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Most British birds of prey have largely recovered from historical persecution, but the beleaguered Hen Harrier is still struggling and remains far less common than it should be. This is a particular shame, because it is one of our most inspiring raptors. Spectacular sky-dancing displays and balletic food passes from male to female brighten up the moors in summer. And in winter, communal roosts in the lowlands attract birders from far and wide to catch sight of this now-elusive species. This book follows the Hen Harrier over a year: from rearing young hidden away in dense heather, to the fight for survival in the harshest months of winter. Interspersed among the monthly accounts are chapters on the history and status of this iconic bird, as well as an overview of one of the most intractable conflicts in modern conservation: the Hen Harrier’s liking for grouse moors (and the grouse that are raised there) wins it few friends among shooters, and ongoing persecution continues to hamper its recovery. There are tentative signs of progress, but its fate as a breeding bird in England hangs in the balance. Evocative illustrations, in part based on privileged access to the handful of breeding birds that remain on England’s moors, showcase the Hen Harrier’s exploits through the seasons. These will delight admirers of this species and hopefully foster a greater interest in its wellbeing. The Hen Harrier needs all the help it can get.

A new approach is presented for combinatorial development of polymer nanocomposites with compositional gradients (CGs). The CGs were developed using transient processing conditions in twin screw extrusion with small quantities of expensive nanoscale fillers. Convolution of step input with normalized residence volume distributions (RVDs) was used to establish the processing-structure relationship for the CGs. The normalized RVD was established as a process characteristic independent of processing conditions and measured in situ using an optical probe. The CG determined nondestructively using the new combinatorial approach was validated through comparison with more time-consuming and destructive thermogravimetric analysis. The CG could also be established with relatively inexpensive microscale fillers using the normalized RVD obtained with nanoscale fillers, suggesting that transient effects of the mixing process are independent of the size of the filler. Finally, structure-property relationship of combinatorially developed polymer nanocomposites was established by characterizing their dynamic mechanical behavior (storage modulus, G', and loss modulus, G"). The dynamic mechanical behavior of the combinatorially developed composites correlated well with the batch-processed ones, indicating that the transient mixing conditions in extrusion do not affect the material properties.

A systematic electrical and rheological characterization of percolation in commercial polydisperse polystyrene (PS) nanocomposites containing multiwall carbon nanotubes (MWCNTs) is presented. The MWCNTs confer appreciable electrical conductivities (up to ca. 1 S/m) to these nanocomposites at a concentration of 8 vol %. In addition to enhancing the electrical properties, even at small concentrations (ca. 2 vol %), MWCNTs significantly enhance the rheological properties of PS melts. At concentrations exceeding 2 vol %, a plateau appears in the storage modulus G‘ at low frequencies, indicating the formation of a percolated MWCNT network that responds elastically over long timescales. Network formation, in turn, implies a diverging complex viscosity vs complex modulus curve. A focus of this study is on the correlation between electrical and rheological properties at the onset of percolation. The experimental results indicate that the elastic load transfer and electrical conductivity are far more sensitive to ...

This case study is presented for use with graduate students in educational administration. The intent is to further those students’ preparation to deal with cultural and organizational change, along with the examination of the role of the administrative team as instructional leaders. One of the primary roles of the building principal is to be the instructional leader and create a climate that is conducive to learning. The scenario for this case is built around a negative atmosphere that will require campus-level administrators to transform the campus into a high-performing school in a brief period of time.

Polyaromatic compounds, with terminal functional groups, can be non-covalently bonded to the sidewall of carbon nanotubes. This architecture preserves the structural, mechanical, electrical, and electromechanical properties of the CNTs and ensures that an unhindered functional group is available to bond with an extended polymer matrix. Spectroscopic measurements and high resolution imaging are used to confirm the functionalization and incorporation of functionalized MWNTs into a nylon 12 matrix.

For the first time, an interpenetrating phase polymer nanocomposite formed by the percolation of multiwalled carbon nanotubes (MWCNTs) in polystyrene (PS) has been quantitatively characterized through electrical conductivity measurements and melt rheology. Both sets of measurements, in conjunction with scanning electron microscopy (SEM) images, indicate the presence of a continuous phase of percolated MWCNTs appearing at particle concentrations exceeding 2 vol% MWCNTs in PS. To quantify the amount of this continuous phase present in the PS/MWCNT composite, electrical conductivity data at various MWCNT concentrations, β, are correlated with a proposed degree of percolation, , developed using a conventional power-law formula with and without a percolation threshold. To quantify the properties of the interpenetrating phase polymer nanocomposite, the PS/MWCNT composite is treated as a combination of two phases: a continuous phase consisting of a pseudo-solid-like network of percolated MWCNTs, and a continuous PS phase reinforced by non-interacting MWCNTs. The proposed degree of percolation is used to quantify the distribution of MWCNTs among the phases, and is then used in a rule-of-mixtures formulation for the storage modulus, , and the loss modulus, , to quantify the properties of the continuous phase consisting of percolated MWCNTs and the continuous PS phase reinforced by non-interacting MWCNTs from the experimental melt rheology data. The properties of the continuous phase of percolated MWCNTs are indicative of a scaffold-like microstructure exhibiting an elastic behavior with a complex modulus of 360 kPa at lower frequencies and viscoplastic behavior with a complex viscosity of 6 kPa s rad−1 at higher frequencies, most likely due to a stick–slip friction mechanism at the interface of the percolated MWCNTs. Additional evidence of this microstructure was obtained via scanning electron microscopy. This research has important implications in providing a new methodology based on the electrical and rheological properties of the polymer nanocomposite for quantifying the continuous phase formed by the percolation of new functionalized nanostructures being developed for: (a) controlling the percolation of the nanostructures through self-assembly, (b) enhancing their interaction with the continuous reinforced polymer phase, (c) enhancing the cohesion between nanostructures.

To completely establish the processing–structure–property relationships of polymer composites such as Carbon Nanofibers (CNFs) in high-impact polystyrene, it is necessary to understand the effects of different processes and processing conditions on the properties of the composites. In this work, using thermogravimetric analysis, the effects of solvent processing and twin-screw extrusion on the weight loss rates and the corresponding temperatures were studied. While there were only marginal effects of the CNF concentration, the type of processing significantly affected the thermo-oxidative behavior. Extrusion resulted in composites that had better thermal stability compared to the solvent processed ones. Furthermore, higher shear rates in extrusion also led to composites with higher thermal stability. This has important implications in choosing the appropriate process and processing conditions for producing polymer-CNF composites. It was also demonstrated that thermogravimetric analysis can provide a means of characterizing the degree of dispersion resulting from the processing of the composites that complements conventional microscopy techniques. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers