Seeking to enhance the bioenergy of municipal sludge: Effect of alkali pre-treatment and soluble organic matter supplementation

The aim of this research is to enhance the mesophilic anaerobic digestion of municipal sludge from Cadiz-San Fernando (Spain) wastewater treatment plant at 20 days hydraulic retention time (HRT). Two different strategies were tested to improve the process: co-digestion with the addition of soluble organic matter (1% v/v); and alkali sludge pre-treatment (NaOH) prior to co-digestion with glycerine (1% v/v). Methane production (MP) was substantially enhanced (from 0.36 ± 0.09 L CH4 l/d to 0.85 ± 0.16 L CH4 l/d), as was specific methane production (SMP) (from 0.20 ± 0.05 L CH4/g VS to 0.49 ± 0.09 L CH4/g VS) when glycerine was added. The addition of glycerine does not seem to affect sludge stability, the quality of the effluent in terms of pH and organic matter content, i.e. volatile fatty acids (VFA), soluble organic matter and total volatile solid, or process stability (VFA/Alkalinity ratio < 0.4). Alkali pre-treatment prior to co-digestion resulted in a high increase in soluble organic loading rates (more than 20%) and acidification yield (more than 50%). At 20 days HRT, however, it led to overload of the system and total destabilization of the mesophilic anaerobic co-digestion of sewage sludge and glycerine

Mesophilic anaerobic co-digestion of sewage sludge with glycerine: Effect of solids retention time

The main objective of this paper is to examine the effect of the increase in organic loading rates (OLRs), by reducing the solids retention time (SRT) from 20 d to 5 d, in single-phase mesophilic anaerobic co-digestion of sewage sludge with glycerine (1% v/v). It was experimentally confirmed that anaerobic co-digestion of these biowastes under steady-state conditions can achieve an 85 ± 5% reduction in volatile fatty acids (VFA) at SRTs of between 20 and 9 d, with a methane production yield of around 0.8 l CH4/l/d. Decreases in the SRT not only allow the sludge stability and biogas production to be maintained, but also lead to an increase in the waste that could be treated and lower operating costs. Therefore, mesophilic anaerobic co-digestion of sewage sludge and glycerin at a SRT lower than 20 d is possible and preferable due to being more economical and environmentally friendl

Modelling of atmospheric boundary layer: Generation of shear.

Roughness length, z0 and friction velocity, u* are the defining parameters of wind log profile that must be matched in wind tunnel simulation. To fully understand the role of these parameters, the basics and review from the primitive equations and its relation to the logarithmic profile obtained for wind tunnel conditions were discussed. The problem of roughness, although well known, still needs to be addressed more rigorously especially when determining values of z0 and u* from wind tunnel data and their relation to the roughness element geometry. A review of classic literature and new published material were carried out, focusing on the applicability to wind tunnel modelling

Diet and BMI Correlate with Metabolite Patterns Associated with Aggressive Prostate Cancer

Three metabolite patterns have previously shown prospective inverse associations with the risk of aggressive prostate cancer within the European Prospective Investigation into Cancer and Nutrition (EPIC). Here, we investigated dietary and lifestyle correlates of these three prostate cancer-related metabolite patterns, which included: 64 phosphatidylcholines and three hydroxysphingomyelins (Pattern 1), acylcarnitines C18:1 and C18:2, glutamate, ornithine, and taurine (Pattern 2), and 8 lysophosphatidylcholines (Pattern 3). In a two-stage cross-sectional discovery (n = 2524) and validation (n = 518) design containing 3042 men free of cancer in EPIC, we estimated the associations of 24 dietary and lifestyle variables with each pattern and the contributing individual metabolites. Associations statistically significant after both correction for multiple testing (False Discovery Rate = 0.05) in the discovery set and at p < 0.05 in the validation set were considered robust. Intakes of alcohol, total fish products, and its subsets total fish and lean fish were positively associated with Pattern 1. Body mass index (BMI) was positively associated with Pattern 2, which appeared to be driven by a strong positive BMI-glutamate association. Finally, both BMI and fatty fish were inversely associated with Pattern 3. In conclusion, these results indicate associations of fish and its subtypes, alcohol, and BMI with metabolite patterns that are inversely associated with risk of aggressive prostate cancer.Cancer Research UK C8221/A30904 C8221/A29017World Health OrganizationDepartment of Epidemiology and Biostatistics, School of Public Health, Imperial College LondonDanish Cancer SocietyLigue Contre le Cancer (France) Institut Gustave Roussy (France) Mutuelle Generale de l'Education Nationale (France)Institut National de la Sante et de la Recherche Medicale (Inserm)Deutsche KrebshilfeGerman Cancer Research Center (DKFZ) (Germany) German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE) (Germany)Federal Ministry of Education & Research (BMBF)Fondazione AIRC per la ricerca sul cancro Compagnia di San Paolo Consiglio Nazionale delle Ricerche (CNR)Netherlands Government Netherlands GovernmentWorld Cancer Research Fund International (WCRF)Health Research Fund (FIS)-Instituto de Salud Carlos III (ISCIII) (Spain)Junta de AndaluciaPrincipality of AsturiasRegional Government of Basque Country (Spain) Regional Government of Murcia (Spain) Regional Government of Navarra (Spain) Catalan Institute of Oncology-ICO (Spain)Swedish Cancer Society Swedish Research Council County Council of Skane (Sweden) County Council of Vasterbotten (Sweden)UK Research & Innovation (UKRI) Medical Research Council UK (MRC) 1000143 MR/N003284/1 MC-UU_12015/1 MC_UU_00006/1 MR/M012190/

