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The yield stress in magnetorheological (MR) fluids is enhanced through their directed self-assembly under toggled (unsteady) magnetic fields. Experimental yield stress data are compared to previous experiments from the literature involving continuous (DC) fields in a wide range of particle concentrations at magnetic saturation using a double-gap magnetorheometer. Data generated with toggled fields are closer to theoretical predictions than conventional DC fields suggesting that generated structures under toggled fields are gap-spanning and closer to minimum energy state configurations. Experiments are in good agreement with particle level simulations.
Guillermo Camacho Villar; Jose R Morillas; Juan de Vicente. Enhancing Magnetorheology through the Directed Self-assembly under Toggled Magnetic Fields in Saturation. Smart Materials and Structures 2021, 1 .
AMA StyleGuillermo Camacho Villar, Jose R Morillas, Juan de Vicente. Enhancing Magnetorheology through the Directed Self-assembly under Toggled Magnetic Fields in Saturation. Smart Materials and Structures. 2021; ():1.
Chicago/Turabian StyleGuillermo Camacho Villar; Jose R Morillas; Juan de Vicente. 2021. "Enhancing Magnetorheology through the Directed Self-assembly under Toggled Magnetic Fields in Saturation." Smart Materials and Structures , no. : 1.
Although Mediterranean wetlands are characterized by extreme natural water level fluctuations in response to irregular precipitation patterns, global climate change is expected to amplify this pattern by shortening precipitation seasons and increasing the incidence of summer droughts in this area. As a consequence, a part of the lake sediment will be exposed to air-drying in dry years when the water table becomes low. This periodic sediment exposure to dry/wet cycles will likely affect biogeochemical processes. Unexpectedly, to date, few studies are focused on assessing the effects of water level fluctuations on the biogeochemistry of these ecosystems. In this review, we investigate the potential impacts of water level fluctuations on phosphorus dynamics and on greenhouse gases emissions in Mediterranean wetlands. Major drivers of global change, and specially water level fluctuations, will lead to the degradation of water quality in Mediterranean wetlands by increasing the availability of phosphorus concentration in the water column upon rewetting of dry sediment. CO2 fluxes are likely to be enhanced during desiccation, while inundation is likely to decrease cumulative CO2 emissions, as well as N2O emissions, although increasing CH4 emissions. However, there exists a complete gap of knowledge about the net effect of water level fluctuations induced by global change on greenhouse gases emission. Accordingly, further research is needed to assess whether the periodic exposure to dry–wet cycles, considering the extent and frequency of the cycles, will amplify the role of these especial ecosystems as a source of these gases and thereby act as a feedback mechanism for global warming. To conclude, it is pertinent to consider that a better understanding about the effect of water level fluctuations on the biogeochemistry of Mediterranean wetlands will help to predict how other freshwater ecosystems will respond.
Inmaculada de Vicente. Biogeochemistry of Mediterranean Wetlands: A Review about the Effects of Water-Level Fluctuations on Phosphorus Cycling and Greenhouse Gas Emissions. Water 2021, 13, 1510 .
AMA StyleInmaculada de Vicente. Biogeochemistry of Mediterranean Wetlands: A Review about the Effects of Water-Level Fluctuations on Phosphorus Cycling and Greenhouse Gas Emissions. Water. 2021; 13 (11):1510.
Chicago/Turabian StyleInmaculada de Vicente. 2021. "Biogeochemistry of Mediterranean Wetlands: A Review about the Effects of Water-Level Fluctuations on Phosphorus Cycling and Greenhouse Gas Emissions." Water 13, no. 11: 1510.
Temporary Mediterranean wetlands are characterized by both intra and interannual variations in their environmental conditions. These inherent fluctuations in limnological features affect the seasonal variation in the structure and dynamics of the aquatic communities. In this study, we hypothesized that zooplankton community is coupled to seasonal changes of the environmental variables along the hydroperiod. To get this purpose, the study was focused in monitoring, by collecting monthly samples during an annual period, seven temporary Mediterranean ponds located in the south-eastern region of the Iberian Peninsula (Alto Guadalquivir region, Andalusia). The relationships between zooplankton community and the different limnological variables were analyzed based on two approaches: a Spearman correlation analysis and a correspondence canonical analysis (CCA). The results have shown that chlorophyll-a concentration, Secchi depth, total nitrogen concentration, wetland area and depth were the variables with a greater influence on the zooplankton community, explaining the zooplankton species replacement. Moreover, optima and tolerance of the zooplankton species were obtained from the position of species within CCA diagram, allowing the separation of different groups of zooplankton along the hydroperiod. We finally highlight that the monitoring of zooplankton community and environmental conditions are necessary to evaluate how theses singular and endangered aquatic ecosystems will be affected by anthropogenic activities in the future.
