A multilevel projection‐based model order reduction framework for nonlinear dynamic multiscale problems in structural and solid mechanics

A reduction/hyper reduction framework is presented for dramatically accelerating the solution of nonlinear dynamic multiscale problems in structural and solid mechanics. At each scale, the dimensionality of the governing equations is reduced using the method of snapshots for proper orthogonal decomposition, and computational efficiency is achieved for the evaluation of the nonlinear reduced‐order terms using a carefully designed configuration of the energy conserving sampling and weighting method. Periodic boundary conditions at the microscales are treated as linear multipoint constraints and reduced via projection onto the span of a basis formed from the singular value decomposition of Lagrange multiplier snapshots. Most importantly, information is efficiently transmitted between the scales without incurring high‐dimensional operations. In this proposed proper orthogonal decomposition–energy conserving sampling and weighting nonlinear model reduction framework, training is performed in two steps. First, a microscale hyper reduced‐order model is constructed in situ, or using a mesh coarsening strategy, in order to achieve significant speedups even in non‐parametric settings. Next, a classical offline–online training approach is performed to build a parametric hyper reduced‐order macroscale model, which completes the construction of a fully hyper reduced‐order parametric multiscale model capable of fast and accurate multiscale simulations. A notable feature of this computational framework is the minimization, at the macroscale level, of the cost of the offline training using the in situ or coarsely trained hyper reduced‐order microscale model to accelerate snapshot acquisition. The effectiveness of the proposed hyper reduction framework at accelerating the solution of nonlinear dynamic multiscale problems is demonstrated for two problems in structural and solid mechanics. Speedup factors as high as five orders of magnitude are shown to be achievable. Copyright © 2017 John Wiley & Sons, Ltd.     

Preliminary Evidence for a Relationship between Elevated Plasma TNFα and Smaller Subcortical White Matter Volume in HCV Infection Irrespective of HIV or AUD Comorbidity

Classical inflammation in response to bacterial, parasitic, or viral infections such as HIV includes local recruitment of neutrophils and macrophages and the production of proinflammatory cytokines and chemokines. Proposed biomarkers of organ integrity in Alcohol Use Disorders (AUD) include elevations in peripheral plasma levels of proinflammatory proteins. In testing this proposal, previous work included a group of human immunodeficiency virus (HIV)-infected individuals as positive controls and identified elevations in the soluble proteins TNFα and IP10; these cytokines were only elevated in AUD individuals seropositive for hepatitis C infection (HCV). The current observational, cross-sectional study evaluated whether higher levels of these proinflammatory cytokines would be associated with compromised brain integrity. Soluble protein levels were quantified in 86 healthy controls, 132 individuals with AUD, 54 individuals seropositive for HIV, and 49 individuals with AUD and HIV. Among the patient groups, HCV was present in 24 of the individuals with AUD, 13 individuals with HIV, and 20 of the individuals in the comorbid AUD and HIV group. Soluble protein levels were correlated to regional brain volumes as quantified with structural magnetic resonance imaging (MRI). In addition to higher levels of TNFα and IP10 in the 2 HIV groups and the HCV-seropositive AUD group, this study identified lower levels of IL1β in the 3 patient groups relative to the control group. Only TNFα, however, showed a relationship with brain integrity: in HCV or HIV infection, higher peripheral levels of TNFα correlated with smaller subcortical white matter volume. These preliminary results highlight the privileged status of TNFα on brain integrity in the context of infection.     

Translucent network design from a CapEx/OpEx perspective

Translucent wdm network design has been widely investigated during the last 10 years. Translucent networks stand halfway between opaque and transparent networks improving the signal budget while reducing the network cost. On one hand, opaque networks provide satisfying quality from source to destination by the use of electrical reg regeneration (Re-amplifying, Re-shaping, and Re-timing) at each network node. In addition to their high cost inherent to numerous 3R regenerations, opaque networks are also constrained by the bit-rate dependence of electrical components. Transparent networks, on the other hand, do not include any electrical regeneration; therefore, the signal quality is degraded due to the accumulation of linear and non-linear effects along the signal’s route. Translucent networks include electrical regeneration at some network nodes. Among the different possible strategies for translucent network design, sparse regeneration inserts regenerators whenever needed to help establish connection requests. In this context the objective of translucent network design is to judiciously choose the regeneration sites in order to guarantee a certain quality of transmission while minimizing the network cost. In this paper, we propose to solve the translucent network design problem by introducing a heuristic for routing, wavelength assignment, and regenerator placement. This heuristic, called COR2P (Cross-Optimization for RWA and Regenerator Placement) aims not only to minimize the number of required regenerators, but also to minimize the number of regeneration sites. In this perspective, we introduce an original cost function that contributes to the optimization of CapEx/OpEx expenditures in translucent network design. In fact, the CapEx-to-OpEx ratio strongly depends on the pricing and management strategy of the carrier. In this respect, COR2P is designed in a way that its parameters can be adjusted according to carriers’ strategies. In order to discuss its different features, we compare COR2P performance with two other algorithms proposed in the literature for translucent network design.     

