Macadamia nuts (Macadamia integrifolia) grown in Venezuela have showed an average total fat content of 70%. Oleic acid (18:1) was the main monounsaturated fatty acid (MUFA) (51.3%), followed by palmitoleic acid (16:1,...Macadamia nuts (Macadamia integrifolia) grown in Venezuela have showed an average total fat content of 70%. Oleic acid (18:1) was the main monounsaturated fatty acid (MUFA) (51.3%), followed by palmitoleic acid (16:1, 22.6%). The content of polyunsaturated fatty acids (PUFAs), C18:2 and C18:3 represented 5.4%. Thus, MUFAs and PUFAs together constituted more than 80% of the total fatty acids present. Trans-vaccenic acid was also present (3%). As regards to other phytochemical compounds, tocopherols and tocotrienols were not found in the sample, but the presence of squalene was detected.The antioxidant activity (44.2%) of the extract was produced by the phytochemicals present.展开更多
This paper investigates the effect of initial volume fraction on the runout characteristics of collapse of granular columns on slopes in fluid. 2-D sub-grain scale numerical simulations are performed to understand the...This paper investigates the effect of initial volume fraction on the runout characteristics of collapse of granular columns on slopes in fluid. 2-D sub-grain scale numerical simulations are performed to understand the flow dynamics of granular collapse in fluid. The discrete element method（DEM） technique is coupled with the lattice Boltzmann method（LBM）, for fluid-grain interactions, to understand the evolution of submerged granular flows. The fluid phase is simulated using multiple-relaxation-time LBM（LBM-MRT） for numerical stability. In order to simulate interconnected pore space in 2-D, a reduction in the radius of the grains（hydrodynamic radius） is assumed during LBM computations. The collapse of granular column in fluid is compared with the dry cases to understand the effect of fluid on the runout behaviour. A parametric analysis is performed to assess the influence of the granular characteristics（initial packing） on the evolution of flow and run-out distances for slope angles of 0 °, 2.5°, 5 ° and 7.5 °. The granular flow dynamics is investigated by analysing the effect of hydroplaning, water entrainment and viscous drag on the granular mass. The mechanism of energy dissipation, shape of the flow front, water entrainment and evolution of packing density is used to explain the difference in the flow characteristics of loose and dense granular column collapse in fluid.展开更多
One-pot chemical activation and pyrolysis process was developed for biochar production from red macroalgae residue of Gelidium sesquipedale.The macroalgae residue was activated by various catalysts(KOH,NaOH,H_(3)PO_(4...One-pot chemical activation and pyrolysis process was developed for biochar production from red macroalgae residue of Gelidium sesquipedale.The macroalgae residue was activated by various catalysts(KOH,NaOH,H_(3)PO_(4),and CH_(4)ON_(2))with the two concentrations(2.5 wt%and 5 wt%)using a pulverization system followed by slow pyrolysis at 500℃.The activated biochars showed a porous morphology with an increase of water holding capacity compared to the unactivated one.The properties of activated biochar observed by further characterization(i.e.,FTIR,SEM,TGA)revealed their feasibility to be used as an adsorbent.The results of adsorption experiment confirmed that adsorption was dependent not only on the surface area but also on the surface charge,and functional groups.The sorption performance of activated biochars(AcBC),in terms of the adsorption of methylene blue,was comparable to commercial activated charcoal(Norit^(■)).NaOH(2.5 wt%)-activated biochar had the removal efficiency of 87%versus 97%for commercial activated charcoal.展开更多
The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra...The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra-high hydrostatic pressures as high as 2.34 GPa for ACP and 4 GPa for HAP. At ambient pressure, the XRD patterns of the ACP and HAP samples in capillary tubes and their environmental scanning electron micrographs indicated amorphous and crystalline characteristics for ACP and HAP, respectively. At pressures greater than 0.25 GPa, an additional broad peak was observed in the XRD pattern of the ACP phase, indicating a partial phase transition from an amorphous phase to a new high-pressure amorphous phase. The peak areas and positions of the ACP phase, as obtained through fitting of the experimental data, indicated that the ACP exhibited increased pseudo-crystalline behavior at pressures greater than 0.96 GPa. Conversely, no structural changes were observed for the HAP phase up to the highest applied pressure of 4 GPa. For HAP, a unit-cell reduction during compression was evidenced by a reduction in both refined lattice parameters a and c. Both ACP and HAP reverted to their original structures when the pressure was fully released to ambient pressure.展开更多
文摘Macadamia nuts (Macadamia integrifolia) grown in Venezuela have showed an average total fat content of 70%. Oleic acid (18:1) was the main monounsaturated fatty acid (MUFA) (51.3%), followed by palmitoleic acid (16:1, 22.6%). The content of polyunsaturated fatty acids (PUFAs), C18:2 and C18:3 represented 5.4%. Thus, MUFAs and PUFAs together constituted more than 80% of the total fatty acids present. Trans-vaccenic acid was also present (3%). As regards to other phytochemical compounds, tocopherols and tocotrienols were not found in the sample, but the presence of squalene was detected.The antioxidant activity (44.2%) of the extract was produced by the phytochemicals present.
