A field study was performed at rivers in Gunung Jerai forest reserve(Kedah,Malaysia) to assess seasonal changes in mayfly community structure and abundance in relation to altitude and water physicochemistry.Rivers at ...A field study was performed at rivers in Gunung Jerai forest reserve(Kedah,Malaysia) to assess seasonal changes in mayfly community structure and abundance in relation to altitude and water physicochemistry.Rivers at lower(Batu Hampar River) and higher(Teroi River) elevations were visited through dry and wet seasons in September 2007 to August 2008.Monthly visits were made to 20 sites on each river,and water and aquatic insects were sampled using D-pond aquatic nets.Water was warmer,more acid,and more turbid in Teroi River during wet season.Ammonia was the only nutrient exhibiting significant seasonal variations(greater during wet season).Chemical oxygen demand content was higher in Teroi River where biochemical oxygen demand content was low during wet season.Species richness was higher in Batu Hampar River,but displayed seasonal variations only in Teroi River.Among the eight families encountered,Baetidae was the commonest.Baetid abundance was usually high during wet season,and those belonging to the dominant genus(Baetis) were more abundant in Teroi River.Heptageniidae was the second commonest family;its predominant genus,Thalerospyrus was more abundant in Teroi River during dry season.Caenidae,Leptophlebiidae and Oligoneuriidae were only found in Batu Hampar River where their abundances peaked during dry season,i.e.,Habrophlebiodes sp.and Isonychia sp.Ephemerellidae and Teloganodidae occurred only in Teroi River,with the first found only during dry season.Mayflies were recorded under very distinct physicochemical conditions,illustrating their potential usefulness for assessing water quality.Caenids,leptophlebids,oligoneurids ephemerellids and teloganodids seem to be particularly sensitive to temperature,acidity,turbidity,chemical oxygen demand and biochemical oxygen demand,parameters that varied with river altitude.展开更多
In Morocco,hydrological and hydrobiological surveys of wadis,river and stream are rare.In this research,we plan to attempt to characterize the physico-chemistry of surface waters of sixteen stations sampled at the lev...In Morocco,hydrological and hydrobiological surveys of wadis,river and stream are rare.In this research,we plan to attempt to characterize the physico-chemistry of surface waters of sixteen stations sampled at the level of the Sebou basin during the period 2013-2023.The diagnosis showed that this natural watercourse is highly enriched in oce-anic salts.A large fluctuation in the chemical nature of the waters was recorded,as well as electrical conductivity(EC),which oscillates between 629 and 22,766μS/cm.Hydrogen Potential ranges from 8.01 to 8.79 while remaining basic.Nitrate(NO3-)concentrations range from a maximum of 886.9 mg/l to a minimum of 0.24 mg/l.Similarly,the am-monium concentration varies from 0.04 to 15.34 mg/l.It was also noted that the waters were very rich in chloride ions(860.27 to 145.55 mg/l),in sodium Na+ion(51 to 2,530 mg/l),in sulfate ions SO4--(441.4 to 37.62 mg/l),in calcium ions Ca2+(97.6 to 1,072.8 mg/l)and in magnesium ions Mg2+(631.2 to 17.28 mg/l)which explains the high hardness of these waters.The concentrations of potassium ions(K+)range from 2.54 to 17.55 mg/l.The high alkalinity is due to the high concentrations of bicarbonate ions(75.64 to 362.34 mg/l).Our study concludes that the waters of the Sebou re-main below the irrigation threshold authorized by Moroccan law when moving away from its Atlantic estuary.They are too degraded and we suggest that urban and industrial wastewater be pre-treated as a priority to reduce natural environment.展开更多
For around fifty years,the regression and degradation of wetlands were considered so worrying that they were the subject of an international Convention signed on 2 February 1971,in Iran(RAMSAR).This treaty aims to con...For around fifty years,the regression and degradation of wetlands were considered so worrying that they were the subject of an international Convention signed on 2 February 1971,in Iran(RAMSAR).This treaty aims to conserve wetlands meeting criteria of international importance through the notion of rational use of these spaces and their biodiversity.The national and even international value of Lake Sidi Boughaba(Kenitra,Morocco)lies in its biodiversity which allowed its inclusion on the Ramsar list in 1980.This importance motivated us to begin an ecological assessment of the level of its pollution through spatiotemporal monitoring and analysis of physicochemical tracers from surface waters at seven sampling stations between January and December 2023.The waters of Lake Sidi Boughaba are relatively basic(pH=8.63),cold(15.14℃),very hard(64 meq/L),quite turbid(7.65 NTU),very salty(1935.85μs/cm)and well saturated with Calcium ions=312;Magnesium=605;Chlorides=5892;Sulfates=944;Silicates=26(mg/l).Other elements including nitrates(1.29 mg/l),ammonium(1.56 mg/l),fluorides(410μg/l),iron(350μg/l)and manganese(35μg/l)are low.This study concludes that Lake Sidi Boughaba is classified in the category of oligomesotrophic lakes and that it is too threatened by the progressive transformation of its fresh water into brackish water and consequently the change in its benthic and planktonic fauna necessary for food of avian fauna.The study further concludes that this wetland is under significant threat,and to protect its biodiversity,innovative approaches to hydrological development are necessary.展开更多