Juan Gilbert; Inmaculada de Vicente; Fernando Ortega; Francisco Guerrero. Zooplankton Community Dynamics in Temporary Mediterranean Wetlands: Which Drivers Are Controlling the Seasonal Species Replacement? Water 2021, 13, 1447 .
AMA StyleJuan Gilbert, Inmaculada de Vicente, Fernando Ortega, Francisco Guerrero. Zooplankton Community Dynamics in Temporary Mediterranean Wetlands: Which Drivers Are Controlling the Seasonal Species Replacement? Water. 2021; 13 (11):1447.
Chicago/Turabian StyleJuan Gilbert; Inmaculada de Vicente; Fernando Ortega; Francisco Guerrero. 2021. "Zooplankton Community Dynamics in Temporary Mediterranean Wetlands: Which Drivers Are Controlling the Seasonal Species Replacement?" Water 13, no. 11: 1447.
A new type of magnetorheological (MR) material is reported that brings together conventional MR composites (MRCs) and biomaterials. Living MRCs based on carbonyl iron microparticles (CIPs) as magnetoactive filler, sodium alginate as elastomer and cells as biological components were prepared and characterized. The effect of CIPs concentration in isotropic alginate composites was examined by using Thermogravimetric Analysis (TGA), infrared spectroscopy, swelling and degradation tests in culture medium (Dulbecco's Modified Eagle's Medium, DMEM). To self-assemble the CIPs within the polymer matrix, the cross-linking process took place under an external magnetic field (24 mT). The cytotoxicity experiments were performed with human mesenchymal stem cells (hMSCs) and human fibroblasts (hFBs) loaded inside of the hydrogel. It was demonstrated that the living MRCs supported cell survival and proliferation. The rheological response of the MRCs was evaluated in dynamic oscillatory tests in the absence and presence of magnetic fields. The viscoelastic response of the living MRCs improved when a magnetic field was applied. This work demonstrates the possibility to use CIPs in the fabrication of living composites with magnetorheological response. Results could be of interest in smart biomedical applications.
Stefania Nardecchia; Carlos Chocarro-Wrona; Paola Sánchez-Moreno; José Rafael Zambrano-Marín; Juan Antonio Marchal; Juan de Vicente. Living magnetorheological composites: from the synthesis to the in vitro characterization. Smart Materials and Structures 2021, 30, 065015 .
AMA StyleStefania Nardecchia, Carlos Chocarro-Wrona, Paola Sánchez-Moreno, José Rafael Zambrano-Marín, Juan Antonio Marchal, Juan de Vicente. Living magnetorheological composites: from the synthesis to the in vitro characterization. Smart Materials and Structures. 2021; 30 (6):065015.
Chicago/Turabian StyleStefania Nardecchia; Carlos Chocarro-Wrona; Paola Sánchez-Moreno; José Rafael Zambrano-Marín; Juan Antonio Marchal; Juan de Vicente. 2021. "Living magnetorheological composites: from the synthesis to the in vitro characterization." Smart Materials and Structures 30, no. 6: 065015.
We propose three different techniques to synthesize anisotropic magnetic supraparticles for their incorporation in the formulation of magnetorheological fluids with novel potential applications.
J. R. Morillas; E. Carreón-González; J. de Vicente. Fabrication of strong magnetic micron-sized supraparticles with anisotropic magnetic properties for magnetorheology. Soft Matter 2021, 17, 3733 -3744.
AMA StyleJ. R. Morillas, E. Carreón-González, J. de Vicente. Fabrication of strong magnetic micron-sized supraparticles with anisotropic magnetic properties for magnetorheology. Soft Matter. 2021; 17 (13):3733-3744.
Chicago/Turabian StyleJ. R. Morillas; E. Carreón-González; J. de Vicente. 2021. "Fabrication of strong magnetic micron-sized supraparticles with anisotropic magnetic properties for magnetorheology." Soft Matter 17, no. 13: 3733-3744.
