Comparison of aerodynamic models for Vertical Axis Wind Turbines

Multi-megawatt Vertical Axis Wind Turbines (VAWTs) are experiencing an increased interest for floating offshore applications. However, VAWT development is hindered by the lack of fast, accurate and validated simulation models. This work compares six different numerical models for VAWTS: a multiple streamtube model, a double-multiple streamtube model, the actuator cylinder model, a 2D potential flow panel model, a 3D unsteady lifting line model, and a 2D conformal mapping unsteady vortex model. The comparison covers rotor configurations with two NACA0015 blades, for several tip speed ratios, rotor solidity and fixed pitch angle, included heavily loaded rotors, in inviscid flow. The results show that the streamtube models are inaccurate, and that correct predictions of rotor power and rotor thrust are an effect of error cancellation which only occurs at specific configurations. The other four models, which explicitly model the wake as a system of vorticity, show mostly differences due to the instantaneous or time averaged formulation of the loading and flow, for which further research is needed.Aerodynamics, Wind Energy & PropulsionAerospace Engineerin

Management of sulphur fertiliser to improve durum wheat production and minimise S leaching

Optimisation of S release from decomposing soil organic matter and S fertiliser related to plant S uptake is a central issue and goal in applied research in agricultural systems. Two lysimeter experiments were conducted in central Italy in two subsequent seasons on two commercial durum wheat cultivars to investigate the effects on yield, S and N uptake and leaching of different rates of N and S fertilisers, soil type and split applications of S. Sulphur fertiliser increased grain yield and N and S uptake of both varieties. Grain yield increase was mainly due to an increase of the number of kernels per spike, which was interpreted as a stimulation of the initiation of spikelets and/or florets, or to a reduction the floret mortality. As an average of the two seasons, S leaching during wheat cycle was 35 kg S ha−1. Sulphur fertiliser rate increased S concentration in drainage water and consequently S leached during wheat cycle. Compared to unfertilised control, S leached was by 13 kg ha−1 higher at 60 kg S ha−1 and by 19 kg ha−1 higher at 120 kg S ha−1. The splitting of sulphur fertiliser during crop cycle modified both grain yield and S leaching. The highest grain yield and S plant uptake was obtained with the splitting of S rate into 60 kg S ha−1 before seeding and 60 kg S ha−1 at stem elongation and the lowest amount of S lost by leaching occurred with the application of 36 kg S ha−1 before seeding and 84 kg S ha−1 at stem elongation. Sulphur output was equally accounted for by leaching and plant uptake. The input–output balance of S was positive in both experiments only when the higher S rate was applied, as more S was imported than removed. Thus, no substantial S deficit may be expected in short term, provided that high S fertiliser rate is applied and the availability of S is synchronised with plant needs

Mandibular condyle fractures: evaluation of the Strasbourg Osteosynthesis Research Group classification.

Condylar fractures (CFs) are about 30\% of mandibular fractures. Condylar fractures are treated with several protocols, and unsatisfying outcome is achieved in some cases. A staging system for classifying CFs is of paramount importance to plan therapy, to define prognosis, and to exchange information among trauma centers. The Strasbourg Osteosynthesis Research Group proposed a classification system for CFs, but no report focusing to its effectiveness is still available. Thus, we performed a retrospective study on a series of patients affected by CFs.The Strasbourg Osteosynthesis Research Group classification defines 3 main types of CFs: diacapitular fracture (i.e., through the head of the condyle [DF]), fracture of the condylar neck, and fracture of the condylar base (CBF). A series of 66 patients (and 84 CFs) was evaluated, and age, sex, clinical diagnosis at admission, treatment, and outcome were considered.Fractures of the condylar base and DFs are the most (52.4\%) and the least (4.8\%) frequent fractures, respectively. Conversely, associated fractures of the facial skeleton are found in most cases of DFs (75\%) and in few cases of CBFs (20.5\%). Surgery was performed in about 15\% of all cases: no DF was operated, whereas fractures of the condylar neck and CBFs have an open reduction and an internal rigid fixation in 57\% and 43\%, respectively. Postsurgical and late sequelae were 22.3\% and 19\%. Temporomandibular joint symptoms and malocclusion cover about 80\% and 90\% of postsurgical and late sequelae.The new classification is a simple method to define CFs and can give some elements about the prognosis

Scoring mandibular fractures: a tool for staging diagnosis, planning treatment, and predicting prognosis

BACKGROUND: Mandibular fractures (MF) are a daily problem in maxillofacial surgery. A staging system for classifying MF is of paramount importance to plan surgery, to define prognosis, and to exchange information among trauma centers. In this article, a classification for MF is proposed. METHODS: The mandible is divided into six sites (symphysis, body, angle, ramus, coronoid, and condyle) and the mandibular nerve divides the alveolar process (i.e., the upper part containing teeth) from the basal bone (placed caudally with respect to the nerve). MF can be summarized using three abbreviations: A = alveolar, B = basal, and C = complete. Consequently, MFs are staged as follows: F in situ = a greenstick fracture; F1 = a single mobile fragment of alveolar or basal bone; F2 = double mobile fractures of the alveolar or basal portion or a single complete separation of the mandibular arch continuity; F3 = a complete double separation of the mandibular arch continuity; F4 = triple or more mandibular arch fragments. To evaluate the suitability of the proposed classification, a retrospective study on a series of 128 patients (and 205 MFs) was performed. Age, gender, stage, clinical diagnosis at admission, type of surgery, and outcome were considered. RESULTS: A good correlation between the proposed classification and the studied variables was detected. CONCLUSIONS: The new classification is a simple and precise method for staging MF. It can summarize MFs and be used in daily practice. It is our understanding, however, that a multicenter study should be performed before the effectiveness of the proposed classification can be clearly stated

Application of agent-based modelling to simulate ribosome translation

Translation is a key process in the cell that encompasses the formation of proteins. However, how the translation mechanisms are affected by physiological changes is yet to be determined. Saccharomyces cerevisiae is one of the most used microorganisms to express recombinant proteins, showing great industrial/commercial value. Modelling the translation process in this yeast can thus bring forward novel insights into its mechanisms and how they are affected by changes in the environment. The present work introduces an agent-based model describing the elongation step of the translation process in the yeast. The simulated and theoretical elongation times were almost identical, with a standard deviation of 0.0018\\%, demonstrating the usefulness of the model to simulate this type of scenarios. Results also show a negative correlation between tRNA levels and estimated decoding times of codons, in accordance with biological knowledge. The model holds considerable potential to help unveil new ways of manipulation and thus increase the production of economically relevant yeast-derived products, namely biopharmaceuticals. Further development will address more complex scenarios, such as ribosome queuing or all the phases in the translation process.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte, and of the PhD Grant SFRH/BD/143491/2019. Additionally, it received funding through Base Funding - UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE - funded by national funds through the FCT/MCTES (PIDDAC).info:eu-repo/semantics/publishedVersio