In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR), it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is es...In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR), it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is essential to measure in-situ pH and other chemical parameters(dissolved H2, dissolved H2S) of deep-sea water and hydrothermal fluids in a wide temperature range(2℃―400℃) at MOR vents.The YSZ(Yttria Stabilized Zirconia, 9%Y2O3) ceramic-based(HgO/Hg) chemical sensors possess excellent electrochemical properties at high temperatures, which have been used to measure chemical parameters of hydrothermal fluids above 200℃.A novel Zr/ZrO2 oxidation/reduction electrode was constructed by oxidation of Zr wire in Na2CO3 melt.This Zr/ZrO2 electrode has good chemical stability while measuring pH of high-temperature aqueous solutions, combined with a Ag/AgCl reference electrode.Potentials of the Zr/ZrO2 sensor in association with a Ag/AgCl reference electrode vary linearly with pH over a wide pH range, as tested by various NaCl-HCl-H2O solutions(NaOH-NaCl-H2O for basic solutions), at temperatures in the range of 20℃―200℃.Thus, the Zr/ZrO2 sensors can be utilized in monitoring the fluids over the temperature range of 2℃―200℃.The Zr/ZrO2 electrode combined with Ag/AgCl, Ag/Ag2S, and Au electrodes has been used to measure pH and other chemical parameters(dissolved H2, dissolved H2S) of aqueous fluids from low to high temperatures and high pressures in the laboratory and to monitor those parameters of deep-sea water in South China Sea.展开更多
The physico-chemical parameters of Euphrates River water were studied between Heet and Ramadi cities during November 2008 to June 2009. Water were samples collected from eleven stations and analyzed for Temperature, T...The physico-chemical parameters of Euphrates River water were studied between Heet and Ramadi cities during November 2008 to June 2009. Water were samples collected from eleven stations and analyzed for Temperature, Turbidity, Electrical conductivity (EC), Total suspended solids (TSS), pH, Total dissolved salts (TDS), Dissolved oxygen (DO), Biochemical oxygen demand (BOD), Calcium, Potassium, Sodium, Sulphate, Phosphate, Bicarbonates, Chloride, Nitrate and Total hardness. The observed values of these physico-chemical parameters were compared with WHO standards. Some parameters (Turbidity, TSS, TDS, BOD, Calcium, Sodium and Total hardness) exceeded the permissible limits of WHO standards, while other parameters were within the permissible limits. Statistical studies have been carried out by calculating correlation coefficients between different pairs of parameters. Monthly and spatial variations of physico-chemical parameters were investigated.展开更多
Objective: The study aims to investigate some physical and technological parameters of varieties of maize collected from the most representative areas of maize production in the southern part of Benin, and mainly used...Objective: The study aims to investigate some physical and technological parameters of varieties of maize collected from the most representative areas of maize production in the southern part of Benin, and mainly used by the populations of those areas. Method: The chemical composition, physical and technological characteristics of the grains were determined using standard methods. Results: The results showed that the weight of 1000 grains ranges from 158.01 to 305.12 g, the length from 0.79 to 1.81 cm, the average width from 0.74 to 1.51 cm, thickness from 0.36 to 0.85 cm and density from 1.07 to 1.25. Regarding the technological parameters, the hardness of the grains before and after cooking was between 16.78 and 47.20 kgf, and 0.23 and 0.71 kgf respectively, while the cooking time varies from 71.00 and 158.33 mn. There was a positive and significant correlation (r = 0.405;p < 0.026) between the hardness after cooking and the weight of 1000 grains, between the hardness after cooking and grain width (r = 0.460;p < 0.011). A positive and highly significant correlation (r = 0.527, p < 0.003) was also observed between the hardness after cooking and the grain length, between the hardness after cooking and the thickness of grain (r = 0.476, p < 0.008), and between the grain density and the weight of 1000 grains (r = 0.481, p < 0.007). A positive and highly significant correlation (r = 0.923, p < 0.000) was also observed between maize grain length and width, and between grain length and grain thickness (r = 0.764, p < 0.000) and between the width and thickness (r = 0.764, p < 0.000). On the other hand, a significant negative correlation (r = -0.394, p < 0.031) was found between the hardness before cooking and the thickness and between the hardness before cooking and sphericity index (r = -0465*, p Conclusion: Through its chemical and technological characteristics the maize constitutes an important raw material for many culinary recipes in West African region.展开更多
