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Exchangeable aluminium (Al_(KCI)) and CaCl_2-extractable aluminium (Al_(CaCl_2) approximately the same value in the prognosis of detrimental effect on plants. Additional, more in-depth research should show which of the two applied...
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Exchangeable aluminium (Al_(KCI)) and CaCl_2-extractable aluminium (Al_(CaCl_2) approximately the same value in the prognosis of detrimental effect on plants. Additional, more in-depth research should show which of the two applied methods of exchangeable
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Abstract Purpose Phyllosilicate minerals are the important components in soils and an important source of activated aluminum (Al) during soil acidification. However, the mechanisms for Al activation in phyllosilicate minerals were...
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Abstract Purpose Phyllosilicate minerals are the important components in soils and an important source of activated aluminum (Al) during soil acidification. However, the mechanisms for Al activation in phyllosilicate minerals were not understood well. This study was designed to investigate the role of hydroxyl groups on the surface of montmorillonite in acidification-induced activation of solid aluminum.Materials and methods Montmorillonite was treated at high temperatures to remove the hydroxyl groups from its surface, and then XRD, FTIR, and 27Al NMR of montmorillonite before and after high-temperature treatment were determined. After that, Al activation during acidification of montmorillonite treated at different temperatures was investigated using the constant pH titration method.Results and discussion The results showed that hydroxyl groups on the surface of montmorillonite can effectively be removed when the temperature was raised to 670 °C. After high-temperature treatment, the crystallinity of the montmorillonite was reduced. The montmorillonite layer space was reduced, the pH and cation exchange capacity (CEC) of the mineral were decreased, and consequently the amount of acid consumed during acidification was significantly reduced. The decrease of CEC and surface hydroxyl groups in the mineral was responsible for the reduction in acid consumption during mineral acidification. After high-temperature treatment, the Al coordination structure of montmorillonite was transformed from six-coordination to four-coordination. The removal of surface hydroxyl groups inhibited the activation of Al during montmorillonite acidification, and the inhibition effect was increased with increasing temperatures below the complete dehydroxylation point.Conclusions The activation of Al during montmorillonite acidification was inhibited, suggesting that the hydroxyl groups at the edge of montmorillonite played an important role in Al activation process.
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This study was conducted to ascertain movement potential of imazethapyr resistance and to measure the relative growth and productivity of imazethapyr-resistant(IR) and imzethapyr-susceptible(IS)biotypes of common sunflower under n...
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This study was conducted to ascertain movement potential of imazethapyr resistance and to measure the relative growth and productivity of imazethapyr-resistant(IR) and imzethapyr-susceptible(IS)biotypes of common sunflower under noncompet- itive and competitive conditions. Susceptible biotypes of common sunflower were planted in the field in concentric circles at distances of 5,5,8.0,15.0, and 30.3 m around a center of densely planted IR biotypes in four locations in northeast Kansas in 1998 and 1999.
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The critical behavior of Fe substituted intermetallic compounds Ni_(3-x)Fe_xAl (x = 0, 0.18, and 0.36) has been investigated around the paramagnetic-ferromagnetic (PM-FM) phase transition based on the static magnetization data. Re...
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The critical behavior of Fe substituted intermetallic compounds Ni_(3-x)Fe_xAl (x = 0, 0.18, and 0.36) has been investigated around the paramagnetic-ferromagnetic (PM-FM) phase transition based on the static magnetization data. Reliable critical exponents (β, γ, and δ) and transition temperature T_C are determined for the compounds, by using Modified Arrott plot, Kouvel-Fisher plot, and critical isotherm plot. The self-consistence and reliability of the obtained critical exponents are further verified by the Widom scaling relation δ = 1 + γ/β and scaling equations of the state M(H,e) = ep/±(H/ep+T). It is found that, Fe substitution for Ni dramatically increases T_C from 44.44 K for x = 0 to 301.20 K for x = 0.36. The critical exponents for the three compounds are all found to follow mean-field model. The exchange interaction J(r) is found to decay asr~(-4.657),r~(-4.434), and r~(-4.257) for x=0, 0.18 and 0.36, respectively. The results suggest that, a long range mean-field spin interaction dominates in Ni_(3-x) Fe_xAl (0≤x≤0.36) series. Furthermore, Fe substitution to Ni site is found to increase the spin interaction distance to longer range.
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Resonant magnetic X-ray scattering was employed to investigate the magnetic state of epitaxial a* oriented thin films of the heavy fermion superconductor UNi2Al3. The observed incommensurate propagation vector as well as the Neel ...
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Resonant magnetic X-ray scattering was employed to investigate the magnetic state of epitaxial a* oriented thin films of the heavy fermion superconductor UNi2Al3. The observed incommensurate propagation vector as well as the Neel temperature correspond to those of bulk samples. The 1200 A film shows magnetic order with a correlation length > 800 angstrom parallel to the growth axis. Out of the three possible magnetic domains the one with the moment direction perpendicular to the film surface is not realized.
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In the Cabo Basin, NE Brazil, conglomerates have given rise to soils with attributes that are rarely observed in humid tropical climates and remain relatively unknown within the scientific community. These soils have high levels o...
