Dynamical generation of wormholes with charged fluids in quadratic Palatini gravity

The dynamical generation of wormholes within an extension of General Relativity (GR) containing (Planck's scale-suppressed) Ricci-squared terms is considered. The theory is formulated assuming the metric and connection to be independent (Palatini formalism) and is probed using a charged null fluid as a matter source. This has the following effect: starting from Minkowski space, when the flux is active the metric becomes a charged Vaidya-type one, and once the flux is switched off the metric settles down into a static configuration such that far from the Planck scale the geometry is virtually indistinguishable from that of the standard Reissner-Nordstr\"om solution of GR. However, the innermost region undergoes significant changes, as the GR singularity is generically replaced by a wormhole structure. Such a structure becomes completely regular for a certain charge-to-mass ratio. Moreover, the nontrivial topology of the wormhole allows to define a charge in terms of lines of force trapped in the topology such that the density of lines flowing across the wormhole throat becomes a universal constant. To the light of our results we comment on the physical significance of curvature divergences in this theory and the topology change issue, which support the view that space-time could have a foam-like microstructure pervaded by wormholes generated by quantum gravitational effects.Comment: 14 pages, 3 figures, revtex4-1 style. New content added on section VI. Other minor corrections introduced. Final version to appear in Phys. Rev.

The Spitzer South Pole Telescope Deep Field Survey: Linking galaxies and halos at z=1.5

We present an analysis of the clustering of high-redshift galaxies in the recently completed 94 deg$^2$ Spitzer-SPT Deep Field survey. Applying flux and color cuts to the mid-infrared photometry efficiently selects galaxies at $z\sim1.5$ in the stellar mass range $10^{10}-10^{11}M_\odot$, making this sample the largest used so far to study such a distant population. We measure the angular correlation function in different flux-limited samples at scales $>6^{\prime \prime}$ (corresponding to physical distances $>0.05$ Mpc) and thereby map the one- and two-halo contributions to the clustering. We fit halo occupation distributions and determine how the central galaxy's stellar mass and satellite occupation depend on the halo mass. We measure a prominent peak in the stellar-to-halo mass ratio at a halo mass of $\log(M_{\rm halo} / M_\odot) = 12.44\pm0.08$, 4.5 times higher than the $z=0$ value. This supports the idea of an evolving mass threshold above which star formation is quenched. We estimate the large-scale bias in the range $b_g=2-4$ and the satellite fraction to be $f_\mathrm{sat}\sim0.2$, showing a clear evolution compared to $z=0$. We also find that, above a given stellar mass limit, the fraction of galaxies that are in similar mass pairs is higher at $z=1.5$ than at $z=0$. In addition, we measure that this fraction mildly increases with the stellar mass limit at $z=1.5$, which is the opposite of the behavior seen at low-redshift.Comment: 32 pages, 22 figures. Published in MNRA

Environmental and human health risks associated with exposure to hazardous elements present in urban dust from Barranquilla, Colombian Caribbean

Urban dust is a mixture of deposited particles from different sources usually linked to potentially toxic elements (PTEs). Despite the industrialization of many South American countries, little is known about the impact of particulate matter in large cities, data necessary to promote environmental policies aiming to protect human health. The main objective of this work was to evaluate the particle size distribution, composition, as well as environmental and human health risks of settled dust particles from Barranquilla, a Colombian Caribbean industrialized area. Trace elements were analyzed by ICP‐MS from thirty‐five different sites, covering all city areas. Dust was mostly composed of 10–70 μm particles. The average concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Sn, Sb, Pb, and Bi were above background. High spatial heterogeneity was observed for Cu, Zn, As, Se, Mo, Ag, Sn, Sb, and Bi. Concentration factors suggest urban dusts are extremely contaminated by Zn and Cu. The ecological risk associated with specific elements decreased in the order Cd > Cu > As > Hg > Pb > Ni > Co ≈ Zn ≈ Cr, and the contamination load index showed that 91% of the samples are polluted by PTEs. Although the carcinogenic risks of Cr, Ni, As, Co, and Cd were low, chronic exposure to several PTEs may be impacting the quality of life. Educational programs, as well as monitoring and greater control on traffic, industry, and construction activities, are needed in order to protect environmental and human healt

