3. |
- Ahuja, Gaurav, 1978, et al.
(författare)
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Sandwich Construction - Application on a superstructure
- 2005
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Ingår i: INMAT 2005. ; , s. 11-
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Konferensbidrag (refereegranskat)abstract
- The use of light weight materials is increasing at a rapid pace in the present day industry. Automobiles, aircrafts, ships and several other fields are increasingly finding large potential in using lighter materials for construction. In the past few years a number of water borne means of transportation have been moulded from composites. For ships, this leads to reducing the light weight and thus an increase in the capacity of the payload. A reduction in the light weight of the ship implies more cargo and more revenue generation for the ship owner. Over an average lifetime of 25 years, the amount of revenue generated could be significant, due to which a number of ship owners are giving a serious thought to the usage of light weight materials in shipping. Stena Line, a Swedish shipping company has a number of passenger ferries running in the European region. They are also the proud owners of the HSS series of ships, which are unique as they are catamarans made completely in aluminium. Being the pioneers in the shipping industry, they have considered the possibility of having a sandwich superstructure for one of their ferries, HSS 900. This paper looks into the preliminary design of the structure under DNV regulations. While fire safety is also part of the project, this paper focuses on the structure. Different kinds of fibres, resins and cores could be used for making the sandwich construction. The fibre making the faces could be E-glass, S-glass, carbon fibre etc, the resin systems also provide a variety of options like the polyesters, vinyl esters and phenolics. Similarly the core material could be honeycomb, PVC or PU. In this paper, possibilities of using these materials for the making the superstructure has been looked into. A preliminary calculation shows how much in terms of light weight of the vessel could be saved if sandwich construction is used. As it is weight critical approach that is the driving factor in using light weight materials, an optimization of the structure by breaking it up into sandwich panel, spacing of the transverses and longitudinal has also been performed. While optimizing the sandwich panel, four major criteria of maximum normal stress, maximum shear stress, wrinkling stress and maximum allowed deflection have been explored. The limit point where all the four requirements are met and the weight is minimum possible has been considered as the optimum point. All in all it is a sandwich superstructure, which has been optimized for weight.
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4. |
- Gerkin, Richard C., et al.
(författare)
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Recent Smell Loss Is the Best Predictor of COVID-19 Among Individuals With Recent Respiratory Symptoms
- 2021
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 46
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Tidskriftsartikel (refereegranskat)abstract
- In a preregistered, cross-sectional study, we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0–100 visual analog scales (VAS) for participants reporting a positive (C19+; n = 4148) or negative (C19−; n = 546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19− groups exhibited smell loss, but it was significantly larger in C19+ participants (mean ± SD, C19+: −82.5 ± 27.2 points; C19−: −59.8 ± 37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC = 0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0–10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4 < OR < 10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable.
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