A preform deformation and resin flow coupled model including the cure kinetics and chemo-rheology for the VARTM process

The present paper deals with preform deformation and resin flow coupled to cure kinetics and chemo-rheology for the VARTM process. By monitoring the coupled resin infusion and curing steps through temperature control, our primary aim is to reduce the cycle time of the process. The analysis is based on the two-phase porous media flow and the preform deformation extended with cure kinetics and heat transfer. A novel feature is the consideration of temperature and preform deformation coupled to resin viscosity and permeability in the VARTM process. To tackle this problem, we extend the porous media framework with the heat transfer and chemical reaction, involving additional convection terms to describe the proper interactions with the resin flow. Shell kinematics is applied to thin-walled preforms, which significantly reduces the problem size. The proposed finite element discretized system of coupled models is solved in a staggered way to handle the partially saturated flow front under non-isothermal conditions efficiently. From the numerical example, we conclude that the cycle time of the VARTM infusion process can be shortened over 68%with the proper temperature control. Moreover, the proposed framework can be applied to optimize the processing parameters and check the compatibility of a resin system for a given infusion task

Modeling and Experimental Validation of the VARTM Process for Thin-Walled Preforms

In this paper, recent shell model is advanced towards the calibration and validation of the Vacuum-assisted Resin Transfer Molding (VARTM) process in a novel way. The model solves the nonlinear and strongly coupled resin flow and preform deformation when the 3-D flow and stress problem is simplified to a corresponding 2-D problem. In this way, the computational efficiency is enhanced dramatically, which allows for simulations of the VARTM process of large scale thin-walled structures. The main novelty is that the assumptions of the neglected through-thickness flow and the restricted preform deformation along the normal of preform surface suffice well for the thin-walled VARTM process. The model shows excellent agreement with the VARTM process experiment. With good accuracy and high computational efficiency, the shell model provides an insight into the simulation-based optimization of the VARTM process. It can be applied to either determine locations of the gate and vents or optimize process parameters to reduce the deformation

Association Between Hypertensive Disorders of Pregnancy and Neurodevelopmental Outcomes Among Offspring

Importance: Hypertensive disorders of pregnancy (HDP) have been associated with poorer neurodevelopmental outcomes in offspring, but the role of familial confounding in these associations is unclear. Objective: To investigate associations of maternal HDP with risks in offspring of autism spectrum disorders (ASDs), attention-deficit/hyperactivity disorder (ADHD), and intellectual disability (ID), as well as variation in overall cognitive performance in offspring. Design, Setting, and Participants: This Swedish register-based study used data from a birth cohort divided into 1 085 024 individuals born between 1987 and 1996 and followed up until December 31, 2014, and 285 901 men born between 1982 and 1992 who attended assessments for military conscription, including a cognitive function test. Statistical analysis was performed from April 1, 2019, to June 1, 2020. Exposures: Diagnoses of HDP, which were provided by the Medical Birth Register. Main Outcomes and Measures: Diagnoses of ASDs, ADHD, and ID were extracted from the National Patient Register. Cognitive function was assessed using written tests and summarized as a single 9-point score. Whole-cohort and within-sibship analyses were performed; the latter accounted for unmeasured familial confounding factors shared by siblings. Results: The study included 1 085 024 individuals (556 912 male participants [51.3%]) born between 1987 and 1996 and 285 901 men born between 1982 and 1992 who attended assessments for military conscription. The prevalence of maternal HDP was 4.0% in the 1987-1996 birth cohort (n = 42 980) and 5.1% in the military conscription cohort (n = 14 515). A total of 15 858 participants received a diagnosis of ASD, 36 852 received a diagnosis of ADHD, and 8454 received a diagnosis of ID. The mean (SD) cognitive score among the men in the conscription cohort was 5.1 (1.9). In whole-cohort analyses with multivariable adjustment, HDP were associated with offspring ASDs (hazard ratio [HR], 1.22; 95% CI, 1.13-1.31), ADHD (HR, 1.10; 95% CI, 1.05-1.16), and ID (HR, 1.39; 95% CI, 1.27-1.53). Analyses comparing siblings discordant for HDP were less statistically powered but indicated estimates of similar magnitude for ASDs (HR, 1.19; 95% CI, 1.00-1.42) and possibly ADHD (HR, 1.09; 95% CI, 0.95-1.24), but not for ID (HR, 1.04; 95% CI, 0.83-1.29). Hypertensive disorders of pregnancy were associated with somewhat lower cognitive scores in whole-cohort analysis (mean difference comparing offspring exposed with those unexposed, -0.10; 95% CI, -0.13 to -0.07), but in within-sibship analysis, the association was null (mean difference, 0.00; 95% CI, -0.09 to 0.08). Conclusions and Relevance: The study results suggest that HDP are associated with small increased risks of ASDs and possibly ADHD in offspring, whereas associations with ID and cognitive performance are likely confounded by shared familial (environmental or genetic) factors

