The microstructure and mechanical properties of austenitic stainless steel 316 LVM (Low Vacuum Melting) blasted with either small and rounded ZrO2 particles or larger and angular shaped Al2O3 ...particles are analysed through magnetic force microscopy, synchrotron radiation diffraction and ultramicroindentation techniques. It is shown that blasting causes a severe plastic deformation that roughens the surface and produces a significant subsurface grain refinement and work hardening. The gradient in the plastic deformation and the volume increase associated with the deformation induced α′-martensite account for the development of compressive residual stresses with a maximum value close to the surface. All these features yield a gradient in hardness with a maximum value beneath the surface. Compared with the Al2O3 particles, the ZrO2 particles cause a higher value of compressive residual stress and a lower increase in hardness. Also, the Al2O3 particles lead to more α′-martensite formation at deeper regions from the surface than the ZrO2 particles. The different results are related with the specific morphology of the particles and their specific role in the blasting process.
This work deals with the mechanical characterization by depth-sensing indentation (DSI) of PLLA and PLDA composites reinforced with micro-particles of Mg (up to 15wt%), which is a challenging task ...since the indented volume must provide information of the bulk composite, i.e. contain enough reinforcement particles. The composites were fabricated by combining hot extrusion and compression moulding. Physico-chemical characterization by TGA and DSC indicates that Mg anticipates the thermal degradation of the polymers but does not compromise their stability during processing. Especial emphasis is devoted to determine the effect of strain rate and Mg content on mechanical behavior, thus important information about the visco-elastic behavior and time-dependent response of the composites is obtained. Relevant for the intended application is that Mg addition increases the elastic modulus and hardness of the polymeric matrices and induces a higher resistance to flow. The elastic modulus obtained by DSI experiments shows good agreement with that obtained by uniaxial compression tests. The results indicate that DSI experiments are a reliable method to calculate the modulus of polymeric composites reinforced with micro-particles. Taking into consideration the mechanical properties results, PLA/Mg composite could be used as substitute for biodegradable monolithic polymeric implants already in the market for orthopedics (freeform meshes, mini plates, screws, pins, …), craniomaxillofacial, or spine.
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•PLLA and PLDA composites were reinforced with micro-particles of Mg.•Mg does not compromise the polymer stability during thermoplastic processing.•Mg increases elastic modulus, hardness and resistance to flow of polymers.•Depth-sensing indentation was used to calculate their mechanical properties.•Depth sensing analysis correlates well with uniaxial compression data.
Background
There is a research gap regarding safety concerns of patients at the end of life. The aim of this study was, therefore, to explore whether patients under specialist community palliative ...care feel safe at home and which factors affect the perceived safety. Furthermore, we investigated if perception of safety is associated with different aspects of subsequent care.
Methods
Using a standardized questionnaire, a cross-sectional survey was conducted among 100 specialist community palliative care patients. Logistic regression was used to examine the strength of the association between clinical and socio-demographic variables and the perception of safety. After a 6-month follow-up period, we analyzed differences in various care-related outcomes between patients with unaffected and impaired perceptions of safety.
Results
In our study, one in five patients receiving specialist community palliative care expressed safety concerns. Subdomains of safety that were reported most frequently were physical disability (60%), physical symptoms (30%), psychological symptoms (26%), and side effects/complications of drug therapy (19%). Of the participants surveyed after the initial COVID-19 lockdown, 35.1% reported that they felt their safety had been adversely affected by the pandemic. Compromised safety perception was associated with higher levels of palliative care-related problems, and proximity to death.
Conclusions
Our study uncovered relevant safety concerns of palliative care patients receiving specialist community palliative care. The insights gained into patient-reported problems may help healthcare professionals to identify situations where patients feel unsafe. Further research should address primary and secondary prevention measures to improve the quality of end-of-life care in the home environment.
In recent years, kaolinite‐based wastes are focusing the attention of researchers to obtain recycled metakaolinite, with consequent environmental and socioeconomic benefits. One of these lines of ...research is based on coal mining waste, which once activated thermally, it becomes a highly pozzolanic product (ACM). This study reports the influence of activated carbon mining waste on the formation and evolution of the mineralogical phases in the ACM/cement system as well as their influence on the microstructure up to 90 d of reaction. Mineralogical analyses clearly show that the addition of ACM modified mineralogical compounds of blended cements. The C4AH13 and C4AC¯H12 were the predominant phases in this type of cements; while in the ordinary portland cement cements, portlandite, ettringite, and carboaluminate were main hydrated phases. Two differential zones in the pore size distribution of the C–S–H gels at 12 and 4.5 nm were observed, predominating the formation of C–S–H gels at 12 nm when 20% of ACM was added to the cement.
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•Pharmaceutical compounds occurring in wastewater are an environmental concern.•A novel process for removal emerging pollutants was developed.•The process is a sequential treatment ...with cyclodextrins and pulsed light.•The process removes pharmaceutical compounds from water by 91 %.
