The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 ...The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice(T1), no-tillage and ridge culture of rice(T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation(T4)) were measured with the closed chamber technique in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH_4 emission from paddy fields under these land management practices. In 1996 and 1998, CH_4 emission was 71 48% and 78 82%(T2), 65 93% and 57 18%(T3), and 61 53% and 34 22%(T4) of that in T1 during the rice growing season. During the non-rice growing season, CH_4 emission from rice fields was 76 23% in T2 and 38 69% in T1 The accumulated annual CH_4 emission in T2, T3 and T4 in 1996 decreased by 33 53%, 63 30% and 65 73%, respectively, as compared with that in T1 In 1998, the accumulated annual CH_4 emission in T1, T2, T3 and T4 was 116 96 g/m^2, 68 44 g/m^2, 19 70 g/m^2 and 11 80 g/m^2, respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH_4 emission observed. The relative contribution of various influencing factors to CH_4 emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH_4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH_4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH_4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global(climatic) change.展开更多
The relationships between mechanical characteristics of rock and microcosmic mechanism at high temperatures were investigated by MTS815, as well as the stress-strain behavior of granite under the action of temperature...The relationships between mechanical characteristics of rock and microcosmic mechanism at high temperatures were investigated by MTS815, as well as the stress-strain behavior of granite under the action of temperatures ranging from room temperature to 1200 ℃. Based on a micropore structure analyzer and SEM, the changes in rock porosity and micro structural morphology of sample fractures and brittle-plastic characteristics under high temperatures were analyzed. The results are as follows： 1） Mechanical characteristics do not show obvious variations before 800 ℃; strength decreases suddenly after 800 ℃ and bearing capacity is almost lost at 1200 ℃. 2） Rock porosity increases with rising temperatures; the threshold temperature is about 800 ℃; at this temperature its effect is basically uniform with strength decreasing rapidly. 3） The failure type of granite is a brittle tensile fracture at temperatures below 800 ℃ which transforms into plasticity at temperatures higher than 800 ℃ and crystal formation takes place at this time. Chemical reactions take place at 1200 ℃. Failure of granite under high temperature is a common result of thermal stress as indicated by an increase in the thermal expansion coefficient, transformation to crystal formation of minerals and structural chemical reactions.展开更多
Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three dif...Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three different treatments including non-organic addition as the control, low-organic enrichment (2 g DW green algae per 150 mL) and high-organic enrichment (10 g DW green algae per 150 mL). After 21 d, the meiofauna richness decreased in both organic enrichment treatments. Among the three treatments, total meiofauna abundance was significantly different, and the control groups had higher abundance than the other two treatment groups. However, the responses of the meiofauna abundance in the two organic enrichment treatments were non-significantly different. The relationship of meiofaunal abundance and nematode/copepod ratios to organic matter and oxygen level in the microcosm experiments were discussed.展开更多
The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decr...The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decrease the service life of a concrete structure if improperly handled. In this paper the microstructure of concrete is observed by using Scanned Electric Microscope (SEM) through contrasting experiments in media of acid, alkali and salt with that of freezing-thawing in the same medium environment. This study is to supply a certain basis for changing traditional thinking of mechanical design and to combine construction reliability design with durability of concrete design.展开更多
A greenhouse study was conducted on phytoextraction and accumulation of lead (Pb) and cadmium (Cd) from contaminated soil – water microcosms by the narrow-leaved cattail, Typha angustifolia. The plants were grown in ...A greenhouse study was conducted on phytoextraction and accumulation of lead (Pb) and cadmium (Cd) from contaminated soil – water microcosms by the narrow-leaved cattail, Typha angustifolia. The plants were grown in sandy loam soil containing 1,666 and 38.5 mg/L of Pb(NO3)2 and Cd(NO3)2 respectively. The trends of lead and cadmium by T. angustifolia for all soil – water microcosms suggested interaction effects as decreased soil lead concentrations and increased water cadmium concentrations over time. T. angustifolia expressed trends as increased biomass in all contaminated shoots and roots examined. Cadmium uptake in shoot and root biomass slightly decreased when lead was initially added to the soil but cadmium uptake in root biomass increased after 30 days. Data suggested an interaction between lead and cadmium and possible that lead uptake was inhibited when cadmium was present.展开更多