With the gradual reduction in high-quality iron ore resources,the global steel industry faces long-term challenges.For example,the continuous increase in the Al_(2)O_(3) content of iron ore has led to a decrease in th...With the gradual reduction in high-quality iron ore resources,the global steel industry faces long-term challenges.For example,the continuous increase in the Al_(2)O_(3) content of iron ore has led to a decrease in the metallurgical performance of sinter and fluctuations in slag properties.Considering calcium ferrite(CF)and composite CF(silico-ferrite of calcium and aluminum,SFCA)play a crucial role as a binding phase in high-alkalinity sinter and exhibit excellent physical strength and metallurgical performance,we propose incorporating excess Al_(2)O_(3) into SFCA to form a new binding phase with excellent properties for high-quality sinter preparation.In the synthesis of high-Al_(2)O_(3) SFCA,two high-Al_(2)O_(3) phases were identified as types A(Al_(1.2)Ca_(2.8)Fe_(8.7)O_(2)0Si_(0.8))and B(Ca_(4)Al_(4.18)Fe_(1.82)Si_(6)O_(26)).Results show that type A SFCA sample had a higher cell density(4.13 g/cm^(3))and longer Fe-O bond length(2.2193Å)than type B(3.46 g/cm^(3) and 1.9415Å),with a significantly greater lattice oxygen concentration(7.86%vs.1.85%),which demonstrates advantages in strength and reducibility.Type A SFCA sample contained a lower proportion of silicates,was predominantly composed of SFCA,and exhibited minimal porosity.Melting point and viscosity simulation tests indicate that type A SFCA sample formed a liquid phase at 880°C with a viscosity range of 0-0.35 Pa·s,which is notably lower than that of type B SFCA sample(1220°C and 0-20 Pa·s).This finding suggests that type A SFCA sample has a low initial melting temperature and viscosity,which facilitates increasing liquid-phase generation and improving flow properties.Such a condition enhances the adhesion to surrounding ore particles.Compressive strength tests reveal that type A SFCA sample(36.83-42.48 MPa)considerably outperformed type B SFCA sample(5.98-12.79 MPa)and traditional sinter(5.02-13.68 MPa).In addition,at 900°C,type A SFCA sample achieved a final reducibility of 0.89,which surpassed that of type B SFCA sample(0.83).In summary,type A SFCA sample demonstrates superior structural,thermophysical,and metallurgical properties,which highlights its promising potential for industrial applications.展开更多
基金supported by the Fundamental Research Grant Scheme (FRGS) from the Ministry of Science, Technology and Innovation (MOSTI)
文摘A field study was performed at rivers in Gunung Jerai forest reserve(Kedah,Malaysia) to assess seasonal changes in mayfly community structure and abundance in relation to altitude and water physicochemistry.Rivers at lower(Batu Hampar River) and higher(Teroi River) elevations were visited through dry and wet seasons in September 2007 to August 2008.Monthly visits were made to 20 sites on each river,and water and aquatic insects were sampled using D-pond aquatic nets.Water was warmer,more acid,and more turbid in Teroi River during wet season.Ammonia was the only nutrient exhibiting significant seasonal variations(greater during wet season).Chemical oxygen demand content was higher in Teroi River where biochemical oxygen demand content was low during wet season.Species richness was higher in Batu Hampar River,but displayed seasonal variations only in Teroi River.Among the eight families encountered,Baetidae was the commonest.Baetid abundance was usually high during wet season,and those belonging to the dominant genus(Baetis) were more abundant in Teroi River.Heptageniidae was the second commonest family;its predominant genus,Thalerospyrus was more abundant in Teroi River during dry season.Caenidae,Leptophlebiidae and Oligoneuriidae were only found in Batu Hampar River where their abundances peaked during dry season,i.e.,Habrophlebiodes sp.and Isonychia sp.Ephemerellidae and Teloganodidae occurred only in Teroi River,with the first found only during dry season.Mayflies were recorded under very distinct physicochemical conditions,illustrating their potential usefulness for assessing water quality.Caenids,leptophlebids,oligoneurids ephemerellids and teloganodids seem to be particularly sensitive to temperature,acidity,turbidity,chemical oxygen demand and biochemical oxygen demand,parameters that varied with river altitude.
