The performance and perception of wetland systems for the treatment of highway runoff

Constructed wetlands are increasingly being seen as a viable solution to the treatment of highway runoff although currently there are no established design and performance criteria for highway runoff treatment systems. In order to assess the heavy metal removal performance by different wetland systems receiving urban runoff, a natural and constructed wetland site were monitored for metal removal performance and metal accumulation by the sediment and four macrophyte species. Although there is active metal uptake by the sediment and macrophytes, aqueous metal concentrations remain unchanged in the natural wetland. The initial results from the constructed wetland system show variable metal removal performance although an improvement in performance is expected as the system becomes more established. An experimental laboratory-based wetland system showed efficient treatment performance of water dosed with heavy metals. The distribution of metals in the substrate highlight the importance of the hydraulic design, and the need to reduce the possibility of shortcircuiting, in constructed wetlands for runoff treatment. A questionnaire survey was used to assess the public's perception of the aesthetic and wildlife value of wetlands and their attitudes towards the use of wetland treatment systems for water pollution control. A predictive model for the visual preference of wetland landscapes was developed from the results of the survey. The results show that the public has a clear preference for clean natural looking wetland environments with landscape complexity, diverse vegetation and the presence of wildlife. The public have reservations about the use of wetlands for wastewater treatment indicating the need for background information to allay these concerns. Design criteria are proposed for the engineering of the wetland that will be constructed by the Environmental Agency (EA) at the natural wetland site to treat highway runoff. The results of the survey provide recommendations for the landscaping design of treatment wetland systems

Nacelle design

The external cowlings of engine nacelles on large turbofan powered aircraft are good candidates for application of natural laminar flow. These nacelles usually have shorter characteristic lengths than other candidate surfaces such as wings and fuselages and therefore have lower characteristic Reynolds numbers. A conceptive figure of the natural flow nacelle (NLF) is shown. On the typical nacelle the flow accelerates to a curvature induced velocity peak near the lip and then decelerates over the remainder of the nacelle length. Transition occurs near the start of the deceleration, so turbulent flow with high friction coefficient exists over most of the nacelle length. On the other hand, the NLF nacelle is contoured to have an accelerating flow over most of its length, so transition is delayed, and a relatively lower friction drag exists over most of the nacelle. The motivation for development of the LFN is a potential 40 to 50 percent reduction in nacelle friction drag

Synthesis of chemically modified guide RNAs and their applications

The genome editing tool CRISPR has transformed our understanding of how genetics affects human health. The Cas9 endonuclease, guided by a guide RNA (gRNA) has been used for genome editing, live cell imaging as well as for diagnostic purposes. The CRISPR-Cas9 system has been repurposed for live-cell imaging by mutating the Cas9 protein to inactivate the DNA cleavage activity (dCas9) and by appending green fluorescent proteins (GFP). This enables sgRNA-programmed localisation of GFP to any genomic loci. However, this method results in significant background fluorescence. To overcome this, we designed a metastable fluorescent gRNA that is only activated once it reaches the nucleus, to label its target. Live cell imaging showed a significant reduction in cytoplasmic accumulation of the fluorophore. To study cells and the genome, key modifications must be made on the sgRNA such as fluorophores or ligands that can aid cell delivery. These site-specific modifications cannot be introduced by transcription-mediated RNA synthesis and are expensive and difficult to source by solid-phase synthesis approach. We developed a novel method of introducing chemical modifications into the sgRNA; by extending the 3'-end and by crosslinking a short oligonucleotide that bears the modification. All the modifications were well tolerated by Cas9 in vitro. However, further work is required to test the modified sgRNAs in cells. Lastly, the R-loop structure was exploited as a means to introduce modifications into the CRISPR-Cas9 system. To test this hypothesis, we designed a short fluorescent oligonucleotide to bind to the R-loop structure formed after the sgRNA-Cas9 complex binds to their target, the telomeres. This method proved to be a successful tool for live cell imaging and will be applied to other areas in the future

Teacher Films: Examining Hollywood Representations of our Practice

What does it mean to teach and be taught? How have we come to know what schooling is? And, how can engagement with these pervasive, and oftentimes troubling representations of schooling, teaching, and students with our preservice teachers in/form their teacher identities? Taking Hollywood feature film as our inquiry into education, schooling, and social studies (teacher) education, this paper reflects upon the course Dangerous Minds, Dead Poets, and Democratic Education on the Silver Screen, a course the authors first developed as graduate students and have since offered variations of at their respective institutions. While course content has been relatively constant (using Dangerous Minds, Dead Poets Society, and Blackboard Jungle), additions of Clueless, School of Rock, Mean Girls, and Fist Fight have allowed for more intentional discussions of race, class, and gender, particularly as they relate to dominant tropes of representation for those in targeted identity groups

High speed turboprop aeroacoustic study (single rotation). Volume 1: Model development

A frequency-domain noncompact-source theory for the steady loading and volume-displacement (thickness) noise of high speed propellers has been developed and programmed. Both near field and far field effects have been considered. The code utilizes blade surface pressure distributions obtained from three-dimensional nonlinear aerodynamic flow field analysis programs as input for evaluating the steady loading noise. Simplified mathematical models of the velocity fields induced at the propeller disk by nearby wing and fuselage surfaces and by angle-of-attack operation have been developed to provide estimates of the unsteady loading imposed on the propeller by these potential field type interactions. These unsteady blade loadings have been coupled to a chordwise compact propeller unsteady loading noise model to provide predictions of unsteady loading noise caused by these installation effects. Finally, an analysis to estimate the corrections to be applied to the free-field noise predictions in order to arrive at the measurable fuselage sound pressure levels has been formulated and programmed. This analysis considers the effects of fuselage surface reflection and diffraction together with surface boundary layer refraction. The steady loading and thickness model and the unsteady loading model have been verified using NASA-supplied data for the SR-2 and SR-3 model propfans. In addition, the steady loading and thickness model has been compared with data from the SR-6 model propfan. These theoretical models have been employed in the evaluation of the SR-7 powered Gulfstream aircraft in terms of noise characteristics at representative takeoff, cruise, and approach operating conditions. In all cases, agreement between theory and experiment is encouraging