The presence of pharmaceutical compounds (PhCs) in the effluents of wastewater treatment plants (WWTPs) is an ecological concern. The issue could be alleviated by trapping those substances by cyclodextrin (CD) polymers or photolyzing them by pulsed light (PL). Consequently, a sequential CD polymer/PL system was tested for the removal of PhCs. Firstly, a survey detected the presence of recurrent PhCs in the effluents of local WWTPs. Then, pure water was spiked with 21 PhCs, 100 μg/L each one. The three-dimensional network provides amphiphilic features to the CD polymer that reduced the pollutant concentration by 77 %. Sorption involves a plead of physical and chemical mechanisms hindering the establishment of a general removal model for all compounds. The performed simulations hint that the retention capacity mainly correlates with the computed binding energies, so that theoretical models are revealed as valuable tools for further improvements. The complementary action of PL rose the elimination to 91 %. The polymer can be reused at least 10 times for ibuprofen (model compound) removal, and was able to eliminate the ecotoxicity of an ibuprofen solution. Therefore, this novel sequential CD polymer/PL process seems to be an efficient alternative to eliminate PhCs from wastewater.
Technological advancements have provided heritage with new learning environments via the use of virtual and augmented reality, which can foster the accessibility and understanding of culture and ...propose new ways of interacting with heritage. Therefore, in this study, a systematic evaluation is carried out of n=197 heritage education programs listed in the database of the Observatorio de Educación patrimonial en España (OEPE) (the Spanish Heritage Education Observatory–SHEO) which, in their descriptions, integrate the use of virtual environments and/or augmented reality to promote learning on the part of the user. The objectives of this study are: (1) to analyse the state of the art, (2) to evaluate the quality of their educational designs via the “analysis and assessment sequential method for heritage education programs” (SAEPEP-OEPE) and (3) to identify variables which can be improved or which have a significant influence on the quality of the programs. Highlights of the results include: (a) the increasing implementation of these technologies in heritage education programs, with the greater presence of virtual resources than of learning environments, (b) the low level of the scope of educational quality in their designs, particularly their assessment, and (c) the inclusion of advanced technologies slightly decreases the specificity of the educational design.
•Comparative and validation of an electrical model for six electrochemical cells.•Validation of a novel hysteresis model for the different technologies.•Comparative study of the main characteristics ...for six electrochemical cells.•Definition and comparative of the main variables of hysteresis effect.
This paper studies the influence on the voltage estimation accuracy of a novel hysteresis effect model. The model is applied to six different battery technologies: Lead–acid AGM, Lead–acid gel, Nickel–cadmium, Nickel–metal hydride, Lithium-ion, Lithium-ion polymer. The proposed hysteresis electrical model estimates the variation of the parameters in a classical model when considering hysteresis effects. A general model is proposed and the characterization process is optimized so that it can be applied to all studied cells. The model is composed of three circuits: voltage–current circuit, Ah counting circuit and hysteresis electrical model circuit. All the parameters for all six technologies are calculated and compared. The model evaluation is carried out through 18 case studies. The results are compared in terms of increment of voltage estimation accuracy when considering hysteresis and influence of hysteresis on a certain technology. The model average voltage estimation error of all technologies is 0.48%. When hysteresis effect is included the average error reduces in 0.71%.
Although Heat Waves (HWs) are expected to increase due to global warming, they are a regional phenomenon that demands for local analyses. In this paper, we assess four HW metrics (HW duration, HW ...frequency, HW amplitude, and number of HWs per season) as well as the share of extremely warm days (TX95, according to the 95th percentile) in South America (SA). Our analysis included observations as well as simulations from global and regional models. In particular, Regional Climate Models (RCMs) from the Coordinated Regional Climate Downscaling Experiment (CORDEX), and Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were used to project both TX95 estimates and HW metrics according to two representative concentration pathways (RCP4.5 and RCP8.5). We found that in recent decades the share of extremely warm days has at least doubled over the period December-January-February (DJF) in northern SA; less significant increases have been observed in southern SA. We also found that by midcentury, under the RCP4.5 scenario, extremely warm DJF days (as well as the number of HWs per season) are expected to increase by 5-10 times at locations close to the Equator and in the Atacama Desert. Increases are expected to be less pronounced in southern SA. Projections under the RCP8.5 scenario are more striking, particularly in tropical areas where half or more of the days could be extremely warm by midcentury.
We report the first density functional study of water catalytic effect in the double proton transfer (DPT) taking place in the adenine−thymine (AT) base pair. To gain more insight regarding the ...accuracy of several theoretical methods, the ability of various functionals and models for describing the geometry of this system has first been checked. According to our results, BP86/6-311++G(d,p) is the best option for describing the solvation effects in AT when applied to a two-water-molecule-featuring model. The two possible mechanisms for DPT in solution are explored: in the first one, water molecules only remain passive elements, whereas in the second one they are directly included in the reaction path. For the noncatalyzed mechanism, the stable structures constitute the canonical form of the base pair and the first proton transfer product. Nevertheless, by involving the two water molecules in the reaction, we found three stable species: canonical base pair, first proton transfer product, and double proton transfer product. Although the thermodynamic analysis confirms that AT does not contribute to spontaneous mutation through proton transfer catalyzed by surrounding water, our results suggest that microhydration may play a crucial role for DPT reaction in others DNA or RNA basis pair.
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