All impressions of acts,desires,and thoughts are preserved in the highly elastic Manakasa.They are transmitted to destination by the elasticity and constitute centres of further acts.These impressions travel life thro...All impressions of acts,desires,and thoughts are preserved in the highly elastic Manakasa.They are transmitted to destination by the elasticity and constitute centres of further acts.These impressions travel life through life and are known as Samskaras and determine the circumstances,qualities,and attitudes of an individual.They form the founding belief system which firms up and matures with spiritual training,development,and experience of an individual in the small space allocated to free-will.The fountainhead of quantum spiritual force field is the Supreme Being;field is compact in purely spiritual,lesser in spiritual-material,loose in material-spiritual region,and void in nether pole.The basic flux is the attraction of spirit,mind,and the matter respectively which bind the particles together.The God-particle discovered by scientists is the physical particle of the material-spiritual region.The God-particle of spiritual-material region is subtler.The supreme God-particle of spiritual region is the subtlest.The scientists are far from it.All arrangements in creation are carried through currents.Similarly,the entire economy of this physical body is regulated by currents,known collectively as the nervous system.Networks of currents spread out in individual systems/sub-systems.Humans are wired in these networks and constitute its quanta in the quantum force field.Network conductors in the creation are so programmed as to recognize only the Dhunyatmak sounds which reverberate on their own.The sensory conductors in the human body shall take the call only when the individual spirit tunes in with the Dhunyatmak sound characteristic of that Region.When that happens,one’s spirit is transported to that region.The spiritual force field is agitated by the meditation;the particles of that force field coalesce to form conducting particles which constitute the path thru the particular artery connecting the spirit entity with the presiding deity on virtual form.Belief,degree of consciousness,faith,and love for a deity are synonymous.Belief system is fundamental to human existence.One’s religion is basically his/her belief system.Each individual belief system is unique.Human existence is composed of spirit,mind,and the body each having its own reservoir.Man is de-facto the microcosm while creation is macrocosm.Man represents all spheres of the creation.Devotion,love,and faith for the Lord are embedded in the microcosm or individual belief system with sustained meditation over a period of time which help in establishing communication channels with the macrocosm.Nevertheless,the devotion of a helpless human being can never be perfect and pure.It is always corrupted by the internal noise and pernicious propensities.God is conquered and he is willing to be conquered by his lovers.Lord is the sea of“grace and mercy”.He accepts even the corrupt Bhaktieven when the belief systems are not firmly embedded in the nerve systems of the people who are driven to prayer meets by personal and selfish ends.展开更多
The objective of this study is the phytochemical analysis and the determination of the antibacterial activity of aqueous and hydro-ethanolic extracts obtained from the leaves and bark of the trunk of Albizia zygia, ag...The objective of this study is the phytochemical analysis and the determination of the antibacterial activity of aqueous and hydro-ethanolic extracts obtained from the leaves and bark of the trunk of Albizia zygia, against Escherichia coli and Salmonella typhi bacteria in aquatic microcosms. Phytochemical screening was performed as described by Pareck. The results obtained show that the hydro-ethanolic and aqueous extracts of Albizia zygia trunk bark recorded higher extraction yields (26.71% and 33.2% respectively) compared to the aqueous and hydro-ethanolic extracts of leaves of the same plant. Secondary metabolites with antibacterial activities such as anthraquinones, anthocyanins, flavonoids, polyphenols, tannins and saponins were found in both types of extracts. Flavonoids and anthocyanins were relatively more abundant than the other chemical constituents. The highest cellular inhibition rate of Escherichia coli was 99.88%, obtained after 9 hours of exposure in the hydro-ethanolic extract solution of trunk bark at the concentration 1.5 g/L. The Salmonella typhi rate was 99.95% after 9 hours of exposure of bacterial cells to the hydro-ethanol extract of the bark of the trunk at the concentration 1.5 g/L. This rate increased proportionally with the bacterial-extract contact time. The temperature of the medium did not significantly influence bacterial inhibition (P > 0.05). The obtained results justify the use of the plant Albizia zygia in the reduction of the flow of bacterio-pollutants contained in water intended for consumption.展开更多
