599 research outputs found
An investigation of the degradation of ceramic coatings on metals using a microwave technique
Metal components for use in high temperature oxidising or
corrosive environments often require protection. Many of the
coatings used are complex but the two basic types are as shown
in figure 1. In type A, source material is diffused into the
surface of the component. When heated in air some of the source
material oxidises to form a thin protective ceramic layer. The
coating continues to be protective as long as there is an adequate
supply of source material to provide new ceramic to replace any
lost from the surface. Any non-destructive testing system for
such a coating must give information on the amount of source
material in reserve. In system B (figure 1) the relatively
thick ceramic coating is applied as a slurry or is sprayed on by
flame or plasma arc. The ceramic gives erosion corrosion and
thermal protection. Owing to the porosity of the ceramic
oxidation/corrosion of the protected metal will eventually take
place. This attack is the preliminary stage t- separation of the
ceramic from the metal and also to failure of the metal component.
Non-destructive testing, must give information on the interfacial
region between ceramic and metal
Survival of the Fittest? The Rebranding of West Virginia Higher Education
During the years 1996 to 2005, West Virginia produced the greatest proportion (56.25%) of regionally accredited institutional rebrandings. In addition, the state experienced the greatest proportion (25%) of the specific “college-to-university” rebranding strategy than any other state. This study set out to discover the reasons why West Virginia produced such a high percentage of “college-to-university” changes. Using a mixed method approach of analysis, the researcher used quantitative and qualitative methods to determine the rationale, strategies, and implications of the college-to-university change. As West Virginia was viewed as a nested population in Appalachia, a population of 51 institutions that experienced the college-to-university change located in 10 states containing Appalachian counties was generated. Administrators from these schools were surveyed and the returns provided a basis for interviews of West Virginia administrators. Additionally, 103 institutions in the United States that rebranded as universities were analyzed in regard to effects of the rebranding five years following the change. The variables studied included the following: enrollment, tuition, Carnegie Classifications, the numbers and types of graduate programs, and undergraduate selectivity. The study focused on the rebrandings at the following West Virginia institutions: The University of Charleston (1979), Salem Teikyo University (1989), Wheeling Jesuit University (1996), West Virginia University Institute of Technology (1996), Mountain State University (2001), Concord University (2004), Fairmont State University (2004), Shepherd University (2004), West Virginia State University (2004), Ohio Valley University (2005), and the planned changes at West Liberty State College. This dissertation features information concerning the rationale for change, how the change was realized, the relationship of the change to regulatory bodies, reactions by stakeholders to the change, the effect of the change on enrollment, the implications of institutional prestige, and administrative advice regarding the change. In addition, a case study on retaining an institutional brand was conducted of the “Allegheny” higher education brand and its usage among institutions in Appalachia was included. This case study examined how Allegheny College has protected its brand and gained brand dominance in the wake of the rebranding efforts of other institutions. To understand the rebranding phenomenon, a total of 22 individuals were interviewed, 34 administrators returned surveys, and an additional 48 individuals provided information specific responses. A total of 102 unduplicated respondents participated in this study and these included: past and present university administrators, institutional staff, researchers, governmental representatives, alumni, accreditation liaisons, and educational consortia staff
Cloning, purification and substrate conformations of aminoglycoside acetyltransferase (3)-IIIb
The aminoglycoside resistance protein aminoglycoside acetyltransferase (3)-IIIb (AAC3- nib) was successfully cloned, expressed and purified. This will allow many future experiments to be done using AAC3-IIIb. Using 2D NMR and molecular modeling, the conformations of two aminoglycosides, kanamycin and ribostamycin, were determined when bound to AAC3-lIIb. The structures determined for ribostamycin were divided into two conformers defined by the phi-psi angles of the glycosidic bonds as follows: Conformer 1 (11 total): Φ1A = -22 +/- 3, &Psi,1A= -42 +/-1, Φ1C= -9 +/- 4, Ψ1C = 51 +/-1 and for Conformer 2 (11 total): Φ1A = -67 +/- 0.7, Ψ1A = -59 +/- 0.8, Φ1C = -9 +/-3, Ψ1C = 49 +/-1. This gives the C to B ring orientation with respect to one another to be the same in both conformers. For kanamycin there were three conformers determined using the phi-psi angles as follows: Conformer 1 (9 structures): Φ1A = -11 +/- 3, Ψ1A= - 45 +/- 3, Φ1C= -9 +/- 4, Ψ1C = 50 +/- 2; Conformer 2 (6 structures): Φ1A = -8 +/- 3, Ψ1A = 48 +/- 2, Φ1C= -18 +/- 2, Ψ1C = -42 +/-2; and Conformer 3 (5 structures): Phi;1A = -73 +/- 0.6, Psi;1A= -57 +/- 0.2, Φ1C -14 +/- 0.5, Ψ1C = 51 +/- 0.2. Because the B to C orientation was the same for Conformer 1 and Conformer 3, this gives 14 out of 20 structures with that conformation for these rings. The C ring appears to be more constrained when either aminoglycoside is used while the A ring is somewhat more flexible. However, a comparison of the two aminoglycosides gives the A ring in one orientation (Conformer 1 for both ribostamycin and kanamycin) more than the others. This suggests that this may be the proper orientation of this ring. It has been suggested that the A and B rings provide the most important contributions when binding to both other aminoglycoside modifying enzymes and to RNA (Fourmy et al, 1996; Yoshizawa et al, 1998; Serpersu et al, 2000). Comparisons superimposing these rings with other enzyme bound aminoglycosides as well as RNA bound aminoglycosides shows remarkable similarity among the conformations. This gives important conformational information that may be used in future drug and enzyme inhibitor design studies
Novel transition metal-catalysed syntheses of carboxylic acid derivatives
