A statistical treatment of the loss of stiffness during cyclic loading for short fiber reinforced injection molded composites

Injection molded short fiber reinforced composites (SFRC) have different local fiber orientation distribution (FOD) at every point. SN curves of short fiber reinforced composites are known to depend on the fiber orientation distribution. Such materials also suffer from continuous loss of stiffness during cyclic loading. It is not known whether the loss of stiffness is different for SFRC with different FOD. A statistical analysis of the loss of stiffness curves is presented in this paper. Tension-tension fatigue experiments are performed and loss of stiffness is collected for every data point in the SN curve. A systematic method for comparing the loss of stiffness is developed. It is concluded that the difference in loss of stiffness curves for coupons of SFRC with different FOD is not statistically significant. (C) 2016 Elsevier Ltd. All rights reserved

AflaB2® and osteoarthritis: a multicentric, observational, post-marketing surveillance study in Indian patients suffering from knee osteoarthritis

Background: Osteoarthritis (OA) is one of the most debilitating chronic degenerative joint disorder characterized by pain, inflammation and stiffness of joints with wear and tear of the cartilage. Recent evidences suggest the involvement of the immune pathway in OA development. This study was conducted to evaluate the efficacy and safety of AflaB2® capsules containing Aflapin® and native collagen type II in knee OA patients.Methods: Total 40 knee OA subjects were enrolled at the out-patient department (OPD) of three different sites under supervision of physicians as per the inclusion and exclusion criteria of the study. Subjects were instructed to consume AflaB2® capsules once daily orally for three months. They were informed to visit the respective study center as per the schedule visits to assess and record the efficacy and safety.Results: AflaB2® treatment showed significant reduction in pain and stiffness with improvement in physical functions compared to the baseline. The reduction in pain score was observed from 2nd visit on visual analogue scale (VAS). The VAS score was reduced to 1.63±1.23 (p<0.001) from its baseline score 6.0±1.04 at the end of the treatment. The WOMAC Total Score was reduced to 18.1±6.04 (p<0.001) from its baseline score 74.4±8.07 at the end of the treatment. The improvement was observed in WOMAC pain, stiffness and physical functions score. No significant side-effect was reported with AflaB2® treatment throughout the study.Conclusions: The present study provides the evidence in support of the potential efficacy and excellent tolerability of oral intake of AflaB2® capsules in reducing OA symptoms

A feasibility study of the Master SN curve approach for short fiber reinforced composites

Short fiber reinforced composite (SFRC) materials have a different fiber orientation distribution (FOD) at every point. The fatigue properties of SFRC are known to depend on the FOD. The Master SN curve (MSNC) method for predicting an SN curve for a given FOD based on the known SN curve for the reference FOD is used to predict the local SN curve of a SFRC component by relating the damage at the microscopic level to the macroscopic fatigue properties. A simplified version of MSNC method, which needs even less experimental input, uses an assumption of constant SN curve slope is also presented in this paper. The paper validates both variants of the MSNC method on three sets of experimental data on fatigue of short fiber composites and analyses their accuracy. It is demonstrated that the MSNC approach needs only one SN curve as input with no specific requirements to the fiber orientation of the test coupon. Test coupons could have either uniform fiber orientation in the thickness or a "skin core" orientation variation. (C) 2016 Elsevier Ltd. All rights reserved

Pseudo-grain discretization and full Mori Tanaka formulation for random heterogeneous media : predictive abilities for stresses in individual inclusions and the matrix

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The Master SN curve approach : a hybrid multi-scale fatigue simulation of short fiber reinforced composites

