Ash fusibility characteristics of some biomass feedstocks and examination of the effects of inorganic additives.

The increased consumption of solid biomass for energy production has raised a number of technical problems that are mainly related to the variability of the chemical-physical characteristics of feedstocks. The low melting temperature of their inorganic fraction is the main cause of these problems. In this work analysis and comparison of the thermal behaviour of ash from 20 different feedstocks highlighted that biomass materials with the same origin share similar qualitative and quantitative characteristics. A feedstock from a starch group, corn grain, was tested for the effects of four mineral additives (MgO, CaO, Ca- CO3, and SiO2) on ash deformation temperature. MgO and CaO seemed to be the most effective, raising ash melting temperature and enhancing the thermal behaviour of the feedstock. The results of supplementation of the initial corn grain, wheat straw and sunflower cake biomass demonstrated that the amount of additive to be used is a function of biomass type and can depend on its ash content.</p

EFFETTO DELLA PRESSURIZZAZIONE DEI FORI E DELL’INDENTAZIONE ANULARE SULLA VITA A FATICA DI PROVINI IN LEGA DI ALLUMINIO

Nel lavoro è investigato il comportamento a fatica di lastre forate in lega di alluminio. In particolare è valutata l‟influenza combinata dell‟espansione a freddo dei fori e dell‟indentazione sul miglioramento della vita a fatica. A tal fine sono state condotte diverse prove di fatica aventi lo scopo di valutare il numero di cicli a rottura e la conseguente curva di Wöhler. I risultati sperimentali sono stati confrontati con quelli ottenuti senza la realizzazione di alcun processo di espansione e di espansione-indentazione. Lo studio ha permesso di concludere che il processo di espansione ed indentazione anulare determina un ritardo nella nascita della cricca e della conseguente rottura a fatica

Effects of design and operational conditions on performance of constructed wetlands for agricultural pollution control - critical review

Constructed wetlands (CWs) can be considered as an efficient nature-based solution for treatment of agricultural drainage water (ADW) and consequently for the mitigation of the non-point source pollution. Aiming to provide suggestions for the construction and implementation of CWs, this paper proposes and discusses key parameters of CW design and operation. In order to verify the effect of these features, different case studies were reviewed, focusing on the performance of CWs that are treating agricultural drainage water. The findings showed that design and operational factors (e.g., the application of simple hydraulic structures and vegetation establishment) can improve the pollutant removal efficiencies by increasing hydraulic retention time. Hydraulic efficiency of CWs can also be enhanced through certain shape characteristics (e.g., adoption of a high aspect ratio, creation a long and narrow CW shape). The careful consideration of these parameters before and during CW implementation can therefore help these systems to achieve their full potential. However, further study is recommended to assess effects of some parameters (e.g., flow direction and the application of deep zones)

A novel global postural alteration? Qualitative assessment of hallux valgus and swallowing disorder in human posture: A preliminary investigation on the incidence during age span for promoting psycho-physical and postural well-being

Hallux Valgus (HV) and Swallowing Disorder (SD) are two multifactorial postural and biomechanical alterations. It is very important to look for the incidence of these two conditions in order to promote psycho-physical and postural well-being. Our study aimed to clinically assess the presence of HV and SD in a large group with different ages spans. Fours skilled professionals performed the assessment following clinical criteria. A total of 61 volunteers subjects (163.5 ± 14.1 cm; 59.7 ± 15.7 kg; 22.9 ± 13.2 yrs.) were selected for the study. The 51% of the sample showed the HV alteration, 30% and 73% respectively for male and female. Regarding ages cluster, the HV was present in 44% under 20 yrs., in 53% between 21 and 40 yrs., in 75% over 40 yrs. The 46% of the sample showed a SD condition, 50% and 42% respectively for male and female. As for ages cluster, the incidence of SD was in 50% of subjects under 20 yrs., in 41% between 21 and 40 yrs., in 50% over 40 yrs. The 39% of subjects with HV showed a SD condition. On the other hand, the 43% of subjects with SD showed the HV deformity. HV and SD are postural disorders and most often occur together. In this framework, HV and SD should be interpreted as sign of global postural alteration and for this reason it is fundamental to assess them. Further research is needed on these two parameters in order to find out the optimal relationship between HV and SD

Assessment of a microcontroller for safety-critical avionics and automotive systems