文摘In Morocco,hydrological and hydrobiological surveys of wadis,river and stream are rare.In this research,we plan to attempt to characterize the physico-chemistry of surface waters of sixteen stations sampled at the level of the Sebou basin during the period 2013-2023.The diagnosis showed that this natural watercourse is highly enriched in oce-anic salts.A large fluctuation in the chemical nature of the waters was recorded,as well as electrical conductivity(EC),which oscillates between 629 and 22,766μS/cm.Hydrogen Potential ranges from 8.01 to 8.79 while remaining basic.Nitrate(NO3-)concentrations range from a maximum of 886.9 mg/l to a minimum of 0.24 mg/l.Similarly,the am-monium concentration varies from 0.04 to 15.34 mg/l.It was also noted that the waters were very rich in chloride ions(860.27 to 145.55 mg/l),in sodium Na+ion(51 to 2,530 mg/l),in sulfate ions SO4--(441.4 to 37.62 mg/l),in calcium ions Ca2+(97.6 to 1,072.8 mg/l)and in magnesium ions Mg2+(631.2 to 17.28 mg/l)which explains the high hardness of these waters.The concentrations of potassium ions(K+)range from 2.54 to 17.55 mg/l.The high alkalinity is due to the high concentrations of bicarbonate ions(75.64 to 362.34 mg/l).Our study concludes that the waters of the Sebou re-main below the irrigation threshold authorized by Moroccan law when moving away from its Atlantic estuary.They are too degraded and we suggest that urban and industrial wastewater be pre-treated as a priority to reduce natural environment.
文摘For around fifty years,the regression and degradation of wetlands were considered so worrying that they were the subject of an international Convention signed on 2 February 1971,in Iran(RAMSAR).This treaty aims to conserve wetlands meeting criteria of international importance through the notion of rational use of these spaces and their biodiversity.The national and even international value of Lake Sidi Boughaba(Kenitra,Morocco)lies in its biodiversity which allowed its inclusion on the Ramsar list in 1980.This importance motivated us to begin an ecological assessment of the level of its pollution through spatiotemporal monitoring and analysis of physicochemical tracers from surface waters at seven sampling stations between January and December 2023.The waters of Lake Sidi Boughaba are relatively basic(pH=8.63),cold(15.14℃),very hard(64 meq/L),quite turbid(7.65 NTU),very salty(1935.85μs/cm)and well saturated with Calcium ions=312;Magnesium=605;Chlorides=5892;Sulfates=944;Silicates=26(mg/l).Other elements including nitrates(1.29 mg/l),ammonium(1.56 mg/l),fluorides(410μg/l),iron(350μg/l)and manganese(35μg/l)are low.This study concludes that Lake Sidi Boughaba is classified in the category of oligomesotrophic lakes and that it is too threatened by the progressive transformation of its fresh water into brackish water and consequently the change in its benthic and planktonic fauna necessary for food of avian fauna.The study further concludes that this wetland is under significant threat,and to protect its biodiversity,innovative approaches to hydrological development are necessary.
基金financially supported by the National Natural Science Foundation of China(Nos.52204331 and 52374315)the Major Industrial Innovation Plan of the Anhui Provincial Development and Reform Commission,China(No.AHZDCYCX-LSDT2023-01).
文摘With the gradual reduction in high-quality iron ore resources,the global steel industry faces long-term challenges.For example,the continuous increase in the Al_(2)O_(3) content of iron ore has led to a decrease in the metallurgical performance of sinter and fluctuations in slag properties.Considering calcium ferrite(CF)and composite CF(silico-ferrite of calcium and aluminum,SFCA)play a crucial role as a binding phase in high-alkalinity sinter and exhibit excellent physical strength and metallurgical performance,we propose incorporating excess Al_(2)O_(3) into SFCA to form a new binding phase with excellent properties for high-quality sinter preparation.In the synthesis of high-Al_(2)O_(3) SFCA,two high-Al_(2)O_(3) phases were identified as types A(Al_(1.2)Ca_(2.8)Fe_(8.7)O_(2)0Si_(0.8))and B(Ca_(4)Al_(4.18)Fe_(1.82)Si_(6)O_(26)).Results show that type A SFCA sample had a higher cell density(4.13 g/cm^(3))and longer Fe-O bond length(2.2193Å)than type B(3.46 g/cm^(3) and 1.9415Å),with a significantly greater lattice oxygen concentration(7.86%vs.1.85%),which demonstrates advantages in strength and reducibility.Type A SFCA sample contained a lower proportion of silicates,was predominantly composed of SFCA,and exhibited minimal porosity.Melting point and viscosity simulation tests indicate that type A SFCA sample formed a liquid phase at 880°C with a viscosity range of 0-0.35 Pa·s,which is notably lower than that of type B SFCA sample(1220°C and 0-20 Pa·s).This finding suggests that type A SFCA sample has a low initial melting temperature and viscosity,which facilitates increasing liquid-phase generation and improving flow properties.Such a condition enhances the adhesion to surrounding ore particles.Compressive strength tests reveal that type A SFCA sample(36.83-42.48 MPa)considerably outperformed type B SFCA sample(5.98-12.79 MPa)and traditional sinter(5.02-13.68 MPa).In addition,at 900°C,type A SFCA sample achieved a final reducibility of 0.89,which surpassed that of type B SFCA sample(0.83).In summary,type A SFCA sample demonstrates superior structural,thermophysical,and metallurgical properties,which highlights its promising potential for industrial applications.
