In tropical regions, such as in the Amazon, the use of optical sensors is limited by high cloud coverage throughout the year. As an alternative, Synthetic Aperture Radar (SAR) products could be used, ...alone or in combination with optical images, to monitor tropical areas. In this sense, we aimed to select the best Land Use and Land Cover (LULC) classification approach for tropical regions using Sentinel family products. We choose the city of Belém, Brazil, as the study area. Images of close dates from Sentinel-1 (S-1) and Sentinel-2 (S-2) were selected, preprocessed, segmented, and integrated to develop a machine learning LULC classification through a Random Forest (RF) classifier. We also combined textural image analysis (S-1) and vegetation indexes (S-2). A total of six LULC classifications were made. Results showed that the best overall accuracy (OA) was found for the integration of S-1 and S-2 (91.07%) data, followed by S-2 only (89.53%), and S-2 with radiometric indexes (89.45%). The worse result was for S-1 data only (56.01). For our analysis the integration of optical products in the stacking increased de OA in all classifications. However, we suggest the development of more investigations with S-1 products due to its importance for tropical regions.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•Electrochromic (EC) windows as an alternative to traditional shading devices.•Adjustment of the optical properties of EC glasses as a function of incident solar radiation.•EC windows, a valid option ...for the East and West facades, not South ones.•An effective control set point corresponds to 150W/m2 to cause a total coloured state.•EC technology is an effective option in cooling dominated buildings.
During the next decades the refurbishment of old buildings will be an essential way to contribute to the global improvement of buildings energy performance indicators. Within this context, the present paper is focused on the use of electrochromic (EC) windows, an emerging technology alternative to shading devices, to control solar gains in buildings located in Mediterranean climates. The optical properties adjustments of the EC glasses are discussed based on the incident solar radiation. The ESP-r building energy simulation software was used to study the energy savings resulting from the application of electrochromic windows, considering the comparison of several windows solutions (single, double-glazing and EC windows) and windows orientations (East, South and West). In addition, different transition ranges for the optical properties of the EC glasses are assessed through the analysis of the energy needs for space heating and cooling. The main conclusion is that EC technology is an effective option in cooling dominated buildings. The impact of EC windows is highly dependent on facade orientation, being a valid option particularly in the cases of the East and West facades. For these facades, the control set point found to be effective corresponds to an incident solar radiation on the glass of 150W/m2 to impose a total coloured state. For the South facade the results show no significant advantage of using EC windows.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Significance Stable genome maintenance inside viral particles and its controlled delivery to the host are critical for virus infection. We report cryoEM structures of a tailed bacterial virus genome ...gatekeeper mimicking the states before and after DNA release. The subnanometer resolution allowed precise fitting of individual protein components. We found concerted structural rearrangements in the portal through which DNA traffic occurs. DNA is locked in a capsid by gp16 loops that close the channel by an allosteric mechanism. Gp16 appears to open by a diaphragm-like motion, allowing the genome to exit the capsid through the tail tube to the host cell. We propose a molecular mechanism by which the largest group of viruses on Earth controls its DNA movement.
Many icosahedral viruses use a specialized portal vertex to control genome encapsidation and release from the viral capsid. In tailed bacteriophages, the portal system is connected to a tail structure that provides the pipeline for genome delivery to the host cell. We report the first, to our knowledge, subnanometer structures of the complete portal–phage tail interface that mimic the states before and after DNA release during phage infection. They uncover structural rearrangements associated with intimate protein–DNA interactions. The portal protein gp6 of bacteriophage SPP1 undergoes a concerted reorganization of the structural elements of its central channel during interaction with DNA. A network of protein–protein interactions primes consecutive binding of proteins gp15 and gp16 to extend and close the channel. This critical step that prevents genome leakage from the capsid is achieved by a previously unidentified allosteric mechanism: gp16 binding to two different regions of gp15 drives correct positioning and folding of an inner gp16 loop to interact with equivalent loops of the other gp16 subunits. Together, these loops build a plug that closes the channel. Gp16 then fastens the tail to yield the infectious virion. The gatekeeper system opens for viral genome exit at the beginning of infection but recloses afterward, suggesting a molecular diaphragm-like mechanism to control DNA efflux. The mechanisms described here, controlling the essential steps of phage genome movements during virus assembly and infection, are likely to be conserved among long-tailed phages, the largest group of viruses in the Biosphere.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Structural design taking into account fatigue damage requires a thorough knowledge of the behaviour of materials. In addition to the monotonic behaviour of the materials, it is also important to ...assess their cyclic response and fatigue crack propagation behaviour under constant and variable amplitude loading. Materials whenever subjected to fatigue cracking may exhibit mean stress effects as well as crack closure effects. In this paper, a theoretical model based on the same initial assumptions of the analytical models proposed by Hudak and Davidson and Ellyin is proposed to estimate the influence of the crack closure effects. This proposal based further on Walker’s propagation law was applied to the P355NL1 steel using an inverse analysis (back-extrapolation) of experimental fatigue crack propagation results. Based on this proposed model it is possible to estimate the crack opening stress intensity factor, K o p , the relationship between U = Δ K e f f / Δ K quantity and the stress intensity factor, the crack length, and the stress ratio. This allows the evaluation of the influence of the crack closure effects for different stress ratio levels, in the fatigue crack propagation rates. Finally, a good agreement is found between the proposed theoretical model and the analytical models presented in the literature.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
•The stress intensity factor is experimentally calculated using thermoelastic stress analysis.•The model is numerically simulated using finite element and meshless methods.•The obtained numerical ...results are very close with the experimental solution, validating the methodology proposed.•This work possesses a hybrid numerical/experimental attitude.•The obtained stress result is combined with an overdeterministic algorithm to evaluate the stress intensity factor.