Texture Evolution of AZ31 Magnesium Alloy Sheet at High Strain Rates

In the current contribution the mechanical behaviour at high strain rates of AZ31 magnesium alloy sheet is studied. Uniaxial deformation properties were studied by means of tensile split Hopkinson pressure bar (SHPB) at different temperatures. The influence of the strain rate and temperature on the deformation mechanisms was investigated by means of electron backscatter diffraction (EBSD) and neutron diffraction. It is shown that twinning plays an important role on high strain rate deformation of this alloy, even at elevated temperatures. Significant evidence of prismatic slip as a deformation mechanism is observed, also at warm temperatures, leading to the alignment of directions with the tensile axis and to a spread of the intensities of the basal pole figure towards the in-plane direction perpendicular to the tensile axis. The rate of decrease of the CRSS of non-basal systems is observed to be slower than at quasi-static rates. Secondary twinning and pyramidal slip were also outlined for some conditions. At warm temperatures, in contrast to quasi-static range, a generalized dynamic recrystallization is not observed. Moreover, the activation of rotational recrystallization mechanisms is reporte

Influence of geometrical parameters on the linear stability of a Benard-Marangoni problem

[EN] A linear stability analysis of a thin liquid film flowing over a plate is performed. The analysis is performed in an annular domain when momentum diffusivity and thermal diffusivity are comparable (relatively low Prandtl number, Pr = 1.2). The influence of the aspect ratio (Gamma) and gravity, through the Bond number (Bo), in the linear stability of the flow are analyzed together. Two different regions in the Gamma-Bo plane have been identified. In the first one the basic state presents a linear regime (in which the temperature gradient does not change sign with r). In the second one, the flow presents a nonlinear regime, also called return flow. A great diversity of bifurcations have been found just by changing the domain depth d. The results obtained in this work are in agreement with some reported experiments, and give a deeper insight into the effect of physical parameters on bifurcations.The computations shown in this work were made possible by a generous grant of computer time from the supercomputation center of the Universitat Politecnica de Valencia.Hoyas, S.; Fajardo, P.; Pérez Quiles, MJ. (2016). Influence of geometrical parameters on the linear stability of a Benard-Marangoni problem. Physical Review E. 93(4). https://doi.org/10.1103/PhysRevE.93.043105S934Bénard, H. (1901). Les tourbillons cellulaires dans une nappe liquide. - Méthodes optiques d’observation et d’enregistrement. Journal de Physique Théorique et Appliquée, 10(1), 254-266. doi:10.1051/jphystap:0190100100025400Smith, M. K., & Davis, S. H. (1983). Instabilities of dynamic thermocapillary liquid layers. Part 1. Convective instabilities. Journal of Fluid Mechanics, 132, 119-144. doi:10.1017/s0022112083001512Garnier, N., & Chiffaudel, A. (2001). Two dimensional hydrothermal waves in an extended cylindrical vessel. The European Physical Journal B, 19(1), 87-95. doi:10.1007/s100510170352Hoyas, S., Herrero, H., & Mancho, A. M. (2002). Bifurcation diversity of dynamic thermocapillary liquid layers. Physical Review E, 66(5). doi:10.1103/physreve.66.057301Hoyas, S., Herrero, H., & Mancho, A. M. (2002). Thermal convection in a cylindrical annulus heated laterally. Journal of Physics A: Mathematical and General, 35(18), 4067-4083. doi:10.1088/0305-4470/35/18/306Hoyas, S., Mancho, A. M., Herrero, H., Garnier, N., & Chiffaudel, A. (2005). Bénard–Marangoni convection in a differentially heated cylindrical cavity. Physics of Fluids, 17(5), 054104. doi:10.1063/1.1876892Herrero, H., & Mancho, A. M. (1998). Influence of aspect ratio in convection due to nonuniform heating. Physical Review E, 57(6), 7336-7339. doi:10.1103/physreve.57.7336Mancho, A., Herrero, H., & Burguete, J. (1997). Primary instabilities in convective cells due to nonuniform heating. Physical Review E, 56(3), 2916-2923. doi:10.1103/physreve.56.2916Ezersky, A. B., Garcimartín, A., Burguete, J., Mancini, H. L., & Pérez-García, C. (1993). Hydrothermal waves in Marangoni convection in a cylindrical container. Physical Review E, 47(2), 1126-1131. doi:10.1103/physreve.47.1126Hoyas, S., Gil, A., Fajardo, P., & Pérez-Quiles, M. J. (2013). Codimension-three bifurcations in a Bénard-Marangoni problem. Physical Review E, 88(1). doi:10.1103/physreve.88.015001Peng, L., Li, Y.