| 1. |
- Talabazar, Farzad Rokhsar, et al.
(författare)
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Removal of per- and polyfluoroalkyl substances (PFAS) from wastewater using the hydrodynamic cavitation on a chip concept
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 495
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Tidskriftsartikel (refereegranskat)abstract
- The elimination of micropollutants such as highly fluorinated substances, including per- and polyfluoroalkyl substances (PFAS), in wastewater treatment plants has been receiving growing attention due to the urgent need to minimize their adverse effects on natural water and associated ecosystems. Conventional treatment methods often fall short in effectively removing PFAS. In this study, the Hydrodynamic Cavitation on a Chip concept (HCOC) was utilized to degrade 11 common PFAS variants (PFAS11) for the first time in three different hydrodynamic cavitation reactor set-ups, each enhanced with surface modifications involving roughness elements. Stockholm municipal wastewater treated by a Membrane BioReactor (MBR) process was subjected to fully developed cavitating flow treatment using the three distinct microscale hydrodynamic cavitation (HC) reactors. The obtained results indicate that the chemical-free HCOC technique employed in this study has a significant potential in the degradation of nearly all investigated PFAS11 compounds at a notable rate of 36.1 % while the combination with MBR process can prevent blockage within the fluidic channels, enabling continuous operation with high throughput processing rates. Our proposed methodology demonstrated promising results in eliminating PFAS and could contribute to advancements in the use of microscale HC to treat micropollutants in wastewater. These findings could be a major leap in water treatment technologies addressing the global burden of resource-efficient micropollutant water treatment.
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| 2. |
- Bahrami, Ataallah, et al.
(författare)
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Oxidation-reduction effects in the flotation of copper sulfide minerals and molybdenite – A proof of concept at industrial scale
- 2022
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Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 180
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Tidskriftsartikel (refereegranskat)abstract
- Redox potential (Eh) control plays a significant role during sulfide mineral flotation by influencing the reactions on the surface of the minerals and accordingly the flotation behaviour. In this study, the metallurgical performance of typical copper sulfide minerals, molybdenite as well as gangue minerals (e.g., pyrite, tennantite, and enargite) under different pH and Eh conditions of the flotation cell were investigated. The copper and molybdenum processing plant at the Sungun complex-Iran were selected as a case study. For this purpose, Eh of flotation cells of phases 1 and 2 of copper and molybdenum processing circuits – Sungun complex – were measured by off-line method. After performing chemical analysis, the mineralogical study of the input load and products of each of the aforementioned flotation circuits in the rougher, cleaner, re-cleaner, and scavenger stages was performed. Based on the results, the potential in cells of phases 1 and 2 of copper concentration plants is in the range of −60 to −100 mV; and for the molybdenum plant, is in the range of −500 to −700 mV. The potentials of more than −100 mV in the phases of copper concentration plants have created suitable conditions for the separation of copper sulfide and molybdenite minerals from gangue minerals, especially pyrite. Adjustment of Eh in the range of −500 to −700 mV in the molybdenum processing plant has also led to the depression of copper minerals and the flotation of molybdenite, resulting in the effective separation of these minerals. However, grade analysis and mineralogical studies indicate the misplaced copper minerals into tailings, the passage of chalcopyrite and pyrite to molybdenum concentrate, the misplaced molybdenite to copper concentrate, and also the presence of minerals containing harmful elements such as arsenic in copper concentrate. Eh fluctuations in phase 1 and 2 of copper plants, the interaction of copper sulfide minerals, especially chalcopyrite with pyrite (and the depression of pyrite in Eh more than −100 mV), are reasons for the misplaced copper minerals into tailings. The interaction of chalcopyrite and pyrite with molybdenite and the high flotation tendency of molybdenite at the potential of +600 mV is the main factor in increasing the Cu and Fe grade in molybdenite concentrate. The interaction of copper minerals with arsenic-bearing minerals and the similar flotation behavior of these minerals in the potential of the rougher cells of the molybdenum processing plant has increased the arsenic grade in the copper concentrate or molybdenum tailings.
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| 3. |
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| 4. |
- Ghorbani, Morteza, et al.