BACKGROUND Chronic gastritis(CG)is a common gastrointestinal disorder characterized by inflammation of the stomach lining.Liver-stomach disharmony(LSD)syndrome is believed to contribute to CG symptoms.AIM To evaluate ...BACKGROUND Chronic gastritis(CG)is a common gastrointestinal disorder characterized by inflammation of the stomach lining.Liver-stomach disharmony(LSD)syndrome is believed to contribute to CG symptoms.AIM To evaluate the efficacy and safety of microcosmic syndrome differentiation and Chinese herbal medicine(CHM)treatment in patients with CG and LSD syndrome.METHODS Sixty-four patients with CG and LSD syndrome were randomly divided into two groups:The treatment group received CHM based on microcosmic syndrome differentiation and the control group received conventional Western medicine.The treatment course lasted 12 wk.The primary outcome was improvement in dyspeptic symptoms,measured using the Nepean Dyspepsia Index.The secondary outcomes included the improvement rate of endoscopic findings,histopathological findings,and microcosmic syndrome scores and the incidence of adverse events.RESULTS After 12 wk of treatment,the treatment group showed significantly greater improvement in dyspeptic symptoms than the control group(93.75%vs 65.63%,P<0.01).The treatment group also showed a significantly higher improvement rate in endoscopic findings than the control group(81.25%vs 53.13%,P<0.05).The improvement rates of histopathological findings and microcosmic syndrome scores were not significantly different between the two groups(P>0.05).No serious adverse events were observed in either group.CONCLUSION Microcosmic syndrome differentiation and CHM treatment can effectively improve dyspeptic symptoms and endoscopic findings in patients with CG and LSD syndrome and have a good safety profile.Further studies with larger sample sizes and longer follow-up periods are required to confirm the long-term efficacy and mechanism of action of this treatment.展开更多
Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining,...Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining, industrial activities, improper usage of fertilizers and pesticides, and indiscriminate open waste disposal bring about an increase in the presence of heavy metals in the environment. In the Keffi Metropolis, different elements lead to land contamination which debilitates soil quality, plant survival, human well-being, and the environment as a result of extensive dispersion or quantity of heavy metals in the soil and water. In recent years, biochar has emerged as a promising soil amendment for mitigating heavy metal pollution due to its unique physicochemical properties. This paper provides the effects of softwood pellet biochar on the retention of heavy metals in contaminated soils. A microcosm experiment was carried out to investigate the effects of biochar on the retention of heavy metals in contaminated soils. This research aimed to give an overview of the effects of softwood biochar at different temperatures (550˚C and 700˚C) on the retention of heavy metals and metalloids released from the soil during water inundation. The results show that the addition of organic matter (grass chippings) minimizes heavy metal mobilization. Also, biochar at high temperatures is more effective than those at low temperatures. The expected outcome of the research analysis includes providing insights into the role of biochar in retaining heavy metal contamination and further understanding the use of biochar as a sorbent for the management of contaminated soil.展开更多
The conventional measurement of a relative permeability curve (RPC) is usually conducted at room temperature, which is much lower than the reservoir temperature. Previous research work on high temperature relative...The conventional measurement of a relative permeability curve (RPC) is usually conducted at room temperature, which is much lower than the reservoir temperature. Previous research work on high temperature relative permeability mainly take oil-wetted cores as objective. In this paper, laboratory test and measurement are conducted using water-wet cores from the Lunnan Oilfield. Since irreducible water saturation (Swi) is a critical factor that affects and controls the relative permeability curve, special tests are conducted to measure Swi at different temperatures for water-wet cores in the course of the experiment of relative permeability. The experimental results indicate that for the water-wet cores Swi decreased with the increasing temperature from ambient to 105℃,and the relative permeability curve shifted in a low water saturation direction, i.e. moved toward the left, while it moved toward the right for oil wetness reservoirs. Seen from both macroscopic and microcosmic view, the reasons and mechanisms of relative permeability change with temperature are discussed, and factors including core wetness, viscosity force, capillary forces, contact angle, interfacial tension change are considered.展开更多
