Mesoscopic modeling of the rtm process for homogenization

Intrinsic hybrids can be manufactured in a modified resin transfer molding (RTM) process for fibre reinforced polymers. Our work concentrates on mesoscopic modeling for temperature-dependent visco-elastic effects accompanied by curing within the RTM process. During hybridization and later thermal loading the periodic mesostructure defined by resin and fibres is taken into account as a representative volume element (RVE) subjected to thermo-mechanical loading. Homogenization leads to results on the less resolved macroscale. In the examples we illustrate the characteristic behavior of the mesoscopic model, such as shrinking due to curing and temperature dependence and simulate the RTM process as well as thermal loading of the cured composite with the finite-element-method

Evidence, illness, and causation: an epidemiological perspective on the Russo-Williamson Thesis.

According to the Russo-Williamson Thesis, causal claims in the health sciences need to be supported by both difference-making and mechanistic evidence. In this article, we attempt to determine whether Evidence-based Medicine (EBM) can be improved through the consideration of mechanistic evidence. We discuss the practical composition and function of each RWT evidence type and propose that exposure-outcome evidence (previously known as difference-making evidence) provides associations that can be explained through a hypothesis of causation, while mechanistic evidence provides finer-grained associations and knowledge of entities that ultimately explains a causal hypothesis. We suggest that mechanistic evidence holds untapped potential to add value to the assessment of evidence quality in EBM and propose initial recommendations for the integration of mechanistic and exposure-outcome evidence to improve EBM by robustly leveraging available evidence in support of good medical decisions

Impact of Daily Arctic Sea Ice Variability in CAM3.0 during Fall and Winter

Climate projections suggest that an ice-free summer Arctic Ocean is possible within several decades and with this comes the prospect of increased ship traffic and safety concerns. The daily sea ice concentration tendency in five Coupled Model Intercomparison Project phase 5 (CMIP5) simulations is compared with observations to reveal that many models underestimate this quantity that describes high-frequency ice movements, particularly in the marginal ice zone. To investigate whether high-frequency ice variability impacts the atmosphere, the Community Atmosphere Model, version 3.0 (CAM3.0), is forced by sea ice with and without daily fluctuations. Two 100-member ensemble experiments with daily varying (DAILY) and smoothly varying (SMTH) sea ice are conducted, along with a climatological control, for an anoma- lously low ice period (August 2006–November 2007). Results are presented for three periods: September 2006, October 2006, and December–February (DJF) 2006/07. The atmospheric response differs between DAILY and SMTH. In September, sea ice differences lead to an anomalous high and weaker storm activity over northern Europe. During October, the ice expands equatorward faster in DAILY than SMTH in the Siberian seas and leads to a local response of near-surface cooling. In DJF, there is a 1.5-hPa positive sea level pressure anomaly over North America, leading to anomalous northerly flow and anomalously cool continental U.S. temperatures. While the atmospheric responses are modest, the differences arising from high temporal frequency ice variability cannot be ignored. Increasing the accuracy of coupled model sea ice variations on short time scales is needed to improve short-term coupled model forecasts

Entrained Flow Gasification: Experiments and Mathematical Modelling Based on RANS

Interdisciplinary research has been conducted in the frame of the Helmholtz Virtual Institute for Gasification Technology (HVIGasTech) [1-4]. The main objective is to develop a validated numerical simulation tool for describing the entrained flow gasification of biomass (cf. bioliq® process [5]). This paper presents work-in-progress and reports the recent experimental and numerical results for the entrained flow gasification of model fuels (ethylene glycol, 90 % ethylene glycol + 10 % wood-char) under atmospheric conditions. Three experimental campaigns have been carried out at the Research Entrained flow GAsifier (REGA). Radial profiles of gas phase composition (CH$_{4}$, CO, CO$_{2}$, H$_{2}$) and temperature have been measured at burner distances of 300 mm and 680 mm. In parallel to the experimental campaigns, RANS based simulations have been performed using ANSYS Fluent. Turbulence-chemistry interaction has generally been described by the Eddy Dissipation Concept (EDC). EDC has been used in combination with two global reaction mechanisms for the entrained flow gasification of ethylene glycol: the HVI1 mechanism and the extended Jones-Lindstedt mechanism [3]. Devolatilisation and the heterogeneous reactions of wood-char with CO$_{2}$ and H$_{2}$O are computed using kinetics derived from measurements [6, 7]. The numerical results for the entrained flow gasification of ethylene glycol show good agreement with the measured data. In particular, the model based on EDC and the HVI1 mechanism predicts the gas composition well. Gas temperatures are slightly overpredicted. The numerical results for the gasification of slurry deviate from the experimental results concerning the gas phase composition. Further research needs to be carried out to close this gap

Evidence, illness, and causation: an epidemiological perspective on the Russo-Williamson Thesis.