Weak convergence of finite element approximations of linear stochastic evolution equations with additive noise II. Fully discrete schemes

We present an abstract framework for analyzing the weak error of fully discrete approximation schemes for linear evolution equations driven by additive Gaussian noise. First, an abstract representation formula is derived for sufficiently smooth test functions. The formula is then applied to the wave equation, where the spatial approximation is done via the standard continuous finite element method and the time discretization via an I-stable rational approximation to the exponential function. It is found that the rate of weak convergence is twice that of strong convergence. Furthermore, in contrast to the parabolic case, higher order schemes in time, such as the Crank-Nicolson scheme, are worthwhile to use if the solution is not very regular. Finally we apply the theory to parabolic equations and detail a weak error estimate for the linearized Cahn-Hilliard-Cook equation as well as comment on the stochastic heat equation

Planar Infusion Flow Modelling of Thin-Walled Components with Deformable Perform

The vacuum assisted resin transfer modeling is one of the essential processes to produce large-scale thin-walled FRP components. To simulate the resin flow moving inside the preform, we provide a model to predict preform deformation together with the in-plain resin flow. Instead of a full 3-D model, the process is simplified as 2-D resin flow pass through the 3-D deformable preform ignoring the through-thickness flow.The model dramatically reduces the corresponding 3-D problem and increases the computational efficiency

Posterior Contraction Rates for the Bayesian Approach to Linear Ill-Posed Inverse Problems

We consider a Bayesian nonparametric approach to a family of linear inverse problems in a separable Hilbert space setting with Gaussian noise. We assume Gaussian priors, which are conjugate to the model, and present a method of identifying the posterior using its precision operator. Working with the unbounded precision operator enables us to use partial differential equations (PDE) methodology to obtain rates of contraction of the posterior distribution to a Dirac measure centered on the true solution. Our methods assume a relatively weak relation between the prior covariance, noise covariance and forward operator, allowing for a wide range of applications

Using macromolecular composition to predict optimal process settings in ring-die biomass pellet production

This study was performed to investigate if the process settings that give high pellet durability can be modelled from the biomass’ macromolecular composition. Process and chemical analysis data was obtained from a previous pilot-scale study of six biomass assortments that by Principal Component Analysis (PCA) was confirmed as representative for their biomass types: hardwood, softwood bark, short rotation coppice (SRC), and straw and energy crops. Orthogonal Partial Least Squares Projections to Latent Structures (OPLS) models were created with the content of macromolecules as factors and the die compression ratio and the feedstock moisture content at which the highest pellet durability was obtained as responses. The models for die compression ratio (R2X = 0.90 and Q2 = 0.58) and feedstock moisture content (R2X = 0.87 and Q2 = 0.60), rendered a prediction error for obtained mechanical durability of approximately ±1%-unit, each. Important factors for modelling of the die compression ratio were: soluble lignin (negative), acetyl groups (negative), acetone extractives (positive), and arabinan (positive). For modelling of the feedstock moisture content, Klason lignin (negative), xylan (positive), water-soluble extractives (negative), and mannan (negative), were the most influential. Results obtained in this study indicate that it is possible to predict optimal process conditions in pelletizing based on the macromolecular composition of the raw material. In practice, this would mean a higher raw material flexibility in the pellet factories through drastically reduced risk when introducing new raw materials

