Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbo...Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.展开更多
Soil salinity is a serious land degradation issue in agriculture.It is a major threat to agriculture productivity.Extra irrigation water is applied to leach down the salts from the root zone of the plants in the form ...Soil salinity is a serious land degradation issue in agriculture.It is a major threat to agriculture productivity.Extra irrigation water is applied to leach down the salts from the root zone of the plants in the form of a Leaching fraction(LF)of irrigation water.For the leaching process to be effective,the LF of irriga-tion water needs to be adjusted according to the environmental conditions and soil salinity level in the form of Evapotranspiration(ET)rate.The relationship between environmental conditions and ET rate is hard to be defined by a linear relationship and data-driven Machine learning(ML)based decisions are required to determine the calibrated Evapotranspiration(ETc)rate.ML-assisted ETc is pro-posed to adjust the LF according to the ETc and soil salinity level.A regression model is proposed to determine the ETc rate according to the prevailing tempera-ture,humidity,and sunshine,which would be used to determine the smart LF according to the ETc and soil salinity level.The proposed model is trained and tested against the Blaney Criddle method of Reference evapotranspiration(ETo)determination.The validation of the model from the test dataset reveals the accu-racy of the ML model in terms of Root mean squared errors(RMSE)are 0.41,Mean absolute errors(MAE)are 0.34,and Mean squared errors(MSE)are 0.28 mm day-1.The applications of the proposed solution in a real-time environ-ment show that the LF by the proposed solution is more effective in reducing the soil salinity as compared to the traditional process of leaching.展开更多
A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surfa...A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH4+-N + NO3- -N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH4+-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4+-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4+-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4+-N fixation or volatilization in the soil during the fertigation process.展开更多
Baking meat by wrapping them in Aluminum (Al) foil is common in many countries. The excessive use of Al foil in baking and the disagreement about using Al foils were the motivation to do this study especially after th...Baking meat by wrapping them in Aluminum (Al) foil is common in many countries. The excessive use of Al foil in baking and the disagreement about using Al foils were the motivation to do this study especially after the 2007 WHO/FDA Report. In this investigation, a gravimetric and a UV-Vis spectrophotometric method are used to estimate Aluminum (Al) leaching into meat baked by wrapping in Al foil. Three kinds of meat were used fish, cow stakes and chicken. The importance of Al exposure area was neglected by many studies. Five factors affecting Al leaching into meat are studied (baking temperature, baking time, additives, Al exposure area and weight of meat). The effect of cooking times (20, 40, 60 minutes) at 180℃ and cooking temperatures (160℃, 180℃, 200℃) at 60 minutes on the amount of Al leaching were evaluated. It was found that Al leaching into meat increased with increasing temperature, baking time, additives and Al exposure area. Moreover, Al exposure area was more effective than the weight of the meat. The Al leaching was highest in fish and lowest in chicken. Comparing the present results with the Provisional Tolerance Weekly Intake of Al approved by WHO/FDA, it shows that Al leaching into meat baked by wrapping in Al foil may add considerable doses into the diet. Continuous monitoring of Al foil used for baking meat is recommended.展开更多
Due to the complex chemical composition of nickel ores, the requests for the decrease of production costs, and the increase of nickel extraction in the existing depletion of high-grade sulfide ores around the world, c...Due to the complex chemical composition of nickel ores, the requests for the decrease of production costs, and the increase of nickel extraction in the existing depletion of high-grade sulfide ores around the world, computer modeling of nickel ore leaching process be- came a need and a challenge. In this paper, the design of experiments （DOE） theory was used to determine the optimal experimental design plan matrix based on the D optimality criterion. In the high-pressure sulfuric acid leaching （HPSAL） process for nickel laterite in ＂Rudjinci＂ ore in Serbia, the temperature, the