基金Supported by the "863" Project of the Ministry of Science and Technology of China (Grant Nos. 2001AA612020-3, 2003AA612020-3, 2001DEA30041, 2002DEA30084, 2003DEA2C021, 2001DEA20023B, DY105-03-01, K2007-1-13)the National Natural Science Foundation of China (Grant Nos. 20373064, 50602042)
文摘In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR), it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is essential to measure in-situ pH and other chemical parameters(dissolved H2, dissolved H2S) of deep-sea water and hydrothermal fluids in a wide temperature range(2℃―400℃) at MOR vents.The YSZ(Yttria Stabilized Zirconia, 9%Y2O3) ceramic-based(HgO/Hg) chemical sensors possess excellent electrochemical properties at high temperatures, which have been used to measure chemical parameters of hydrothermal fluids above 200℃.A novel Zr/ZrO2 oxidation/reduction electrode was constructed by oxidation of Zr wire in Na2CO3 melt.This Zr/ZrO2 electrode has good chemical stability while measuring pH of high-temperature aqueous solutions, combined with a Ag/AgCl reference electrode.Potentials of the Zr/ZrO2 sensor in association with a Ag/AgCl reference electrode vary linearly with pH over a wide pH range, as tested by various NaCl-HCl-H2O solutions(NaOH-NaCl-H2O for basic solutions), at temperatures in the range of 20℃―200℃.Thus, the Zr/ZrO2 sensors can be utilized in monitoring the fluids over the temperature range of 2℃―200℃.The Zr/ZrO2 electrode combined with Ag/AgCl, Ag/Ag2S, and Au electrodes has been used to measure pH and other chemical parameters(dissolved H2, dissolved H2S) of aqueous fluids from low to high temperatures and high pressures in the laboratory and to monitor those parameters of deep-sea water in South China Sea.
文摘The physico-chemical parameters of Euphrates River water were studied between Heet and Ramadi cities during November 2008 to June 2009. Water were samples collected from eleven stations and analyzed for Temperature, Turbidity, Electrical conductivity (EC), Total suspended solids (TSS), pH, Total dissolved salts (TDS), Dissolved oxygen (DO), Biochemical oxygen demand (BOD), Calcium, Potassium, Sodium, Sulphate, Phosphate, Bicarbonates, Chloride, Nitrate and Total hardness. The observed values of these physico-chemical parameters were compared with WHO standards. Some parameters (Turbidity, TSS, TDS, BOD, Calcium, Sodium and Total hardness) exceeded the permissible limits of WHO standards, while other parameters were within the permissible limits. Statistical studies have been carried out by calculating correlation coefficients between different pairs of parameters. Monthly and spatial variations of physico-chemical parameters were investigated.
文摘Objective: The study aims to investigate some physical and technological parameters of varieties of maize collected from the most representative areas of maize production in the southern part of Benin, and mainly used by the populations of those areas. Method: The chemical composition, physical and technological characteristics of the grains were determined using standard methods. Results: The results showed that the weight of 1000 grains ranges from 158.01 to 305.12 g, the length from 0.79 to 1.81 cm, the average width from 0.74 to 1.51 cm, thickness from 0.36 to 0.85 cm and density from 1.07 to 1.25. Regarding the technological parameters, the hardness of the grains before and after cooking was between 16.78 and 47.20 kgf, and 0.23 and 0.71 kgf respectively, while the cooking time varies from 71.00 and 158.33 mn. There was a positive and significant correlation (r = 0.405;p < 0.026) between the hardness after cooking and the weight of 1000 grains, between the hardness after cooking and grain width (r = 0.460;p < 0.011). A positive and highly significant correlation (r = 0.527, p < 0.003) was also observed between the hardness after cooking and the grain length, between the hardness after cooking and the thickness of grain (r = 0.476, p < 0.008), and between the grain density and the weight of 1000 grains (r = 0.481, p < 0.007). A positive and highly significant correlation (r = 0.923, p < 0.000) was also observed between maize grain length and width, and between grain length and grain thickness (r = 0.764, p < 0.000) and between the width and thickness (r = 0.764, p < 0.000). On the other hand, a significant negative correlation (r = -0.394, p < 0.031) was found between the hardness before cooking and the thickness and between the hardness before cooking and sphericity index (r = -0465*, p Conclusion: Through its chemical and technological characteristics the maize constitutes an important raw material for many culinary recipes in West African region.
