138 research outputs found
Climate Change Challenges for Extension Educators: Technical Capacity and Cultural Attitudes
We surveyed Extension educators in the southern Great Plains about their attitudes and beliefs regarding climate change, their interactions with constituents surrounding climate change, and challenges they face in engaging constituents on the topic of climate change. Production-oriented and sociocultural challenges in meeting constituents\u27 information needs exist. Educators reported (a) lacking capacity for addressing climate change issues and (b) needing information, especially regarding drought and extreme or unseasonable weather events and related management practices. Educators also identified a need for more educational resources, including print materials and online decision aids. Implications are relevant to educators working beyond the study area and in any agricultural production system
Phylogenetics from paralogs
Motivation: Sequence-based phylogenetic approaches heavily rely on initial data sets to be composed of orthologous sequences only. Paralogs are treated as a dangerous nuisance that has to be detected and removed. Recent advances in mathematical phylogenetics, however, have indicated that gene duplications can also convey meaningful phylogenetic information provided orthologs and paralogs can be distinguished with a degree of certainty.
Results: We demonstrate that plausible phylogenetic trees can be inferred from paralogy information only. To this end, tree-free estimates of orthology, the complement of paralogy, are first corrected to conform cographs and then translated into equivalent event-labeled gene phylogenies. A certain subset of the triples displayed by these trees translates into constraints on the species trees. While the resolution is very poor for individual gene families, we observe that genome-wide data sets are sufficient to generate fully resolved phylogenetic trees of several groups of eubacteria. The novel method introduced here relies on solving three intertwined NP-hard optimization problems: the cograph editing problem, the maximum consistent triple set problem, and the least resolved tree problem. Implemented as Integer Linear Program, paralogy-based phylogenies can be computed exactly for up to some twenty species and their complete protein complements.
Availability:The ILP formulation is implemented in the Software ParaPhylo using IBM ILOG CPLEX (TM) Optimizer 12.6 and is freely available from http://pacosy.informatik.uni-leipzig.de/paraphyl
Structural optimization through biomimetic-inspired material-specific application of plant-based natural fiber-reinforced polymer composites (Nfrp) for future sustainable lightweight architecture
Rheology, dispersion, and cure kinetics of epoxy filled with amine‐ and non‐functionalized reduced graphene oxide for composite manufacturing
This study evaluates the effect of plasma surface functionalization of reduced graphene oxide particles on the processing characteristics and homogeneity of dispersion of a bisphenol A‐(epichlorhydrin) epoxy matrix and amine‐based hardener with varying weight fractions from 0.00 to 1.50 wt%. It was observed that amine‐functionalized reduced graphene oxide leads to a more drastic viscosity increase of up to 18‐fold of the uncured suspensions and that its presence influences the conversion rates of the curing reaction. Optical microscopy of thin sections and transmission electron microscopy analysis showed that a more homogeneous dispersion of the particles could be achieved especially at higher weight fractions by using an appropriate surface functionalization. This knowledge can be used to define suitable processing conditions for epoxies with amine‐based hardeners depending on the loading and functionalization of graphene‐related particles
Multilevel modelling of mechanical properties of textile composites: ITOOL Project
The paper presents an overview of the multi-level modelling of textile composites in the ITOOL project, focusing on the models of textile reinforcements, which serve as a basis for micromechanical models of textile composites on the unit cell level. The modelling is performed using finite element analysis (FEA) or approximate methods (method of inclusions), which provide local stiffness and damage information to FEA of composite part on the macro-level
Functional Integration of Subcomponents for Hybridization of Fused Filament Fabrication
One of the main advantages of additive manufacturing by Fused Filament Fabrication is its wide variety of materials and cost-effective production systems. However, the resolution and tightness of the produced structures are limited. The following article describes a novel approach of the functional integration of stereolithographic produced subcomponents into the Fused Filament Fabrication process and the challenges during integration in terms of adhesion, taking into account different surface pretreatments. Furthermore, it is investigated how conductive polymer composites could be used successfully for conducting mechatronic subcomponents automatically. With the help of these investigations it is aimed to extend the field of application of additive manufactured plastic components
A method for communication between user materials during runtime in ABAQUS®
The application of the Finite Element Method (FEM) has developed considerably in recent decades. While in the early days of the FEM only linear-elastic material models were available in commercial Finite Element (FE) programs, today non-linear and also damage-considering material models are offered. But even these are often not capable of correctly representing the complex material behaviour of modern composite materials. Therefore, FE programs often provide the users with the option of integrating their own material models into the simulation. These programs, often called "user subroutines" or "user materials", represent an intensively researched area in the simulation of material behaviour, which is reflected in the large number of publications on such developments (exemplarily see [1-14]). These material models often require a large amount of data values if they are introduced within the simulation model by finite elements [2]. Especially in the field of composites there is a need to use a separate "user material" for each constituent material. Since there is a mutual interaction between the components in real composites, it is obvious that this interaction must also be represented The 8th European Congress on Computational Methods in Applied Sciences and Engineering ECCOMAS Congress 2022 5 – 9 June 2022, Oslo, Norway PHILIP F. ROSE, LUKAS MÜNCH, MARKUS LINKE AND PETER MIDDENDORF 2 between the material models within a simulation in order to make accurate predictions about the material behaviour. To enable such an interaction between different material models in a simulation, a communication during runtime is required in which additionally needed data from the surrounding elements is exchanged between the user materials. In this paper, a method is presented to enable such information exchange during simulation runtime in the commercial FE software ABAQUS/CAE 2019 (Dassault Systèmes, Vélizy-Villacoublay, France) using external databases as well as structured global arrays and some built-in functions of the software. This allows the simultaneous application of several advanced user material models within one simulation and enable them to communicate during runtime, resulting in the possibility of making high accurate simulations of composite materials
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