742 research outputs found
Can we detect internal moisture content in hardened concrete with an infrared camera?
The main goal of this paper was to assess the ability of infrared thermography to detect non-superficial moisture content in concrete elements. For this purpose, a commercial camera (Flir i5) was used and firstly its capacities and technical limitations were analyzed by comparing it with other commonly commercialized. Secondly, the experiments were undertaken using a concrete specimen (water/cement=0.5) and water under a pressure of 500 kPa was injected over 72 hours into one side of the specimen. The specimen was then left at room temperature (20ºC) for 24 hours, so the surface moisture disappeared. Prior to the images acquisition, the specimen surface was heated by a lamp located at a distance of 0.68 m from the central point of the specimen. In this way, two areas (dry and injected) to be registered would receive the same energy, since they were equidistant from the heating source. The first record was acquired before heating the specimen and then, the heating process was interrupted every 10 minutes to perform the infrared images acquisitions. Finally, by means of the destructive test, the average water penetration depth was assessed to be 3 cm. The infrared images acquired before heating the specimen showed a small temperature variation as a result of the presence of water, 16,3 ºC in the dry area and 15,8 ºC in the injected area. However, after the heating, due to the greater specific heat of water, the injected part achieved a temperature 4º C lower than the symmetrical dry area. This result was very interesting because, in the initial moment (before heating) the surface specimen was dry, but there was a wet area inside of the specimen that was not visually identifiable. Nevertheless, by means of infrared imaging an indicator was obtained that allowed to detect the presence of this internal moisture content
Holocene atmospheric dust deposition in NW Spain
This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.Atmospheric dust plays an important role in terrestrial and marine ecosystems, particularly those that are nutrient limited. Despite that most dust originates from arid and semi-arid regions, recent research has shown that past dust events may have been involved in boosting productivity in nutrient-poor peatlands. We investigated dust deposition in a mid-latitude, raised bog, which is surrounded by a complex geology (paragneiss/schist, granite, quartzite and granodiorite). As proxies for dust fluxes, we used accumulation rates of trace (Ti, Zr, Rb, Sr and Y) as well as major (K and Ca) lithogenic elements. The oldest, largest dust deposition event occurred between ~8.6 and ~7.4 ka BP, peaking at ~8.1 ka BP (most probably the 8.2 ka BP event). The event had a large impact on the evolution of the mire, which subsequently transitioned from a fen into a raised bog in ~1500 years. From ~6.7 to ~4.0 ka BP, fluxes were very low, coeval with mid-Holocene forest stability and maximum extent. In the late Holocene, after ~4.0 ka BP, dust events became more prevalent with relatively major deposition at ~3.2–2.5, ~1.4 ka BP and ~0.35–0.05 ka BP, and minor peaks at ~4.0–3.7, ~1.7, ~1.10–0.95 ka BP and ~0.74–0.58 ka BP. Strontium fluxes display a similar pattern between ~11 and ~6.7 ka BP but then became decoupled from the other elements from the mid Holocene onwards. This seems to be a specific signal of the granodiorite batholith, which has an Sr anomaly. The reconstructed variations in dust fluxes bear a strong climatic imprint, probably related to storminess controlled by North Atlantic Oscillation conditions. Complex interactions also arise because of increased pressure from human activities.Natural Environment Research Council (NERC)Consiliencia networkFunding for Consolidation and Structuration of Research Unit
Effect of soiling in CPV systems
The effect of soiling in flat PV modules has been already studied, causing a reduction of the electrical output of 4% on average. For CPV's, as far as soiling produces light scattering at the optical collector surface, the scattered rays should be definitively lost because they cannot be focused onto the receivers again. While the theoretical study becomes difficult because soiling is variable at different sites, it becomes easier to begin the monitoring of the real field performance of concentrators and then raise the following question: how much does the soiling affect to PV concentrators in comparison with flat panels?? The answers allow to predict the PV concentrator electrical performance and to establish a pattern of cleaning frequency. Some experiments have been conducted at the IES-UPM and CSES-ANU sites, consisting in linear reflective concentration systems, a point focus refractive concentrator and a flat module. All the systems have been measured when soiled and then after cleaning, achieving different increases of ISC. In general, results show that CPV systems are more sensitive to soiling than flat panels, accumulating losses in ISC of about 14% on average in three different tests conducted at IESUPM and CSES-ANU test sites in Madrid (Spain) and Canberra (Australia). Some concentrators can reach losses up to 26% when the system is soiled for 4 months of exposure