One of the most important worldwide environmental challenges is the alteration of the biogeochemical cycle of phosphorus (P). P is globally exported from terrestrial to aquatic ecosystems, causing the eutrophication of the receiving waters. In this context, magnetic microparticles (MPs) have been recently proposed for trapping P in natural eutrophicated ecosystems, as well as in treated wastewaters. The main advantage of using MPs is that both P and MPs can be recovered from the treated water. Thus, the working hypothesis of the present study is that P can be desorbed from P-loaded MPs and recovered P can be later used as a fertilizer. To test this hypothesis, the best working conditions for desorbing P from P-loaded MPs were identified; then, an experiment with different plant nutrient solutions (neutralized solutions containing recovered P and an unfertilized control) was carried out with three different plant species: Ocimum basilicum L., Cucumis sativus L. and Cucumis melo L. Finally, germination, height, root and shoot biomass and P concentration in root and shoot were compared among treatments. Our results show that the best conditions for P desorption from P-loaded MPs occurred when using 0.1 M NH4OH and using H3PO4 for neutralizing pH. The greenhouse fertirrigation pot experiment showed that the neutralized solution containing desorbed P from P-loaded MPs can be used as a liquid fertilizer, since its combination with macro and microelements significantly increased plant height, growth rate, shoot and root biomass and shoot and root P concentration. As a result, MPs can be proposed to be used for counteracting the widespread and coupled problems of the exhaustion of the P reserves and the eutrophication of aquatic ecosystems.
I. Álvarez-Manzaneda; N. Laza; F.B. Navarro; E.M. Suárez-Rey; M.L. Segura; I. de Vicente. Assessing the viability of recovered phosphorus from eutrophicated aquatic ecosystems as a liquid fertilizer. Journal of Environmental Management 2021, 285, 112156 .
AMA StyleI. Álvarez-Manzaneda, N. Laza, F.B. Navarro, E.M. Suárez-Rey, M.L. Segura, I. de Vicente. Assessing the viability of recovered phosphorus from eutrophicated aquatic ecosystems as a liquid fertilizer. Journal of Environmental Management. 2021; 285 ():112156.
Chicago/Turabian StyleI. Álvarez-Manzaneda; N. Laza; F.B. Navarro; E.M. Suárez-Rey; M.L. Segura; I. de Vicente. 2021. "Assessing the viability of recovered phosphorus from eutrophicated aquatic ecosystems as a liquid fertilizer." Journal of Environmental Management 285, no. : 112156.
The most pressing need in cartilage tissue engineering (CTE) is the creation of a biomaterial capable to tailor the complex extracellular matrix of the tissue. Despite the standardized used of polycaprolactone (PCL) for osteochondral scaffolds, the pronounced stiffness mismatch between PCL scaffold and the tissue it replaces remarks the biomechanical incompatibility as main limitation. To overcome it, the present work was focused in the design and analysis of several geometries and pore sizes and how they affect cell adhesion and proliferation of infrapatellar fat pad-derived mesenchymal stem cells (IPFP-MSCs) loaded in biofabricated 3D thermoplastic scaffolds. A novel biomaterial for CTE, the 1,4-butanediol thermoplastic polyurethane (b-TPUe) together PCL were studied to compare their mechanical properties. Three different geometrical patterns were included: hexagonal (H), square (S), and, triangular (T); each one was printed with three different pore sizes (PS): 1, 1.5 and 2 mm. Results showed differences in cell adhesion, cell proliferation and mechanical properties depending on the geometry, porosity and type of biomaterial used. Finally, the microstructure of the two optimal geometries (T1.5 and T2) was deeply analyzed using multiaxial mechanical tests, with and without perimeters, μCT for microstructure analysis, DNA quantification and degradation assays. In conclusion, our results evidenced that IPFP-MSCs-loaded b-TPUe scaffolds had higher similarity with cartilage mechanics and T1.5 was the best adapted morphology for CTE.
D. Martínez-Moreno; G. Jiménez; C. Chocarro-Wrona; E. Carrillo; E. Montañez; C. Galocha-León; B. Clares-Naveros; P. Gálvez-Martín; G. Rus; J. de Vicente; J.A. Marchal. Pore geometry influences growth and cell adhesion of infrapatellar mesenchymal stem cells in biofabricated 3D thermoplastic scaffolds useful for cartilage tissue engineering. Materials Science and Engineering: C 2021, 122, 111933 .
