The Experts below are selected from a list of 88131 Experts worldwide ranked by ideXlab platform
K H Teng - One of the best experts on this subject based on the ideXlab platform.
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calcium carbonate fouling on double pipe heat exchanger with different heat exchanging surfaces
2017Co-Authors: T Chew, S N Kazi, K H Teng, Ahmad Amiri, A F Habali, M. Abu A. Aka, A I Alshammaa, A Shaw, K H SolangiAbstract:Abstract An experimental setup of double pipe heat exchanger fouling test rig was built to investigate the mineral Scale Deposition on different heat exchanger pipe surfaces. Progressive fouling Deposition on different material surfaces under the similar solution conditions were observed and analyzed. Measurable data on the progressive build-up of Scale deposits, Deposition rate, as well as the composition and crystal morphology of the deposits were studied after each experimental run by analyzing the deposited Scale on the test pipes. In this research the artificial calcium carbonate deposit on different material surfaces is considered as it is one of the major constituents of the most Scales found in heat exchanging equipment. Fouling on different smooth test pipes were investigated in the centrally located larger concentric pipe heat exchanger. Uniform flow condition near the pipe surface was maintained by constant flow rate throughout the system. The calcium carbonate Deposition rates on five different metal surfaces (Stainless steel 316, brass, copper, aluminium and carbon steel) were investigated. The results illustrated an upward trend for fouling rate with time on the tested specimens. The Deposition on the surfaces showed a linear growth with the enhancement of thermal conductivity of the metals. However, Deposition on carbon steel metal surfaces did not follow the typical linear trend of thermal conductivity over Deposition as its surface was altered by corrosion effects. In addition, temperature, velocity, and concentration effects on fouling Deposition were investigated on the SS316 metal surface. It is noted that the fouling Deposition increases with the increase of temperature and concentration due to enhanced Deposition potential whereas reduces due to the increase of velocity which enhances shear stress.
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retardation of heat exchanger surfaces mineral fouling by water based diethylenetriamine pentaacetate treated cnt nanofluids
2017Co-Authors: S N Kazi, K H Teng, Ahmad Amiri, A I Alshammaa, M A Bakar, B T Chew, A ShawAbstract:Abstract Mineral Scale Deposition on heat exchanging surfaces increases the thermal resistance and reduces the operating service life. The effect is usually intensified at higher temperatures due to the inverse temperature solubility characteristics of some minerals in the cooling water. Scale formation build up when dissolved salt crystallize from solution onto the heated surface, forming an adherent deposit. It is very important for heat transfer applications to cope with the fouling problems in industry. In this present study, a set of fouling experiments was conducted to evaluate the mitigation of calcium carbonate scaling by applying DTPA-treated MWCNT-based water nanofluids on heat exchanger surfaces. Investigation of additive DTPA-treated MWCNT-based water nanofluids (benign to the environment) on fouling rate of Deposition was performed. 300 mg L −1 of artificially-hardened calcium carbonate solution was prepared as a fouling solution for deposit analysis. Assessment of the Deposition of calcium carbonate on the heat exchanger surface with respect to the inhibition of crystal growth was conducted by Scanning Electron Microscope (SEM). The results showed that the formation of calcium carbonate crystals can be retarded significantly by adding MWCNT-DTPA additives as inhibition in the solution.
Manish Chhowalla - One of the best experts on this subject based on the ideXlab platform.
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highly uniform 300 mm wafer Scale Deposition of single and multilayered chemically derived graphene thin films
2010Co-Authors: Hisato Yamaguchi, Goki Eda, Cecilia Mattevi, Hokwon Kim, Manish ChhowallaAbstract:The Deposition of atomically thin highly uniform chemically derived graphene (CDG) films on 300 mm SiO(2)/Si wafers is reported. We demonstrate that the very thin films can be lifted off to form uniform membranes that can be free-standing or transferred onto any substrate. Detailed maps of thickness using Raman spectroscopy and atomic force microscopy height profiles reveal that the film thickness is very uniform and highly controllable, ranging from 1-2 layers up to 30 layers. After reduction using a variety of methods, the CDG films are transparent and electrically active with FET devices yielding high mobilities of approximately 15 cm(2)/(V s) and sheet resistance of approximately 1 kOmega/sq at approximately 70% transparency.
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highly uniform 300 mm wafer Scale Deposition of single and multilayered chemically derived graphene thin films
2009Co-Authors: Hisato Yamaguchi, Goki Eda, Cecilia Mattevi, Hokwon Kim, Manish ChhowallaAbstract:The Deposition of atomically thin highly uniform chemically derived graphene (CDG) films on 300 mm SiO2/Si wafers is reported. We demonstrate that the very thin films can be lifted off to form uniform membranes than can be free-standing or transferred onto any substrate. Detailed maps of thickness using Raman spectroscopy and atomic force microscopy (AFM) height profiles reveal that the film thickness is very uniform and highly controllable, ranging from 1-2 layers up to 30 layers. After reduction using a variety of methods, the CDG films are transparent and electrically active with FET devices yielding exceptionally high mobilities of ~ 15 cm2/Vs and sheet resistance of ~ 1 k Ohm/sq at ~ 70 % transparency.
Martijn Boerkamp - One of the best experts on this subject based on the ideXlab platform.