Nowadays, microcontrollers used in critical real-time embedded systems use mostly one core, but are being replaced with more powerful hardware platforms that implement multicore systems. Among the latter, it is possible to identify in the space domain, for instance, the Cobham Gaisler NGMP developed for the European Space Agency (ESA), which is built with a SPARC quad-core processor that has a two-level cache hierarchy. For what concerns automotive and avionics environments, very flexible platforms like the Zynq UltraScale+ EG one has been regarded as a very powerful platform for these high-performance safety-critical systems. In fact, the aforementioned Zynq board implements two multicore clusters, namely an ARM dual-core Cortex R5 and an ARM quad-core Cortex A53, as well as a GPU and an FPGA. Due to the industrial trend towards the deployment of autonomous driving in the automotive domain and unmanned vehicles in the avionics domain, boards with such multicore systems are very promising. The use of multicores brings a concern related to contention (interference) in the access to shared hardware resources, which challenges timing verification needed to prove that all critical real-time tasks will execute by their respective deadlines. In particular, Worst-Case Execution Time (WCET) estimates for tasks need to account for the impact in execution time that contention in shared resources may have. While such analysis has been performed on relatively-simple multicores, like the NGMP, it needs to be carried out on the more powerful and complex Zynq UltraScale+ EG platform. In particular, it is required to analyze the different sources of interference for the multicore clusters and how tasks need to be consolidated so that resource sharing is performed efficiently across tasks, thus minimizing the impact on execution time for the most critical real-time tasks. In this Master thesis work, the measurement-based methodology developed at Barcelona Supercomputing Center (BSC) to quantify the interference that arises across cores due to contention in shared hardware resources, is ported from the (simple) NGMP platform to each of the computing clusters of the Zynq UltraScale+ EG platform. Such methodology consists in the use of small microbenchmarks that aim at stressing specific shared hardware resources to create very high contention. Hence, this thesis investigates how to produce high contention in the shared hardware resources of the Zynq UltraScale+ EG platform, thus integrating those concepts working on the SPARC V8 instruction set of the NGMP to the ARM v7 and ARM v8 instruction sets of the Zynq platform. This requires porting and adapting microbenchmarks written partly in assembly code, verifying the Performance Monitoring Unit, and analyzing the sources of contention. As final step, guidelines are devised to properly consolidate software to be implemented on the target platform in order to contain as much as possible interference on critical tasks

Resonance shifts and spill-out effects in self-consistent hydrodynamic nanoplasmonics

The standard hydrodynamic Drude model with hard-wall boundary conditions can give accurate quantitative predictions for the optical response of noble-metal nanoparticles. However, it is less accurate for other metallic nanosystems, where surface effects due to electron density spill-out in free space cannot be neglected. Here we address the fundamental question whether the description of surface effects in plasmonics necessarily requires a fully quantum-mechanical approach, such as time-dependent density-functional theory (TD-DFT), that goes beyond an effective Drude-type model. We present a more general formulation of the hydrodynamic model for the inhomogeneous electron gas, which additionally includes gradients of the electron density in the energy functional. In doing so, we arrive at a Self-Consistent Hydrodynamic Model (SC-HDM), where spill-out emerges naturally. We find a redshift for the optical response of Na nanowires, and a blueshift for Ag nanowires, which are both in quantitative agreement with experiments and more advanced quantum methods. The SC-HDM gives accurate results with modest computational effort, and can be applied to arbitrary nanoplasmonic systems of much larger sizes than accessible with TD-DFT methods. Moreover, while the latter typically neglect retardation effects due to time-varying magnetic fields, our SC-HDM takes retardation fully into account.Comment: 27 pages, including 4 figures. Supplemental Material is available upon request to author

Anaerobic Digestion of Olive Mill Wastewater in the Presence of Biochar

Biological treatments focused on stabilizing and detoxifying olive mill wastewater facilitate agronomic reuse for irrigation and fertilization. Anaerobic digestion is particularly attractive in view of energy recovery, but is severely hampered by the microbial toxicity of olive mill wastewater. In this work, the addition of biochar to the digestion mixture was studied to improve the stability and efficiency of the anaerobic process. Kinetics and yields of biogas production were evaluated in batch digestion tests with biochar concentrations ranging from 0 to 45 g L−1. The addition of biochar reduced sensibly the lag phase for methanogenesis and increased the maximum rate of biogas generation. Final yields of hydrogen and methane were not affected. Upon addition of biochar, soluble COD removal increased from 66% up to 84%, and phenolics removal increased from 50% up to 95%. Digestate phytotoxicity, as measured by seed germination tests, was reduced compared to raw wastewater. Addition of biochar further reduced phytotoxicity and, furthermore, a stimulatory effect was observed for a twenty-fold dilution. In conclusion, biochar addition enhances the anaerobic digestion of olive mill wastewaters by effectively reducing methanogenesis inhibition and digestate phytotoxicity, thus improving energy and biomass recovery

Water diffusion and swelling stresses in highly crosslinked epoxy matrices

The present work investigates the swelling induced stresses arising in two epoxy systems during water uptake. The analysed systems are two epoxy resin based on DGEBA monomer and DGEBF monomer respectively, both fully cured by DDS amine. The systems achieve different cross-link density degrees, and are characterised by high glass transition temperatures ranging between 200 and 230 °C. Both epoxies have been conditioned in deionized water baths at two different temperatures (50 °C and 80 °C). A desorption process at room temperature in a dry airborne environment was performed after saturation. Dynamic Mechanical Thermal Analysis, carried out at the various stages of hydrothermal conditioning, has allowed to characterise the modifications occurring in the network structures during aging. Photoelastic Stress Analysis is adopted to monitor the evolution of stresses on rectangular beam samples during absorption and desorption of water. Correlation of water uptake, dynamic mechanical behaviour and transitory stress fields, has allowed to make some assumptions about the influence of the epoxy network on the swelling behaviour