AMA StyleD. Martínez-Moreno, G. Jiménez, C. Chocarro-Wrona, E. Carrillo, E. Montañez, C. Galocha-León, B. Clares-Naveros, P. Gálvez-Martín, G. Rus, J. de Vicente, J.A. Marchal. Pore geometry influences growth and cell adhesion of infrapatellar mesenchymal stem cells in biofabricated 3D thermoplastic scaffolds useful for cartilage tissue engineering. Materials Science and Engineering: C. 2021; 122 ():111933.
Chicago/Turabian StyleD. Martínez-Moreno; G. Jiménez; C. Chocarro-Wrona; E. Carrillo; E. Montañez; C. Galocha-León; B. Clares-Naveros; P. Gálvez-Martín; G. Rus; J. de Vicente; J.A. Marchal. 2021. "Pore geometry influences growth and cell adhesion of infrapatellar mesenchymal stem cells in biofabricated 3D thermoplastic scaffolds useful for cartilage tissue engineering." Materials Science and Engineering: C 122, no. : 111933.
Hydrogels with self-healing properties constitute one of the most versatile three-dimensional (3D) materials for application in biomedicine due to the possibility of modulating their characteristics and incorporating specific elements such as magnetic particles (MPs). Herein, we describe a simple approach on the fabrication of self-healing magnetic hydrogels with anisotropic characteristics. Magnetic hydrogels are prepared by means of Schiff's base reaction starting from a suspension of MPs in a polysaccharide's solution. The MPs within the hydrogels are self-assembled by the superposition of an external magnetic field (from 5 to 240 kA/m). The synthesized hydrogels are then characterized using infrared spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy and rheometry. The results demonstrate a remarkable influence of the magnetic field strength on the MPs structuration and mechanical properties of the material. The manuscript envisages the possibility to manufacture more complex 3D materials that can be used as multidimensional platforms with potential applications in biomedicine.
Stefania Nardecchia; Ana Jiménez; Jose R. Morillas; Juan de Vicente. Synthesis and rheological properties of 3D structured self-healing magnetic hydrogels. Polymer 2021, 218, 123489 .
AMA StyleStefania Nardecchia, Ana Jiménez, Jose R. Morillas, Juan de Vicente. Synthesis and rheological properties of 3D structured self-healing magnetic hydrogels. Polymer. 2021; 218 ():123489.
Chicago/Turabian StyleStefania Nardecchia; Ana Jiménez; Jose R. Morillas; Juan de Vicente. 2021. "Synthesis and rheological properties of 3D structured self-healing magnetic hydrogels." Polymer 218, no. : 123489.
Traditionally, the rheological properties of magnetorheological (MR) fluids are investigated under uniaxial steady (DC) fields. These basic fields promote the aggregation of magnetically attractive particles into chain-like structures aligned in the field driven direction. In this manuscript we show how triaxial unsteady fields can generate a variety of exotic mesostructures and influence the rheological response of the MR fluids. We bridge understanding the rheological response to each unique particle structure through videomicroscopy, X-ray microtomography (Micro-CT) and rheometry tests. Small-amplitude oscillatory shear (SAOS) and steady shear tests lay out an unmistakable argument for MR enhancement with both elevated storage modulus and yield stress responses following a sequence of steady uniaxial and unsteady fields. We demonstrate that structures assembled through time-averaged particle interactions or typical dipole-dipole magnetostatic interactions, especially when columnar structures are strengthened through lateral chain coalescence, can boost rheological response.
Matthew Bennett Terkel; Juan De Vicente. Magnetorheology of exotic magnetic mesostructures generated under triaxial unsteady magnetic fields. Smart Materials and Structures 2020, 30, 014005 .
AMA StyleMatthew Bennett Terkel, Juan De Vicente. Magnetorheology of exotic magnetic mesostructures generated under triaxial unsteady magnetic fields. Smart Materials and Structures. 2020; 30 (1):014005.
Chicago/Turabian StyleMatthew Bennett Terkel; Juan De Vicente. 2020. "Magnetorheology of exotic magnetic mesostructures generated under triaxial unsteady magnetic fields." Smart Materials and Structures 30, no. 1: 014005.
