| |
Records |
Links |
|
Author |
Lang, X.; Ouyang, Y.; Vandewalle, L.A.; Goshayeshi, B.; Chen, S.; Madanikashani, S.; Perreault, P.; Van Geem, K.M.; van Geem, K.M. |
|
| |
Title |
Gas-solid hydrodynamics in a stator-rotor vortex chamber reactor |
Type |
A1 Journal article |
| |
Year  |
2022 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
Chem Eng J |
|
| |
Volume |
446 |
Issue |
5 |
Pages |
137323-12 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
|
| |
Abstract |
The gas-solid vortex reactor (GSVR) has enormous process intensification potential. However the huge gas consumption can be a serious disadvantage for the GSVR in some applications such as fast pyrolysis. In this work, we demonstrate a recent novel design, where a stator-rotor vortex chamber (STARVOC) is driven by the fluid's kinetic energy, to decouple the solids bed rotation and gas. Gas-solid fluidization by using air and monosized aluminum balls was performed to investigate the hydrodynamics. A constructed fluidization flow regime map for a fixed solids loading of 100 g shows that the bed can only be fluidized for a rotation speed between 200 and 400 RPM. Below 200 RPM, particles settle down on the bottom plate and cannot form a stable bed due to inertia and friction. Above 400 RPM, the bed cannot be fluidized with superficial velocities up to 1.8 m/s (air flow rate of 90 Nm(3)/h). The bed thickness shows some non-uniformities, being smaller at the top of the bed than at the bottom counterpart. However by increasing the air flow rate or rotation speed the axial nonuniformity can be resolved. The bed pressure drop first increases with increasing gas flow rate and then levels off, showing similar characteristics as conventional fluidized beds. Theoretical pressure drops calculated from mathematical models such as Kao et al. model agree well with experimental measurements. Particle velocity discrepancies between the top and bottom particles reveal that the impact of gravity cannot be completely neglected. Design guidelines and possible applications for further development of STARVOC concept are proposed based on fundamental data provided in this work. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000833418100006 |
Publication Date |
2022-06-01 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1385-8947; 1873-3212 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
15.1 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
|
Approved |
Most recent IF: 15.1 |
|
| |
Call Number |
UA @ admin @ c:irua:189283 |
Serial |
7167 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Zillner, J.; Boyen, H.-G.; Schulz, P.; Hanisch, J.; Gauquelin, N.; Verbeeck, J.; Kueffner, J.; Desta, D.; Eisele, L.; Ahlswede, E.; Powalla, M. |
|
| |
Title |
The role of SnF₂ additive on interface formation in all lead-free FASnI₃ perovskite solar cells |
Type |
A1 Journal article |
| |
Year |
2022 |
Publication |
Advanced functional materials |
Abbreviated Journal |
Adv Funct Mater |
|
| |
Volume |
|
Issue |
|
Pages |
2109649-9 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Tin-based perovskites are promising alternative absorber materials for leadfree perovskite solar cells but need strategies to avoid fast tin (Sn) oxidation. Generally, this reaction can be slowed down by the addition of tin fluoride (SnF2) to the perovskite precursor solution, which also improves the perovskite layer morphology. Here, this work analyzes the spatial distribution of the additive within formamidinium tin triiodide (FASnI(3)) films deposited on top of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transporting layers. Employing time-of-flight secondary ion mass spectrometry and a combination of hard and soft X-ray photoelectron spectroscopy, it is found that Sn F2 preferably accumulates at the PEDOT:PSS/perovskite interface, accompanied by the formation of an ultrathin SnS interlayer with an effective thickness of approximate to 1.2 nm. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000779891000001 |
Publication Date |
0000-00-00 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1616-301x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
19 |
Times cited |
22 |
Open Access |
OpenAccess |
|
| |
Notes |
J.Z. and H.-G.B. contributed equally to this work. This project received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 850937 (PERCISTAND). H.-G.B. and D.D. are very grateful to the Research Foundation Flanders (FWO) for funding the HAXPES-lab instrument within the HERCULES program for Large Research Infrastructure of the Flemish government. P.S. thanks the French Agence Nationale de la Recherche for funding under the contract number ANR-17-MPGA-0012. This work was supported by the Federal Ministry for Economic Affairs and Energy (BMWi) Germany under the contract number 03EE1038A (CAPITANO) and financed by the Ministry of Science, Research and the Arts of Baden-Württemberg as part of the sustainability financing of the projects of the Excellence Initiative II (KSOP). |
Approved |
Most recent IF: 19 |
|
