Characterization of Interfacial Corrosion Behavior of Hybrid Laminate EN AW-6082 ∪ CFRP.

The corrosion behavior of a hybrid laminate consisting of laser-structured aluminum EN AW-6082 ∪ carbon fiber-reinforced polymer was investigated. Specimens were corroded in aqueous NaCl electrolyte (0.1 mol/L) over a period of up to 31 days and characterized continuously by means of scanning electron and light microscopy, supplemented by energy dispersive X-ray spectroscopy. Comparative linear sweep voltammetry was employed on the first and seventh day of the corrosion experiment. The influence of different laser morphologies and production process parameters on corrosion behavior was compared. The corrosion reaction mainly arises from the aluminum component and shows distinct differences in long-term corrosion morphology between pure EN AW-6082 and the hybrid laminate. Compared to short-term investigations, a strong influence of galvanic corrosion on the interface is assumed. No distinct influences of different laser structuring and process parameters on the corrosion behavior were detected. Weight measurements suggest a continuous loss of mass attributed to the detachment of corrosion products.

Frequency-based rare diagnoses as a novel and accessible approach for studying rare diseases in large datasets: a cross-sectional study.

BACKGROUND: Up to 8% of the general population have a rare disease, however, for lack of ICD-10 codes for many rare diseases, this population cannot be generically identified in large medical datasets. We aimed to explore frequency-based rare diagnoses (FB-RDx) as a novel method exploring rare diseases by comparing characteristics and outcomes of inpatient populations with FB-RDx to those with rare diseases based on a previously published reference list. METHODS: Retrospective, cross-sectional, nationwide, multicenter study including 830,114 adult inpatients. We used the national inpatient cohort dataset of the year 2018 provided by the Swiss Federal Statistical Office, which routinely collects data from all inpatients treated in any Swiss hospital. Exposure: FB-RDx, according to 10% of inpatients with the least frequent diagnoses (i.e.1.decile) vs. those with more frequent diagnoses (deciles 2-10). Results were compared to patients having 1 of 628 ICD-10 coded rare diseases. PRIMARY OUTCOME: In-hospital death. SECONDARY OUTCOMES: 30-day readmission, admission to intensive care unit (ICU), length of stay, and ICU length of stay. Multivariable regression analyzed associations of FB-RDx and rare diseases with these outcomes. RESULTS: 464,968 (56%) of patients were female, median age was 59 years (IQR: 40-74). Compared with patients in deciles 2-10, patients in the 1. were at increased risk of in-hospital death (OR 1.44; 95% CI: 1.38, 1.50), 30-day readmission (OR 1.29; 95% CI 1.25, 1.34), ICU admission (OR 1.50; 95% CI 1.46, 1.54), increased length of stay (Exp(B) 1.03; 95% CI 1.03, 1.04) and ICU length of stay (1.15; 95% CI 1.12, 1.18). ICD-10 based rare diseases groups showed similar results: in-hospital death (OR 1.82; 95% CI 1.75, 1.89), 30-day readmission (OR 1.37; 95% CI 1.32, 1.42), ICU admission (OR 1.40; 95% CI 1.36, 1.44) and increased length of stay (OR 1.07; 95% CI 1.07, 1.08) and ICU length of stay (OR 1.19; 95% CI 1.16, 1.22). CONCLUSION(S): This study suggests that FB-RDx may not only act as a surrogate for rare diseases but may also help to identify patients with rare disease more comprehensively. FB-RDx associate with in-hospital death, 30-day readmission, intensive care unit admission, and increased length of stay and intensive care unit length of stay, as has been reported for rare diseases.

A Generalized Stress State and Temperature Dependent Damage Indicator Framework for Ductile Failure Prediction in Heat-Assisted Forming Operations.

Heat-assisted forming processes are becoming increasingly important in the manufacturing of sheet metal parts for body-in-white applications. However, the non-isothermal nature of these processes leads to challenges in evaluating the forming limits, since established methods such as Forming Limit Curves (FLCs) only allow the assessment of critical forming strains for steady temperatures. For this reason, a temperature-dependent extension of the well-established GISSMO (Generalized Incremental Stress State Dependent Damage Model) fracture indicator framework is developed by the authors to predict forming failures under non-isothermal conditions. In this paper, a general approach to combine several isothermal FLCs within the temperature-extended GISSMO model into a temperature-dependent forming limit surface is investigated. The general capabilities of the model are tested in a coupled thermo-mechanical FEA using the example of warm forming of an AA5182-O sheet metal cross-die cup. The obtained results are then compared with state of the art of evaluation methods. By taking the strain and temperature path into account, GISSMO predicts greater drawing depths by up to 20% than established methods. In this way the forming and so the lightweight potential of sheet metal parts can by fully exploited. Moreover, the risk and locus of failure can be evaluated directly on the part geometry by a contour plot. An additional advantage of the GISSMO model is the applicability for low triaxialities as well as the possibility to predict the materials behavior beyond necking up to ductile fracture.

Separation and reclamation of automotive hybrid structures made of metal and fibre-reinforced plastic.

