Anomalies in stiffness and damping of a 2D discrete viscoelastic system due to negative stiffness components

The recent development of using negative stiffness inclusions to achieve extreme overall stiffness and mechanical damping of composite materials reveals a new avenue for constructing high performance materials. One of the negative stiffness sources can be obtained from phase transforming materials in the vicinity of their phase transition, as suggested by the Landau theory. To understand the underlying mechanism from a microscopic viewpoint, we theoretically analyze a 2D, nested triangular lattice cell with pre-chosen elements containing negative stiffness to demonstrate anomalies in overall stiffness and damping. Combining with current knowledge from continuum models, based on the composite theory, such as the Voigt, Reuss, and Hashin-Shtrikman model, we further explore the stability of the system with Lyapunov's indirect stability theorem. The evolution of the microstructure in terms of the discrete system is discussed. A potential application of the results presented here is to develop special thin films with unusual in-plane mechanical properties. © 2006 Elsevier B.V. All rights reserved.

The single-phase induction motor:a critical appraisal of the rotating-field and cross-field theories with particular reference to skin effect

The purpose of this thesis is twofold: to examine the validity of the rotating-field and cross-field theories of the single-phase induction motor when applied to a cage rotor machine; and to examine the extent to which skin effect is likely to modify the characteristics of a cage rotor machine. A mathematical analysis is presented for a single-phase induction motor in which the rotor parameters are modified by skin effect. Although this is based on the usual type of ideal machine, a new form of model rotor allows approximations for skin effect phenomena to be included as an integral part of the analysis. Performance equations appropriate to the rotating-field and cross-field theories are deduced, and the corresponding explanations for the steady-state mode of operation are critically examined. The evaluation of the winding currents and developed torque is simplified by the introduction of new dimensionless factors which are functions of the resistance/reactance ratios of the rotor and the speed. Tables of the factors are included for selected numerical values of the parameter ratios, and these are used to deduce typical operating characteristics for both cage and wound rotor machines. It is shown that a qualitative explanation of the mode of operation of a cage rotor machine is obtained from either theory; but the operating characteristics must be deduced from the performance equations of the rotating-field theory, because of the restrictions on the values of the rotor parameters imposed by skin effect.

Visual field and structural alterations in age-related macular degeneration

The thesis investigated progression of the central 10° visual field with structural changes at the macula in a cross-section of patients with varying degrees of agerelated macular degeneration (AMD). The relationships between structure and function were investigated for both standard and short-wavelength automated perimetry (SWAP). Factors known to influence the measure of visual field progression were considered, including the accuracy of the refractive correction on SWAP thresholds and the learning effect. Techniques of assessing the structure to function relationships between fundus images and the visual field were developed with computer programming and evaluated for repeatability. Drusen quantification of fundus photographs and retro-mode scanning laser ophthalmoscopic images was performed. Visual field progression was related to structural changes derived from both manual and automated methods. Principal Findings: • Visual field sensitivity declined with advancing stage of AMD. SWAP showed greater sensitivity to progressive changes than standard perimetry. • Defects were confined to the central 5°. SWAP defects occurred at similar locations but were deeper and wider than corresponding standard perimetry defects. • The central field became less uniform as severity of AMD increased. SWAP visual field indices of focal loss were of more importance when detecting early change in AMD, than indices of diffuse loss. • The decline in visual field sensitivity over stage of severity of AMD was not uniform, whereas a linear relationship was found between the automated measure of drusen area and visual field parameters. • Perimetry exhibited a stronger relationship with drusen area than other measures of visual function. • Overcorrection of the refraction for the working distance in SWAP should be avoided in subjects with insufficient accommodative facility. • The perimetric learning effect in the 10° field did not differ significantly between normal subjects and AMD patients. • Subretinal deposits appeared more numerous in retro-mode imaging than in fundus photography.

Ultrasonic field and temperature sensor based on short in-fibre Bragg gratings

The authors demonstrate that in-fibre Bragg gratings may be successfully used to measure megahertz acoustic fields if the grating length is sufficiently short and the optical fibre is appropriately desensitised. A noise-limited pressure resolution of 4.5 × 10 –3 atm vHz was found. The capability to simultaneously act as a temperature sensor is also demonstrated.