| |
Call Number |
UA @ admin @ c:irua:187969 |
Serial |
7067 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Gonzalez-Quiroga, A.; Shtern, V.; Perreault, P.; Vandewalle, L.; Marin, G.B.; Van Geem, K.M. |
|
| |
Title |
Intensifying mass and heat transfer using a high-g stator-rotor vortex chamber |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Chemical Engineering And Processing |
Abbreviated Journal |
Chem Eng Process |
|
| |
Volume |
169 |
Issue |
|
Pages |
108638-11 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
|
| |
Abstract |
Vortex reactors take advantage of the synergy between enhanced heat and mass transfer rates and multifunctional phenomena at different temporal and spatial scales. Proof-of-concept experiments with our novel and innovative STAtor-Rotor VOrtex Chamber (STARVOC) confirm its advantageous features for the sustainable production of chemicals and fuels. STARVOC is a high-g contactor that uses carrier flow (gas or liquid) tangential injection to drive a rotor attached to low-friction bearings. The vortex chamber inside the rotor contains a secondary phase or phases, such as a solids bed, a liquid layer, or a suspension. Carrier fluid passes through the perforated rotor wall and contacts a densely and uniformly distributed secondary phase with enhanced slip velocities. Experiments focused on pressure profiles, rotor angular velocity, and solids azimuthal velocity. With air as the carrier fluid and different solid particle beds as the secondary phase, STARVOC reached bed azimuthal velocities up to four-fold compared to those reached in Gas-Solid Vortex Units with fully static geometry. These results show its potential to improve interfacial heat and mass transfer rates and take advantage of flow energy and angular momentum. Due to its process intensification capabilities, STARVOC is a promising alternative for the state-of-the-art chemical industry. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000704946900008 |
Publication Date |
2021-09-17 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0255-2701 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.234 |
Times cited |
|
Open Access |
Not_Open_Access |
|
| |
Notes |
|
Approved |
Most recent IF: 2.234 |
|
| |
Call Number |
UA @ admin @ c:irua:181062 |
Serial |
8111 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Nunez Manzano, M.; Gonzalez Quiroga, A.; Perreault, P.; Madanikashani, S.; Vandewalle, L.A.; Marin, G.B.; Heynderickx, G.J.; Van Geem, K.M. |
|
| |
Title |
Biomass fast pyrolysis in an innovative gas-solid vortex reactor : experimental proof of concept |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Journal Of Analytical And Applied Pyrolysis |
Abbreviated Journal |
J Anal Appl Pyrol |
|
| |
Volume |
156 |
Issue |
|
Pages |
105165-12 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
|
| |
Abstract |
Biomass fast pyrolysis has been considered one of the best alternatives for the thermal conversion of biomass into bio-oil. This work introduces a new reactor technology for biomass fast pyrolysis, the Gas-Solid Vortex Reactor (GSVR), to obtain high bio-oil yields. The GSVR was designed to decrease the residence time of the pyrolysis vapors; thus, the secondary cracking reactions are reduced, to enhance the segregation of the char and the unreacted biomass and to improve the heat transfer rate. Biomass fast pyrolysis experiments have been carried out for the first time in a Gas-Solid Vortex Reactor (GSVR) at 773 K, using softwood (pine) and hardwood (poplar) as feedstock. Char yields as low as 10 wt. % in the GSVR were comparable to those reported for the same feedstocks processed in conventional fluidized bed reactors. The yields of non-condensable gases in the range of 15–17 wt. % were significantly lower than those reported for other commonly used biomass fast pyrolysis reactors. Two-dimensional gas chromatography (GC × GC) revealed noticeable differences at the molecular level between the bio-oils from the GSVR and bio-oils from other reactors. The aromatics in the pine bio-oil consist almost entirely (85 wt. %) of guaiacols. For poplar bio-oils no predominant group of aromatics was found, but phenolics, syringols, and catechols were the most pronounced. The experimental results highlight the advantages of the GSVR for biomass pyrolysis, reaching stable operation in around 60 s, removing the formed char selectively during operation, and enabling fast entrainment of pyrolysis vapors. Results indicate a great potential for increasing yield and selectivity towards guaiacols in softwood (e.g., pine) bio-oil. Likewise, decreasing pyrolysis temperature could increase the yield of guaiacols and syringols in hardwood (e.g., poplar) bio-oil. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000663091200002 |
Publication Date |
2021-04-16 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0165-2370 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.471 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
|
Approved |
Most recent IF: 3.471 |
|
| |