A global descriptor of spatial pattern interaction in the galaxy distribution

We present the function J as a morphological descriptor for point patterns formed by the distribution of galaxies in the Universe. This function was recently introduced in the field of spatial statistics, and is based on the nearest neighbor distribution and the void probability function. The J descriptor allows to distinguish clustered (i.e. correlated) from ``regular'' (i.e. anti-correlated) point distributions. We outline the theoretical foundations of the method, perform tests with a Matern cluster process as an idealised model of galaxy clustering, and apply the descriptor to galaxies and loose groups in the Perseus-Pisces Survey. A comparison with mock-samples extracted from a mixed dark matter simulation shows that the J descriptor can be profitably used to constrain (in this case reject) viable models of cosmic structure formation.Comment: Significantly enhanced version, 14 pages, LaTeX using epsf, aaspp4, 7 eps-figures, accepted for publication in the Astrophysical Journa

SFCOMPO 2.0 – A relational database of spent fuel isotopic measurements, reactor operational histories, and design data

SFCOMPO-2.0 is a database of experimental isotopic concentrations measured in destructive radiochemical analysis of spent nuclear fuel (SNF) samples. The database includes corresponding design description of the fuel rods and assemblies, relevant operating conditions and characteristics of the host reactors necessary for modelling and simulation. Aimed at establishing a thorough, reliable, and publicly available resource for code and data validation of safety-related applications, SFCOMPO-2.0 is developed and maintained by the OECD Nuclear Energy Agency (NEA). The SFCOMPO-2.0 database is a Java application which is downloadable from the NEA website

First Experimental Evidence of Amorphous Tin Oxide Formation in Lead-Free Perovskites by Spectroscopic Ellipsometry

The most promising lead-free options for producing perovskite solar cells are tin halide perovskite materials. Herein, while in situ monitoring the optical evolution of the material in humid air, spectroscopic ellipsometry is used to investigate the dielectric function of FASnI3 layers (with and without additives) within the range of 1–5 eV. According to calculations based on the density functional theory that shows oxygen diffusion on FASnI3 surfaces, the steady decrease in absorption coefficient in the band gap region (1.47 eV) and simultaneous increase in absorption in the 3–4.5 eV region suggest the production of amorphous tin oxide. Concurrently, X-ray diffraction reveals a clear degradation of FASnI3. With the addition of sodium borohydride and dipropylammonium iodide, the optically active area of about 1.47 eV is preserved for a longer period while SnO2 production is prevented. Last but not least, FASnI3's stability is investigated in dry N2 environment and shown that it is optically durable for thermal operations up to 100 °C, particularly when additives are used

Influence of atmospheric conditions on the power production of utility-scale wind turbines in yaw misalignment

The intentional yaw misalignment of leading, upwind turbines in a wind farm, termed wake steering, has demonstrated potential as a collective control approach for wind farm power maximization. The optimal control strategy, and resulting effect of wake steering on wind farm power production, are in part dictated by the power degradation of the upwind yaw misaligned wind turbines. In the atmospheric boundary layer, the wind speed and direction may vary significantly over the wind turbine rotor area, depending on atmospheric conditions and stability, resulting in freestream turbine power production which is asymmetric as a function of the direction of yaw misalignment and which varies during the diurnal cycle. In this study, we propose a model for the power production of a wind turbine in yaw misalignment based on aerodynamic blade elements which incorporates the effects of wind speed and direction changes over the turbine rotor area in yaw misalignment. A field experiment is performed using multiple utility-scale wind turbines to characterize the power production of yawed freestream operating turbines depending on the wind conditions, and the model is validated using the experimental data. The resulting power production of a yaw misaligned variable speed wind turbine depends on a nonlinear interaction between the yaw misalignment, the atmospheric conditions, and the wind turbine control system.Comment: 37 pages, 15 figure

Identification of viral infections in the prostate and evaluation of their association with cancer

