Rheology of natural fibers thermoplastic compounds: Flow length and fiber distribution

The presented study investigates the flow length and the corresponding fiber content distribution in the injection‐moulded natural fiber reinforced thermoplastics and its relation to fiber type and processing parameters such as injection pressure, temperature, injection rate and mould tempering by increasing die temperature. In this research, polypropylene compounds with nominally 30 wt % hemp and sisal fibers are investigated. The influence of the injection pressure (500 and 1000 bar), melt temperature (180°C, 200°C, and 220°C), and die temperature (23°C and 80°C) on the fiber content distribution all over the sample is investigated. An increasing linear trend of fiber content along the spiral length is observed as an evidence of a fiber/polymer multiflow system. A pattern for fiber content distribution with respect to the fiber length along the injected spiral can be distinguished, where the longer fibers are usually found at the end of the injected part and the shorter fibers remain near mould entrance point. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39861.     

Carrot cropping on organic soil is a hotspot for nitrous oxide emissions

The emissions of the greenhouse gas nitrous oxide (N₂O) were measured from a non nitrogen fertilized carrot (Daucus carota ssp. sativa) field on an organic soil in Sweden during one cropping and post-harvest season. The cumulative emission during the measuring period of 149?days was 41 (±2.8) kg N₂O ha^?1. Dividing the measuring period into a cropping and a post-harvest period revealed that the presence of carrots strongly stimulated N₂O emissions, as the emission during the cropping period was one order of magnitude higher compared to the post-harvest period. The N₂O emission from the carrot field were higher than fluxes reported from cereal crop and grass production, but in the same order as reported fluxes from vegetable cropping on organic soils. In conclusion, our results indicate that the cultivation of root vegetable, such as carrots, on organic soil can be a high point source for N₂O emissions.     

Accumulation of magnetic iron oxide nanoparticles coated with variably sized polyethylene glycol in murine tumors

Iron oxide nanoparticles have found widespread applications in different areas including cell separation, drug delivery and as contrast agents. Due to water insolubility and stability issues, nanoparticles utilized for biological applications require coatings such as the commonly employed polyethylene glycol (PEG). Despite its frequent use, the influence of PEG coatings on the physicochemical and biological properties of iron nanoparticles has hitherto not been studied in detail. To address this, we studied the effect of 333-20,000 Da PEG coatings that resulted in larger hydrodynamic size, lower surface charge, longer circulation half-life, and lower uptake in macrophage cells when the particles were coated with high molecular weight (M(w)) PEG molecules. By use of magnetic resonance imaging, we show coating-dependent in vivo uptake in murine tumors with an optimal coating M(w) of 10,000 Da.     

Phase Analysis and Thermal Stability of Hot Isostatically Pressed Zirconia–Hydroxyapatite Composites

Composites of zirconia and hydroxyapatite (OHAp) have been processed via hot isostatic pressing (HIP) or sintering in air. When the composites were sintered in air at a temperature of 950°C, decomposition of the OHAp to tricalcium phosphate occurred. Using the HIP technique, composites without any detectable degradation of the OHAp phase were produced at 1200°C. The reactivity between zirconia and OHAp was dependent on both the amount of water lost from OHAp and the geometry of the interaction. The phase composition of the materials prepared was evaluated from their powder X-ray diffraction patterns, and their microstructures were studied via electron microscopy.     

Decay of end effects in graphite/epoxy bolted joints

Almost all analyses of large structures neglect local effects due to the application of loads and due to the transfer of loads between structural elements. In recent years, however, the use in aircraft structures of highly anisotropic materials, such as graphite/epoxy, has motivated more detailed studies of the applicability of Saint-Venant's principle.

In this paper in graphite/epoxy is analysed using the finite element method (FEM). The influence of anisotropy and transition from a thicker to a thinner laminate cross-section (ply-drop) is investigated. The characteristic decay length which is large for highly anisotropic materials is lessened by a change in thickness.     

A little Birdie told me: Social media,organizational legitimacy,and underpricing in initial public offerings

Drawing on the organizational legitimacy literature, we propose and test a set of hypotheses arguing that social media, an artifact of information technology, serves as a mechanism for conferring legitimacy in the market for initial public offerings (IPOs). The extant literature identifies third-party authorities, such as traditional media outlets and industry analysts, as a valuable source of organizational legitimacy. Social media and micro-blogging, however, remain outside current classifications of the phenomenon. This study theoretically develops and empirically tests a new mechanism in the legitimation process: the direct interaction with potential investors and society-at-large via social media. Our findings indicate broad support that having a Twitter account, and the extent to which a firm utilizes Twitter, is associated with systematically higher levels of IPO underpricing. Moreover, we find support that social media variables external to the firm, including number of followers and retweets, also impact the level of underpricing in an IPO. In conclusion, we highlight the emerging role of social media in processes of legitimation and invite additional research at the intersection of IS and management.     

A numerical Hartree-Fock program for diatomic molecules

This paper describes an algorithm and a computer program which solves numerically (virtually exactly) equations of the restricted open-shell Hartree-Fock and Hartree-Fock-Slater model for diatomic molecules     

Working conditions in the engine department – A qualitative study among engine room personnel on board Swedish merchant ships

The specific problems associated with the work on board within the merchant fleet are well known and have over the years been a topic of discussion. The work conditions in the engine room (ER) are demanding due to, e.g. the thermal climate, noise and awkward working postures. The work in the engine control room (ECR) has over recent years undergone major changes, mainly due to the introduction of computers on board. In order to capture the impact these changes had implied, and also to investigate how the work situation has developed, a total of 20 engine officers and engine ratings were interviewed. The interviews were semi-structured and Grounded Theory was used for the data analysis. The aim of the present study was to describe how the engine crew perceive their work situation and working environment on board. Further, the aim was to identify areas for improvements which the engine crew consider especially important for a safe and effective work environment. The result of the study shows that the design of the ECR and ER is crucial for how different tasks are performed. Design which does not support operational procedures and how tasks are performed risk inducing inappropriate behaviour as the crew members’ are compelled to find alternative ways to perform their tasks in order to get the job done. These types of behaviour can induce an increased risk of exposure to hazardous substances and the engine crew members becoming injured.     

Parameterization-free active contour models with topology control

We present a novel approach for representing and evolving deformable active contours by restricting the movement of the contour vertices to the grid lines of a uniform lattice. This restriction implicitly controls the (re)parameterization of the contour and hence makes it possible to employ parameterization-independent evolution rules. Moreover, the underlying uniform grid makes self-collision detection very efficient. Our contour model is also able to perform topology changes, but – more importantly – it can detect and handle self-collisions at subpixel precision. In applications where topology changes are not appropriate, we generate contours that touch themselves without any gaps or self-intersections.