Typical short fiber reinforced composites (SFRCs) components have a different statistical distribution of orientation of fibers at different points leading to different static and fatigue behavior at different locations across the component. To link component-scale calculations with this variability of fiber orientations, each element in the FE model is modeled as a Representative Volume Element (RVE); the static and fatigue properties must be calculated for each of these elements. While there are established methods to estimate the static properties, there are none for the fatigue properties. A hybrid (combination of micromechanics and tests) and multi-scale (damage in micro-scale linked to macroscale fatigue properties) method of predicting the SN curve for every point in a short fiber composite has been developed. This proposed method is based not only on tests but on a combination of manufacturing simulation, tests and multi-scale mechanics. An extensive test program was undertaken to study the fatigue behavior of short fiber composites and validate the concept of the Master SN curve (MSNC) approach. The MSNC approach is compared with two prevalent approaches strength based scaling and test based interpolation. The MSNC approach was found to be in a good agreement with the experimental results and was confirmed to be more accurate than the prevalent methods. (C) 2015 Elsevier Ltd. All rights reserved

Future atmospheric methane concentrations in the context of the stabilization of greenhouse gas concentrations

Abstract. Tropospheric CH 4 concentration depends, according to modeled tropospheric processes, on many factors, including emissions of CH 4 as well as NO x and CO. Illustrative analyses of the relation between emissions and CH 4 concentration give some guidance on the role of CH 4 in the stabilization of greenhouse gas concentrations. The contribution of CH 4 to radiative forcing at the time of stabilization is expected to be modest, provided CH 4 and CO emissions do not go far beyond current rates. However, in cases leading to stabilization the potential mitigation of increases in radiative forcing by methane control could be comparable to that of CO 2 control over the next century. Whether or not this potential is realized will depend partially on the cost of deep reductions of CH 4 , NO x , CO, or CO 2 emissions over the next century, which is not known

2016 International Land Model Benchmarking (ILAMB) Workshop Report

As earth system models (ESMs) become increasingly complex, there is a growing need for comprehensive and multi-faceted evaluation of model projections. To advance understanding of terrestrial biogeochemical processes and their interactions with hydrology and climate under conditions of increasing atmospheric carbon dioxide, new analysis methods are required that use observations to constrain model predictions, inform model development, and identify needed measurements and field experiments. Better representations of biogeochemistryclimate feedbacks and ecosystem processes in these models are essential for reducing the acknowledged substantial uncertainties in 21st century climate change projections

Implementation of corticosteroids in treating COVID-19 in the ISARIC WHO Clinical Characterisation Protocol UK:prospective observational cohort study

BACKGROUND: Dexamethasone was the first intervention proven to reduce mortality in patients with COVID-19 being treated in hospital. We aimed to evaluate the adoption of corticosteroids in the treatment of COVID-19 in the UK after the RECOVERY trial publication on June 16, 2020, and to identify discrepancies in care. METHODS: We did an audit of clinical implementation of corticosteroids in a prospective, observational, cohort study in 237 UK acute care hospitals between March 16, 2020, and April 14, 2021, restricted to patients aged 18 years or older with proven or high likelihood of COVID-19, who received supplementary oxygen. The primary outcome was administration of dexamethasone, prednisolone, hydrocortisone, or methylprednisolone. This study is registered with ISRCTN, ISRCTN66726260. FINDINGS: Between June 17, 2020, and April 14, 2021, 47 795 (75·2%) of 63 525 of patients on supplementary oxygen received corticosteroids, higher among patients requiring critical care than in those who received ward care (11 185 [86·6%] of 12 909 vs 36 415 [72·4%] of 50 278). Patients 50 years or older were significantly less likely to receive corticosteroids than those younger than 50 years (adjusted odds ratio 0·79 [95% CI 0·70–0·89], p=0·0001, for 70–79 years; 0·52 [0·46–0·58], p80 years), independent of patient demographics and illness severity. 84 (54·2%) of 155 pregnant women received corticosteroids. Rates of corticosteroid administration increased from 27·5% in the week before June 16, 2020, to 75–80% in January, 2021. INTERPRETATION: Implementation of corticosteroids into clinical practice in the UK for patients with COVID-19 has been successful, but not universal. Patients older than 70 years, independent of illness severity, chronic neurological disease, and dementia, were less likely to receive corticosteroids than those who were younger, as were pregnant women. This could reflect appropriate clinical decision making, but the possibility of inequitable access to life-saving care should be considered. FUNDING: UK National Institute for Health Research and UK Medical Research Council