Preliminary design of an amphibious aircraft by the multidisciplinary design optimization approach

In the past few decades, besides the important progress that the aeronautical and aerospace engineering have achieved, the requirement of improving aircrafts performances and features, and the need of devising crafts performing special missions were growing meanwhile. Nevertheless, developing unconventional or innovative configurations the reference data extrapolated by known standard configurations are useless. Thus, the concept of Multidisciplinary Design Optimization, MDO, for the preliminary design of aeronautical and aerospace structures is the natural answer to the challenge that aeronautical and aerospace structures represent especially if new configurations of crafts are requested. Hence, the aim of this paper is to present an MDO procedure and an associated overview of the work code called MAGIC, (Multidisciplinary Aircraft desiGn of Innovative Configurations), for conceptual design of non-conventional aircraft configurations in civil aviation. Accordingly, the relevance of an adequate modeling is an essential issue in order to obtain meaningful designing results. Thus, the intimate link between MDO, modeling, and simulations fields is evident. The algorithms used in MAGIC for modeling structures, aerodynamics, and aeroelasticity are first-principles based, since for innovative configurations the designer cannot rely upon past experience. In addition, we emphasize the conceptual design: thus, the algorithms used must be accurate and efficient, so as to produce accurate predictions with a relatively small computational effort. In the paper presented the structural analysis (statics -including the buckling analysis- and dynamics) has been performed using an external commercial FEM code. Furthermore, since the special condition of ground effect flight is considered, we have adopted the specific methodology introduced by Keldysh-Lavrentiev (KL) and available in the steady aerodynamic case for airfoils in bounded domain in order to evaluate the aerodynamic loads. The efficiency of the proposed methodology is illustrated by applications to specific configurations

An Italian prospective multicenter survey on patients suspected of having non-celiac gluten sensitivity.

Background: Non-celiac gluten sensitivity (NCGS) is still an undefined syndrome with several unsettled issues despite the increasing awareness of its existence. We carried out a prospective survey on NCGS in Italian centers for the diagnosis of gluten-related disorders, with the aim of defining the clinical picture of this new syndrome and to establish roughly its prevalence compared with celiac disease. Methods: From November 2012 to October 2013, 38 Italian centers (27 adult gastroenterology, 5 internal medicine, 4 pediatrics, and 2 allergy) participated in this prospective survey. A questionnaire was used in order to allow uniform and accurate collection of clinical, biochemical, and instrumental data. Results: In total, 486 patients with suspected NCGS were identified in this 1-year period. The female/male ratio was 5.4 to 1, and the mean age was 38 years (range 3–81). The clinical picture was characterized by combined gastrointestinal (abdominal pain, bloating, diarrhea and/or constipation, nausea, epigastric pain, gastroesophageal reflux, aphthous stomatitis) and systemic manifestations (tiredness, headache, fibromyalgia-like joint/muscle pain, leg or arm numbness, 'foggy mind,' dermatitis or skin rash, depression, anxiety, and anemia). In the large majority of patients, the time lapse between gluten ingestion and the appearance of symptoms varied from a few hours to 1 day. The most frequent associated disorders were irritable bowel syndrome (47%), food intolerance (35%) and IgE-mediated allergy (22%). An associated autoimmune disease was detected in 14% of cases. Regarding family history, 18% of our patients had a relative with celiac disease, but no correlation was found between NCGS and positivity for HLA-DQ2/-DQ8. IgG anti-gliadin antibodies were detected in 25% of the patients tested. Only a proportion of patients underwent duodenal biopsy; for those that did, the biopsies showed normal intestinal mucosa (69%) or mild increase in intraepithelial lymphocytes (31%). The ratio between suspected NCGS and new CD diagnoses, assessed in 28 of the participating centers, was 1.15 to 1. Conclusions: This prospective survey shows that NCGS has a strong correlation with female gender and adult age. Based on our results, the prevalence of NCGS seems to be only slightly higher than that of celiac disease