-R., Shi, W.-Y., & Imaishi, N. (2007). Three-dimensional thermocapillary–buoyancy flow of silicone oil in a differentially heated annular pool. International Journal of Heat and Mass Transfer, 50(5-6), 872-880. doi:10.1016/j.ijheatmasstransfer.2006.08.015Shi, W., Liu, X., Li, G., Li, Y.-R., Peng, L., Ermakov, M. K., & Imaishi, N. (2010). Thermocapillary Convection Instability in Shallow Annular Pools by Linear Stability Analysis. Journal of Superconductivity and Novel Magnetism, 23(6), 1185-1188. doi:10.1007/s10948-010-0661-8Torregrosa, A. J., Hoyas, S., Pérez-Quiles, M. J., & Mompó-Laborda, J. M. (2013). Bifurcation Diversity in an Annular Pool Heated from Below: Prandtl and Biot Numbers Effects. Communications in Computational Physics, 13(2), 428-441. doi:10.4208/cicp.090611.170212aEckert, E. R. G., Goldstein, R. J., Ibele, W. E., Patankar, S. V., Simon, T. W., Kuehn, T. H., … Garrick, S. (2000). Heat transfer — a review of 1997 literature. International Journal of Heat and Mass Transfer, 43(14), 2431-2528. doi:10.1016/s0017-9310(99)00196-9Hoyas, S., Fajardo, P., Gil, A., & Perez-Quiles, M. J. (2014). Analysis of bifurcations in a Bénard–Marangoni problem: Gravitational effects. International Journal of Heat and Mass Transfer, 73, 33-41. doi:10.1016/j.ijheatmasstransfer.2014.01.061O’Shaughnessy, S. M., & Robinson, A. J. (2013). Heat transfer near an isolated hemispherical gas bubble: The combined influence of thermocapillarity and buoyancy. International Journal of Heat and Mass Transfer, 62, 422-434. doi:10.1016/j.ijheatmasstransfer.2013.02.064Celli, M., Barletta, A., & Alves, L. S. de B. (2015). Marangoni instability of a liquid film flow with viscous dissipation. Physical Review E, 91(2). doi:10.1103/physreve.91.023006Orszag, S. A. (1972). Comparison of Pseudospectral and Spectral Approximation. Studies in Applied Mathematics, 51(3), 253-259. doi:10.1002/sapm1972513253Canuto, C., Hussaini, M. Y., Quarteroni, A., & Zang, T. A. (1988). Spectral Methods in Fluid Dynamics. doi:10.1007/978-3-642-84108-8JIMÉNEZ, J., & HOYAS, S. (2008). Turbulent fluctuations above the buffer layer of wall-bounded flows. Journal of Fluid Mechanics, 611, 215-236. doi:10.1017/s0022112008002747Mancho, A. M., & Herrero, H. (2000). Instabilities in a laterally heated liquid layer. Physics of Fluids, 12(5), 1044-1051. doi:10.1063/1.870359Favre, E., Blumenfeld, L., & Daviaud, F. (1997). Instabilities of a liquid layer locally heated on its free surface. Physics of Fluids, 9(5), 1473-1475. doi:10.1063/1.869470Burguete, J., Mukolobwiez, N., Daviaud, F., Garnier, N., & Chiffaudel, A. (2001). Buoyant-thermocapillary instabilities in extended liquid layers subjected to a horizontal temperature gradient. Physics of Fluids, 13(10), 2773-2787. doi:10.1063/1.1398536Daviaud, F., & Vince, J. M. (1993). Traveling waves in a fluid layer subjected to a horizontal temperature gradient. Physical Review E, 48(6), 4432-4436. doi:10.1103/physreve.48.4432RILEY, R. J., & NEITZEL, G. P. (1998). Instability of thermocapillary–buoyancy convection in shallow layers. Part 1. Characterization of steady and oscillatory instabilities. Journal of Fluid Mechanics, 359, 143-164. doi:10.1017/s0022112097008343Mercier, J. F., & Normand, C. (1996). Buoyant‐thermocapillary instabilities of differentially heated liquid layers. Physics of Fluids, 8(6), 1433-1445. doi:10.1063/1.868920Yu, J.-J., Ruan, D.-F., Li, Y.-R., & Chen, J.-C. (2015). Experimental study on thermocapillary convection of binary mixture in a shallow annular pool with radial temperature gradient. Experimental Thermal and Fluid Science, 61, 79-86. doi:10.1016/j.expthermflusci.2014.10.01