文摘The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice(T1), no-tillage and ridge culture of rice(T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation(T4)) were measured with the closed chamber technique in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH_4 emission from paddy fields under these land management practices. In 1996 and 1998, CH_4 emission was 71 48% and 78 82%(T2), 65 93% and 57 18%(T3), and 61 53% and 34 22%(T4) of that in T1 during the rice growing season. During the non-rice growing season, CH_4 emission from rice fields was 76 23% in T2 and 38 69% in T1 The accumulated annual CH_4 emission in T2, T3 and T4 in 1996 decreased by 33 53%, 63 30% and 65 73%, respectively, as compared with that in T1 In 1998, the accumulated annual CH_4 emission in T1, T2, T3 and T4 was 116 96 g/m^2, 68 44 g/m^2, 19 70 g/m^2 and 11 80 g/m^2, respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH_4 emission observed. The relative contribution of various influencing factors to CH_4 emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH_4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH_4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH_4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global(climatic) change.
基金Projects 50579042 supported by the National Natural Science Foundation of China2002CB412705 by the National Basic Research and Development(973) Program of Chinaok060122 by the Young Foundation of China University of Mining & Technology
文摘The relationships between mechanical characteristics of rock and microcosmic mechanism at high temperatures were investigated by MTS815, as well as the stress-strain behavior of granite under the action of temperatures ranging from room temperature to 1200 ℃. Based on a micropore structure analyzer and SEM, the changes in rock porosity and micro structural morphology of sample fractures and brittle-plastic characteristics under high temperatures were analyzed. The results are as follows： 1） Mechanical characteristics do not show obvious variations before 800 ℃; strength decreases suddenly after 800 ℃ and bearing capacity is almost lost at 1200 ℃. 2） Rock porosity increases with rising temperatures; the threshold temperature is about 800 ℃; at this temperature its effect is basically uniform with strength decreasing rapidly. 3） The failure type of granite is a brittle tensile fracture at temperatures below 800 ℃ which transforms into plasticity at temperatures higher than 800 ℃ and crystal formation takes place at this time. Chemical reactions take place at 1200 ℃. Failure of granite under high temperature is a common result of thermal stress as indicated by an increase in the thermal expansion coefficient, transformation to crystal formation of minerals and structural chemical reactions.
基金funded by the National Natural Science Foundation of China(NOs.40730847,40906063,41076090)
文摘Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach, China, were collected for field study, and subjected to organic enrichment in a laboratory microcosm experiment for 21 d. There were three different treatments including non-organic addition as the control, low-organic enrichment (2 g DW green algae per 150 mL) and high-organic enrichment (10 g DW green algae per 150 mL). After 21 d, the meiofauna richness decreased in both organic enrichment treatments. Among the three treatments, total meiofauna abundance was significantly different, and the control groups had higher abundance than the other two treatment groups. However, the responses of the meiofauna abundance in the two organic enrichment treatments were non-significantly different. The relationship of meiofaunal abundance and nematode/copepod ratios to organic matter and oxygen level in the microcosm experiments were discussed.
文摘The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decrease the service life of a concrete structure if improperly handled. In this paper the microstructure of concrete is observed by using Scanned Electric Microscope (SEM) through contrasting experiments in media of acid, alkali and salt with that of freezing-thawing in the same medium environment. This study is to supply a certain basis for changing traditional thinking of mechanical design and to combine construction reliability design with durability of concrete design.