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In the Cabo Basin, NE Brazil, conglomerates have given rise to soils with attributes that are rarely observed in humid tropical climates and remain relatively unknown within the scientific community. These soils have high levels of Al in the exchangeable phase, diminishing their agricultural and environmental potential in an underdeveloped region of great socioeconomic importance. This paper presents the mineralogy and genesis of soils derived from conglomerates on a slope in the Cabo Basin, with the aim of meeting the demand for studies on Al-rich soils. Three soils were classified, morphologically described and sampled for the accomplishment of chemical, physical and mineralogical analyses, including the main exchangeable cations content, mineralogy of the sand, silt and clay fraction, differentiation of the Fe and Al forms, mineral micromorphology and chemical composition of mineral species. In addition, chemical and physical attributes were used in multivariate analyses. The soil mineralogy is associated with the weathering evolution of three mineralogical zones identified in the Cr horizons. Pathways of alteration followed by feldspars and micas resulted in kaolinite, smectite and hydroxy-Al interlayered smectite formation (argilification). The susceptibility of the conglomerate to weathering, constant releases of Al from the structure of aluminous minerals, low contents of exchangeable bases and consequent low pH values (< 5.3) were associated with high levels of exchangeable Al. At the highest position on the slope, a C/Cr transitional horizon provided evidence of the pedogenesis advance on the Cr horizon. Pedogenetic processes then resulted in morphological, physical and mineralogical differentiation between the A and Bt horizons. In addition, a cluster analysis showed similarities between attributes of the Bt and Cr horizons due to their genetic relationships.
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In the present study we carried out a thermodynamic analysis for explosives with micrometer aluminum (Al) powders, and found that the acceleration of Al powders and heat exchange between Al powders and the detonation products may ...
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In the present study we carried out a thermodynamic analysis for explosives with micrometer aluminum (Al) powders, and found that the acceleration of Al powders and heat exchange between Al powders and the detonation products may have a significant influence on the detonation velocity. Relying on velocity disequilibrium between the two phases at the C-J plane and heat absorption of inert Al powders in the detonation zone, this paper has introduced a new method to study the detonation velocity of explosives with micrometer Al additives. The method is a closed system of algebraic equations and the detonation velocity can be solved efficiently by numerical codes. The detonation velocities predicted by the new method are in excellent agreement with experimental data of RDX-, HMX-, NM- and TNT-based aluminized explosives, and the heat exchange has been proved significant on the detonation velocity, while the acceleration of Al powders is of little effect.
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Biochar, because of its porous nature, calcium carbonate (CaCO3) equivalent, surface functional groups, and other properties, could serve as an acid soil amendment. To investigate the liming potential of biochars, laboratory chara...
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Biochar, because of its porous nature, calcium carbonate (CaCO3) equivalent, surface functional groups, and other properties, could serve as an acid soil amendment. To investigate the liming potential of biochars, laboratory characterization and greenhouse and field experiments were conducted in Hawaii and West Java, Indonesia, respectively. Six wood-derived biochars were characterized and amended to a Hawaiian acid soil (pH 4.6, exchangeable aluminum [Al] 1.8 cmolc kg(-1)) at 2% and 4% alone or in combination with 2 cmolc kg(-1) of lime and then planted with Desmodium intortum (a forage legume sensitive to Al) twice in a greenhouse trial. To the Indonesian acid soils (pH 3.9-4.0, exchangeable Al 8-14 cmolc kg(-1)), a rice husk and a lac tree biochars at 4% and 8% alone or in combination with lime at 4 and 8 cmolc kg(-1) and compost at 0.1 and 0.2% were applied and then planted with soybean (Glycine max) cv. Anjasmoro twice in field trials. Biochar effects on soil properties and plant growth were measured. The results indicated that the six biochars varied in pH, ash content, CaCO3 equivalent, total basic cations, cation exchange capacity, and other properties (pore size, surface functional groups). Soil pH was increased, soil exchangeable Al was reduced, and plant nutrients were enriched to different degrees upon additions of biochars. Total dry weights of Desmodium were increased 2- to 4-fold over the control or lime treatment upon applications of biochar. Similar effects on soils and soybean were obtained for the Indonesian field trials. It was concluded that CaCO3 equivalent and total basic cations were among the most important properties of biochar responsible for improving acid soil productivity and plant growth.
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This article reports an experimental study on the forced convective heat transfer and flow characteristics of a nanofluid consisting of water and different volume concentrations of Al2O3nanofluid (0.3–2)% flowing in a horizontal ...
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This article reports an experimental study on the forced convective heat transfer and flow characteristics of a nanofluid consisting of water and different volume concentrations of Al2O3nanofluid (0.3–2)% flowing in a horizontal shell and tube heat exchanger counter flow under turbulent flow conditions are investigated. The Al2O3nanoparticles of about 30nm diameter are used in the present study. The results show that the convective heat transfer coefficient of nanofluid is slightly higher than that of the base liquid at same mass flow rate and at same inlet temperature. The heat transfer coefficient of the nanofluid increases with an increase in the mass flow rate, also the heat transfer coefficient increases with the increase of the volume concentration of the Al2O3nanofluid, however increasing the volume concentration cause increase in the viscosity of the nanofluid leading to increase in friction factor.
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To determine the geological distribution of acid buffering capacity and exchangeable Al of forest soils in Japan, surface soils under forest vegetation were collected nationwide from a Total of 1.034 sites. Generally, surface soil...
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To determine the geological distribution of acid buffering capacity and exchangeable Al of forest soils in Japan, surface soils under forest vegetation were collected nationwide from a Total of 1.034 sites. Generally, surface soils in Japanese forests are mostly acidic and low in both Exchangeable cation content and exchangeable Al. The median of soil pH (H_2O), total Exchangeable cations, and exchangeable Al are 5.1, 76 mol_(+)kg~-1, and 19.6 mol_(+)kg~-1, Respectively.
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