Call Number |
UA @ admin @ c:irua:178743 |
Serial |
7562 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Spaeth, P.; Adhikari, S.; Le, L.; Jollans, T.; Pud, S.; Albrecht, W.; Bauer, T.; Caldarola, M.; Kuipers, L.; Orrit, M. |
|
| |
Title |
Circular Dichroism Measurement of Single Metal Nanoparticles Using Photothermal Imaging |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Nano Letters |
Abbreviated Journal |
Nano Lett |
|
| |
Volume |
19 |
Issue |
12 |
Pages |
8934-8940 |
|
| |
Keywords |
A1 Journal article; Photothermal microscopy, chirality, circular dichroism, dissymmetry factor, linear dichroism, gold nanostructures; Electron Microscopy for Materials Science (EMAT) ; |
|
| |
Abstract |
Circular dichroism (CD) spectroscopy is a powerful optical technique for the study of chiral materials and molecules. It gives access to an enantioselective signal based on the differential absorption of right and left circularly polarized light, usually obtained through polarization analysis of the light transmitted through a sample of interest. CD is routinely used to determine the secondary structure of proteins and their conformational state. However, CD signals are weak, limiting the use of this powerful technique to ensembles of many molecules. Here, we experimentally realize the concept of photothermal circular dichroism, a technique that combines the enantioselective signal from circular dichroism with the high sensitivity of photothermal microscopy, achieving a superior signal-to-noise ratio to detect chiral nano-objects. As a proof of principle, we studied the chiral response of single plasmonic nanostructures with CD in the visible range, demonstrating a signal-to-noise ratio better than 40 with only 30 ms integration time for these nanostructures. The high signal-to-noise ratio allows us to quantify the CD signal for individual nanoparticles. We show that we can distinguish relative absorption differences for right circularly and left circularly polarized light as small as gmin = 4 × 10–3 for a 30 ms integration time with our current experimental settings. The enhanced sensitivity of our technique extends CD studies to individual nano-objects and opens CD spectroscopy to numbers of molecules much lower than those in conventional experiments. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000502687500074 |
Publication Date |
2019-12-11 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1530-6984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
12.712 |
Times cited |
|
Open Access |
|
|
| |
Notes |
This work was supported by The Netherlands Organisation for Scientific Research (NWO/OCW), as part of the Frontiers of Nanoscience (NanoFront) program, and Open Technology Program (OTP, Project No. 16008). M.C. acknowledges the financial support of the Kavli Institute of Nanoscience Delft through the KIND fellowships program. T.B. and L.K. acknowledge the financial support of the European Research Council (ERC) through Project 340438-CONSTANS. W.A. acknowledges an Individual Fellowship from the Marie Sklodowska-Curie actions (MSCA) under the EU’s Horizon 2020 program (Grant 797153, SOPMEN). The authors acknowledge Dr. Benjamin P. Isaacoff for his help in the initial steps of this project. P.S. thanks Martin Baaske for helpful discussions. M.C. thanks Dr. Felipe Bernal Arango for help with the 3D image rendering. |
Approved |
Most recent IF: 12.712 |
|
| |
Call Number |
EMAT @ emat @c:irua:165087c:irua:165233 |
Serial |
5439 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Piorra, A.; Hrkac, V.; Wolff, N.; Zamponi, C.; Duppel, V.; Hadermann, J.; Kienle, L.; Quandt, E. |
|
| |
Title |
(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 thin films prepared by PLD : relaxor properties and complex microstructure |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
|
| |
Volume |
125 |
Issue |
24 |
Pages |
244103 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Ferroelectric lead-free thin films of the composition (Ba0.85Ca0.15)(Ti0.9Zr0.1)O-3 (BCZT) were deposited by pulsed laser deposition on Pt/TiO2/SiO2/Si substrates using a ceramic BCZT target prepared by a conventional solid state reaction. The target material itself shows a piezoelectric coefficient of d(33)=640pm/V. The (111) textured thin films possess a thickness of up to 1.1 mu m and exhibit a clamped piezoelectric response f of up to 190pm/V, a dielectric coefficient of (r)=2000 at room temperature, and a pronounced relaxor behavior. As indicated by transmission electron microscopy, the thin films are composed of longitudinal micrometersized columns with similar to 100nm lateral dimension that are separated at twin- and antiphase boundaries. The superposition phenomena according to this columnar growth were simulated based on suitable supercells. The major structural component is described as a tetragonal distorted variant of the perovskite parent type; however, frequently coherently intergrown nanodomains were observed indicating a much more complex structure that is characterized by a 7-layer modulation along the growth direction of the films. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000474439600002 |