According to the Russo-Williamson Thesis, causal claims in the health sciences need to be supported by both difference-making and mechanistic evidence. In this article, we attempt to determine whether Evidence-based Medicine (EBM) can be improved through the consideration of mechanistic evidence. We discuss the practical composition and function of each RWT evidence type and propose that exposure-outcome evidence (previously known as difference-making evidence) provides associations that can be explained through a hypothesis of causation, while mechanistic evidence provides finer-grained associations and knowledge of entities that ultimately explains a causal hypothesis. We suggest that mechanistic evidence holds untapped potential to add value to the assessment of evidence quality in EBM and propose initial recommendations for the integration of mechanistic and exposure-outcome evidence to improve EBM by robustly leveraging available evidence in support of good medical decisions

First observations of sea ice flexural–gravity waves with ground-based radar interferometry in Utqiaġvik, Alaska

We investigate the application of ground-based radar interferometry for measuring flexural–gravity waves in sea ice. We deployed a GAMMA Portable Radar Interferometer (GPRI) on top of a grounded iceberg surrounded by landfast sea ice near Utqiaġvik, Alaska. The GPRI collected 238 acquisitions in stare mode during a period of moderate lateral ice motion during 23–24 April 2021. Individual 30 s interferograms exhibit ∼ 20–50 s periodic motion indicative of propagating infragravity waves with ∼ 1 mm amplitudes. Results include examples of onshore wave propagation at the speed predicted by the water depth and a possible edge wave along an ice discontinuity. Findings are supported through comparison with on-ice Ice Wave Rider (IWR) accelerometers and modeled wave propagation. These results suggest that the GPRI can be a valuable tool to track wave propagation through sea ice and possibly detect changes in such properties across variable ice conditions.</p

Early Nutrition and Weight Gain in Preterm Newborns and the Risk of Retinopathy of Prematurity

Objective: To identify nutritional and weight gain limitations associated with retinopathy of prematurity (ROP) severity among very preterm newborns. Patients and Methods 1180 infants <28 weeks GA at birth with ROP examination results were grouped and analyzed by quartile of weekly total calorie, carbohydrate, protein, and lipid intake, as well as growth velocity between postnatal days 7 and 28 (adjusted for GA and birth weight Z-score). ROP was categorized by development of no, mild (<prethreshold), type 2, or type 1 ROP, as well as markers of ROP severity including stage 3 ROP, zone 1 disease, and plus disease. Associations between nutritional intake and ROP severity were compared. Results: Greater risk for Type 1 ROP (risk/95% confidence intervals) was found for infants with lowest quartile receipt of lipids (2.1/1.1, 3.8), total calories (2.2/1.4, 3.6), and carbohydrates (1.7/1.1, 2.9). Development of zone 1 ROP was associated with lipid or total calorie intake in the lowest quartile, and development of stage 3 ROP was associated with lowest quartile of total calorie intake. Growth velocity in the lowest quartile was associated with increased risk of any ROP, including type 1 ROP. Conclusion: The risk of developing severe ROP in extremely premature infants might be reduced by improving nutritional support, specifically targeting lipids and total calories, and perhaps by improving weight gain

Effects of steam and vacuum administration during decontamination on essential oil content in herbal medicines

Saturated steam decontamination is an application for elimination of microorganisms from the surface of different materials. This technique has been optimized for the treatment of dried spices or pharmaceuticals, which could have been contaminated with microorganisms during cultivation, processing, storage or transport. The described saturated steam decontamination is based on the Lemgo process. This method does not kill microorganisms, but removes them physically from the surface.Our investigation focused on measuring the effects of steam temperatures at 120 °C and 100 °C, respectively, for 20 s with a subsequent fl ash vacuum of 20 s. Applications of fl ash vacuum as well as saturated steam heated to 120 °C were also tested separately. The impact of these parameters on the essential oil content and on the surface of different medicinal plants such as marjoram, oregano, fennel and eucalyptus was analysed using gas chromatography and scanning electron microscopy.Especially in herbal drugs with glandular trichomes such as marjoram and oregano severe surface destruction was visible accompanied by high losses of essential oil from 93 % in marjoram tissue to 59 % in oregano tissue. For fennel and eucalyptus that possess protected essential oil storage cells only minor or no reduction of volatiles has been observed during exposure to saturated steam. The experiments show clearly a positive correlation between stability of essential oil cavities and essential oil content preservation

Dynamical Scaling from Multi-Scale Measurements

We present a new measure of the Dynamical Critical behavior: the "Multi-scale Dynamical Exponent (MDE)"Comment: 9 pages,Latex, Request figures from [email protected]