文摘A greenhouse study was conducted on phytoextraction and accumulation of lead (Pb) and cadmium (Cd) from contaminated soil – water microcosms by the narrow-leaved cattail, Typha angustifolia. The plants were grown in sandy loam soil containing 1,666 and 38.5 mg/L of Pb(NO3)2 and Cd(NO3)2 respectively. The trends of lead and cadmium by T. angustifolia for all soil – water microcosms suggested interaction effects as decreased soil lead concentrations and increased water cadmium concentrations over time. T. angustifolia expressed trends as increased biomass in all contaminated shoots and roots examined. Cadmium uptake in shoot and root biomass slightly decreased when lead was initially added to the soil but cadmium uptake in root biomass increased after 30 days. Data suggested an interaction between lead and cadmium and possible that lead uptake was inhibited when cadmium was present.
文摘All impressions of acts,desires,and thoughts are preserved in the highly elastic Manakasa.They are transmitted to destination by the elasticity and constitute centres of further acts.These impressions travel life through life and are known as Samskaras and determine the circumstances,qualities,and attitudes of an individual.They form the founding belief system which firms up and matures with spiritual training,development,and experience of an individual in the small space allocated to free-will.The fountainhead of quantum spiritual force field is the Supreme Being;field is compact in purely spiritual,lesser in spiritual-material,loose in material-spiritual region,and void in nether pole.The basic flux is the attraction of spirit,mind,and the matter respectively which bind the particles together.The God-particle discovered by scientists is the physical particle of the material-spiritual region.The God-particle of spiritual-material region is subtler.The supreme God-particle of spiritual region is the subtlest.The scientists are far from it.All arrangements in creation are carried through currents.Similarly,the entire economy of this physical body is regulated by currents,known collectively as the nervous system.Networks of currents spread out in individual systems/sub-systems.Humans are wired in these networks and constitute its quanta in the quantum force field.Network conductors in the creation are so programmed as to recognize only the Dhunyatmak sounds which reverberate on their own.The sensory conductors in the human body shall take the call only when the individual spirit tunes in with the Dhunyatmak sound characteristic of that Region.When that happens,one’s spirit is transported to that region.The spiritual force field is agitated by the meditation;the particles of that force field coalesce to form conducting particles which constitute the path thru the particular artery connecting the spirit entity with the presiding deity on virtual form.Belief,degree of consciousness,faith,and love for a deity are synonymous.Belief system is fundamental to human existence.One’s religion is basically his/her belief system.Each individual belief system is unique.Human existence is composed of spirit,mind,and the body each having its own reservoir.Man is de-facto the microcosm while creation is macrocosm.Man represents all spheres of the creation.Devotion,love,and faith for the Lord are embedded in the microcosm or individual belief system with sustained meditation over a period of time which help in establishing communication channels with the macrocosm.Nevertheless,the devotion of a helpless human being can never be perfect and pure.It is always corrupted by the internal noise and pernicious propensities.God is conquered and he is willing to be conquered by his lovers.Lord is the sea of“grace and mercy”.He accepts even the corrupt Bhaktieven when the belief systems are not firmly embedded in the nerve systems of the people who are driven to prayer meets by personal and selfish ends.
文摘The objective of this study is the phytochemical analysis and the determination of the antibacterial activity of aqueous and hydro-ethanolic extracts obtained from the leaves and bark of the trunk of Albizia zygia, against Escherichia coli and Salmonella typhi bacteria in aquatic microcosms. Phytochemical screening was performed as described by Pareck. The results obtained show that the hydro-ethanolic and aqueous extracts of Albizia zygia trunk bark recorded higher extraction yields (26.71% and 33.2% respectively) compared to the aqueous and hydro-ethanolic extracts of leaves of the same plant. Secondary metabolites with antibacterial activities such as anthraquinones, anthocyanins, flavonoids, polyphenols, tannins and saponins were found in both types of extracts. Flavonoids and anthocyanins were relatively more abundant than the other chemical constituents. The highest cellular inhibition rate of Escherichia coli was 99.88%, obtained after 9 hours of exposure in the hydro-ethanolic extract solution of trunk bark at the concentration 1.5 g/L. The Salmonella typhi rate was 99.95% after 9 hours of exposure of bacterial cells to the hydro-ethanol extract of the bark of the trunk at the concentration 1.5 g/L. This rate increased proportionally with the bacterial-extract contact time. The temperature of the medium did not significantly influence bacterial inhibition (P > 0.05). The obtained results justify the use of the plant Albizia zygia in the reduction of the flow of bacterio-pollutants contained in water intended for consumption.