Laboratory experiments with intact sediment cores from a hypertrophic very windy exposed shallow lake were conducted to assess the combined effect of anoxia and sediment resuspension on phosphorus (P) dynamics after adding different P adsorbents (CFH-12® and Phoslock®). In this study we hypothesize that the addition of geoengineering materials will increase P retention in the sediment even at the worst physic-chemical conditions such as anoxia and sediment resuspension. Both adsorbents significantly reduced the P release from the sediments after a 54 days-anoxic incubation period (CFH-12® by 85% and Phoslock® by 98%) and even after resuspension events (CFH-12® by 84% and Phoslock® by 88%), indicating that both adsorbents are suitable P inactivating agents for restoring shallow eutrophicated lakes under such circumstances. CFH-12® did not release dissolved Fe to the water column neither after the anoxic period nor after resuspension events compared to Control (no adsorbents addition). The La concentration was significantly higher in Phoslock® (3.5-5.7 μg L-1) than in Control at all sampling days but it was not affected by resuspension. The high efficiency in P removal under anoxia and resuspension, the low risk of toxicity and the high maximum adsorption capacity makes CFH-12® a promising adsorbent for lake restoration. Nevertheless, further research about the influence of other factors (i.e. pH, alkalinity, interfering substances or strict anoxia) on the performance of CFH-12® is needed.
A. Funes; I. Álvarez-Manzaneda; A. del Arco; J. de Vicente. Evaluating the effect of CFH-12® and Phoslock® on phosphorus dynamics during anoxia and resuspension in shallow eutrophic lakes. Environmental Pollution 2020, 269, 116093 .
AMA StyleA. Funes, I. Álvarez-Manzaneda, A. del Arco, J. de Vicente. Evaluating the effect of CFH-12® and Phoslock® on phosphorus dynamics during anoxia and resuspension in shallow eutrophic lakes. Environmental Pollution. 2020; 269 ():116093.
Chicago/Turabian StyleA. Funes; I. Álvarez-Manzaneda; A. del Arco; J. de Vicente. 2020. "Evaluating the effect of CFH-12® and Phoslock® on phosphorus dynamics during anoxia and resuspension in shallow eutrophic lakes." Environmental Pollution 269, no. : 116093.
Overview of magnetorheological materials, major characteristics, kinematics and modes of operation.
Jose R. Morillas; Juan De Vicente. Magnetorheology: a review. Soft Matter 2020, 16, 9614 -9642.
AMA StyleJose R. Morillas, Juan De Vicente. Magnetorheology: a review. Soft Matter. 2020; 16 (42):9614-9642.
Chicago/Turabian StyleJose R. Morillas; Juan De Vicente. 2020. "Magnetorheology: a review." Soft Matter 16, no. 42: 9614-9642.
This study assessed the convenience of using magnetic particles (MPs) to reduce phosphorus (P) concentration in treated wastewater. The working hypothesis is that MP addition increases P removal in artificial wastewater treatment ponds. Water samples were collected at the inlet and outlet of a semi-natural pond receiving secondary municipal effluent that is discharged in a Ramsar site (Fuente de Piedra, Málaga, Spain). Then, laboratory batch experiments were run to (i) assess the effect of adding MPs on the chemical composition of treated wastewater, (ii) identify the number of adsorption cycles (by reusing MPs) which are able to trap a high percentage of P (>50%) and (iii) select the optimum ratio between MP mass and initial dissolved inorganic P (DIP) concentration. The results show the suitability of using MPs to remove P in treated wastewater due to both their high equilibrium adsorption capacity (q) and P removal efficiency. Lastly, considering its practical and economical relevance, based on the advantages (P removal efficiency) and disadvantages (economic price), the optimum dose of MPs (0.16 g MP mg−1 P) to achieve a high P removal efficiency (>50%) was identified.
Inmaculada Álvarez-Manzaneda; Francisco Guerrero; Luis Cruz-Pizarro; Manuel Rendón; Inmaculada de Vicente. Magnetic particles as new adsorbents for the reduction of phosphate inputs from a wastewater treatment plant to a Mediterranean Ramsar wetland (Southern Spain). Chemosphere 2020, 270, 128640 .
AMA StyleInmaculada Álvarez-Manzaneda, Francisco Guerrero, Luis Cruz-Pizarro, Manuel Rendón, Inmaculada de Vicente. Magnetic particles as new adsorbents for the reduction of phosphate inputs from a wastewater treatment plant to a Mediterranean Ramsar wetland (Southern Spain). Chemosphere. 2020; 270 ():128640.
