Comparison between the thermal properties of cement composites using infrared thermal images

The use of agribusiness residual lignocellulosic fibres can be a good alternative in the development of lignocellulosic composites. The current work aimed to investigate the thermal performance of cement-based composites with lignocellulosic materials: Eucalyptus, sugarcane bagasse, coconut fibre in comparison with commercial gypsum board to be used as internal partitions of the building using infrared thermal images. Three repetitions for each kind of lignocellulosic material were made, and three commercial gypsum boards were used. In the production of the panels, the following parameters were applied: material and cement ratio, 1:2.75; water and cement ratio, 1:2.5; hydration water rate of 0.25; additive, 4% (based on cement mass). The calculations were performed for a nominal panel density of 1,200 kg m- ³. The thermal analysis was performed in a chamber composed of MDP (Medium-Density Particleboard) and with an internal layer of rock wool and the heat source (thermal resistance). For the superficial temperature measurement, a FLIR E75 camera was used to capture the infrared images. When the internal temperature of the chamber stabilized at 50 °C, an infrared thermal image was collected from each side of the composite. Thermal properties were analysed: thermal conductivity, resistivity, resistance, and transmittance. Based on the results, sugar cane cement composites were characterized by higher values of thermal conductivity. Related to thermal resistivity, thermal resistance, and thermal transmittance, only the coconut panel presented similar behaviour to the commercial gypsum board. Thus, cement composite using coconut can be a potential alternative that might solve energy and environmental concerns simultaneously

Thermal environment in two broiler barns during the first three weeks of age

The objective of this research was to evaluate the internal thermal environment of two broiler barns featuring different ventilation systems representative of Brazilian and South American poultry production industry: (a) a negative-pressure tunnel and (b) a positive- pressure lateral ventilation system. Environmental parameters such as dry bulb temperature, relative humidity and temperature-humidity index were assessed; temperature maps for day and night average conditions were determined for the first three weeks of life. Better uniformity of the thermal environment and comfort conditions inside the negative-pressure tunnel were found

Perception of sleep duration in adult patients with suspected obstructive sleep apnea

PURPOSE: Discrepancies between subjective and objective measures of total sleep time (TST) are frequent among insomnia patients, but this issue remains scarcely investigated in obstructive sleep apnea (OSA). We aimed to evaluate if sleep perception is affected by the severity of OSA. METHODS: We performed a 3-month cross-sectional study of Brazilian adults undergoing overnight polysomnography (PSG). TST was objectively assessed from PSG and by a self-reported questionnaire (subjective measurement). Sleep perception index (SPI) was defined by the ratio of subjective and objective values. Diagnosis of OSA was based on an apnea/hypopnea index (AHI) ≥ 5.0/h, being its severity classified according to AHI thresholds: 5.0-14.9/h (mild OSA), 15.0-29.9/h (moderate OSA), and ≥ 30.0/h (severe OSA). RESULTS: Overall, 727 patients were included (58.0% males). A significant difference was found in SPI between non-OSA and OSA groups (p = 0.014). Mean SPI values significantly decreased as the OSA severity increased: without OSA (100.1 ± 40.9%), mild OSA (95.1 ± 24.6%), moderate OSA (93.5 ± 25.2%), and severe OSA (90.6 ± 28.2%), p = 0.036. Using logistic regression, increasing SPI was associated with a reduction in the likelihood of presenting any OSA (p = 0.018), moderate/severe OSA (p = 0.019), and severe OSA (p = 0.028). However, insomnia was not considered as an independent variable for the presence of any OSA, moderate/severe OSA, and severe OSA (all p-values > 0.05). CONCLUSION: In a clinical referral cohort, SPI significantly decreases with increasing OSA severity, but is not modified by the presence of insomnia symptoms.publishersversionpublishe

Evolución de los deltas submarinos de los ríos Guadalfeo y Adra en respuesta a las variaciones de los aportes sedimentarios

The Guadalfeo and the Adra submarine deltas off the northern coast of the Alboran Sea have been built up under the direct influence of short and mountainous rivers. The area is subjected to strong climatic seasonality, with sporadic winter torrential floods and high summer aridity. In addition numerous anthropogenic activities have affected these systems, mostly during the last two centuries. In order to decode the influence of climatic variability and anthropogenic impacts on sediment supplies during the recent past, five sediment cores were collected from the Guadalfeo and Adra submarine deltas. Benthic foraminiferal and sedimentological analyses, combined with radiocarbon dating, were performed. The impact of torrential floods alternating with periods of low rainfall or dry periods were recorded in the Adra and Guadalfeo prodeltas. Periods with low abundance of benthic foraminifera and high amounts of coarse-grained sediments, were interpreted as the result of enhanced sediment supply to the shelf triggered by major flood events. On the other hand, periods with high amounts of fine-grained sediments and high abundances of colonizers and opportunistic foraminiferal species indicate the establishment of new environments with distinct ecological constraints. These environments were driven by lower sediment supplies during low rainfall or dry periods. The most recent sedimentation seems to reflect the human interventions in the rivers basins, such as deviation of the main river courses and dams construction, which reduced the sediment input and promoted the deposition of shallow-water submarine deltas.Versión del edito