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monitoring the kinetics of heterogeneous crystal growth using an intrinsic exposed core optical fibre sensor
2017Co-Authors: Martijn Boerkamp, David Lamb, Peter G LyeAbstract:Abstract The prevention of unwanted heterogeneous crystal growth, known as Scale formation, requires accurate detection of the rate and amount of Scale Deposition on surfaces. An Intrinsic Exposed Core Optical Fibre Sensor (IECOFS) has been used to measure heterogeneous crystal growth kinetic parameters, such as the rate of crystal growth and the induction time. Measurements at different temperatures allowed the activation energy to be determined for three crystal types, with excellent agreement with literature values. Crystal growth kinetic parameters were determined for calcium carbonate with the IECOFS and were found to compare well with kinetic parameters extracted from crystal growth measurements on a stainless steel surface. Crystal growth kinetic measurements were also performed in the presence of a poly-acrylic-acid (PAA) crystal growth inhibitor. The IECOFS monitored a reduction in the crystal growth rate and an increase in the induction time, matching well with the expected behaviour of the PAA inhibitor and agreeing with a literature model of crystal growth.
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detecting and monitoring industrial Scale formation using an intrinsic exposed core optical fiber sensor
2010Co-Authors: Martijn Boerkamp, David Lamb, Peter G Lye, Christopher M Fellows, Ali Alhamzah, Andrew WallaceAbstract:Measurements of heterogeneous crystallization (scaling) have been performed using an intrinsic exposed-core optical fiber sensor (IECOFS). The IECOFS showed several advantages over the conventional techniques of Scale detection: turbidity and electrical conductivity, including insensitivity to the presence of suspended crystals caused by homogeneous crystallization and the ability to monitor Scale Deposition under continuous supply conditions. Calibration of the IECOFS, to quantify Scale deposited on a given surface, and the limitations of the technique are also presented.
Peter G Lye - One of the best experts on this subject based on the ideXlab platform.
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monitoring the kinetics of heterogeneous crystal growth using an intrinsic exposed core optical fibre sensor
2017Co-Authors: Martijn Boerkamp, David Lamb, Peter G LyeAbstract:Abstract The prevention of unwanted heterogeneous crystal growth, known as Scale formation, requires accurate detection of the rate and amount of Scale Deposition on surfaces. An Intrinsic Exposed Core Optical Fibre Sensor (IECOFS) has been used to measure heterogeneous crystal growth kinetic parameters, such as the rate of crystal growth and the induction time. Measurements at different temperatures allowed the activation energy to be determined for three crystal types, with excellent agreement with literature values. Crystal growth kinetic parameters were determined for calcium carbonate with the IECOFS and were found to compare well with kinetic parameters extracted from crystal growth measurements on a stainless steel surface. Crystal growth kinetic measurements were also performed in the presence of a poly-acrylic-acid (PAA) crystal growth inhibitor. The IECOFS monitored a reduction in the crystal growth rate and an increase in the induction time, matching well with the expected behaviour of the PAA inhibitor and agreeing with a literature model of crystal growth.
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detecting and monitoring industrial Scale formation using an intrinsic exposed core optical fiber sensor
2010Co-Authors: Martijn Boerkamp, David Lamb, Peter G Lye, Christopher M Fellows, Ali Alhamzah, Andrew WallaceAbstract:Measurements of heterogeneous crystallization (scaling) have been performed using an intrinsic exposed-core optical fiber sensor (IECOFS). The IECOFS showed several advantages over the conventional techniques of Scale detection: turbidity and electrical conductivity, including insensitivity to the presence of suspended crystals caused by homogeneous crystallization and the ability to monitor Scale Deposition under continuous supply conditions. Calibration of the IECOFS, to quantify Scale deposited on a given surface, and the limitations of the technique are also presented.
Hisato Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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highly uniform 300 mm wafer Scale Deposition of single and multilayered chemically derived graphene thin films
2010Co-Authors: Hisato Yamaguchi, Goki Eda, Cecilia Mattevi, Hokwon Kim, Manish ChhowallaAbstract:The Deposition of atomically thin highly uniform chemically derived graphene (CDG) films on 300 mm SiO(2)/Si wafers is reported. We demonstrate that the very thin films can be lifted off to form uniform membranes that can be free-standing or transferred onto any substrate. Detailed maps of thickness using Raman spectroscopy and atomic force microscopy height profiles reveal that the film thickness is very uniform and highly controllable, ranging from 1-2 layers up to 30 layers. After reduction using a variety of methods, the CDG films are transparent and electrically active with FET devices yielding high mobilities of approximately 15 cm(2)/(V s) and sheet resistance of approximately 1 kOmega/sq at approximately 70% transparency.
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highly uniform 300 mm wafer Scale Deposition of single and multilayered chemically derived graphene thin films
2009Co-Authors: Hisato Yamaguchi, Goki Eda, Cecilia Mattevi, Hokwon Kim, Manish ChhowallaAbstract:The Deposition of atomically thin highly uniform chemically derived graphene (CDG) films on 300 mm SiO2/Si wafers is reported. We demonstrate that the very thin films can be lifted off to form uniform membranes than can be free-standing or transferred onto any substrate. Detailed maps of thickness using Raman spectroscopy and atomic force microscopy (AFM) height profiles reveal that the film thickness is very uniform and highly controllable, ranging from 1-2 layers up to 30 layers. After reduction using a variety of methods, the CDG films are transparent and electrically active with FET devices yielding exceptionally high mobilities of ~ 15 cm2/Vs and sheet resistance of ~ 1 k Ohm/sq at ~ 70 % transparency.
