A Review on the Mechanical Modeling of Composite Manufacturing Processes

© 2016, The Author(s). The increased usage of fiber reinforced polymer composites in load bearing applications requires a detailed understanding of the process induced residual stresses and their effect on the shape distortions. This is utmost necessary in order to have more reliable composite manufacturing since the residual stresses alter the internal stress level of the composite part during the service life and the residual shape distortions may lead to not meeting the desired geometrical tolerances. The occurrence of residual stresses during the manufacturing process inherently contains diverse interactions between the involved physical phenomena mainly related to material flow, heat transfer and polymerization or crystallization. Development of numerical process models is required for virtual design and optimization of the composite manufacturing process which avoids the expensive trial-and-error based approaches. The process models as well as applications focusing on the prediction of residual stresses and shape distortions taking place in composite manufacturing are discussed in this study. The applications on both thermoset and thermoplastic based composites are reviewed in detail

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

S

Limitations of processing carbon fibre reinforced plastic/polymer material using automated fibre placement technology

Automated fibre placement was used to optimise the tow steering of carbon fibre reinforced plastic/polymer whereby the minimum defect-free steering radius (Rmin) achievable. The results revealed that in the case of the woven ply surface with unheated tool the Rmin, using 1/4 inch tows, is found to be 1350 mm. For the bare tool surface, the tool temperature had to be raised to 30C in order to achieve the same Rmin of 1350 mm. To attain a seamless transition from part design to manufacture using CAD, automated fibre placement was equipped with software tools (TruPLAN and TruFIBER). From the results of software validation and steering trials on a variable radius tool having a pre-laid UD ply, it is found that the ability to steer around a tighter radius was a vast asset of the 1/8 inch tow over the 1/4 inch one, which makes it the preferred choice for the more geometrically complex parts

Assessment of maxillofacial trauma in emergency department

Introduction: The incidence and epidemiological causes of maxillofacial (MF) trauma varies widely. The objective of this study is to point out maxillofacial trauma patients' epidemiological properties and trauma patterns with simultaneous injuries in different areas of the body that may help emergency physicians to deliver more accurate diagnosis and decisions. Methods: In this study we analyze etiology and pattern of MF trauma and coexisting injuries if any, in patients whose maxillofacial CT scans was obtained in a three year period, retrospectively. Results: 754 patients included in the study consisting of 73.7% male and 26.3% female, and the male-to-female ratio was 2.8:1. Mean age was 40.3 +/- 17.2 years with a range of 18 to 97. 57.4% of the patients were between the ages of 18-39 years and predominantly male. Above 60 years of age, referrals were mostly woman. The most common cause of injuries were violence, accounting for 39.7% of the sample, followed by falls 27.9% and road traffic accidents 27.2%. The primary cause of injuries were violence between ages 20 and 49 and falls after 50. Bone fractures found in 56,0% of individuals. Of the total of 701 fractured bones in 422 patients the most frequent was maxillary bone 28,0% followed by nasal bone 25,3%, zygoma 20,2%, mandible 8,4%, frontal bone 8,1% and nasoethmoidoorbital bone 3,1%. Fractures to maxillary bone were uppermost in each age group. 8, 9% of the patients had brain injury and only frontal fractures is significantly associated to TBI (p < 0.05) if coexisting facial bone fracture occurred. Male gender has statistically stronger association for suffering TBI than female (p < 0, 05). Most common cause of TBI in MF trauma patients was violence (47, 8%). 158 of the 754 patients had consumed alcohol before trauma. No statistically significant data were revealed between alcohol consumption gender and presence of fracture. Violence is statistically significant (p < 0.05) in these patients. Conclusion: Studies subjected maxillofacial traumas yield various etiologic factors, demographic properties and fracture patterns probably due to social, cultural and governmental differences. Young males subjected to maxillofacial trauma more commonly as a result of interpersonal violence