Growth performance and fatty acid profiles of intramuscular and subcutaneous fat from Limousin and Charolais heifers fed extruded linseed

Forty-eight heifers, Limousin (LI) and Charolais (CH) breed, were used to evaluate the effect of a basal mixed diet with linseed supplementation (108g/kg DM) on performance and fatty acid (FA) composition of M. longissimus thoracis (MLT) and subcutaneous fat. The feed intake and weight gains were higher, and feed per gain ratio lower in CH heifers than in LI heifers. The muscle lipids and subcutaneous fat of LI heifers contained significantly more MUFA, PUFA, CLA, and less SFA than the lipids of CH heifers. The feeding of extruded linseed significantly increased the concentration of linolenic acid (C18:3n-3), CLA, and decreased PUFA n-6 to PUFA n-3 ratio in lipids extracted from both tissues. Linseed supplementation decreased SFA and increased PUFA in subcutaneous fat. In MLT lipids of linseed-fed heifers PUFA of the n-3 series were increased. It can be concluded that the growth performance of LI heifers was lower, but that their lipids contained more FA that are thought to be important for human health. The feeding of linseed at 108g/kg DM enhanced the nutritive value of beef in terms of FA profile. Breed differences were generally more important than effects of the diet. Dietary effects, however, were more pronounced in PUFA n-3 and arachidonic acid (C20:4n-6).     

Solution phase gold nanorings on a viral protein template

Current studies on materials that exhibit metamaterial properties are mainly focused on lithography-generated 2D substrates. Here we report the successful fabrication of 22 nm gold nanoparticle rings with and without a central nanoparticle assembled on Tobacco Mosaic Virus coat protein disks. These structures are one of the first examples of nanorings produced independently of a substrate and represent the first steps toward the realization of a solution-phase or coatings-based metamaterial.     

Premature infant responses to noise reduction by earmuffs: effects on behavioral and physiologic measures

The continuous high-intensity noise in the neonatal intensive care unit (NICU) is both stressful and harmful for the premature infant. Although some researchers have found evidence that loud noise can cause hearing loss and alter physiologic and behavioral responses, no study to date has investigated the benefits of noise reduction by the use of earmuffs. In this study earmuffs were placed over the premature infants' ears to reduce noise intensity in the NICU while physiologic and behavioral responses were measured. Two sites were used to collect data: in the first setting, 17 low birth weight infants were randomly assigned to an experimental and a control group, whereas 13 infants from a second hospital acted as their own controls and were tested with and without earmuffs. Earmuffs that reduced the intensity of noise by 7 to 12 dB were worn by infants in the experimental group only during the observation periods. Infants in the control group were exposed to the usual noise in the NICU. The infant's physiologic and behavioral responses were observed for four 2-hour intervals, morning and evening, on two consecutive days. Most of the significant results were from the site at which infants acted as their own controls. When infants wore the earmuffs, they had significantly higher mean oxygen saturation levels and less fluctuation in oxygen saturation. Furthermore, these infants had less frequent behavioral state changes, spent more time in the quiet sleep state, and had longer bouts in the sleep state. It is imperative that NICUs develop aggressive antinoise policies to substantially and consistently reduce noise.     

Photo‐Thermo‐Mechanical Behaviour Under Quasi‐Static Tensile Conditions of a PMMA‐Core Optical Fibre

As the optical power transmitted by an optical fibre under tensile stress varies with strain, it can be used as a sensor for strain monitoring in structural elements. In the present work, quasi‐static tensile tests of step index polymer optical fibres (POF) with simultaneous measurement of surface temperature and optical power are described. Young's modulus, yield stress and tensile strength are derived from experimental tests. Morphological characterization of the POF fibres using scanning electron microscope images and differential calorimetry technique is performed. The contributions of both elastic and plastic strain components to the variation of temperature and optical power loss are also estimated. The evolution of the POF mechanical properties as well as that of temperature and optical power loss is explained in terms of the progressive relative movement and alignment of the molecular chains in the direction of the applied load. Strain, temperature and optical power loss are then correlated.     

Growth,carcass traits,chemical composition and fatty acid profile in beef from Charolais and Simmental bulls fed different types of dietary lipids

BACKGROUND: The effect of breed and whole sunflower seed on performance, carcass traits and the composition of meat was evaluated in Charolais (CH) and Simmental (SI) bulls. Samples of musculus longissimus lumborum (MLL) and musculus infraspinatus (MIS) were analysed. RESULTS: The CH bulls had a lower feed intake per kg of gain, a higher killing‐out percentage and produced more valuable carcasses. The muscles from SI bulls contained more monounsaturated fatty acids (FA) and less saturated FA (in g kg^?1 FA) than the muscles from CH bulls. The sunflower seed supplement increased the proportions of linoleic acid and c9t11 conjugated linoleic acid and the ratio of polyunsaturated fatty acids (PUFA) to saturated FA and decreased the index of atherogenicity of FA in meat lipids. CONCLUSION: The results of this study demonstrated the superiority of the CH over the SI breed in a number of economically important traits. The breed effect on the nutritional quality of meat was ambiguous. Meat lipids of the SI bulls contained more unsaturated FA but also more PUFA n‐6 and a higher PUFA n‐6/PUFA n‐3 ratio. Copyright © 2008 Society of Chemical Industry