Currently, resource efficiency is getting more importance due to a build-up of disposed waste in landfills. The closed raw material cycle is an important topic in industries as it is economic and pollute free. This scenario applies to both existing and innovative future materials. To tackle the pollute emission of vehicles, multi-material and hybrid structures are gaining importance in lightweight construction. Hybrid structures that are a combination of metallic materials and carbon-fibre-reinforced plastics (CFRP) are often used for lightweight structures. In the present work, a method is presented that can separate hybrid structures (metal and CFRP) using thermal process so that they can be recycled separately. The thermal process was investigated with the help of different heating techniques such as the furnace, induction, resistance, and infrared on the hybrid structures. Corresponding process windows and the boundary conditions for respective heating techniques are investigated in the current work. The influence of various heating techniques on the separation process is validated using microscopic results.

Frailty, underweight and impaired mobility are associated with institutionalisation after post-acute care.

AIMS OF THE STUDY: Post-acute care (PAC) is intended for older adult patients who are unable to return home directly after acute hospitalisation but who do not otherwise qualify for specific rehabilitation. However, data on potential predictors of PAC outcomes remain limited. Our aim was to identify patient characteristics upon admission to PAC that are associated with subsequent institutionalisation. METHODS: Prospective cohort study enrolling 140 former acute care inpatients aged 60 and older who were referred to PAC units at nursing homes in Zurich, Switzerland. MEASURES: Geriatric assessment at admission included Barthel Index (BI), Short Physical Performance Battery (SPPB), frailty status (Fried phenotype), nutrition and cognitive status. Logistic regression was used to determine statistically significant associations. RESULTS: Mean age was 84.1 (standard deviation [SD] 8.6) years; 62.9% of participants were women. Mean body mass index (BMI) was 25.0 (SD 5.8) kg/m2, with 12.1% being underweight (BMI <20 kg/m2). Mean BI at admission was 62.1 (SD 19.1), mean SPPB score was 5.2 (SD 2.8), and 55% were frail (≥3 Fried criteria present). After a mean length of stay in PAC of 30.9 (SD 16.5) days, 48.6% were institutionalised. Patients who were frail at admission had a 2.97-fold higher (odds ratio [OR] 2.9,7 95% confidence interval [CI] 1.04–8.42), and patients who were underweight had a 4.94-fold higher (OR 4.94, 95% CI 1.11–22.01) chance of institutionalisation. Conversely, each points increment on the SBBP score lowered the likelihood of institutionalisation by 23% (OR 0.77, 95% CI 0.65–0.92). CONCLUSIONS: Frailty, low Short Physical Performance Battery score and being underweight at admission to PAC were significantly associated with a higher chance of subsequent institutionalisation. Strategies to improve these factors could improve post-acute care outcomes.

Cyclodextrin as sizing for carbon fibers: new bonding mechanism improves adhesion in carbon fiber reinforced epoxy resin.

In this study, ß-cyclodextrin was covalently bonded on carbon fibers and its influence through host-guest complex formation was analyzed. Since cyclodextrins act as host molecules for aromatic compounds, complex formations can be performed in carbon fiber reinforced epoxy resins, between the carbon fiber surface and the aromatic compounds of the surrounding plastic. This interface design leads to improved adhesion between fiber and plastic. An increase of the interfacial shear strength from 12 MPa to 38 MPa was detected. It was possible to increase the interfacial shear strength even further, to 41 MPa, through a prior complex formation with one of the plastics components. In addition to the micromechanical analysis, energy-dispersive x-ray spectroscopy and contact angle measurements were performed to confirm the covalent coating of cyclodextrin on the carbon fiber surface.

Do older adults benefit from post-acute care following hospitalisation? A prospective cohort study at three Swiss nursing homes.

BACKGROUND: Post-acute care (PAC) programmes appear favourable for older adult inpatients too fragile to be discharged home without extensive support, but otherwise not qualifying for specific rehabilitation. Consequently, many Swiss nursing homes have opened PAC wards after a new federal law refined reimbursement in 2012. However, PAC outcomes in this setting have not been well studied. OBJECTIVE: To investigate the functional outcomes of a nursing home-based PAC programme for older adult patients and to evaluate the influences of age, gender and frailty status on these outcomes. METHODS: This was a prospective cohort study in 135 consecutive patients aged 60 and older admitted to PAC at three nursing homes in Zurich, Switzerland, over a two-month period. Geriatric assessment at admission included mobility, physical performance, cognition, nutrition, frailty, activities of daily living (ADL) and social support. The primary outcomes of the study, Short Physical Performance Battery (SPPB), handgrip strength (HGS) and Barthel Index (BI), were repeated before discharge from PAC. Multivariable linear models were used to analyse differences between these primary outcomes at admission and discharge, adjusting for baseline age, gender, BMI, length of stay (LOS), polypharmacy, cognition, and prior living status. RESULTS: We identified statistically significant improvements between admission and discharge (mean [95% confidence interval]; % change) in BI (69.0 [65.0–72.9] vs 79.6 [75.6–83.6]; +15.4%), gait speed (0.55 [0.48–0.62] vs 0.65 [0.58–0.71] m/s; +18.2%) and SPPB scores (5.5 [5.0–6.1] vs 6.9 [6.3–7.4]; +24%), p-values for all comparisons <0.001. CONCLUSIONS: In this real-word sample, PAC resulted in a significant and clinically relevant improvement in physical performance and ADL. However, our study should be replicated with a larger sample. Furthermore, long-term outcomes of PAC warrant additional investigation.