The evolution of the Guadalfeo submarine delta (northern Alboran Sea) during the last ca. 200 years

The Guadalfeo submarine delta is located on the northern Alboran Sea shelf in the western Mediterranean Sea. The sedimentary dynamics of the deltaic system is governed by the discharge of one of the major rivers in this area draining the western sector of the near-coastal Sierra Nevada Mountains. The area is under the influence of a Mediterranean climate, with high spatial and temporal (i.e., inter- and intra-annual) rain variability. Major anthropogenic forcing affected the river system during the 1930’s, with the deviation of the main river channel 2.5 km to the west, to its present position. More recently, the construction of Béznar (1977-1985) and Rules (1993-2003) dams have also contributed to limit the amount of sediments exported to the deltaic system. In order to understand the interaction between river discharges and the evolution of the submarine delta at different timescales, sediment cores were collected off the ancient (core 13) and present-day (cores12 and 15) river courses. A chronological framework was performed and combined with sedimentological and benthic foraminiferal analyses. Radiocarbon dating of plant debris from the base of the cores indicates that the sedimentary record goes back 200 years. In core 13, the variations between coarse and fine fractions along the core and the upward increase of benthic foraminiferal population density, would indicate that deposition possibly occurred until the deviation of the main river course to its present position. In the lower part of core 12, the strong alternation between coarse and fine sediment textures and the variable amounts of benthic foraminiferal species are interpreted as the result of an active fluvial regime. The upper part, with high percentages of fine sediments and high values of population density, could be attributed to the stabilization of the river course in its present-day location. Core 15, located at 11 m water depth, showed the highest content of gravel in the lower part of the core, high contents of silt at two core depths and increased percentages of sand to the top, indicating the strong influence of human interventions in the river basin and consequent changes in the sediment supply to the Guadalfeo submarine delta.info:eu-repo/semantics/publishedVersio

Multi-proxy evidence of rainfall variability recorded in subaqueous deltaic deposits off the Adra River, southeast Iberian Peninsula

The Adra River deltaic system, southeast Iberian Peninsula, shows a steep topography and is subjected to strong climatic seasonality. This system has been affected by alternating wet and dry periods, and it has also undergone numerous anthropogenic activities such as deforestation, mining activities, river channel deviations and dam construction, particularly during the last two centuries. Two sediment cores were retrieved off the Adra River, from the western (MS_V9) and eastern (MS_V4) lobes of the subaqueous deltaic deposit. A multi-proxy study was carried out, including grain size, benthic foraminiferal assemblages, magnetic susceptibility and geochemical element analyses, in order to understand the sedimentary expression of recent climatic cycles and anthropogenic interventions in the river basin. Periods of increased deposition of coarse-grained sediments, low absolute abundance of benthic foraminifera and high elemental ratios indicative of terrigenous contributions, were interpreted as periods of increased sediment supply to the shelf. Four flooding events were recorded in core MS_V9 and three events on core MS_V4, of which two were observed in both cores. They were related to periods with major floods that were documented on the southern Iberian Peninsula around 1770e1810 and 1860 e1870 AD. On the other hand, sediment core intervals exhibiting increasing proportion of fine-grained sediments and higher abundances of foraminiferal species assigned as successful colonizers (Textularia earlandi) and opportunistic species that feed on bacteria or terrestrial organic matter (Bolivina ordinaria, Bulimina elongata, Eggerelloides scaber and Ammonia beccarii or tepida), indicate the establishment of new environments with new ecological constraints. They were related to significant decreases of terrigenous sediment input during low rainfall or dry periods. The increase of opportunistic species feeding on fresh phytodetritus (Nonionella iridea, Nonionella stella, Nonionella sp., Brizalina dilatata, Epistominella vitrea and Bolivinellina pseudopuntata), under more stable environmental conditions, also point to a stronger marine influence on the prodeltaic environments during these periods. The human interventions on the river basin after 1872 AD, with the deviation of the main river channel to the east, led to a drastic reduction of the sediment exported to the western delta lobe. This study showed that the sedimentation on the Adra subaqueous deltaic deposit was mainly controlled by rainfall variability from 1663 to 1872 AD, and afterwards by anthropogenic interventions.En prensa2,247

Semigroup Closures of Finite Rank Symmetric Inverse Semigroups

We introduce the notion of semigroup with a tight ideal series and investigate their closures in semitopological semigroups, particularly inverse semigroups with continuous inversion. As a corollary we show that the symmetric inverse semigroup of finite transformations $\mathscr{I}_\lambda^n$ of the rank $\leqslant n$ is algebraically closed in the class of (semi)topological inverse semigroups with continuous inversion. We also derive related results about the nonexistence of (partial) compactifications of classes of semigroups that we consider.Comment: With the participation of the new coauthor - Jimmie Lawson - the manuscript has been substantially revised and expanded. Accordingly, we have also changed the manuscript titl