Twinning and grain subdivision during dynamic deformation of a Mg AZ31 sheet alloy at room temperature

The microstructural evolution of an AZ31 rolled sheet during dynamic deformation at strain rates of ∼103 s−1 has been investigated by electron backscatter diffraction, X-ray and neutron diffraction. The influence of orientation on the predominant deformation mechanisms and on the recovery processes taking place during deformation has been systematically examined. The results have been compared with those corresponding to the same alloy tested quasi-statically under equivalent conditions. It has been found that strain rate enhances the activation of extension twinning dramatically, while contraction and secondary twinning are not significantly influenced. The polarity of extension twinning is even reversed in some grains under selected testing conditions. Significant grain subdivision by the formation of geometrically necessary boundaries (GNBs) takes place during both quasi-static and dynamic deformation of this AZ31 alloy. It is remarkable that GNBs of high misorientations form even at the highest strain rates. The phenomenon of recovery has been found to be orientation dependen

DNS of thermal channel flow up to Re-tau=2000 for medium to low Prandtl numbers

[EN] Direct Numerical Simulations of turbulent heat transfer in a channel flow are presented for three different Reynolds numbers, namely Re-tau = 500, 1000 and 2000. Medium and low values of the molecular Prandtl number are studied, ranging from 0.71 (air), down to 0.007 (molten metals), in order to study its effect on the thermal flow. Mixed boundary conditions at both walls are used for the thermal flow. Mean value and intensities of the thermal field were obtained. Two different behaviors were observed, depending on the Prandtl and Peclet numbers. The expected logarithmic behavior of the thermal flow completely disappears for Prandtl below 0.3. This is a direct effect of the thicker viscous thermal layer generated as the Prandtl number is reduced. Von Karman constant was computed for cases above this Prandtl, and turbulent Prandtl and Nusselt numbers were obtained for all the cases. Finally, the turbulent budgets for heat fluxes, temperature variance and its dissipation rate are presented. As a general result, there is a scaling failure near the wall in very cases studied, which is accentuated for lower Prandtl numbers. The statistics of all simulations can be downloaded from the web page of our group. (C) 2018 Elsevier Ltd. All rights reserved.This work was supported by MINECO/FEDER, under project ENE2015-71333-R. The computations of the new simulations were made possible by a generous grant of computing time from the Barcelona Supercomputing Centre, reference FI-2018-1-0037. We are grateful to Messiers Kawamura, Pirozzoli, Bernardini and Orlandi for providing us with copies of their original data.Alcántara-Ávila, F.; Hoyas, S.; Pérez Quiles, MJ. (2018). DNS of thermal channel flow up to Re-tau=2000 for medium to low Prandtl numbers. International Journal of Heat and Mass Transfer. 127:349-361. https://doi.org/10.1016/j.ijheatmasstransfer.2018.06.149S34936112

Dexamethasone-doped nanoparticles improve mineralization, crystallinity and collagen structure of human dentin

zation. This study aims to evaluate bonding ability and both mechanical and chemical behavior of demineralized dentin infiltrated with polymeric nanoparticles doped with dexamethasone (Dex-NPs). Methods: Dentin conditioned surfaces were infiltrated with NPs, Dex-NPs or Dex-Zn-NPs. Bonded interfaces were also created and stored for 24 h or 21d, and then submitted to microtensile bond strength testing. Dentin remineralization was analyzed by Nanohardness, Young’s modulus and Raman analysis. Results: At 21d of storage, dentin treated with undoped-NPs attained the lowest nanohardness and Young’s modulus. Dex-NPs and Zn-Dex-NPs increased dentin nanohardness and Young’s modulus after 21d Raman analysis showed high remineralization, crystallinity, crosslinking and better structure of collagen when functionalized Dex-NPs were present at the dentin interface. Conclusions: Infiltration of dentin with Dex-NPs promoted functional remineralization as proved by nanomechanical and morpho-chemical evaluation tests. Dexamethasone in dentin facilitated crystallographic maturity, crystallinity and improved maturity and secondary structure of dentin collagen. Clinical significance: Using dexamethasone-functionalized NPs before resin infiltration is a clear option to obtain dentin remineralization, as these NPs produce the reinforcement of the dentin structure, which will lead to the improvement of the longevity of resin restorationsGrant PID2020-114694RB-I00 funded by MCIN/AEI 10.13039/501100011033Funding for open access charge: Universidad de Granada / CBUA