Mechanical behaviour modelling of a new anchor system for large diameter GFRP bars

The strong anisotropy of unidirectionally-reinforced FRP composites makes it difficult to design an efficient anchorage for measuring the tensile strength and this difficulty increases together with the cross section area of the specimen. To overcome this difficulty a new anchor system was developed for tension testing of large diameter GFRP bars in a universal testing machine. The anchor body designed and tested consists of two shells, pushed one against the other by the jaws of the testing machine, leaving an inner conical hole. The ends of the bar are provided with resin heads having the shape of the hole inside the anchor body. The present paper details the modelling investigation to verify and improve the shape and hence the performances of this anchor system. The approach adopted consists in a parametric numerical analysis that rests on the experimental data already gathered.     

A simplified method to evaluate the energy performance of CO2 heat pump units

The prediction of the performances of CO₂ transcritical heat pumps demands accurate calculation methods, where a particular effort is devoted to the gas cooler modelling, as the correlation between high pressure and gas cooler outlet temperature strongly affects the cycle performance. The above-mentioned methods require a large amount of input data and calculation power. As a consequence they are often useless for the full characterisation of heat pumps which are sold on the market.A simplified numerical method for the performance prediction of vapour compression heat pumps working in a transcritical cycle is presented, based only on performance data at the nominal rating conditions. The proposed procedure was validated against experimental data of two different tap water heat pumps. For the considered units, simulation results are in good agreement with the experimental ones. The deviations range from −6.4% to +1.7% and from −3.8% to +5.8% for the COP_H of the air/water heat pump and the water/water heat pump, respectively. The heating capacity deviations stayed within −5.5% and +1.7% range and within −5.0% and +7.9% range for the same units.The proposed mathematical model appears to be a reliable tool to be used by the refrigeration industry or to be implemented into dynamic building-plant energy simulation codes. Finally, it represents a useful instrument for the definition of tailored approximated optimal high pressure curve considering the operating characteristics of the specific CO₂ transcritical unit. It could also be implemented on board of a real unit control system where it could be used as model coupled to computational intelligence algorithms for pressure optimisation.     

Autothermal reforming of JP8 on a Pt/Rh catalyst: Catalyst durability studies and effects of sulfur

Autothermal reforming (ATR) of commercial grade JP8 was performed on a Pt/Rh catalyst deposited on a monolith. This study investigated catalyst performance under three test conditions: (i) 120 startup and shutdown cycles, (ii) 80 h of continuous operation with sulfur-free fuel, and (iii) 370 h of testing with JP8 containing 125 ppm of sulfur. Axial reactor temperature profiles and gas composition data showed that startup and shutdown cycling had no impact on catalyst performance. When durability testing was done with fuel containing 125 ppm of sulfur, the catalyst deactivated initially, which was reflected by a decrease in H₂ concentration and decrease in fuel conversion. However, after 250 h of operation the activity stabilized at 66% fuel conversion and product concentrations were constant for the remaining 120 h of testing. The presence of sulfur resulted in higher CO selectivity, lower H₂ concentrations, and lower fuel conversions compared to data with sulfur-free fuel. The data suggests that the presence of sulfur primarily affects steam reforming reactions, and CO oxidation. Regeneration was attempted with air and with fuel-lean combustion but initial H₂ yields and carbon selectivity were not achieved.     

Identification of potential areas for biomass production in China: Discussion of a recent approach and future challenges

A standard methodology is needed to recognize potentially suitable areas for sustainable bioenergy crop production. This facilitates better identification of promising crops and cropping systems, logistical and economic studies, and work needed to meet regulatory criteria. A possible approach is built upon three layers of internationally available spatial data: (1) degrading and abandoned areas, (2) potentially suitable land cover classes, (3) exclusion zones such as nature reserves and areas of high biodiversity. For China, areas identified as potentially suitable range from 1.2 to 6.0% of the national territory, depending on different levels of statistical confidence in degrading area status and allowable limits of terrestrial carbon. Verification on the ground showed that about 60% of points tested conformed to the remote suitability assessment in the scenario, which represents the results for the combination of all degrading areas and a terrestrial carbon stock limit of 200 t ha⁻¹. A top-down approach is useful in framing potentially suitable locations, but a complementary bottom-up analysis is still required to ultimately identify areas for sustainable bio-fuel production.     

Fatigue behaviour of concrete bridge deck slabs reinforced with GFRP bars

GFRP bars are often used for the internal reinforcement of concrete bridge deck slabs as an alternative to traditional steel reinforcements with excellent results in terms of corrosion resistance. Several experiments on bridge decks were conducted to evaluate their structural behaviour but their fatigue performance still needs an adequate experimental investigation. This paper presents the results of an experimental campaign on four full scale concrete bridge deck specimens reinforced with GFRP bars that were designed, constructed and tested to resist cyclic moving loads. Two hydraulic jacks were used to simulate moving concentrated loads. After the cycles, the load was increased to the static failure. The slabs reinforced with GFRP bars showed a better fatigue performance compared to the requests of the European codes.     

Vertical sintering to measure the uniaxial viscosity of thin ceramic layers

A novel method is proposed for the determination of the uniaxial viscosity of porous ceramic layers upon sintering. This approach is based on the application of a continuous but very low tensile stress to the densifying powder compact whose deformation is continuously monitored by an optical system. The viscosity of the system can be determined as a function of temperature and density from the sintering rate differences measured between loaded and unloaded samples. The uniaxial viscosity of porous Y₂O₃ doped ZrO₂ (YSZ) and NiO–YSZ composites was measured using the proposed approach. The results were used to predict the curvature evolution of bilayers used in solid oxide fuel cell applications, obtaining a fairly good agreement between the model and the data recorded experimentally.     

New method based on capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) to monitor interaction between nanoparticles and the amyloid-β peptide

A novel application of capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was proposed to efficiently detect and monitor the interaction between polymeric nanoparticles and the β-Amyloid peptide (Aβ(1-42)), a biomarker for Alzheimer's Disease (AD), at concentrations close to physiological conditions. The CE-LIF method allowed the interaction between PEGylated poly(alkyl cyanoacrylate) nanoparticles (NPs) and the soluble Aβ(1-42) peptide monomers to be highlighted. These results were confirmed by surface plasmon resonance (SPR) and confocal laser scanning microscopy (CLSM). Whereas SPR showed an interaction between the NPs and the Aβ(1-42) peptide, CLSM allowed the formation of large aggregates/assemblies at high NP and peptide concentrations to be visualized. All these results suggested that these nanoparticles could bind the Aβ(1-42) peptide and influence its aggregation kinetics. Interestingly, the non-PEGylated poly(alkyl cyanoacrylate) NPs did not alter the aggregation kinetics of the Aβ(1-42) peptide, thus emphasizing the high level of discrimination of the CE-LIF method with respect to NPs.     

Solutions of Falkner–Skan equation with heat transfer by Fourier series

In this paper, we solve the Falkner–Skan equation with heat transfer through an expansion in Fourier series, results are improved by incorporating an asymptotic analysis for the Fourier series coefficients. The results show that the classical expansion in Fourier series together with the incorporation of an asymptotic analysis for coefficients of the series delivers a solution with very good accuracy and rapid convergence when it is compared with other methods of solution found in the literature as finite difference and shooting method.