(författare)
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On ``Cavitation on Chip'' in Microfluidic Devices With Surface and Sidewall Roughness Elements
- 2019
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Ingår i: Journal of microelectromechanical systems. - : Institute of Electrical and Electronics Engineers Inc.. - 1057-7157 .- 1941-0158. ; 28:5, s. 890-899
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, cavitating flows are characterized in 29 microfluidic devices in order to achieve a comprehensive perspective regarding flow patterns in microscale, which is crucial in the applications, such as energy harvesting and biomedical treatment. While the assessment of size effects is vital for the design and development of microfluidic devices involving phase change, surface/sidewall roughness and pressure pulses as a result of nanomechanical oscillations increase the performance with respect to cavitation by providing more cavitation bubbles. A typical device generates cavitating flows under different conditions (from inception to choked flow). In this device, a restrictive element and a big channel downstream of the restrictive element--where the cavitation is formed and developed--are included. The cavitating flows are obtained inside 24 sidewall roughened and 5 surface roughened/plain microfluidic devices at different pressure drops. The length and height of the sidewall roughness elements are varied to achieve the most optimum performance in terms of cavitation generation. Moreover, different surface roughened and plain devices are considered to provide a comprehensive overview of cavitation generation in microscale. The results show that sidewall roughness elements have a remarkable effect on the cavitation inception and flow patterns. [2019-0025] IEEE
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| 5. |
- Ghorbani, Shaban Reza, et al.
(författare)
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Disorder Driven Localization in Charge Neutrally Doped 123 Superconductors
- 2006
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Ingår i: Low Temperature Physics. - : AIP. ; , s. 439-440
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Konferensbidrag (refereegranskat)abstract
- Charge neutral dopings with equal amounts of CaTh or CaPr on rare earth site in Nd-123 have been investigated by studies of the normal state electrical resistivity, p, the Seebeck coefficient S, and the Hall coefficient R-H. In spite of comparable rates of depression of the superconducting T, significant differences are observed in the doping concentration dependence of p, S, and RH between the two dopings. These results are discussed in terms of disorder induced localization.
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| 6. |
- Ghorbani, Shaban Reza, et al.
(författare)
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Neutron diffraction studies of Nd1-xPrxBa2Cu3O7-delta : Evidence for hole localization
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69:1, s. 145031-
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Tidskriftsartikel (refereegranskat)abstract
- Sintered samples of Nd1-xPrxBa2Cu3O7-delta with x=0, 0.05, 0.10, 0.15, 0.20, and 0.30 have been studied by neutron diffraction, x-ray diffraction, and resistivity measurements. Sample stoichiometry was carefully checked. Atomic distances within the unit cell and the oxygen content were shown to be almost independent of Pr doping. Bond valence sums (BVSs) were calculated from the neutron diffraction data assuming either a constant valence or a mixed valence for Cu and Pr ions. The planar Cu2 valence is independent of Pr doping and the chain Cu1 valence is roughly constant, while the hole concentration in the planes and chains decrease with increasing Pr doping for both BVS calculation methods. All together, this indicates that hole localization on the Nd(Pr) site is a main reason for the decrease of the hole concentration in the planes. A consistent relation between the hole concentration in the planes calculated from the constant valence method and the depression of the critical temperature is also obtained, both for Pr-doped Nd-123 and for Y(Pr)-123 studied previously.
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| 7. |
- Ghorbani, Shaban Reza, et al.
(författare)
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Normal state Hall effect in Nd1-xCaxBa2Cu3O7-delta : competition between added charge and disorder
- 2003
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Ingår i: Physica. C, Superconductivity. - : Elsevier BV. - 0921-4534 .- 1873-2143. ; 390:2, s. 160-166
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Tidskriftsartikel (refereegranskat)abstract
- The transport properties of sintered samples of Nd1-xCaxBa2CU3O7-delta with 0 less than or equal to x less than or equal to 0.20 have been studied in the normal state by Hall resistivity measurements. The Hall coefficient, R-H(x, T) was well described in terms of two different models. In a phenomenological narrow band model, the conduction band width became narrower with increasing Ca concentration while the density of states band width decreased slightly. A competition between two effects (i) added charge, and (ii) disorder introduced into the CuO2 planes by doping, could be the main reason for the observed small decrease of the band widths. In the Anderson model, the temperature dependent part of the Hall angle was independent of hole concentration and disorder while the temperature independent part increased linearly with increasing Ca content. The results in both models support that Ca introduces disorder in the CuO2 planes.
