)mass concentrations of refractory black carbon(rBC)in each rainfall event varied,ranging from 10.8 to 78.9μg/L.The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events.The geometric mean median mass-equivalent diameter(MMD)decreased under precipitation,indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging.A positive correlation(R2=0.73)between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process.Additionally,the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74%and 26%to wet scavenging,respectively.The scavenging ratio of rBC particles was estimated to be 0.06 on average.This study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.
基金supported by the National Natural Sciences Foundation of China(Grant Nos.411751154083010240575013 and 40175032)
文摘Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon (WIRC) component of total suspended particulates (TSP), collected weekly during 2003, as well as from October 2005 to May 2006 at the WMO-GAW Mt. Waliguan (WLG) site. The overall average WlRC mass concentration was (1183 ± 120)ng/m3 (n = 79), while seasonal averages were 2081 ± 1707 (spring), 454±205 (summer), 650 ±411 (autumn), and 1019 ± 703 (winter) ng/m3. Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer, although WIRC concentrations were typically higher, especially in winter and spring. The δ13C PDB value (-25.3 ± 0.8)%0 determined for WIRC suggests that its sources are C3 biomass or fossil fuel combustion. No seasonal change in δ13C PDB was evident. The average percent Modern Carbon (pMC) for 14C in WIRC for winter and spring was (67.2 ± 7.7)% (n = 29). Lower pMC values were associated with air masses trans- ported from the area east of WLG, while higher pMC values were associated with air masses from the Tibetan Plateau, southwest of WLG. Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event.