文摘BACKGROUND Chronic gastritis(CG)is a common gastrointestinal disorder characterized by inflammation of the stomach lining.Liver-stomach disharmony(LSD)syndrome is believed to contribute to CG symptoms.AIM To evaluate the efficacy and safety of microcosmic syndrome differentiation and Chinese herbal medicine(CHM)treatment in patients with CG and LSD syndrome.METHODS Sixty-four patients with CG and LSD syndrome were randomly divided into two groups:The treatment group received CHM based on microcosmic syndrome differentiation and the control group received conventional Western medicine.The treatment course lasted 12 wk.The primary outcome was improvement in dyspeptic symptoms,measured using the Nepean Dyspepsia Index.The secondary outcomes included the improvement rate of endoscopic findings,histopathological findings,and microcosmic syndrome scores and the incidence of adverse events.RESULTS After 12 wk of treatment,the treatment group showed significantly greater improvement in dyspeptic symptoms than the control group(93.75%vs 65.63%,P<0.01).The treatment group also showed a significantly higher improvement rate in endoscopic findings than the control group(81.25%vs 53.13%,P<0.05).The improvement rates of histopathological findings and microcosmic syndrome scores were not significantly different between the two groups(P>0.05).No serious adverse events were observed in either group.CONCLUSION Microcosmic syndrome differentiation and CHM treatment can effectively improve dyspeptic symptoms and endoscopic findings in patients with CG and LSD syndrome and have a good safety profile.Further studies with larger sample sizes and longer follow-up periods are required to confirm the long-term efficacy and mechanism of action of this treatment.
文摘Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining, industrial activities, improper usage of fertilizers and pesticides, and indiscriminate open waste disposal bring about an increase in the presence of heavy metals in the environment. In the Keffi Metropolis, different elements lead to land contamination which debilitates soil quality, plant survival, human well-being, and the environment as a result of extensive dispersion or quantity of heavy metals in the soil and water. In recent years, biochar has emerged as a promising soil amendment for mitigating heavy metal pollution due to its unique physicochemical properties. This paper provides the effects of softwood pellet biochar on the retention of heavy metals in contaminated soils. A microcosm experiment was carried out to investigate the effects of biochar on the retention of heavy metals in contaminated soils. This research aimed to give an overview of the effects of softwood biochar at different temperatures (550˚C and 700˚C) on the retention of heavy metals and metalloids released from the soil during water inundation. The results show that the addition of organic matter (grass chippings) minimizes heavy metal mobilization. Also, biochar at high temperatures is more effective than those at low temperatures. The expected outcome of the research analysis includes providing insights into the role of biochar in retaining heavy metal contamination and further understanding the use of biochar as a sorbent for the management of contaminated soil.
文摘The conventional measurement of a relative permeability curve (RPC) is usually conducted at room temperature, which is much lower than the reservoir temperature. Previous research work on high temperature relative permeability mainly take oil-wetted cores as objective. In this paper, laboratory test and measurement are conducted using water-wet cores from the Lunnan Oilfield. Since irreducible water saturation (Swi) is a critical factor that affects and controls the relative permeability curve, special tests are conducted to measure Swi at different temperatures for water-wet cores in the course of the experiment of relative permeability. The experimental results indicate that for the water-wet cores Swi decreased with the increasing temperature from ambient to 105℃,and the relative permeability curve shifted in a low water saturation direction, i.e. moved toward the left, while it moved toward the right for oil wetness reservoirs. Seen from both macroscopic and microcosmic view, the reasons and mechanisms of relative permeability change with temperature are discussed, and factors including core wetness, viscosity force, capillary forces, contact angle, interfacial tension change are considered.