sulfuric acid to ore ratio, the stirring speed, and the leaching time as the predictor variables, and the degree of nickel extraction as the response have been considered. To model the process, the multiple linear regression （MLR） and response surface method （RSM）, together with the two-level and four-factor full factorial central composite design （CCD） plan, were used. The proposed re- gression models have not been proven adequate. Therefore, the artificial neural network （ANN） approach with the same experimental plan was used in order to reduce operational costs, give a better modeling accuracy, and provide a more successful process optimization. The model is based on the multi-layer neural networks with the back-propagation （BP） learning algorithm and the bipolar sigmoid activation function.展开更多
Curcumin aqueous extract is used successfully as a green corrosion inhibitor at quasi-cooking conditions (90℃) to inhibit leaching from Aluminum cook wares in solutions containing vegetables or meat. Aluminum cook wa...Curcumin aqueous extract is used successfully as a green corrosion inhibitor at quasi-cooking conditions (90℃) to inhibit leaching from Aluminum cook wares in solutions containing vegetables or meat. Aluminum cook wares were bought from the market from four countries and cut to make the Aluminum samples. Six types of vegetables and three kinds of meat were chosen. Each type of vegetable and meat was used to prepare 30% w/v aqueous solutions. Three methods were used in the present study: Gravimetric method, Atomic Absorption and FTIR. Gravimetric method was applied to determine the leaching rate and the corrosion inhibition efficiency with/without NaCl. The effect of Curcumin concentration, Tab water, immersion time, alloying elements was investigated. There was a good consistency between Gravimetric and Atomic Absorption methods. The adsorption of Curcumin on the aluminum surface was in accordance with Langmuir isotherm. The values of the adsorption constant (K<sub>ads</sub>) and the free energy of adsorption (G<sub>ads</sub>o</sup>) were calculated and discussed. FTIR spectrum indicated that Curcumin coordinated with Al<sup>3+</sup> resulting in the formation of Al<sup>3+</sup>-Curcumin complex on the metal surface. Using a small amount of Curcumin decreased leaching from Aluminum cook wares into food by 60% - 80% depending about the type of food.展开更多
The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,micr...The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 min.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction controlled.Moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.展开更多
基金The National Natural Science Foundation of China under contract Nos 41530964,41776047,41876048 and 91528304。
文摘Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.
基金funded by the Deanship of Scientific Research(DSR),King AbdulAziz University,Jeddah,Saudi Arabia under Grant No.(RG-11-611-43).
文摘Soil salinity is a serious land degradation issue in agriculture.It is a major threat to agriculture productivity.Extra irrigation water is applied to leach down the salts from the root zone of the plants in the form of a Leaching fraction(LF)of irrigation water.For the leaching process to be effective,the LF of irriga-tion water needs to be adjusted according to the environmental conditions and soil salinity level in the form of Evapotranspiration(ET)rate.The relationship between environmental conditions and ET rate is hard to be defined by a linear relationship and data-driven Machine learning(ML)based decisions are required to determine the calibrated Evapotranspiration(ETc)rate.ML-assisted ETc is pro-posed to adjust the LF according to the ETc and soil salinity level.A regression model is proposed to determine the ETc rate according to the prevailing tempera-ture,humidity,and sunshine,which would be used to determine the smart LF according to the ETc and soil salinity level.The proposed model is trained and tested against the Blaney Criddle method of Reference evapotranspiration(ETo)determination.The validation of the model from the test dataset reveals the accu-racy of the ML model in terms of Root mean squared errors(RMSE)are 0.41,Mean absolute errors(MAE)are 0.34,and Mean squared errors(MSE)are 0.28 mm day-1.The applications of the proposed solution in a real-time environ-ment show that the LF by the proposed solution is more effective in reducing the soil salinity as compared to the traditional process of leaching.
基金Project supported by the National Natural Science Foundation of China (Nos. 30230230 and 30370288)the NationalKey Laboratory for Soil Erosion and Dryland Farming on the Loess Plateau (No. 10501-116).