基金the Cambridge Commonwealth, Overseas Trust and the ShellCambridge-Brazil collaboration for the financial support to pursue this research
文摘This paper investigates the effect of initial volume fraction on the runout characteristics of collapse of granular columns on slopes in fluid. 2-D sub-grain scale numerical simulations are performed to understand the flow dynamics of granular collapse in fluid. The discrete element method（DEM） technique is coupled with the lattice Boltzmann method（LBM）, for fluid-grain interactions, to understand the evolution of submerged granular flows. The fluid phase is simulated using multiple-relaxation-time LBM（LBM-MRT） for numerical stability. In order to simulate interconnected pore space in 2-D, a reduction in the radius of the grains（hydrodynamic radius） is assumed during LBM computations. The collapse of granular column in fluid is compared with the dry cases to understand the effect of fluid on the runout behaviour. A parametric analysis is performed to assess the influence of the granular characteristics（initial packing） on the evolution of flow and run-out distances for slope angles of 0 °, 2.5°, 5 ° and 7.5 °. The granular flow dynamics is investigated by analysing the effect of hydroplaning, water entrainment and viscous drag on the granular mass. The mechanism of energy dissipation, shape of the flow front, water entrainment and evolution of packing density is used to explain the difference in the flow characteristics of loose and dense granular column collapse in fluid.
文摘One-pot chemical activation and pyrolysis process was developed for biochar production from red macroalgae residue of Gelidium sesquipedale.The macroalgae residue was activated by various catalysts(KOH,NaOH,H_(3)PO_(4),and CH_(4)ON_(2))with the two concentrations(2.5 wt%and 5 wt%)using a pulverization system followed by slow pyrolysis at 500℃.The activated biochars showed a porous morphology with an increase of water holding capacity compared to the unactivated one.The properties of activated biochar observed by further characterization(i.e.,FTIR,SEM,TGA)revealed their feasibility to be used as an adsorbent.The results of adsorption experiment confirmed that adsorption was dependent not only on the surface area but also on the surface charge,and functional groups.The sorption performance of activated biochars(AcBC),in terms of the adsorption of methylene blue,was comparable to commercial activated charcoal(Norit^(■)).NaOH(2.5 wt%)-activated biochar had the removal efficiency of 87%versus 97%for commercial activated charcoal.
基金funded through an FRDF funding (Grant 3702239) provided by the University of Auckland, New Zealand
文摘The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra-high hydrostatic pressures as high as 2.34 GPa for ACP and 4 GPa for HAP. At ambient pressure, the XRD patterns of the ACP and HAP samples in capillary tubes and their environmental scanning electron micrographs indicated amorphous and crystalline characteristics for ACP and HAP, respectively. At pressures greater than 0.25 GPa, an additional broad peak was observed in the XRD pattern of the ACP phase, indicating a partial phase transition from an amorphous phase to a new high-pressure amorphous phase. The peak areas and positions of the ACP phase, as obtained through fitting of the experimental data, indicated that the ACP exhibited increased pseudo-crystalline behavior at pressures greater than 0.96 GPa. Conversely, no structural changes were observed for the HAP phase up to the highest applied pressure of 4 GPa. For HAP, a unit-cell reduction during compression was evidenced by a reduction in both refined lattice parameters a and c. Both ACP and HAP reverted to their original structures when the pressure was fully released to ambient pressure.