Visual field and structural correlates of progression in age-related macular degeneration

Presentation Purpose:To examine the correlation of central visual field loss and progression of structural changes in the macular area in age-related macular degeneration (AMD). Methods:Central 10° standard and short-wavelength automated perimetry (SWAP) visual fields were acquired in 39 eyes of 24 patients with AMD using a Humphrey Field Analyzer. Stereoscopic fundus photographs were graded1 by two independent observers and the stage of disease determined2. Custom software mapped perimetric data onto fundus images in order to relate structural changes to functional loss. Results:Mean deviation (MD) in standard perimetry changed from 0.04 dB at stage 1 to -12.39 dB at stage 4 (r2=0.48, p<0.001). The group mean SWAP MD was -5.26 dB at stage 1 and increased to -17.08 dB at stage 4 (r2=0.53, p<0.001). Pattern standard deviation (PSD) also increased with advancing stage in standard perimetry; 1.32 dB to 8.67 dB at stage 1 and 4, respectively (r2=0.54, p<0.001). In SWAP, PSD increased from 2.86 dB to 5.63 dB at stage 1 and stage 4 (r2=0.43, p<0.001). Defect frequency was greater in SWAP than standard perimetry. Early stage defects occurred with the greatest frequency at eccentricities of 3.2° and 5.1° in standard perimetry and at 4.2° in SWAP. Late stage defects were most frequent at 1° eccentricity in standard perimetry and at 1° and 9° in SWAP. MD declined with increasing affected retinal area over the central 3000µm; by 0.20 dB (r2=0.67, p<0.001) and 0.18 dB (r2=0.49, p<0.001) per % increase in defect area for standard perimetry and SWAP respectively. 41% of defects were associated with structural changes on the retina in standard perimetry and 43% in SWAP. Conclusions:Sensitivity decreased with advancing stage of AMD, with a greater effect demonstrated in SWAP compared to standard perimetry. The central field became less uniform as stage increased. SWAP defects occurred at similar locations but were deeper and wider than corresponding defects in standard perimetry. Central loss in SWAP is a sensitive marker of functional progression in AMD.1. Bird et al. (1995) Surv Ophthalmol 39:367-3742. van Leeuwen et al. (2003) Arch Ophthalmol 121:519-526

Theoretical perspectives in purchasing and supply chain management:an analysis of the literature

Purpose – This paper attempts to seek answers to four questions. Two of these questions have been borrowed (but adapted) from the work of Defee et al.: RQ1. To what extent is theory used in purchasing and supply chain management (P&SCM) research? RQ2. What are the prevalent theories to be found in P&SCM research? Following on from these questions an additional question is posed: RQ3. Are theory-based papers more highly cited than papers with no theoretical foundation? Finally, drawing on the work of Harland et al., the authors have added a fourth question: RQ4. To what extent does P&SCM meet the tests of coherence, breadth and depth, and quality necessary to make it a scientific discipline? Design/methodology/approach – A systematic literature review was conducted in accordance with the model outlined by Tranfield et al. for three journals within the field of “purchasing and supply chain management”. In total 1,113 articles were reviewed. In addition a citation analysis was completed covering 806 articles in total. Findings – The headline features from the results suggest that nearly a decade-and-a-half on from its development, the field still lacks coherence. There is the absence of theory in much of the work and although theory-based articles achieved on average a higher number of citations than non-theoretical papers, there is no obvious contender as an emergent paradigm for the discipline. Furthermore, it is evident that P&SCM does not meet Fabian's test necessary to make it a scientific discipline and is still some way from being a normal science. Research limitations/implications – This study would have benefited from the analysis of further journals, however the analysis of 1,113 articles from three leading journals in the field of P&SCM was deemed sufficient in scope. In addition, a further significant line of enquiry to follow is the rigour vs relevance debate. Practical implications – This article is of interest to both an academic and practitioner audience as it highlights the use theories in P&SCM. Furthermore, this article raises a number of important questions. Should research in this area draw more heavily on theory and if so which theories are appropriate? Social implications – The broader social implications relate to the discussion of how a scientific discipline develops and builds on the work of Fabian and Amundson. Originality/value – The data set for this study is significant and builds on a number of previous literature reviews. This review is both greater in scope than previous reviews and is broader in its subject focus. In addition, the citation analysis (not previously conducted in any of the reviews) and statistical test highlights that theory-based articles are more highly cited than non-theoretically based papers. This could indicate that researchers are attempting to build on one another's work.