Publication Date |
2019-06-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0021-8979; 1089-7550 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.068 |
Times cited |
|
Open Access |
|
|
| |
Notes |
; The authors want to thank Dr. Martina Luysberg and Dr. Lothar Houben from the Ernst Ruska Centre in Julich for discussion and CS-corrected microscopy. Funding of this work via the DFG (No. CRC1261) “Magnetoelectric Sensors: From Composite Materials to Biomagnetic Diagnostics” and the PAK902 is gratefully acknowledged. ; |
Approved |
Most recent IF: 2.068 |
|
| |
Call Number |
UA @ admin @ c:irua:161310 |
Serial |
5399 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Vandewalle, L.A.; Gonzalez-Quiroga, A.; Perreault, P.; Van Geem, K.M.; Marin, G.B. |
|
| |
Title |
Process intensification in a gas–solid vortex unit : computational fluid dynamics model based analysis and design |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Industrial and engineering chemistry research |
Abbreviated Journal |
|
|
| |
Volume |
58 |
Issue |
28 |
Pages |
12751-12765 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
|
| |
Abstract |
The process intensification abilities of gas–solid vortex units (GSVU) are very promising for gas–solid processes. By working in a centrifugal force field, much higher gas–solid slip velocities can be obtained compared to gravitational fluidized beds, resulting in a significant increase in heat and mass transfer rates. In this work, local azimuthal and radial particle velocities for an experimental GSVU are simulated using the Euler–Euler framework in OpenFOAM and compared with particle image velocimetry measurements. With the validated model, the effect of the particle diameter, number of inlet slots and reactor length on the bed hydrodynamics is assessed. Starting from 1g-Geldart-B type particles, increasing the particle diameter or density, increasing the number of inlet slots or increasing the gas injection velocity leads to an increased bed stability and uniformity. However, a trade-off has to be made since increased bed stability and uniformity lead to higher shear stresses and attrition. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000476686000027 |
Publication Date |
2019-06-19 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0888-5885; 1520-5045 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:162122 |
Serial |
8416 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Gonzalez-Quiroga, A.; Kulkarni, S.R.; Vandewalle, L.; Perreault, P.; Goel, C.; Heynderickx, G.J.; van Geem, K.M.; Marin, G.B. |
|
| |
Title |
Azimuthal and radial flow patterns of 1g-Geldart B-type particles in a gas-solid vortex reactor |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Powder technology |
Abbreviated Journal |
|
|
| |
Volume |
354 |
Issue |
|
Pages |
410-422 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
|
| |
Abstract |
Processes requiring intensive interfacial momentum, mass and heat exchange between gases and particulate solids can be greatly enhanced by operating in a centrifugal field. This is realized in the Gas-Solid Vortex Reactor (GSVR) with centrifugal accelerations up to two orders of magnitude higher than the Earth's gravitational acceleration. Here, the flow patterns of two 1g-Geldart B-type particles are experimentally assessed, over the gas inlet velocity range 82–126 m s−1, in an 80 mm diameter and 15 mm height GSVR. The particles are monosized aluminum spheres of 0.5 mm diameter, and walnut shell in the sieve fraction 0.50–0.56 mm and aspect ratio 1.3 ± 0.2. Two dimensional Particle Image Velocimetry combined with Digital Image Analysis and pressure measurements revealed that periodic fluctuations in solids azimuthal and radial velocity between gas inlet slots are strongly related to the average solids azimuthal velocity and bed uniformity. Aluminum particles feature steeper changes in azimuthal velocity and more attenuated changes in radial velocity than walnut shell particles. Within the assessed gas inlet velocity range the solids bed of aluminum exhibits average azimuthal velocities and bed voidages 40–50% and ≈10% lower than those of walnut shell. The aerodynamic response time of the particles, i.e. ρsdp2/18μg, emerged as an important parameter to assess the influence of the carrier gas jet on the radial deflection of the particles and the interaction solids bed-outer wall. Too low aerodynamic response time relates to nonuniformity in bed voidage due to solids radial velocity fluctuations. Excessive aerodynamic response time indicates low solids azimuthal velocities due to solids bed-outer wall friction. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000490625500041 |
Publication Date |
2019-06-17 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0032-5910 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:162120 |
Serial |
7543 |
|
| Permanent link to this record |