Sonic crystal lenses that obey Lensmaker's formula
This paper presents a theoretical study of the phenomenon of acoustic imaging
by sonic crystals, which are made of two-dimensional regular arrays of rigid
cylinders placed in parallel in air. The scattering of acoustic waves is
computed using the standard multiple scattering theory, and the band structures
are computed by the plane-wave expansion method. It is shown that properly
arranged arrays not only can behave as acoustic lenses, but also the focusing
effect can be well described by Lensmaker's formula. Possible applications are
also discussed.Comment: 4 pages, 5 figure
Protocol d’actuació davant la malaltia meningocòccica
Malalties transmissibles; Epidemiologia; Meningitis MeningocòccicaEnfermedades transmisibles; Epidemiología; Meningitis MeningocóccicaTransmissible disease; Epidemiology: Meningococcal meningitisProtocol d’actuació davant la malaltia meningocòccica; el seu diagnòstic i la seva prevenció.Protocolo de actuación ante la enfermedad meningocócica; su diagnóstico y su prevenciónAction protocol against meningococcal disease; its diagnosis and prevention
Genetic Algorithm in the Optimization of the Acoustic Attenuation System
[EN] It is well known that Genetic Algorithms (GA) is an optimization method which can be used in problems where the traditional optimization techniques are difficult to be applied. Sonic Crystals (SC) are periodic structures that present ranges of sound frequencies related with the periodicity of the structure, where the sound propagation is forbidden. This means that in the acoustic spectrum there are ranges of frequencies with high acoustic attenuation. This attenuation can be improved producing vacancies in the structure. In this paper we use a parallel implementation of a GA to optimize those structures, by means of the creation of vacancies in a starting SC, in order to obtain the best acoustic attenuation in a predetermined range of frequencies. The cost function used in GA is based on the Multiple Scattering Theory (MST), which is a self consistent method for calculating acoustic pressure in SCs. As a final result we achieve a quasi ordered structures that presents a high acoustic attenuation in a predetermined range of frequencies, independent of the periodicity of the SC.The authors acknowledge financial support provided by the Spanish MEC (Project No. MAT2006-03097) and by the Generalitat Valenciana (Spain) under Grant No. GV/2007/191. This work also has been partially supported by MEC (Spanish government) and FEDER funds: projects DPI2005-07835, DPI2004- 8383-C03-02 and GVA-026.Romero García, V.; Fuster García, E.; Sánchez Pérez, JV.; García Raffi, LM.; Blasco, X.; Herrero Durá, JM.; Sanchís Saez, J. (2007). Genetic Algorithm in the Optimization of the Acoustic Attenuation System. Lecture Notes in Computer Science. 4507:614-621. https://doi.org/10.1007/978-3-540-73007-1_74S6146214507Martínez-Sala, R., Sancho, J., Sánchez Pérez, J.V., Llinares, J., Meseguer, F.: Sound attenuation by sculpture. Nature (London) 387, 241 (1995)Hushwaha, M.S., Halevi, P., Martínez, G., Dobrynski, L., Djafari-Rouhani, B.: Theory of acoustic band structure of periodic elastic composites. Phys. Rev. B 49(4), 2313–2322 (1994)Liu, Z., Zhang, X., Mao, Y., Zhu, Y.Y., Yang, Z., Xhan, C.T., Sheng, P.: Locally resonatn sonic materials. Science 289, 1734 (2000)Hu, X., Chan, C.T., Zi, J.: Two dimensional sonic crystals with Helmholtz resonators. Phys. Rev. E 71, 055601 (2005)Umnova, O., Attenborough, K., Linton, C.M.: Effects of porous covering on sound attenuation by poriodi arrays of cylinders. J. Acoust. Soc. Am. 119, 278 (2006)Caballero, D., Sánchez-Dehesa, J., Martínez-Sala, R., Rubio, C., Sánchez Pérez, J.V.S., Sanchis, L., Meseguer, F.: Suzuki phase in two-dimensional sonic crystals. Phys. Rev. B 64, 064303 (2001)Hakansson, A., Sánchez-Dehesa, J., Sanchis, L.: Acoustic lens design by genetic algorithms. Phys. Rev. B 70, 214302 (2004)Romero-García, V., Fuster, E., García-Raffi, L.M., Sánchez-Pérez, E.A., Sopena, M., Llinares, J., Sánchez-Pérez, J.V.: Band gap creation using quasiordered strutures based on sonic crystals. Appl. Phys. Lett. 88, 174104-1 174104-3 (2006)Chen, Y.Y., Ye, Z.: Theoretical analysis of acoustic stop bands in two-dimensional periodic scattering arrays. Phys. Rev. E 64, 036616 (2001)Economou, E.N., Sigalas, M.M.: Classical wave propagation in periodic structures: Cermet versus network topology. Phys. Rev. B 48(18), 13434 (1993)Sigalas, M.M., Economou, E.N., Kafesaki, M.: Spectral gaps for electromagnietic and scalar waves: Possible explanation for certain differences. Phys. Rev. B 50(5), 3393 (1994)Goldberg, D.E.: Genetic Algorithms in search, optimization and machine learning. Addison-Wesley, London (1989)Bäck, T.: Evolutionaty Algorithms in theory and practice. Oxford University Press, New York (1996)Baker, J.E.: Reducing bias and inefficiency in the selection algorithm. In: Proc. Second International Conference on Genetic Algorithms (1987)Mühlenbein, H., Schlierkamp-Voosen, D.: Predictive Models for the Breeder Genetic Algorithm I. Continuous Parameter Optimization. Evolutionary Computation 1(1) (1993)Cantú-Paz, E.: A summary of resaearch on parallel genetic algorithms. Technical Report 95007, Illinois Genetic Algorithms Laboratory. IlliGAL (1995
Assessment of the dielectric anisotropy in timber using the nondestructive GPR technique
In the realm of architecture ground-penetrating radar has been used as nondestructive technique to assess physical properties of wood structures in situ. However, a better understanding of the dielectric anisotropy of timber is needed to develop this application. An experiment was conducted on samples of sawn timber of different species (densities) to study their dielectric responses according to the grain directions using a GPR with a 1.6 GHz antenna. Interesting differences were found: the propagation velocities, as well as the amplitudes of the direct and reflected waves always presented lesser when the electric field was longitudinal to the grain than when transverse. But when the field was propagated in whatever transverse direction some of those parameters not differ greatly.On the other hand, this work is supported partly by the "Programa de Apoyo a la Investigacion y Desarrollo (PAID-00-11)" of the Universitat Politecnica de Valencia. The authors would like to acknowledge the contribution of Dr Briggs of the School of Forest Resources at the University of Washington, Seattle (USA).Martínez Sala, RM.; Rodríguez Abad, I.; Díez Barra, R.; Capuz Lladró, R. (2013). Assessment of the dielectric anisotropy in timber using the nondestructive GPR technique. Construction and Building Materials. 38:903-911. doi:10.1016/j.conbuildmat.2012.09.052S9039113
How are the ancient cystic fibrosis patients?: Cystic fibrosis diagnosed over 60 years-old
Background and aims To specify the prevalence of patients diagnosed with CF at age of ≥60 year-old and to analyze their characteristics. Patients and methods Observational study of CF patients which were diagnosed at age ≥60 year-old. The analyzed variables were: age, sex, nationality, lung function parameters, conditions present at diagnosis, microbiological characteristics and genetic findings. Results eight patients were included. 7 patients were female (87.5%) with a mean age of 70.6 years (median 71.5 years, range 60–78 years). The most important findings were: sweat test > 60 mEq/l; heterozygotes F508del; bronchiectasis in CT; methicillin-sensitive Staphylococcus aureus (50%) in sputum. The most patients presented a normal or mild obstructive lung function. Conclusions CF must also be considered a disease diagnosed in adulthood, incorporating the sweat test within the usual techniques of differential diagnosis in patients with different diseases associated with CF, because genetic counselling is esencial
Effects of sardine-enriched diet on metabolic control, inflammation and gut microbiota in drug-naïve patients with type 2 diabetes: a pilot randomized trial.
Nutrition therapy is the cornerstone of treating diabetes mellitus. The inclusion of fish (particularly oily fish) at least two times per week is recommended by current international dietary guidelines for type 2 diabetes. In contrast to a large number of human studies examining the effects of oily fish on different cardiovascular risk factors, little research on this topic is available in patients with type 2 diabetes. The aims of this pilot study were to investigate the effects of a sardine-enriched diet on metabolic control, adiponectin, inflammatory markers, erythrocyte membrane fatty acid (EMFA) composition, and gut microbiota in drug-naïve patients with type 2 diabetes.