Chicago/Turabian StyleInmaculada Álvarez-Manzaneda; Francisco Guerrero; Luis Cruz-Pizarro; Manuel Rendón; Inmaculada de Vicente. 2020. "Magnetic particles as new adsorbents for the reduction of phosphate inputs from a wastewater treatment plant to a Mediterranean Ramsar wetland (Southern Spain)." Chemosphere 270, no. : 128640.
The diatom Encyonema nevadense S.Blanco & al. sp. nov. is described as a new species, from epilithic samples collected from a high mountain pond in Sierra Nevada National Park. This taxon is characterized by the presence of narrow lanceolate valves with a moderate dorsiventrality, and the presence of areolae with irregular external openings. The type population is compared with Encyonema perpusillum (A.Cleve) D.G.Mann and its varieties, the morphologically closest species within the genus. The ecological and biogeographic implications of the discovery are briefly discussed.
Saúl Blanco; Adriana Olenici; Inmaculada De Vicente; Francisco Guerrero. Contribution to the inventory of Iberian diatoms: Encyonema nevadense S.Blanco & al. sp. nov. (Cymbellales, Gomphonemataceae). Anales del Jardín Botánico de Madrid 2019, 76, 088 .
AMA StyleSaúl Blanco, Adriana Olenici, Inmaculada De Vicente, Francisco Guerrero. Contribution to the inventory of Iberian diatoms: Encyonema nevadense S.Blanco & al. sp. nov. (Cymbellales, Gomphonemataceae). Anales del Jardín Botánico de Madrid. 2019; 76 (2):088.
Chicago/Turabian StyleSaúl Blanco; Adriana Olenici; Inmaculada De Vicente; Francisco Guerrero. 2019. "Contribution to the inventory of Iberian diatoms: Encyonema nevadense S.Blanco & al. sp. nov. (Cymbellales, Gomphonemataceae)." Anales del Jardín Botánico de Madrid 76, no. 2: 088.
Magnetic colloids were formulated by dispersion of magnetic oxide spheres in water. Their rheological behavior was investigated for a wide range of particle diameters covering in detail the magnetic single-multidomain transition and therefore spanning the gap between ferrofluids and conventional magnetorheological fluids. The magnetoviscous effect (i.e., the ratio between the viscosity increment under field and the viscosity value in the absence of field) was found to reach a maximum for a critical particle size in the single-multidomain transition region. The observations were explained in terms of magnetization changes with particle size. The results obtained are applicable to any magnetic material (not only iron oxides) and therefore constitute a new route to enhance the magnetorheological effect. For very small particle sizes (in the superparamagnetic region), thermal motion plays a crucial role and the dimensionless viscosity scales with the Peclet number as expected for Brownian Hard Spheres. For larger particle sizes and λ>1, the dimensionless viscosity scales with the Mason number and closely follows the structural viscosity model under the mean magnetization approximation.
Keshvad Shahrivar; Jose R. Morillas; Yurena Luengo; Helena Gavilan; Puerto Morales; Claas Bierwisch; Juan De Vicente. Rheological behavior of magnetic colloids in the borderline between ferrofluids and magnetorheological fluids. Journal of Rheology 2019, 63, 547 -558.
AMA StyleKeshvad Shahrivar, Jose R. Morillas, Yurena Luengo, Helena Gavilan, Puerto Morales, Claas Bierwisch, Juan De Vicente. Rheological behavior of magnetic colloids in the borderline between ferrofluids and magnetorheological fluids. Journal of Rheology. 2019; 63 (4):547-558.
Chicago/Turabian StyleKeshvad Shahrivar; Jose R. Morillas; Yurena Luengo; Helena Gavilan; Puerto Morales; Claas Bierwisch; Juan De Vicente. 2019. "Rheological behavior of magnetic colloids in the borderline between ferrofluids and magnetorheological fluids." Journal of Rheology 63, no. 4: 547-558.
