20 research outputs found
Damage mechanisms of hat-shaped GRP beams
In this study, the behaviour of hat-shaped glass-reinforced plastic (GRP) composite beams was investigated experimentally and numerically to predict the effect of different material composition on: • Flexural stiffness of the beams • Ultimate collapse strength of beams • Failure mechanisms of the beams The materials used in this study were chopped strand mat (CSM) in different weight e.g., 600, 450 and 225 g/m2 and 1600 g/m2 unidirectional (UD) glass fibre, 600 g/m2 woven rowing (WR) and 600 g/m2 biaxial [±45°] with polyester resin (isopthalic and orthopthalic) and polyurethane (PU) foam. Two types of top hat composite beam have been tested under four-point bending loads. The finite element predictions were compared with the test data and good agreement was obtained
ESTIMATION OF INCREASED HOSPITAL STAY DUE TO NOSOCOMIAL INFECTIONS IN SURGICAL PATIENTS - COMPARISON OF MATCHED GROUPS
An investigation, using a prospective cohort study, was performed to estimate the prolongation of hospital stay caused by nosocomial infections in surgical patients. An evaluation of the one-to-one matching method, as a model for similar studies was also undertaken. Between 1992 and 1994, 225 of 1482 surgical patients (15%) developed infection. Of these, 223 evaluable patients were compared with 1256 uninfected cases, in an unmatched analysis. In a further analysis, 151 infected cases were matched one-to-one with uninfected controls, and other factors such as age, length of preoperative stay, presence of malignancy or diabetes and presence of foley catheters or drains, were evaluated. Patients with infection were hospitalized for 10.6 days longer than the matched controls. In the unmatched analysis, infected patients appear to remain in hospital for a further 17 days
Predictive values of D-dimer assay, GRACE scores and TIMI scores for adverse outcome in patients with non-ST-segment elevation myocardial infarction
Muhammet Hulusi Satilmisoglu,1 Sinem Ozbay Ozyilmaz,1 Mehmet Gul,1 Hayriye Ak Yildirim,2 Osman Kayapinar,3 Kadir Gokturk,4 Huseyin Aksu,1 Korhan Erkanli,5 Abdurrahman Eksik1 1Department of Cardiology, 2Department of Biochemistry, Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, 3Department of Cardiology, Duzce University Faculty of Medicine, Duzce, 4Department of Infectious Diseases, 5Department of Thoracic and Cardiovascular Surgery, Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey Purpose: To determine the predictive values of D-dimer assay, Global Registry of Acute Coronary Events (GRACE) and Thrombolysis in Myocardial Infarction (TIMI) risk scores for adverse outcome in patients with non-ST-segment elevation myocardial infarction (NSTEMI).Patients and methods: A total of 234 patients (mean age: 57.2±11.7 years, 75.2% were males) hospitalized with NSTEMI were included. Data on D-dimer assay, GRACE and TIMI risk scores were recorded. Logistic regression analysis was conducted to determine the risk factors predicting increased mortality.Results: Median D-dimer levels were 349.5 (48.0–7,210.0) ng/mL, the average TIMI score was 3.2±1.2 and the GRACE score was 90.4±27.6 with high GRACE scores (>118) in 17.5% of patients. The GRACE score was correlated positively with both the D-dimer assay (r=0.215, P=0.01) and TIMI scores (r=0.504, P=0.000). Multivariate logistic regression analysis revealed that higher creatinine levels (odds ratio =18.465, 95% confidence interval: 1.059–322.084, P=0.046) constituted the only significant predictor of increased mortality risk with no predictive values for age, D-dimer assay, ejection fraction, glucose, hemoglobin A1c, sodium, albumin or total cholesterol levels for mortality.Conclusion: Serum creatinine levels constituted the sole independent determinant of mortality risk, with no significant values for D-dimer assay, GRACE or TIMI scores for predicting the risk of mortality in NSTEMI patients. Keywords: acute coronary syndrome, non-ST-segment elevation myocardial infarction, GRACE score, D-dimer assay, TIMI scor
Implications of failure criteria choices on the rapid concept design of composite grillage structures using multiobjective optimisation
Grillage topologies are commonly used in many composite structural applications to produce low mass designs that have a high stiffness. While composite failure criteria are being compared in many different simple structures, for example plates and tubes, literature must also compare more complicated applications, including grillages, as there are distinct differences in behaviour. This paper therefore performs analysis of grillage structures with more up to date failure criteria, taken from the world wide failure exercise, than previously investigated. The grillage theory selected is that of Navier theory with elastic equivalent properties due to its low computational expense for use with a genetic algorithm to optimise a composite structure. The results take an example from leisure boatbuilding showing the grillages produced from the different limit states, comparing the cost and mass. The final results show that the method allows a rapid analysis of grillages and that the selection of the limit state has an important effect on the optimised grillage topolog