The Experts below are selected from a list of 266550 Experts worldwide ranked by ideXlab platform
Cesar Ricardo Teixeira Tarley - One of the best experts on this subject based on the ideXlab platform.
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assessment on the performance of nano carbon black as an Alternative Material for extraction of carbendazim tebuthiuron hexazinone diuron and ametryn
Journal of environmental chemical engineering, 2017Co-Authors: Maiyara Carolyne Prete, Fernanda Midori De Oliveira, Cesar Ricardo Teixeira TarleyAbstract:Abstract The aim of this study is to evaluate the adsorptive performance of nano-carbon black for removing pesticides from aqueous media. The characterization of Material was accomplished by SEM, FT-IR, TGA as well as by surface area measurements. Pesticide adsorption occurs in a wide pH range (2–7). The nano-carbon black presented a high surface area (306.9 m2 g−1) and the maximum adsorption capacities were found to be 74.4, 63.1, 59.7, 89.5 and 105.2 mg g−1 for carbendazim, tebuthiuron, hexazinone, diuron and ametryn, respectively, obtained from dual site Langmuir-Freundlich isotherm model. From kinetic data, the equilibrium times were found to be 30 min for diuron, 80 min for ametryn and 45 min for the other pesticides, while experimental data were well adjusted to pseudo-second-order models, thus suggesting that the adsorption of pesticides takes place in binding sites with different energies. From thermodynamic adsorption parameters, it was observed for all pesticides negative values of ΔG and ΔH, thus suggesting that the adsorption process is spontaneous and of exothermic nature. Multiresidue adsorption was not affected by the presence of 1.0 mg L−1 humic acid. When compared to other carbonaceous adsorbent Materials, nano-carbon black has as the main advantages the low equilibrium time, low cost and satisfactory adsorption capacity.
Sakdirat Kaewunruen - One of the best experts on this subject based on the ideXlab platform.
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monitoring in service performance of fibre reinforced foamed urethane sleepers bearers in railway urban turnout systems
Structural Monitoring and Maintenance, 2014Co-Authors: Sakdirat KaewunruenAbstract:Special track systems used to divert a train to other directions or other tracks are generally called ‘railway turnout’. A traditional turnout system consists of steel rails, switches, crossings, steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints and construction complexities may dominate the choice of track forms or certain components. With the difficulty to seek for high-quality timbers with dimensional stability, a methodology to replace aged timber bearers in harsh dynamic environments is to adopt an Alternative Material that could mimic responses and characteristics of timber in both static and dynamic loading conditions. A critical review has suggested an application of an Alternative Material called fibre-reinforced foamed urethane (FFU). The full-scale capacity design makes use of its comparable engineering characteristics to timber, high-impact attenuation, high damping property, and a longer service life. A field trial to investigate in-situ behaviours of a turnout grillage system using an Alternative Material, ‘fibre-reinforced foamed urethane (FFU)’ bearers, has been carried out at a complex turnout junction under heavy mixed traffics at Hornsby, New South Wales, Australia. The turnout junction was renewed using the FFU bearers altogether with new special track components. Influences of the FFU bearers on track geometry (recorded by track inspection vehicle ‘AK Car’), track settlement (based on survey data), track dynamics, and acoustic characteristics have been measured. Operational train pass-by measurements have been analysed to evaluate the effectiveness of the replacement methodology. Comparative studies show that the use of FFU bearers generates higher rail and sleeper accelerations but the damping capacity of the FFU help suppress vibration transferring onto other track components. The survey data analysis suggests a small vertical settlement and negligible lateral movement of the turnout system. The static and dynamic behaviours of FFU bearers appear to equate that of natural timber but its service life is superior.
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monitoring in service performance of fibre reinforced foamed urethane sleepers bearers in railway urban turnout systems
Structural Monitoring and Maintenance, 2014Co-Authors: Sakdirat KaewunruenAbstract:Special track systems used to divert a train to other directions or other tracks are generally called \'railway turnout\'. A traditional turnout system consists of steel rails, switches, crossings, steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints and construction complexities may dominate the choice of track forms or certain components. With the difficulty to seek for high-quality timbers with dimensional stability, a methodology to replace aged timber bearers in harsh dynamic environments is to adopt an Alternative Material that could mimic responses and characteristics of timber in both static and dynamic loading conditions. A critical review has suggested an application of an Alternative Material called fibre-reinforced foamed urethane (FFU). The full-scale capacity design makes use of its comparable engineering characteristics to timber, high-impact attenuation, high damping property, and a longer service life. A field trial to investigate in-situ behaviours of a turnout grillage system using an Alternative Material, \'fibre-reinforced foamed urethane (FFU)\' bearers, has been carried out at a complex turnout junction under heavy mixed traffics at Hornsby, New South Wales, Australia. The turnout junction was renewed using the FFU bearers altogether with new special track components. Influences of the FFU bearers on track geometry (recorded by track inspection vehicle
Maiyara Carolyne Prete - One of the best experts on this subject based on the ideXlab platform.