This work aims at determining the stress intensity factor (SIF) for a compact tension specimen (CT) during a fatigue crack growth test with Thermoelastic Stress Analysis (TSA). Additionally, the problem is addressed using advanced discretization techniques, Radial Point Interpolation Meshless method (RPIM) and Finite Element Method (FEM) to obtain a stress distribution and calculate SIF range. Based on an optimization procedure, a functional stress relation was designated where the TSA analysis relies upon. The stress fields obtained with the FEM and the RPIM, are graphically represented and both methodologies are compared with the experimental TSA analysis in the presence of mode I fatigue loading test. The stress field in front of the crack tip is obtained with TSA and used in Williams series expansion, together with an overdeterministic algorithm to compute the SIF under mode I loading. This proposed procedure possesses a hybrid experimental-computational feature in which the SIF determination hinges on a stress field obtained with an optical technique, TSA. The robustness of the numerical FE and RPIM computations were thereby experimentally validated with the achieved SIF solution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A general procedure for fatigue life prediction of structural details based on Fracture Mechanics approach is presented in this paper, taking advantage of the new normalized fatigue crack growth ...model proposed by Castillo et al., here denoted as CCS model. An extension to the CCS model is proposed by adopting the cyclic J-integral range instead of the stress intensity factor range as reference parameter. This enables the generalized elastoplastic conditions resulting for the cracked geometry of the structural detail to be considered by means of the cyclic J-integral values obtained from a finite element analysis, for different loading levels and crack lengths. As a practical application, the proposed approach is applied to a notched plate made of P355NL1 steel, using the equivalent initial flaw size (EIFS) concept. Fatigue crack growth data for CT specimens from the literature is evaluated to estimate the modified CCS crack growth model parameters. The predicted fatigue propagation lifetime prediction is compared with the results and, finally, the goodness of the predictions is analysed and deviations discussed.
•A procedure for fatigue life prediction of structural details/mechanical components proposed.•A fatigue approach based on Fracture Mechanics is followed.•Equivalent initial flaw size concept is used and identified using inverse analysis.•A generalisation of the normalized crack growth model based on Gumbel distribution is proposed.•Cyclic J-integral is introduced to allow generalized elastoplastic conditions.•S-N data of notched plate of P355NL1 steel satisfactorily correlated using simulated results.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Friction stir welding (FSW) is a solid-state joining technique, which has been developed remarkably during the last decade. Due to its benefits over conventional welding techniques, along with ...growing industrial demands for lightweight design structures, FSW found its way into becoming one of the fascinating engineering subjects of today. FSW process is based on the generation of heat due to friction and material deformation under an axial force. Originally, this method was developed for welding metallic materials which were difficult to weld with conventional techniques. However, due to the significant increase in polymeric materials consumption in the industry, the possibility for implementing this technique in polymer welding received a considerable share of interest. Nevertheless, polymeric materials behave differently from metallic ones and, currently, there is still a limited number of research works in the literature concerning this specific topic. This article reviews previous studies, which were focused on welding polymers using the FSW technique. Development of FSW tools, welds strength and the most effective welding parameters for different polymeric materials are now analysed. New materials, configurations and test specifications are currently under research, including the possibility for dissimilar materials joining, taking FSW into a new phase in industrial applications.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Numerous viruses package their dsDNA genome into preformed capsids through a portal gatekeeper that is subsequently closed. We report the structure of the DNA gatekeeper complex of bacteriophage SPP1 ...(gp6
gp15
gp16
) in the post-DNA packaging state at 2.7 Å resolution obtained by single particle cryo-electron microscopy. Comparison of the native SPP1 complex with assembly-naïve structures of individual components uncovered the complex program of conformational changes leading to its assembly. After DNA packaging, gp15 binds via its C-terminus to the gp6 oligomer positioning gp15 subunits for oligomerization. Gp15 refolds its inner loops creating an intersubunit β-barrel that establishes different types of contacts with six gp16 subunits. Gp16 binding and oligomerization is accompanied by folding of helices that close the portal channel to keep the viral genome inside the capsid. This mechanism of assembly has broad functional and evolutionary implications for viruses of the prokaryotic tailed viruses-herpesviruses lineage.
Portugal is impacted by the rapid growth of the aging population, which has significant implications for its health care system. However, nurses have received little education focusing on the unique ...and complex care needs of older adults. This gap in the nurses′ education has an enormous impact in their knowledge and attitudes and affects the quality of nursing care provided to older adults. A cross‐sectional study was conducted among 1068 Portuguese nurses in five hospitals (northern and central region) with the following purposes: (i) explore the knowledge and attitudes of nurses about four common geriatric syndromes (pressure ulcer, incontinence, restraint use and sleep disturbance) in Portuguese hospitals; and (ii) evaluate the influence of demographic, professional and nurses' perception about hospital educational support, geriatric knowledge, and burden of caring for older adults upon geriatric nursing knowledge and attitudes. The mean knowledge and attitudes scores were 0.41 ± 0.15 and 0.40 ± 0.21, respectively (the maximum score was 1). Knowledge of nurses in Portuguese hospitals about the four geriatric syndromes (pressure ulcers, sleep disturbance, urinary incontinence and restraint use) was found inadequate. The nurses' attitudes towards caring for hospitalized older adults were generally negative. Nurses who work in academic hospitals demonstrated significantly more knowledge than nurses in hospital centers. The attitudes of nurses were significantly associated with the hospital and unit type, region, hospital educational support, staff knowledge, and perceived burden of caring for older adults. The study findings support the need for improving nurses' knowledge and attitudes towards hospitalized older adults and implementing evidence‐based guidelines in their practice.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
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