Understanding magnetorheology in saturating fields is crucial for success in high torque applications. In this paper we use numerical computations, analytical developments, and experimental data (using a double-gap magnetocell) to study the saturation behavior of model magnetorheological fluids for different particle loadings. Numerical calculations demonstrate a nonlinear dependence of both shear and normal stresses with particle concentration in contrast with analytical predictions. These predictions are in very good agreement with numerical calculations at low volume fractions when the interchain interactions can be safely neglected. Numerical calculations for the (yield) shear stress overestimate experimental data for small and medium concentrations. However, a reasonably good qualitative agreement is found for the larger particle loadings. Normal stresses are extraordinarily sensitive to the particular microstructure; experiments suggest sample dilatation in good agreement with simulations in lattices with a body-centered basis.
Jose R. Morillas; Juan de Vicente. Magnetorheology in saturating fields. Physical Review E 2019, 99, 062604 .
AMA StyleJose R. Morillas, Juan de Vicente. Magnetorheology in saturating fields. Physical Review E. 2019; 99 (6):062604.
Chicago/Turabian StyleJose R. Morillas; Juan de Vicente. 2019. "Magnetorheology in saturating fields." Physical Review E 99, no. 6: 062604.
Traditionally, Finite Element Method Magnetostatics (FEMM) simulations used in magnetorheology consider that the shearing affine deformation of the particle lattice can be divided in two motions: first, an elongation, and second, a rotation of the elongated structure. This allows reducing the magnetostatic problem to an axisymmetric one with a smaller computational cost. However, supposed symmetries also impose, without any physical reason, that both the magnetic field direction and particle magnetization are aligned with the chain axis for any strain. The first assumption leads to an incorrect interchain interaction while the second one neglects the magnetization rotation during the strain process. In this letter we analyze the limitations within these classical assumptions under the frame of a recently proposed reduced field formulation that is capable to truly simulate large shear strains and concentrations in model structures [Compos. Part B: Eng. 160 626-31].
Jose R Morillas; Juan De Vicente. On the importance of interchain interaction and rotational contribution to the computation of the yield stress in magnetorheology. Smart Materials and Structures 2019, 28, 08LT01 .
AMA StyleJose R Morillas, Juan De Vicente. On the importance of interchain interaction and rotational contribution to the computation of the yield stress in magnetorheology. Smart Materials and Structures. 2019; 28 (8):08LT01.
Chicago/Turabian StyleJose R Morillas; Juan De Vicente. 2019. "On the importance of interchain interaction and rotational contribution to the computation of the yield stress in magnetorheology." Smart Materials and Structures 28, no. 8: 08LT01.
The behavior of complex fluids in thin films under the isoviscous elastohydrodynamic lubrication regime is a topic of current interest. A vast majority of the materials used to lubricate compliant contacts are shear-thinning fluids and, in comparison, very little is known about the lubrication properties of shear-thickening fluids. In this work we carried out both rheological and tribological experiments on shear-thickening fluids based on cornstarch suspensions. We investigated the influence of the polarity and viscosity of the carrier fluid and the cornstarch particles' concentration. From a rheological perspective, the shear-thickening response is diminished (as the shear-thinning region enlarges) when non-polar carriers are used (e.g. silicone oil) while a marked thickening is observed for polar carriers (e.g. glycerol-water mixtures). From a tribological perspective, the friction coefficient at slow sliding speeds is strongly affected by the nature of the carrier fluid, and in particular its wettability in contact with hydrophobic PDMS tribopairs. We demonstrate that experimental data, plotted in terms of Stribeck curves, provide useful information on the entrainment of particles/fluid through the contact. Finally, experimental results are also compared with numerical solutions of the Reynolds equation for inelastic non-Newtonian fluids in the isoviscous elastohydrodynamic regime. A Carreau-Yasuda constitutive equation for the viscosity-shear rate relationship is used.
E. M. Ortigosa-Moya; Keshvad Shahrivar; Roque Hidalgo-Alvarez; Juan De Vicente. Soft lubrication of cornstarch-based shear-thickening fluids. Smart Materials and Structures 2019, 28, 085044 .
AMA StyleE. M. Ortigosa-Moya, Keshvad Shahrivar, Roque Hidalgo-Alvarez, Juan De Vicente. Soft lubrication of cornstarch-based shear-thickening fluids. Smart Materials and Structures. 2019; 28 (8):085044.
Chicago/Turabian StyleE. M. Ortigosa-Moya; Keshvad Shahrivar; Roque Hidalgo-Alvarez; Juan De Vicente. 2019. "Soft lubrication of cornstarch-based shear-thickening fluids." Smart Materials and Structures 28, no. 8: 085044.