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assessment on the performance of nano carbon black as an Alternative Material for extraction of carbendazim tebuthiuron hexazinone diuron and ametryn
Journal of environmental chemical engineering, 2017Co-Authors: Maiyara Carolyne Prete, Fernanda Midori De Oliveira, Cesar Ricardo Teixeira TarleyAbstract:Abstract The aim of this study is to evaluate the adsorptive performance of nano-carbon black for removing pesticides from aqueous media. The characterization of Material was accomplished by SEM, FT-IR, TGA as well as by surface area measurements. Pesticide adsorption occurs in a wide pH range (2–7). The nano-carbon black presented a high surface area (306.9 m2 g−1) and the maximum adsorption capacities were found to be 74.4, 63.1, 59.7, 89.5 and 105.2 mg g−1 for carbendazim, tebuthiuron, hexazinone, diuron and ametryn, respectively, obtained from dual site Langmuir-Freundlich isotherm model. From kinetic data, the equilibrium times were found to be 30 min for diuron, 80 min for ametryn and 45 min for the other pesticides, while experimental data were well adjusted to pseudo-second-order models, thus suggesting that the adsorption of pesticides takes place in binding sites with different energies. From thermodynamic adsorption parameters, it was observed for all pesticides negative values of ΔG and ΔH, thus suggesting that the adsorption process is spontaneous and of exothermic nature. Multiresidue adsorption was not affected by the presence of 1.0 mg L−1 humic acid. When compared to other carbonaceous adsorbent Materials, nano-carbon black has as the main advantages the low equilibrium time, low cost and satisfactory adsorption capacity.
D Bimberg - One of the best experts on this subject based on the ideXlab platform.
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230 s room temperature storage time and 1 14 ev hole localization energy in in0 5ga0 5as quantum dots on a gaas interlayer in gap with an alp barrier
Applied Physics Letters, 2015Co-Authors: Leo Bonato, T Nowozin, D Bimberg, Elisa M Sala, G Stracke, Andre Strittmatter, Mohammed N Ajour, Khaled DaqrouqAbstract:A GaP n+p-diode containing In0.5Ga0.5As quantum dots (QDs) and an AlP barrier is characterized electrically, together with two reference samples: a simple n+p-diode and an n+p-diode with AlP barrier. Localization energy, capture cross-section, and storage time for holes in the QDs are determined using deep-level transient spectroscopy. The localization energy is 1.14(±0.04) eV, yielding a storage time at room temperature of 230(±60) s, which marks an improvement of 2 orders of magnitude compared to the former record value in QDs. Alternative Material systems are proposed for still higher localization energies and longer storage times.
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800 mev localization energy in gasb gaas al0 3ga0 7as quantum dots
Applied Physics Letters, 2013Co-Authors: T Nowozin, Leo Bonato, A Hogner, A Wiengarten, D Bimberg, Weihsun Lin, Shihyen Lin, Charles J Reyner, Baolai Liang, D L HuffakerAbstract:The localization energies, capture cross sections, and storage times of holes in GaSb quantum dots (QDs) are measured for three GaSb/GaAs QD ensembles with different QD sizes. The structural properties, such as height and diameter, are determined by atomic force microscopy, while the electronic properties are measured using deep-level transient spectroscopy. The various QDs exhibit varying hole localization energies corresponding to their size. The maximum localization energy of 800 (±50) meV is achieved by using additional Al0.3Ga0.7As barriers. Based on an extrapolation, Alternative Material systems are proposed to further increase the localization energy and carrier storage time of QDs.
E Navara - One of the best experts on this subject based on the ideXlab platform.
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austempered ductile iron an Alternative Material for earth moving components
Cement & Concrete Composites, 2003Co-Authors: J Zimba, D J Simbi, E NavaraAbstract:Abstract Traditionally steels have enjoyed some kind of monopoly in earth movement applications like ripper tips and grader blades. Earth movement demands that the Material possesses both wear resistance and toughness. Ironically, the limitation of steels is that it is difficult to get a good combination of these properties. Recent research efforts in earth movement have focused on austempered ductile iron (ADI) as an Alternative Material, which exhibits both these properties. ADI is obtained when ductile cast iron is accorded a special heat treatment known as austempering. Before the usage of ADI can flourish, there is a need to thoroughly understand its mechanical and tribological behaviour. This paper details the heat treatment of ductile iron to yield ADI and also examines its mechanical and abrasive wear properties. These properties are compared with those of a proprietary quenched and tempered (Q&T) steel used in applications requiring wear resistance. Typically, when a load of 0.25 N mm−2 is used, the relative abrasion resistance (RAR) of ADI austempered at 375 °C with an initial hardness of 315 Hv is 2.01, while that of a Q&T steel, of hardness 635 Hv is 2.02. The good wear resistance exhibited by ADI despite the low initial hardness can be attributed to the surface transformation of retained austenite to martensite during abrasion. This phenomenon has been positively confirmed by XRD.