<p>Abstract</p> <p>Background</p> <p>Several viruses with known oncogenic potential infect prostate tissue, among these are the polyomaviruses BKV, JCV, and SV40; human papillomaviruses (HPVs), and human cytomegalovirus (HCMV) infections. Recently, the Xenotropic Murine Leukemia Virus-related gammaretrovirus (XMRV) was identified in prostate tissue with a high prevalence observed in prostate cancer (PC) patients homozygous for the glutamine variant of the RNASEL protein (462Q/Q). Association studies with the R462Q allele and non-XMRV viruses have not been reported. We assessed associations between prostate cancer, prostate viral infections, and the RNASEL 462Q allele in Mexican cancer patients and controls.</p> <p>Methods</p> <p>130 subjects (55 prostate cancer cases and 75 controls) were enrolled in the study. DNA and RNA isolated from prostate tissues were screened for the presence of viral genomes. Genotyping of the RNASEL R462Q variant was performed by Taqman method.</p> <p>Results</p> <p>R/R, R/Q, and Q/Q frequencies for R462Q were 0.62, 0.38, and 0.0 for PC cases and 0.69, 0.24, and 0.07 for controls, respectively. HPV sequences were detected in 11 (20.0%) cases and 4 (5.3%) controls. XMRV and HCMV infections were detected in one and six control samples, respectively. The risk of PC was significantly increased (Odds Ratio = 3.98; 95% CI: 1.17-13.56, p = 0.027) by infection of the prostatic tissue with HPV. BKV, JCV, and SV40 sequences were not detected in any of the tissue samples examined.</p> <p>Conclusions</p> <p>We report a positive association between PC and HPV infection. The 462Q/Q RNASEL genotype was not represented in our PC cases; thus, its interaction with prostate viral infections and cancer could not be evaluated.</p

Assessment of Multilocus Sequence Analysis (MLSA) for Identification of Candidatus Liberibacter Solanacearum from Different Host Plants in Spain