Cocker Spaniel cardiomyopathy

Estudaram-se no presente trabalho 28 casos de cardiomiopatia (CM) do Cocker Spaniel, com a finalidade de determinar as características epidemiológicas, clínicas e etiológicas da doença. Para tanto, os animais foram avaliados por meio de anamnese, exame físico, exame radiológico e eletrocardiograma. Dos 28 animais, 13 eram machos e 15 fêmeas, com idade variando entre 18 e 144 meses. As manifestações clínicas mais freqüentemente associadas com este tipo de CM foram intolerância ao exercício, tosse, dispnéia e engasgo, observados, respectivamente, em 23, 14, 7 e 7 casos. O exame radiográfico foi realizado em 12 animais e revelou como alterações mais comuns: desvio dorsal de traquéia (8/12), aumento da parede cranial e direita do coração (7/12), cardiomegalia global (5/12) e aumento do interstício pulmonar (4/12). O exame eletrocardiográfico revelou freqüência cardíaca variando entre 60 e 180 b.p.m. Os ritmos cardíacos mais freqüentes foram arritmia sinusal associada a marcapasso migratório (11/28), ritmo sinusal normal (6/28) e arritmia sinusal (5/28); o eixo cardíaco no plano frontal mostrou-se dentro da normalidade na maioria dos casos (27/28); o eletrocardiograma revelou, ainda, sobrecarga ventricular direita (28/28) e sobrecarga ventricular esquerda (20/28).Twenty-eight cases of Cocker Spaniel cardiomyopathy (CM) were studied to determine the epidemiologic, clinic and etiologic characteristics of the disease. The animals were assessed by anamnesis, physical examination, radiographic and electrocardiographic exams. Among the 28 dogs which were examined, 13 were male and 15 female, their age being from 18 to 144 months. The most frequent clinical manifestations observed were exercise dislike, cough, dyspnea and choking, respectively, in 23, 14, 7 and 7 cases. The radiographic exams were possible in 12 dogs andrevealed deviation of the trachea (8/12), increase of the right side of the heart (7/12), global cardiomegaly (5/12) and pulmonary interstitium density (4/12). Electrocardiographic assessment, made in all 28 dogs, revealed cardiac frequency changing from 60 to 180 b.p.m. The most frequent cardiac rhythms were sinusal arrhythmia with wanderingpacemaker (11/28), normal sinusal rhythm (6/28) and sinusal arrhythmia (5/28); the cardiac axis in frontal plan was normal in 27 out of 28 dogs. Moreover, by the electrocardiographic assessment it was possible to diagnose right ventricular overload (28/28) and left ventricular overload (20/28)

Influencer Marketing - ytlig inspiration eller något djupare?

Title: "Influencer Marketing - Superficial Inspiriation or Something Deeper?" - A qualitative research about the relationship between fashion influencers and their followers from a Consumer Culture Perspective Seminar date: 2018-01-11 Course: FEKH29, Business Administration: Bachelor Degree Project In Marketing Undergraduate Level, 15 Credits Authors: Michelle Da Silva Pereira, Eric Larsson, Oscar Molin Advisor: Jon Bertilsson Key words: Influencer, Follower, Consumer Culture Theory, Brand Relationship, Fashion Purpose: The purpose of this study is to create a better understanding of followers' view of their relationship to fashion influencers and what kind of motives that underlie their reasons to follow, from a Consumer Culture Perspective. Methodology: A qualitative study has been conducted based on semi-structured interviews. An abductive approach with a hermeneutical view has been used as a foundation throughout the study. The collected empirical material is analysed together with theories from existing literature to generate new knowledge. Theoretical perspectives: The essay takes a starting point in the Consumer Culture Theory perspective focusing on "brand relationship" and elements such as Identity, Group Identity and Symbolism. Empirical foundation: Ten semi-structured in-depth interviews have been conducted with young adults that look upon themselves as followers to fashion influencers. The empirical material that was gathered became a foundation for the research analysis. Conclusion: This study has with help of followers subjective opinions contributed to an understanding of their relationhips with fashion influencers. Prominent discoveries have been a model consisting of four types of relationhips between followers and fashion influencers and has raised the question of whether the power ratio should be revalued.Examensarbetets titel: "Influencer Marketing - ytlig inspiration eller något djupare?" - En kvalitativ studie om relationen mellan modeinfluencers och följare ur ett konsumentkulturperspektiv Seminariedatum: 2018-01-11 Kurs: FEKH29, Examensarbete kandidatnivå i marknadsföring, 15 hp Författare: Michelle Da Silva Pereira, Eric Larsson, Oscar Molin Handledare: Jon Bertilsson Fem nyckelord: Influencer, Follower, Consumer Culture Theory, Brand relationship, Fashion Syfte: Studien ämnar att utifrån ett konsumentkulturperspektiv lämna ett kunskapsbidrag som ger en utökad förståelse för följares syn på relationen till modeinfluencers samt vilka motiv som kan tänkas ligga bakom följarskapet. Metod: En kvalitativ studie har genomförts som baserats på semistrukturerade intervjuer. I uppsatsen har en abduktiv forskningsansats tillämpats med ett hermeneutiskt synsätt. Således har insamlad empiri i kombination med befintlig teori genererat ny kunskap. Teoretiska perspektiv: Uppsatsen tar utgångspunkt i CCT-forskning med fokus på "brand relationship" samt beståndsdelar såsom identitet, grupptillhörighet och symbolik. Empiri: Tio semistrukturerade djupintervjuer genomfördes med unga vuxna som anses vara följare till en eller flera modeinfluencers. Det insamlade empiriska materialet har legat till grund för studiens analys. Resultat: Studien har med hjälp av följares subjektiva åsikter bidragit till en förståelse för relationen mellan modeinfluencers och följare. Framträdande upptäckter är bland annat en modell bestående av fyra olika typer av relationer mellan följare och modeinfluencers samt det faktum att maktförhållandet dem emellan eventuellt kan behöva omvärderas