Short-term standardized laboratory tests were carried out for evaluating acute and chronic toxicological effects of novel phosphorus (P) adsorbents on Raphidocelis subcapitata (algal growth rate inhibition) and on Daphnia magna (immobilization, with direct and indirect exposure to adsorbents, and uptake-depuration tests). Four P adsorbents were tested: two magnetic (HQ and Fe3O4) and two non magnetic (CFH-12® and Phoslock®). For the case of the algal growth inhibition test, the EC50 was 1.5 and 0.42 g L-1 for HQ and CFH-12®, respectively, and no inhibition patterns were observed neither for Fe3O4 nor for Phoslock®. When organisms were exposed to a direct contact, in the D. magna immobilization test, no statistically significant differences were found in the EC50 values among the four studied adsorbents. The huge difference between direct and indirect contact experiments suggests that toxicity is mainly physically mediated. The uptake-depuration test evidenced a much faster uptake and depuration rates for Phoslock®, which was precisely the adsorbent with the highest particle size. In a realistic worst-case scenario using data from Honda lake (Almería, Spain), where lake restoration is carried out by a adding a single large dose to bind surplus P in the lake, the predicted environmental concentrations for all adsorbents were lower than EC50 for all adsorbents and they were found to exceed a provisional limit value for ecotoxicity after a short-term exposure. All in all, since neither accumulation nor longer term effects of P adsorbents in the pelagic phase is expected, this risk may however, on a case-to-case basis, be acceptable.
I. Álvarez-Manzaneda; Anders Baun; L. Cruz-Pizarro; I. de Vicente. Ecotoxicity screening of novel phosphorus adsorbents used for lake restoration. Chemosphere 2019, 222, 469 -478.
AMA StyleI. Álvarez-Manzaneda, Anders Baun, L. Cruz-Pizarro, I. de Vicente. Ecotoxicity screening of novel phosphorus adsorbents used for lake restoration. Chemosphere. 2019; 222 ():469-478.
Chicago/Turabian StyleI. Álvarez-Manzaneda; Anders Baun; L. Cruz-Pizarro; I. de Vicente. 2019. "Ecotoxicity screening of novel phosphorus adsorbents used for lake restoration." Chemosphere 222, no. : 469-478.
The yielding behavior of magnetorheological fluids is revisited through the use of finite element method calculations on model structures and carefully conducted experiments in a magnetorheometer.
Jose R Morillas; Juan De Vicente. Yielding behavior of model magnetorheological fluids. Soft Matter 2019, 15, 3330 -3342.
AMA StyleJose R Morillas, Juan De Vicente. Yielding behavior of model magnetorheological fluids. Soft Matter. 2019; 15 (16):3330-3342.
Chicago/Turabian StyleJose R Morillas; Juan De Vicente. 2019. "Yielding behavior of model magnetorheological fluids." Soft Matter 15, no. 16: 3330-3342.
We simulate the thin-film and frictional properties of shear-thinning and shear-thickening fluids in the isoviscous elastohydrodynamic (I-EHL) regime in point contacts. A double-Newtonian Carreau-Yasuda viscosity model is employed to incorporate the shear rate dependence of the viscosity. Regression formulas for the film thickness and friction coefficient are proposed for both non-Newtonian fluids. A master curve is proposed by using the product between the entrainment speed and the effective viscosity in the contact. Numerical results are satisfactorily compared with experimental data in xantham gum solutions and fumed silica suspensions in the form of Stribeck curves.
K. Shahrivar; E.M. Ortigosa-Moya; R. Hidalgo-Alvarez; J. De Vicente. Isoviscous elastohydrodynamic lubrication of inelastic Non-Newtonian fluids. Tribology International 2019, 140, 105707 .
AMA StyleK. Shahrivar, E.M. Ortigosa-Moya, R. Hidalgo-Alvarez, J. De Vicente. Isoviscous elastohydrodynamic lubrication of inelastic Non-Newtonian fluids. Tribology International. 2019; 140 ():105707.
Chicago/Turabian StyleK. Shahrivar; E.M. Ortigosa-Moya; R. Hidalgo-Alvarez; J. De Vicente. 2019. "Isoviscous elastohydrodynamic lubrication of inelastic Non-Newtonian fluids." Tribology International 140, no. : 105707.