[EN] Liberibacteris a bacterial group causing different diseases and disorders in plants. Among liberibacters,CandidatusLiberibacter solanaceraum (CLso) produces disorders in several species mainly within Apiaceae and Solanaceae families. CLso isolates are usually grouped in defined haplotypes according to single nucleotide polymorphisms in genes associated with ribosomal elements. In order to characterize more precisely isolates of CLso identified in potato in Spain, a Multilocus Sequence Analysis (MLSA) was applied. This methodology was validated by a complete analysis of ten housekeeping genes that showed an absence of positive selection and a nearly neutral mechanism for their evolution. Most of the analysis performed with single housekeeping genes, as well as MLSA, grouped together isolates of CLso detected in potato crops in Spain within the haplotype E, undistinguishable from those infecting carrots, parsnips or celery. Moreover, the information from these housekeeping genes was used to estimate the evolutionary divergence among the different CLso by using the concatenated sequences of the genes assayed. Data obtained on the divergence among CLso haplotypes support the hypothesis of evolutionary events connected with different hosts, in different geographic areas, and possibly associated with different vectors. Our results demonstrate the absence in Spain of CLso isolates molecularly classified as haplotypes A and B, traditionally considered causal agents of zebra chip in potato, as well as the uncertain possibility of the present haplotype to produce major disease outbreaks in potato that may depend on many factors that should be further evaluated in future worksThis research was funded by Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), grant numbers AT2016-007 and RTA2014-00008-C04-03-E, co-financed by FEDER.Ruiz-Padilla, A.; Redondo, C.; Asensio, A.; Garita-Cambronero, J.; Martinez, C.; Perez-Padilla, V.; Marquinez, R.... (2020). Assessment of Multilocus Sequence Analysis (MLSA) for Identification of Candidatus Liberibacter Solanacearum from Different Host Plants in Spain. Microorganisms. 8(9):1-19. https://doi.org/10.3390/microorganisms8091446S11989Haapalainen, M. (2014). Biology and epidemics ofCandidatusLiberibacter species, psyllid-transmitted plant-pathogenic bacteria. Annals of Applied Biology, 165(2), 172-198. doi:10.1111/aab.12149Raddadi, N., Gonella, E., Camerota, C., Pizzinat, A., Tedeschi, R., Crotti, E., … Alma, A. (2010). ‘Candidatus Liberibacter europaeus’ sp. nov. that is associated with and transmitted by the psyllid Cacopsylla pyri apparently behaves as an endophyte rather than a pathogen. Environmental Microbiology, 13(2), 414-426. doi:10.1111/j.1462-2920.2010.02347.xWang, N., Pierson, E. A., Setubal, J. C., Xu, J., Levy, J. G., Zhang, Y., … Martins, J. (2017). The Candidatus Liberibacter–Host Interface: Insights into Pathogenesis Mechanisms and Disease Control. Annual Review of Phytopathology, 55(1), 451-482. doi:10.1146/annurev-phyto-080516-035513Morris, J., Shiller, J., Mann, R., Smith, G., Yen, A., & Rodoni, B. (2017). Novel ‘Candidatus Liberibacter’ species identified in the Australian eggplant psyllid, Acizzia solanicola. Microbial Biotechnology, 10(4), 833-844. doi:10.1111/1751-7915.12707Alfaro-Fernández, A., Hernández-Llopis, D., & Font, M. I. (2017). Haplotypes of ‘Candidatus Liberibacter solanacearum’ identified in Umbeliferous crops in Spain. European Journal of Plant Pathology, 149(1), 127-131. doi:10.1007/s10658-017-1172-2Haapalainen, M., Wang, J., Latvala, S., Lehtonen, M. T., Pirhonen, M., & Nissinen, A. I. (2018). Genetic Variation of ‘Candidatus Liberibacter solanacearum’ Haplotype C and Identification of a Novel Haplotype from Trioza urticae and Stinging Nettle. Phytopathology®, 108(8), 925-934. doi:10.1094/phyto-12-17-0410-rHaapalainen, M., Latvala, S., Wickström, A., Wang, J., Pirhonen, M., & Nissinen, A. I. (2019). A novel haplotype of ‘Candidatus Liberibacter solanacearum’ found in Apiaceae and Polygonaceae family plants. European Journal of Plant Pathology, 156(2), 413-423. doi:10.1007/s10658-019-01890-0Mauck, K. E., Sun, P., Meduri, V. R., & Hansen, A. K. (2019). New Ca. Liberibacter psyllaurous haplotype resurrected from a 49-year-old specimen of Solanum umbelliferum: a native host of the psyllid vector. Scientific Reports, 9(1). doi:10.1038/s41598-019-45975-6Teixeira, D. C., Eveillard, S., Sirand-Pugnet, P., Wulff, A., Saillard, C., Ayres, A. J., & Bove, J. M. (2008). The tufB-secE-nusG-rplKAJL-rpoB gene cluster of the