35 drug-naïve patients with type 2 diabetes were randomized to follow either a type 2 diabetes standard diet (control group: CG), or a standard diet enriched with 100 g of sardines 5 days a week (sardine group: SG) for 6 months. Anthropometric, dietary information, fasting glycated hemoglobin, glucose, insulin, adiponectin, inflammatory markers, EMFA and specific bacterial strains were determined before and after intervention.
There were no significant differences in glycemic control between groups at the end of the study. Both groups decreased plasma insulin (SG: -35.3%, P = 0.01, CG: -22.6%, P = 0.02) and homeostasis model of assessment--insulin resistance (HOMA-IR) (SG: -39.2%, P = 0.007, CG: -21.8%, P = 0.04) at 6-months from baseline. However only SG increased adiponectin in plasma compared to baseline level (+40.7%, P = 0.04). The omega-3 index increased 2.6% in the SG compared to 0.6% in the CG (P = 0.001). Both dietary interventions decreased phylum Firmicutes (SG and CG: P = 0.04) and increased E. coli concentrations (SG: P = 0.01, CG: P = 0.03) at the end of the study from baseline, whereas SG decreased Firmicutes/Bacteroidetes ratio (P = 0.04) and increased Bacteroides-Prevotella (P = 0.004) compared to baseline.
Although enriching diet with 100 g of sardines 5 days a week during 6 months to a type 2 diabetes standard diet seems to have neutral effects on glycemic control in drug-naïve patients with type 2 diabetes, this nutritional intervention could have beneficial effects on cardiovascular risk. Furthermore, both dietary interventions decreased HOMA-IR and altered gut microbiota composition of drug-naïve patients with type 2 diabetes.
Trial number and name of the registry: NCT02294526, ClinicalTrials.gov
Mediterranean diet supplemented with nuts reduces waist circumference and shifts lipoprotein subfractions to a less atherogenic pattern in subjects at high cardiovascular risk
[Objective]: The PREDIMED trial showed that Mediterranean diets supplemented with either extra-virgin olive oil or nuts reduced incident cardiovascular events compared to a control diet. Consumption of both supplemental foods has been associated with reduced LDL-cholesterol, but it is unknown whether they can shift lipoprotein subfractions to a less atherogenic pattern. We investigated changes in adiposity and lipoprotein subfractions after consumption of the PREDIMED diets.[Methods]: In a PREDIMED sub-cohort (n = 169), lipoprotein subclasses (particle concentrations and size) were determined by nuclear magnetic resonance spectroscopy at baseline and after intervention for 1 year.[Results]: Participants allocated to the Mediterranean diet supplemented with nuts showed significant reductions from baseline of waist circumference (mean [95% CI]; −5 cm [−7; −3]) and concentrations of medium-small (−27 nmol/l [−46; −8]) and very small LDL (−111 nmol/l [−180; −42]); decreased LDL particle number (a nuclear magnetic resonance-specific measurement) (−98 nmol/l [−184; −11]); and an increase of large LDL concentrations (54 nmol/l [18; 90]), with a net increase (0.2 nmol/l [0.1; 0.4]) of LDL size. The Mediterranean diets with olive oil and nuts increased large HDL concentrations (0.6 μM [0.0; 1.1] and 1.0 μM [0.4; 1.5], respectively). Compared to the other two intervention groups, participants in the nut-enriched diet showed significantly reduced waist circumference (p ≤ 0.006, both) and increased LDL size (p < 0.05, both).[Conclusion]: Lipoprotein subfractions are shifted to a less atherogenic pattern by consumption of Mediterranean diets enriched with nuts. The results contribute mechanistic evidence for the reduction of cardiovascular events observed in the PREDIMED trial.This study was funded in part by ISCIII (Spanish Ministry of Economy) through grants RTIC G03/140, RTIC RD 06/0045, and FIS PS09/01292 and grant CNIC 06/2007 from Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain. AS-V was supported by post-doctoral contract FIS CD07/0083. MF was supported by a joint contract of ISCIII and the Health Department of the Catalan Government (Generalitat de Catalunya), CP 06/00100
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