文摘A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH4+-N + NO3- -N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH4+-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4+-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4+-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4+-N fixation or volatilization in the soil during the fertigation process.
文摘Baking meat by wrapping them in Aluminum (Al) foil is common in many countries. The excessive use of Al foil in baking and the disagreement about using Al foils were the motivation to do this study especially after the 2007 WHO/FDA Report. In this investigation, a gravimetric and a UV-Vis spectrophotometric method are used to estimate Aluminum (Al) leaching into meat baked by wrapping in Al foil. Three kinds of meat were used fish, cow stakes and chicken. The importance of Al exposure area was neglected by many studies. Five factors affecting Al leaching into meat are studied (baking temperature, baking time, additives, Al exposure area and weight of meat). The effect of cooking times (20, 40, 60 minutes) at 180℃ and cooking temperatures (160℃, 180℃, 200℃) at 60 minutes on the amount of Al leaching were evaluated. It was found that Al leaching into meat increased with increasing temperature, baking time, additives and Al exposure area. Moreover, Al exposure area was more effective than the weight of the meat. The Al leaching was highest in fish and lowest in chicken. Comparing the present results with the Provisional Tolerance Weekly Intake of Al approved by WHO/FDA, it shows that Al leaching into meat baked by wrapping in Al foil may add considerable doses into the diet. Continuous monitoring of Al foil used for baking meat is recommended.
文摘Due to the complex chemical composition of nickel ores, the requests for the decrease of production costs, and the increase of nickel extraction in the existing depletion of high-grade sulfide ores around the world, computer modeling of nickel ore leaching process be- came a need and a challenge. In this paper, the design of experiments （DOE） theory was used to determine the optimal experimental design plan matrix based on the D optimality criterion. In the high-pressure sulfuric acid leaching （HPSAL） process for nickel laterite in ＂Rudjinci＂ ore in Serbia, the temperature, the sulfuric acid to ore ratio, the stirring speed, and the leaching time as the predictor variables, and the degree of nickel extraction as the response have been considered. To model the process, the multiple linear regression （MLR） and response surface method （RSM）, together with the two-level and four-factor full factorial central composite design （CCD） plan, were used. The proposed re- gression models have not been proven adequate. Therefore, the artificial neural network （ANN） approach with the same experimental plan was used in order to reduce operational costs, give a better modeling accuracy, and provide a more successful process optimization. The model is based on the multi-layer neural networks with the back-propagation （BP） learning algorithm and the bipolar sigmoid activation function.
文摘Curcumin aqueous extract is used successfully as a green corrosion inhibitor at quasi-cooking conditions (90℃) to inhibit leaching from Aluminum cook wares in solutions containing vegetables or meat. Aluminum cook wares were bought from the market from four countries and cut to make the Aluminum samples. Six types of vegetables and three kinds of meat were chosen. Each type of vegetable and meat was used to prepare 30% w/v aqueous solutions. Three methods were used in the present study: Gravimetric method, Atomic Absorption and FTIR. Gravimetric method was applied to determine the leaching rate and the corrosion inhibition efficiency with/without NaCl. The effect of Curcumin concentration, Tab water, immersion time, alloying elements was investigated. There was a good consistency between Gravimetric and Atomic Absorption methods. The adsorption of Curcumin on the aluminum surface was in accordance with Langmuir isotherm. The values of the adsorption constant (K<sub>ads</sub>) and the free energy of adsorption (G<sub>ads</sub>o</sup>) were calculated and discussed. FTIR spectrum indicated that Curcumin coordinated with Al<sup>3+</sup> resulting in the formation of Al<sup>3+</sup>-Curcumin complex on the metal surface. Using a small amount of Curcumin decreased leaching from Aluminum cook wares into food by 60% - 80% depending about the type of food.
基金BAP project FBA-2021-4691 for their financial support。
文摘The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 min.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction controlled.Moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.