liberibacters: sequence comparisons, phylogeny and speciation. INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 58(6), 1414-1421. doi:10.1099/ijs.0.65641-0Glaeser, S. P., & Kämpfer, P. (2015). Multilocus sequence analysis (MLSA) in prokaryotic taxonomy. Systematic and Applied Microbiology, 38(4), 237-245. doi:10.1016/j.syapm.2015.03.007Gevers, D., Cohan, F. M., Lawrence, J. G., Spratt, B. G., Coenye, T., Feil, E. J., … Swings, J. (2005). Re-evaluating prokaryotic species. Nature Reviews Microbiology, 3(9), 733-739. doi:10.1038/nrmicro1236Swisher Grimm, K. D., & Garczynski, S. F. (2019). Identification of a New Haplotype of ‘CandidatusLiberibacter solanacearum’ inSolanum tuberosum. Plant Disease, 103(3), 468-474. doi:10.1094/pdis-06-18-0937-reLin, H., Lou, B., Glynn, J. M., Doddapaneni, H., Civerolo, E. L., Chen, C., … Vahling, C. M. (2011). The Complete Genome Sequence of ‘Candidatus Liberibacter solanacearum’, the Bacterium Associated with Potato Zebra Chip Disease. PLoS ONE, 6(4), e19135. doi:10.1371/journal.pone.0019135Thompson, S. M., Johnson, C. P., Lu, A. Y., Frampton, R. A., Sullivan, K. L., Fiers, M. W. E. J., … Smith, G. R. (2015). Genomes of ‘Candidatus Liberibacter solanacearum’ Haplotype A from New Zealand and the United States Suggest Significant Genome Plasticity in the Species. Phytopathology®, 105(7), 863-871. doi:10.1094/phyto-12-14-0363-fiLin, H., Pietersen, G., Han, C., Read, D. A., Lou, B., Gupta, G., & Civerolo, E. L. (2015). Complete Genome Sequence of « Candidatus Liberibacter africanus,» a Bacterium Associated with Citrus Huanglongbing. Genome Announcements, 3(4). doi:10.1128/genomea.00733-15Wulff, N. A., Zhang, S., Setubal, J. C., Almeida, N. F., Martins, E. C., Harakava, R., … Gabriel, D. W. (2014). The Complete Genome Sequence of ‘Candidatus Liberibacter americanus’, Associated with Citrus Huanglongbing. Molecular Plant-Microbe Interactions®, 27(2), 163-176. doi:10.1094/mpmi-09-13-0292-rDuan, Y., Zhou, L., Hall, D. G., Li, W., Doddapaneni, H., Lin, H., … Gottwald, T. (2009). Complete Genome Sequence of Citrus Huanglongbing Bacterium, ‘CandidatusLiberibacter asiaticus’ Obtained Through Metagenomics. Molecular Plant-Microbe Interactions®, 22(8), 1011-1020. doi:10.1094/mpmi-22-8-1011Katoh, H., Miyata, S., Inoue, H., & Iwanami, T. (2014). Unique Features of a Japanese ‘Candidatus Liberibacter asiaticus’ Strain Revealed by Whole Genome Sequencing. PLoS ONE, 9(9), e106109. doi:10.1371/journal.pone.0106109Leonard, M. T., Fagen, J. R., Davis-Richardson, A. G., Davis, M. J., & Triplett, E. W. (2012). Complete genome sequence of Liberibacter crescens BT-1. Standards in Genomic Sciences, 7(2), 271-283. doi:10.4056/sigs.3326772Teresani, G. R., Bertolini, E., Alfaro-Fernández, A., Martínez, C., Tanaka, F. A. O., Kitajima, E. W., … Font, M. I. (2014). Association of ‘Candidatus Liberibacter solanacearum’ with a Vegetative Disorder of Celery in Spain and Development of a Real-Time PCR Method for Its Detection. Phytopathology®, 104(8), 804-811. doi:10.1094/phyto-07-13-0182-rLi, W., Hartung, J. S., & Levy, L. (2006). Quantitative real-time PCR for detection and identification of Candidatus Liberibacter species associated with citrus huanglongbing. Journal of Microbiological Methods, 66(1), 104-115. doi:10.1016/j.mimet.2005.10.018Munyaneza, J. E., Sengoda, V. G., Crosslin, J. M., De la Rosa-Lozano, G., & Sanchez, A. (2009). First Report of ‘Candidatus Liberibacter psyllaurous’ in Potato Tubers with Zebra Chip Disease in Mexico. Plant Disease, 93(5), 552-552. doi:10.1094/pdis-93-5-0552aPhillips, J. L., & Gnanakaran, S. (2014). A data-driven approach to modeling the tripartite structure of multidrug resistance efflux pumps. Proteins: Structure, Function, and Bioinformatics, 83(1), 46-65. doi:10.1002/prot.24632Kumar, S., Stecher, G., Li, M., Knyaz, C., & Tamura, K. (2018). MEGA X: Molecular Evolutionary Genetics Analysis across Computing Platforms. Molecular Biology and Evolution, 35(6), 1547-1549. doi:10.1093/molbev/msy096Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees. (1993). Molecular Biology and Evolution. doi:10.1093/oxfordjournals.molbev.a040023Rozas, J., Ferrer-Mata, A., Sánchez-DelBarrio, J. C., Guirao-Rico, S., Librado, P., Ramos-Onsins, S. E., & Sánchez-Gracia, A. (2017). DnaSP 6: DNA Sequence Polymorphism Analysis of Large Data Sets. Molecular Biology and Evolution, 34(12), 3299-3302. doi:10.1093/molbev/msx248Liao, J., Wiedmann, M., & Kovac, J. (2017). Genetic Stability and Evolution of the sigB Allele, Used for Listeria Sensu Stricto Subtyping