Implicit leadership and followership theories 'in the wild':taking stock of information-processing approaches to leadership and followership in organizational settings

For over 30. years information-processing approaches to leadership and more specifically Implicit Leadership Theories (ILTs) research has contributed a significant body of knowledge on leadership processes in applied settings. A new line of research on Implicit Followership Theories (IFTs) has re-ignited interest in information-processing and socio-cognitive approaches to leadership and followership. In this review, we focus on organizational research on ILTs and IFTs and highlight their practical utility for the exercise of leadership and followership in applied settings. We clarify common misperceptions regarding the implicit nature of ILTs and IFTs, review both direct and indirect measures, synthesize current and ongoing research on ILTs and IFTs in organizational settings, address issues related to different levels of analysis in the context of leadership and follower schemas and, finally, propose future avenues for organizational research. © 2013 Elsevier Inc.

Ultrasonic field and temperature sensor based on short in-fibre Bragg gratings

The authors demonstrate that in-fibre Bragg gratings may be successfully used to measure megahertz acoustic fields if the grating length is sufficiently short and the optical fibre is appropriately desensitised. A noise-limited pressure resolution of 4.5 × 10 –3 atm vHz was found. The capability to simultaneously act as a temperature sensor is also demonstrated.

A comparative study of career management practices in Britain and India

This paper examines the developments in the field of career management in a cross-national comparative context. It investigates a wide range of career practices via two large-scale surveys in 108 Indian and 194 British organisations. The influence of a number of organisational characteristics on career practices is analysed. The study has identified a number of similarities as well as differences in the career management systems of firms operating in both India and Britain. Theoretical and managerial implications for the fields of careers and international HRM are discussed.

A comparative study of HR practices in Britain and India

This paper traces the major developments in the field of human resource management briefly and then highlights the need for more cross-national HRM studies. The results from two parallel surveys of matched Indian and British organizations are presented. The main aim of the surveys was to examine a wide range of HRM policies and practices in a cross-national comparative context. The surveys were run in six industries in the manufacturing sector. The study controlled for a number of variables such as size of the organization, product, industry sector and personnel participation. Influence of a number of contingent variables (such as age, size, nature and life-cycle stage of the organization, presence of unions and human resource strategies) on HRM policies and practices is analysed. The study finds significant differences in recruitment, compensation, training and development and employee communication practices between India and Britain.

Evaluation of research in efficiency and productivity:a survey and analysis of the first 30 years of scholarly literature in DEA

Since the original Data Envelopment Analysis (DEA) study by Charnes et al. [Measuring the efficiency of decision-making units. European Journal of Operational Research 1978;2(6):429–44], there has been rapid and continuous growth in the field. As a result, a considerable amount of published research has appeared, with a significant portion focused on DEA applications of efficiency and productivity in both public and private sector activities. While several bibliographic collections have been reported, a comprehensive listing and analysis of DEA research covering its first 30 years of history is not available. This paper thus presents an extensive, if not nearly complete, listing of DEA research covering theoretical developments as well as “real-world” applications from inception to the year 2007. A listing of the most utilized/relevant journals, a keyword analysis, and selected statistics are presented.

Knowledge management: a review of the field and of OR's contribution

This paper examines the field of knowledge management (KM) and identifies the role of operational research (OR) in key milestones and in KM's future. With the presence of the OR Society journal Knowledge Management Research and Practice and with the INFORMS journal Organization Science, OR may be assumed to have an explicit and a leading role in KM. Unfortunately, the origins and the evidence of recent research efforts do not fully support this assumption. We argue that while OR has been inside many of the milestones there is no explicit recognition of its role and while OR research on KM has considerably increased in the last 5 years, it still forms a rather modest explicit contribution to KM research. Nevertheless, the depth of OR's experience in decision-making models and decision support systems, soft systems with hard systems and in risk management suggests that OR is uniquely placed to lead future KM developments. We suggest that a limiting aspect of whether OR will be seen to have a significant profile will be the extent to which developments are recognized as being informed by OR.

Higher education reform in Kyrgyzstan: the politics of neoliberal agendas in theory and practice

There would seem to be no greater field for observing the effects of neo-liberal reforms in higher education than the former Soviet university, where attempts to legitimize neo-liberal philosophy over Soviet ideology plays out in everyday practices of educational reform. However, ethnographic research about higher education in post-Soviet Central Asia suggests that its “liberalization” is both an ideological myth and a complicated reality. This chapter focuses on how and why neo-liberal agendas have “travelled” to the Central Asian republic of Kyrgyzstan, what happens when educators encounter and resist them, and why these spaces of resistance are important starting points for the development of alternative visions of educational possibility in this recently “Third-worlded” society.