Emergence of NDM-1-producing Enterobacteriaceae in China

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Prospect for new guidance in the design of FRP

Over the last twenty years, many innovative solutions have confirmed the usefulness of composite structures realized with FRPs (Fibre Reinforced Polymer or Plastic). The need of European standards for use of fibre-reinforced polymer composites in civil engineering was justified in 2007 in the JRC Report EUR 22864 EN. The new European technical rules will be developed using the existing organization of CEN/TC250. The present report has been worked out in the frame of CEN/TC250/WG4 activities. The report encompasses: • Part I, which introduces the policy framework and the CEN/TC250 initiative • Part II, which gives a prospect for CEN guidance for the design and verification of composite structures realized with FRPs The report presents scientific and technical background intended to stimulate debate and serves as a basis for further work to achieve a harmonized European view on the design and verification of such structures. This has been the main impulse to include the work item of the Fibre Reinforced Polymer Structures in the Mandate M/515 with high priority.JRC.G.4-European laboratory for structural assessmen

Prospect for new guidance in the design of FRP : support to the implementation and further development of the Eurocode

Over the last twenty years, many innovative solutions have confirmed the usefulness of composite structures realized with FRPs (Fibre Reinforced Polymer or Plastic). The need of European standards for use of fibre-reinforced polymer composites in civil engineering was justified in 2007 in the JRC Report EUR 22864 EN. The new European technical rules will be developed using the existing organization of CEN/TC250. The present report has been worked out in the frame of CEN/TC250/WG4 activities. The report encompasses: • Part I, which introduces the policy framework and the CEN/TC250 initiative • Part II, which gives a prospect for CEN guidance for the design and verification of composite structures realized with FRPs The report presents scientific and technical background intended to stimulate debate and serves as a basis for further work to achieve a harmonized European view on the design and verification of such structures. This has been the main impulse to include the work item of the Fibre Reinforced Polymer Structures in the Mandate M/515 with high priority

LC-MS/MS-based reference intervals for hair cortisol in healthy children

Background: Human scalp hair is a valuable matrix for determining long-term cortisol concentrations, with wide-spread applicability in clinical care as well as research. However, pediatric reference intervals are lacking. The aim of this cross-sectional study is to establish age-adjusted reference intervals for hair cortisol in children and to gain insight into hair growth velocity in children up to 2 years old. Methods: A total of 625 healthy children were enrolled through recruitment in pregnancy, infant-welfare clinics, and school visits. Scalp hair cortisol levels were measured using liquid chromatography-tandem mass spectrometry. Age-adjusted reference intervals were established in children from birth to 18 years old. Hair growth velocity was determined in children 0−2 years of age by measuring hair length at 4- to 10-week intervals. Results: Hair cortisol levels were high (162.4 pg/mg, 2.5th-97.5th percentile: 28.8–961) after birth with a sharp fall in the first 3 months of life. This is followed by lower values until age 6 and then by graduated and subtle higher values to adult concentrations are reached at the age of 18 years (3.0 pg/mg, 2.5th-97.5th percentile: 0.53–17.8). Average hair growth velocity measured in mm/month was significantly lower in infants 0–6 months of age compared to children 12–24 months (3.5 versus 9.4, P < 0.001). Conclusions: This is the first study to provide age-adjusted reference intervals for hair cortisol in children from 0−18 years. Higher hair cortisol concentrations in infants might be explained by the significantly lower hair growth rate in the first year of life. The establishment of pediatric hair cortisol reference ranges broadens the potential applications of this biomarker in pediatric clinical care

Feasibility of bolted connectors in hybrid FRP-steel structures

Due to the low weight and excellent durability of composite materials, Fibre Reinforced Polymer (FRP) decks mounted on steel superstructures are becoming increasingly common in engineering practice. Bolted joints are generally used to facilitate connections between an FRP deck and steel girders in road bridges. The connections are subjected to both high magnitude static forces as well as fatigue loading due to overpassing vehicles. With ever increasing traffic on both road and railway bridges, fatigue performance is of critical concern. Bolted FRP joints have been extensively researched in the past under static loading, but less is known about the fatigue and creep behaviour of such joints. Furthermore, little research exists on non-pultruded FRP profiles connected using bolted connections. Therefore, the objective of this research is to investigate connectors’ feasibility by means of static, fatigue and creep experiments on four different types of bolted joints comprising mechanical connectors and injection techniques. The study focuses on application in vacuum infused GFRP panels with integrated webs made of multi-directional laminates) connected to steel bridge superstructures. In addition, experimental results are used to validate Finite Element Analyses (FEA). Based on the obtained results, the novel injected steel-reinforced resin (iSRR) connector shows promising potential in hybrid steel-FRP bridges where good fatigue endurance of the connection, are required.</p

Feasibility of Bolted Connectors in Hybrid FRP-Steel Structures

Due to the low weight and excellent durability of composite materials, Fibre Reinforced Polymer (FRP) decks mounted on steel superstructures are becoming all the more common in engineering practice. Bolted joints are generally used to facilitate connections between an FRP deck and steel girders in road bridges. The connections are subjected to both high magnitude static forces as well as fatigue loading due to overpassing vehicles. With ever increasing traffic on both road and railway bridges, fatigue performance is of critical concern. Bolted FRP joints have been extensively researched in the past under static loading, but less is known about the fatigue and creep behaviour of such joints. Furthermore, little research exists on non-pultruded FRP profiles connected using bolted connections. Therefore, the objective of this research is to investigate connectors’ feasibility by means of static, fatigue and creep experiments on four different types of bolted joints comprising mechanical connectors and injection techniques. The study focuses on application in vacuum infused GFRP panels with integrated webs made of multi-directional laminates, connected to steel bridge superstructures. In addition, experimental results are validated by Finite Element Analyses (FEA). Based on the obtained results, the novel injected steel-reinforced resin (iSRR) connector developed at TU Delft shows promising potential in hybrid steel-FRP bridges where good fatigue endurance of the connection and local loads in FRP panel, are required.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Steel & Composite Structure

Design of fibre-polymer composite structures – European Technical Specification: Combined stresses

It was essential in the European Technical Specification for the Design of Fibre- Polymer Composite Structures (prCEN/TS 19101) to provide an Ultimate Limit State design procedure for a failure criterion for multi-ply laminates subjected to in-plane combined actions, which will give a generically applicable and a simple design procedure. This paper will discuss the rationale for the project team (of Working Group 4 to CEN/TC250) deciding that the resistance formula is to satisfy a linear interaction failure criterion

Design of fibre-polymer composite structures – European Technical Specification: Combined stresses

It was essential in the European Technical Specification for the Design of Fibre- Polymer Composite Structures (prCEN/TS 19101) to provide an Ultimate Limit State design procedure for a failure criterion for multi-ply laminates subjected to in-plane combined actions, which will give a generically applicable and a simple design procedure. This paper will discuss the rationale for the project team (of Working Group 4 to CEN/TC250) deciding that the resistance formula is to satisfy a linear interaction failure criterion.Steel & Composite Structure