and Phylogenetic Inference. Applied and Environmental Microbiology, 83(12). doi:10.1128/aem.00306-17Tamura, K., Battistuzzi, F. U., Billing-Ross, P., Murillo, O., Filipski, A., & Kumar, S. (2012). Estimating divergence times in large molecular phylogenies. Proceedings of the National Academy of Sciences, 109(47), 19333-19338. doi:10.1073/pnas.1213199109Tamura, K., Tao, Q., & Kumar, S. (2018). Theoretical Foundation of the RelTime Method for Estimating Divergence Times from Variable Evolutionary Rates. Molecular Biology and Evolution, 35(7), 1770-1782. doi:10.1093/molbev/msy044López-Hermoso, C., de la Haba, R. R., Sánchez-Porro, C., Papke, R. T., & Ventosa, A. (2017). Assessment of MultiLocus Sequence Analysis As a Valuable Tool for the Classification of the Genus Salinivibrio. Frontiers in Microbiology, 8. doi:10.3389/fmicb.2017.01107Hajri, A., Loiseau, M., Cousseau-Suhard, P., Renaudin, I., & Gentit, P. (2017). Genetic Characterization of ‘Candidatus Liberibacter solanacearum’ Haplotypes Associated with Apiaceous Crops in France. Plant Disease, 101(8), 1383-1390. doi:10.1094/pdis-11-16-1686-reFang, Y., Wang, Y., Liu, Z., Dai, H., Cai, H., Li, Z., … Wang, D. (2019). Multilocus Sequence Analysis, a Rapid and Accurate Tool for Taxonomic Classification, Evolutionary Relationship Determination, and Population Biology Studies of the Genus Shewanella. Applied and Environmental Microbiology, 85(11). doi:10.1128/aem.03126-18Konstantinidis, K. T., Ramette, A., & Tiedje, J. M. (2006). Toward a More Robust Assessment of IntraspeciesDiversity, Using Fewer GeneticMarkers. Applied and Environmental Microbiology, 72(11), 7286-7293. doi:10.1128/aem.01398-06Ajene, I. J., Khamis, F., Ballo, S., Pietersen, G., van Asch, B., Seid, N., … Mohamed, S. (2020). Detection of Asian Citrus Psyllid (Hemiptera: Psyllidae) in Ethiopia: A New Haplotype and its Implication to the Proliferation of Huanglongbing. Journal of Economic Entomology, 113(4), 1640-1647. doi:10.1093/jee/toaa113Thapa, S. P., De Francesco, A., Trinh, J., Gurung, F. B., Pang, Z., Vidalakis, G., … Coaker, G. (2020). Genome‐wide analyses of Liberibacter species provides insights into evolution, phylogenetic relationships, and virulence factors. Molecular Plant Pathology, 21(5), 716-731. doi:10.1111/mpp.12925Antolinez, C. A., Fereres, A., & Moreno, A. (2017). Risk assessment of ‘Candidatus Liberibacter solanacearum’ transmission by the psyllids Bactericera trigonica and B. tremblayi from Apiaceae crops to potato. Scientific Reports, 7(1). doi:10.1038/srep45534Antolínez, Moreno, Ontiveros, Pla, Plaza, Sanjuan, … Fereres. (2019). Seasonal Abundance of Psyllid Species on Carrots and Potato Crops in Spain. Insects, 10(9), 287. doi:10.3390/insects10090287Wang, J., Haapalainen, M., Schott, T., Thompson, S. M., Smith, G. R., Nissinen, A. I., & Pirhonen, M. (2017). Genomic sequence of «Candidatus Liberibacter solanacearum» haplotype C and its comparison with haplotype A and B genomes. PLOS ONE, 12(2), e0171531. doi:10.1371/journal.pone.0171531Katsir, L., Zhepu, R., Santos Garcia, D., Piasezky, A., Jiang, J., Sela, N., … Bahar, O. (2018). Genome Analysis of Haplotype D of Candidatus Liberibacter Solanacearum. Frontiers in Microbiology, 9. doi:10.3389/fmicb.2018.02933Quintana-González de Chaves, M., Teresani, G. R., Hernández-Suárez, E., Bertolini, E., Moreno, A., Fereres, A., … Siverio, F. (2020). ‘Candidatus Liberibacter Solanacearum’ Is Unlikely to Be Transmitted Spontaneously from Infected Carrot Plants to Citrus Plants by Trioza Erytreae. Insects, 11(8), 514. doi:10.3390/insects1108051

Design and manufacture of a bed supported tidal turbine model for blade and shaft load measurement in turbulent flow and waves

Laboratory testing of tidal turbine models is an essential tool to investigate hydrodynamic interactions between turbines and the flow. Such tests can be used to calibrate numerical models and to estimate rotor loading and wake development to inform the design of full scale machines and array layout. The details of the design and manufacturing techniques used to develop a highly instrumented turbine model are presented. The model has a 1.2 m diameter, three bladed horizontal axis rotor and is bottom mounted. Particular attention is given to the instrumentation which can measure streamwise root bending moment for each blade and torque and thrust for the overall rotor. The model is mainly designed to investigate blade and shaft loads due to both turbulence and waves. Initial results from tests in a 2 m deep by 4 m wide flume are also presented