A study of the prediction of cruise noise and laminar flow control noise criteria for subsonic air transports

General procedures for the prediction of component noise levels incident upon airframe surfaces during cruise are developed. Contributing noise sources are those associated with the propulsion system, the airframe and the laminar flow control (LFC) system. Transformation procedures from the best prediction base of each noise source to the transonic cruise condition are established. Two approaches to LFC/acoustic criteria are developed. The first is a semi-empirical extension of the X-21 LFC/acoustic criteria to include sensitivity to the spectrum and directionality of the sound field. In the second, the more fundamental problem of how sound excites boundary layer disturbances is analyzed by deriving and solving an inhomogeneous Orr-Sommerfeld equation in which the source terms are proportional to the production and dissipation of sound induced fluctuating vorticity. Numerical solutions are obtained and compared with corresponding measurements. Recommendations are made to improve and validate both the cruise noise prediction methods and the LFC/acoustic criteria

Cultural Representations in/as the Global Studies Curriculum: Seeing and Knowing China in the United States

This study is an examination of how two popular magazines, National Geographic and Life magazine, and one educational journal, Social Education, perform the work of representation in general, and representing China more specifically. Drawing on postcolonial theorists (Blaut, 1993; Said, 1978; Tchen, 1999; wa Thiong'o, 1986; Willinsky, 1998), the perspectives employed throughout this study explore how representations can work to fix meaning and extend difference through imperialist structures and an orientalist lens. In addition, theories of photographic representation work alongside postcolonial perspectives to draw out the constructed nature of representation, and how representation - through language and/or image - can work to capture and secure the meaning of difference and perpetuate division. National Geographic, Life, and Social Education are pedagogical in different ways, yet all three used language and image to bring China into view for the Western reader. Conceptualized as sources of cultural pedagogy, these journals employed specific pedagogical practices, which reinforced imperialist structures of Western dominance over the non-Western world. Notably, National Geographic's travelogue, Life's photo-essay, and Social Education's educational resources, worked to teach/instruct their readers, primarily middle class Americans, about China

Studies of the acoustic transmission characteristics of coaxial nozzles with inverted velocity profiles, volume 1

The efficiency of internal noise radiation through coannular exhaust nozzle with an inverted velocity profile was studied. A preliminary investigation was first undertaken to: (1) define the test parameters which influence the internal noise radiation; (2) develop a test methodology which could realistically be used to examine the effects of the test parameters; (3) and to validate this methodology. The result was the choice of an acoustic impulse as the internal noise source in the in the jet nozzles. Noise transmission characteristics of a nozzle system were then investigated. In particular, the effects of fan nozzle convergence angle, core extention length to annulus height ratio, and flow Mach number and temperatures were studied. The results are presented as normalized directivity plots

Issues and Challenges for Network Virtualisation

In recent years, network virtualisation has been of great interest to researchers, being a relatively new and major paradigm in networking. This has been reflected in the IT industry where many virtualisation solutions are being marketed as revolutionary and purchased by enterprises to exploit these promised performances. Adversely, there are certain drawbacks like security, isolation and others that have conceded the network virtualisation. In this study, an investigation of the different state-of-the-art virtualisation technologies, their issues and challenges are addressed and besides, a guideline for a quintessential Network Virtualisation Environment (NVE) is been proposed. A systematic review was effectuated on selectively picked research papers and technical reports. Moreover a comparative study is performed on different Network Virtualisation technologies which include features like security, isolation, stability, convergence, outlay, scalability, robustness, manageability, resource management, programmability, flexibility, heterogeneity, legacy Support, and ease of deployment. The virtualisation technologies comprise Virtual Private Network (VPN), Virtual Local Area Network (VLAN), Virtual Extensible Local Area Network (VXLAN), Software Defined Networking (SDN) and Network Function Virtualisation (NFV). Conclusively the results exhibited the disparity as to the gaps of creating an ideal network virtualisation model which can be circumvented using these as a benchmark

Resource Allocation in 4G and 5G Networks: A Review

The advent of 4G and 5G broadband wireless networks brings several challenges with respect to resource allocation in the networks. In an interconnected network of wireless devices, users, and devices, all compete for scarce resources which further emphasizes the fair and efficient allocation of those resources for the proper functioning of the networks. The purpose of this study is to discover the different factors that are involved in resource allocation in 4G and 5G networks. The methodology used was an empirical study using qualitative techniques by performing literature reviews on the state of art in 4G and 5G networks, analyze their respective architectures and resource allocation mechanisms, discover parameters, criteria and provide recommendations. It was observed that resource allocation is primarily done with radio resource in 4G and 5G networks, owing to their wireless nature, and resource allocation is measured in terms of delay, fairness, packet loss ratio, spectral efficiency, and throughput. Minimal consideration is given to other resources along the end-to-end 4G and 5G network architectures. This paper defines more types of resources, such as electrical energy, processor cycles and memory space, along end-to-end architectures, whose allocation processes need to be emphasized owing to the inclusion of software defined networking and network function virtualization in 5G network architectures. Thus, more criteria, such as electrical energy usage, processor cycle, and memory to evaluate resource allocation have been proposed.  Finally, ten recommendations have been made to enhance resource allocation along the whole 5G network architecture