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| 8. |
- Ghorbani, Shaban Reza, 1962-
(författare)
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Structural and Electrical Transport Properties of Doped Nd-123 Superconductors
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is generally believed that one of the key parameterscontrolling the normal state and superconducting properties ofhigh temperature superconductors is the charge carrierconcentrationpin the CuO2planes.By changing the non-isovalent dopingconcentration on the RE site as well as the oxygen content in(RE)Ba2Cu3O7−δ, an excellent tool is obtained tovary the hole concentration over a wide range from theunderdoped up to the overdoped regime.In the present thesis thefocus is on the doping effects on the structural and normalstate electrical properties in Nd-123 doped with Ca, La, Pr,Ca-Pr, and Ca-Th.T he effects of doping have been investigatedby X-ray and neutron powder diffraction, and by measurements ofthe resistivity, thermoelectric powerS, and Hall coefficient RH.T he thermoelectric power is a powerful tool forstudies of high temperature superconductivity and is highlysensitive to details of the electronic band structure.Sas a function of temperature has been analyzed in twodifferent two band models.The parameters of these models arerelated to charactristic features of the electron bands and asemiempirical physical description of the doping dependence ofSis obtained.So me important results are following:(i)The valence of Pr in the RE-123 family.Results from thestructural investigations, the critical temperature Tc, and thethermoelectric power indicated a valence +4 at low dopingconcentration, which is in agreement with results of chargeneutral doping in the RE-123 family.(ii)Hole localization. The results of bond valence sum (BVS)calculations from neutron diffraction data showed that holelocalization on the Pr+4site was the main reason for the decrease of thehole concentration p.Differ ent types of localization wereinferred by S measurements for Ca-Th and Ca-Pr dopings.(iii)Competition between added charge and disorder. Theresults of RH measurements indicated that Ca doping introduceddisorder in the CuO2planes in addition to added charge.This could bethe main reason for the observed small decrease of thebandwidth of the density of states in the description of aphenomenological narrow band model.(iv) Empirical parabolic relation between γ and p.S data were analyzed and well described by a two-band modelwith an additional linear T term, γT.An empiricalparabolic relation for γ as a function of holeconcentration has been found.Key words:high temperature superconductors, criticaltemperature, resistivity, thermoelectric power, Hallcoefficient, X-ray diffraction, Neutron diffraction, NdBa2Cu3O7−δ, hole concentration,substitution.
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| 9. |
- Ghorbani, Shaban Reza, et al.
(författare)
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Thermoelectric power and resistivity of Nd1-xCaxBa2Cu3Oy and Nd1-xLaxBa2Cu3Oy
- 2000
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Ingår i: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 339:4, s. 245-252
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Tidskriftsartikel (refereegranskat)abstract
- The structural and transport properties of Nd1-xCaxBa2Cu3Oy (x = 0.0, 0.03, 0.06, and 0.10) and Nd1-xLax- Ba2Cu3Oy. (x nominally 0.0, 0.05, 0.10, and 0.15) have been studied by X-ray powder diffraction, electrical resistivity, and thermoelectric power measurements. In both series, the a- and b-axis lattice parameters decrease with increasing doping while the c-axis lattice parameter increases. The transport properties suggest improved metallic behaviour with increasing Ca doping in contrast to La doping. An anomalous sharp peak in the thermoelectric power close to T-c was observed, which depended on the doping content. We analysed the thermoelectric power as a function of temperature with a two-band model with an additional linear T term. An excellent agreement between model and data was obtained.
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| 10. |
- Ghorbani, Shaban Reza, et al.
(författare)
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Thermoelectric power and resistivity of Nd1-xPrxBa2Cu3O7-delta
- 2001
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Ingår i: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 353:1-2, s. 77-84
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Tidskriftsartikel (refereegranskat)abstract
- The structural and transport properties of Nd1-xPrxBa2Cu3O7-delta (x = 0.0, 0.05, 0.10, and 0.15), have been studied by X-ray powder diffraction, electrical resistivity measurements, and thermoelectric power measurements. The decrease of the superconducting critical temperature with doping is described by a parabolic term and a linear term. The c-axis lattice parameter and the cell volume decrease with doping up to x = 0.10. Analyses of the thermoelectric power, critical temperature, c-axis lattice parameter, and the cell volume suggest that the Pr ions have a valence close to +4 at low doping concentration. The room temperature resistivity indicates that hole concentration decreases with increasing Pr doping. The room temperature thermoelectric power is positive for all samples and increases with increasing Pr doping due to a decrease in the carrier concentration. We analyzed the thermoelectric power as a function of temperature with a two-band model with an additional linear T term. An excellent agreement between model and data was obtained. The band width of the narrow band increases and its peak position moves away from the Fermi energy with increasing doping concentration.
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| 11. |
- Haghbin, Saeid, 1977, et al.
(författare)
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An Integrated Motor Drive and Battery Fast Charger Station for Plug-in Vehicles
- 2013
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Ingår i: 13th Spanish Portuguese Conference on Electrical Engineering (13CHLIE).
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Konferensbidrag (refereegranskat)abstract
- Vehicles using grid power to charge the battery are parked during the charge operation. So, there is a possibility to use the traction components in the charger circuit to reduce the size, weight, and cost of charger.Charging power level directly is related to the charging time that is a crucial limiting factor in enhancement of plug-in vehicles. An integrated fast charger station is described that vehicle traction components are used in the charger system to provide a cheap charge solution. An isolated stationary transformer provides electric power or the vehicle inverter to constitute a boost rectifier serves as the battery charger. The system structure, components and operation is described in this paper. Moreover, a small scale laboratory setup is developed to practically verify the idea. The practical system is based on NI CompactRIO platform.
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| 12. |
- Siahboumi, Abbas Ahmadi, et al.
(författare)
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Effect of hafnium addition on microstructure and room temperature mechanical properties of the Ti-48Al-2Cr-2Nb intermetallic alloy
- 2022
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 917, s. 165467-
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Tidskriftsartikel (refereegranskat)abstract
- Microstructures, phase transformations and mechanical properties of the Ti-48Al-2Cr-2Nb-xHf (4822-xHf, x = 0, 2, 4, 6 at%) intermetallic alloys were investigated. The alloys were fabricated by vacuum arc remelting followed by hot isostatic pressing and homogenization treatment. The results showed that Hf alloying leads to a significant microstructure refinement in terms of both colony size and inter-lamellar spacing. Homogenization at 1400 degrees C resulted in a fully lamellar (FL) microstructure in 4822 and 2Hf alloys, while nearly lamellar (NL) in 4Hf and 6Hf alloys. Differential thermal analysis (DTA) demonstrated that Hf addition up to 2 at% has a slight contribution to phase transition sequences, but a significant implication to the phase equilibrium of the alloys with further Hf content. Based on the DTA data and annealing at 1450 degrees C, the solvus temperature of the eutectic phases was estimated to be over the range of 1430-1440 degrees C. Although the eutectic phases of Al3Hf2 and TiAl2 formed during solidification of the high-Hf alloys did not undergo any phase transition, both size and volume fraction of the eutectic cells increased due to the solvus of these metastable eutectic phases. The orientation relationship {111}(Tetragonal)//{001}(Orthorhombic) detected between the eutectic phases and their surrounding matrix confirmed the occurrence of (gamma c) (TiAl) -> eutectics (Al3Hf2, TiAl2) phase transformation. Small punch tests results showed that the 2Hf and 4Hf alloys exhibit a higher maximum load (F-m) than the base 4822 alloy due to the solid solution effect of Hf and finer inter-lamellar spacing. Nevertheless, the brittle behavior of the eutectic phases dramatically deteriorated mechanical performance such that the 6Hf alloy possessed the lowest Fm and displacement. The major fracture mode changed from trans-lamellar to inter-lamellar as the Hf content increased from 4 to 6 at%.
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| 13. |
- Vindel, David, 1986, et al.
(författare)
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Field-Oriented Control of a PMSM Drive System Using the dSPACE Controller
- 2012
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Ingår i: 2012 IEEE International Electric Vehicle Conference, IEVC 2012. Greenville, SC, 4-8 March 2012. - 9781467315623
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Konferensbidrag (refereegranskat)abstract
- Field-oriented control (FOC) of the permanent magnet synchronous motor (PMSM) is one of the widely used scheme in drive system application. Moreover, in some high performance applications, the rotor position information is needed that can be measured by a resolver for example. A drive system is designed and explained based on the FOC of a PMSM using the dSPACE controller. A resolver sensor is used for the position measurement in the system. Simulation and practical implementation results are presented to verify the proper operation of the drive system that is a speed controller in this case.
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