This thesis describes the chemistry developed during a study of novel transition metalcatalysed reactions for the synthesis of carboxylic acid derivatives. Chapter 2 describes a novel protocol for the synthesis of primary amides from alcohols in one-pot where a metal complex mediates two fundamentally different catalytic processes. An iridium catalyst has been shown to be effective for the selective rearrangement of aldoximes into primary amides. In addition, an iridium-catalysed oxidation of activated alcohols via hydrogen transfer has been developed using an alkene as formal oxidant. These reactions have been combined in a sequential process affording good yields for a range of benzylic alcohols. An improved system for the rearrangement of aldoximes into amides using a new ruthenium catalyst is described in Chapter 3. Through a systematic program of optimisation excellent selectivity was achieved for a wide range of substrates at markedly reduced catalyst loading. Chapter 4 describes the development of a ruthenium-catalysed elimination reaction for the conversion of oxime ethers into nitriles. The application of this reaction to tandem and sequential reactions has been explored, albeit with limited success. Also, a method for the ruthenium-catalysed oxidation of alcohols using an electron-deficient alkene as hydrogen acceptor is described, and its application to a tandem oxidation process with a nitrogen nucleophile demonstrated. As an extension of the concept presented in Chapter 4, tandem oxidation processes with oxygen nucleophiles are the subject of Chapter 5. This strategy has been used for the oxidation of primary alcohols to their corresponding methyl esters in one-pot, with good yields obtained for a range of substrates. The use of water as a nucleophile in such a process has also been examined.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Induced periosteum-mimicking membrane with cell barrier and multipotential stromal cell (MSC) homing functionalities
The current management of critical size bone defects (CSBDs) remains challenging and requires multiple surgeries. To reduce the number of surgeries, wrapping a biodegradable fibrous membrane around the defect to contain the graft and carry biological stimulants for repair is highly desirable. Poly(ε-caprolactone) (PCL) can be utilised to realise nonwoven fibrous barrier-like structures through free surface electrospinning (FSE). Human periosteum and induced membrane (IM) samples informed the development of an FSE membrane to support platelet lysate (PL) absorption, multipotential stromal cells (MSC) growth, and the prevention of cell migration. Although thinner than IM, periosteum presented a more mature vascular system with a significantly larger blood vessel diameter. The electrospun membrane (PCL3%-E) exhibited randomly configured nanoscale fibres that were successfully customised to introduce pores of increased diameter, without compromising tensile properties. Additional to the PL absorption and release capabilities needed for MSC attraction and growth, PCL3%-E also provided a favourable surface for the proliferation and alignment of periosteum- and bone marrow derived-MSCs, whilst possessing a barrier function to cell migration. These results demonstrate the development of a promising biodegradable barrier membrane enabling PL release and MSC colonisation, two key functionalities needed for the in situ formation of a transitional periosteum-like structure, enabling movement towards single-surgery CSBD reconstruction
Blended Learning Makes Customizable Learning a Reality
There is no single best, one-size-fits-all blended learning model for every organization or every employee when developing soft skills in the workplace. Instead, a ‘mass customization’ approach that honours the uniqueness of different organizations, learning cultures, and learners can create highly personalized learning paths that enable each and every employee to learn. In this way, blended learning strategies can be used to maximize personal and collective learning in the workplace.York's Knowledge Mobilization Unit provides services and funding for faculty, graduate students, and community organizations seeking to maximize the impact of academic research and expertise on public policy, social programming, and professional practice. It is supported by SSHRC and CIHR grants, and by the Office of the Vice-President Research & Innovation.
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Transforming school culture through inquiry-driven learning and iPads
Purpose –The purpose of this paper is to provide an overview of a commissioned research study that analyzed a schooling initiative with the ambitious goal of transforming learning environments across the district by advancing innovative, inquiry-driven pedagogical practices combined with 1:1 iPad distribution. The paper explores impacts of the initiative on pedagogical innovation, twenty-first century learning, and related impacts on professional learning, collaboration, and culture change in the pilot schools analyzed in the study.
Design/methodology/approach –A multi-dimensional case study approach was used to analyze how the initiative was implemented, and to what extent teaching, learning, and professional cultures were transformed, based on action plan inputs and “change drivers”. Research methods included structured, open-ended interviews conducted with randomly selected teachers and key informants in leadership roles, focus groups held with students, as well as analysis of policy documents, student work samples, and other data sources.
Findings –The authors found evidence of a synergistic relationship between innovations in inquiry-driven pedagogy and professional learning cultures, with evidence of increased collaboration, deepened engagement and persistence, and a climate of collegiality and risk-taking at both classroom and organizational levels. Based on initiative inputs, the authors found that innovations in collaborative technology/pedagogy practices in classrooms paralleled similar innovations and transformations in professional learning cultures and capacity-building networks.
Practical implications –This initiative analyzed in this paper provides a case study in large-scale system change, offering a compelling model for transformative policies and initiatives where interwoven innovations in pedagogy and technology mobilization are supported by multiple drivers for formal and informal professional learning/development and networked collaboration. Challenges and recommendations are highlighted in the concluding discussion.
Originality/value –The transformative initiative analyzed in this paper provides a very timely case-model for innovations in twenty-first century learning and, specifically, for enacting and sustaining large-scale system change where inquiry-driven learning and technology tools are being mobilized to support “deep learning”, “new learning partnerships”, and multilevel transformations in professional learning (Fullan and Donnelly, 2013). This research advances scholarly work in the areas of twenty-first century learning, identifying relationships between technology/pedagogy innovation and professional capital building (Hargreaves and Fullan, 2012).
Keywords - Professional learning, Collaboration, Professional capital, Whole system transformation, Technology innovation, Inquiry-based learning, Pedagogical innovation
Paper type - Research pape
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