Numerical modelling of complex femtosecond laser inscribed fiber gratings - comparison wih experiment

We present experimental studies and numerical modeling based on a combination of the Bidirectional Beam Propagation Method and Finite Element Modeling that completely describes the wavelength spectra of point by point femtosecond laser inscribed fiber Bragg gratings, showing excellent agreement with experiment. We have investigated the dependence of different spectral parameters such as insertion loss, all dominant cladding and ghost modes and their shape relative to the position of the fiber Bragg grating in the core of the fiber. Our model is validated by comparing model predictions with experimental data and allows for predictive modeling of the gratings. We expand our analysis to more complicated structures, where we introduce symmetry breaking; this highlights the importance of centered gratings and how maintaining symmetry contributes to the overall spectral quality of the inscribed Bragg gratings. Finally, the numerical modeling is applied to superstructure gratings and a comparison with experimental results reveals a capability for dealing with complex grating structures that can be designed with particular wavelength characteristics.

Regional evolution and waves of growth:a knowledge-based perspective

The evolution of a regional economy and its competitiveness capacity may involve multiple independent trajectories, through which different sets of resources and capabilities evolve together. However, there is a dearth of evidence concerning how these trends are occurring across the globe. This paper seeks to present evidence in relation to the recent development of the globe’s most productive regions from the viewpoint of their growth trajectories, and the particular form of growth they are experiencing. The aim is to uncover the underlying structure of the changes in knowledge-based resources, capabilities and outputs across regions, and offer an analysis of these regions according to an uncovered set of key trends. The analysis identifies three key trends by which the economic evolution and growth patterns of these regions are differentiated—namely the Fifth Wave Growth, the Third & Fourth Wave Growth, and Government-led Third Wave Growth. Overall, spectacular knowledge-based growth of leading Chinese regions is evident, highlighting a continued shift of knowledge-based resources to Asia. In addition, a superstructure is observed at the global scale, consisting of two separate continuums that explicitly distinguish Chinese regions from the rest in terms of regional growth trajectories.

High performance microwave photonic response of superstructured fibre Bragg grating with designed apodisation function

The microwave photonic responses based on the superstructure fibre Bragg gratings with designed apodisation profile are investigated. The rejection level of more than 60 dB for a bandpass filtering response is demonstrated.

Regional evolution and waves of growth:a knowledge-based perspective

The evolution of a regional economy and its competitiveness capacity may involve multiple independent trajectories through which different sets of resources and capabilities evolve together. However, there is a dearth of evidence concerning how these trends are occurring across the globe. Based on the underlying tenets of the streams of research relating to regional competitiveness, knowledge cities/regions, and knowledge-based urban development, this paper seeks to present an empirical approach to establishing such evidence in relation to the recent development of the globe’s most productive regions from the viewpoint of their growth trajectories and the particular form of growth they are experiencing. The aim is to uncover the underlying structure of the changes in knowledge-based resources, capabilities and outputs across regions, and offer an analysis of these regions according to an uncovered set of key trends. The analysis identifies three key trends by which the economic evolution and growth patterns of these regions are differentiated – namely the Fifth Wave Growth, the Third & Fourth Wave Growth, and Government-led Third Wave Growth. Overall, spectacular knowledge-based growth of leading Chinese regions is evident, highlighting a continued shift of knowledge-based resources to Asia. In addition, a superstructure is observed at the global scale, consisting of two separate continuums that explicitly distinguish Chinese regions from the rest in terms of regional growth trajectories. © 2014 Elsevier Ltd. All rights reserved. © 2014 Elsevier Ltd. All rights reserved.

Numerical modelling of complex femtosecond laser inscribed fiber gratings - comparison wih experiment

We present experimental studies and numerical modeling based on a combination of the Bidirectional Beam Propagation Method and Finite Element Modeling that completely describes the wavelength spectra of point by point femtosecond laser inscribed fiber Bragg gratings, showing excellent agreement with experiment. We have investigated the dependence of different spectral parameters such as insertion loss, all dominant cladding and ghost modes and their shape relative to the position of the fiber Bragg grating in the core of the fiber. Our model is validated by comparing model predictions with experimental data and allows for predictive modeling of the gratings. We expand our analysis to more complicated structures, where we introduce symmetry breaking; this highlights the importance of centered gratings and how maintaining symmetry contributes to the overall spectral quality of the inscribed Bragg gratings. Finally, the numerical modeling is applied to superstructure gratings and a comparison with experimental results reveals a capability for dealing with complex grating structures that can be designed with particular wavelength characteristics.

Split-ARCH

2000 Mathematics Subject Classification: 62M10

Schools and the formation of Black identity during the Civil Rights Movement: Change and resistance in Holly Springs, Mississippi, 1964--1974

Desegregation of social and public spaces was the most visible result of the Civil Rights Movement. After 1960, the integration of schools in Mississippi became a source of conflict. The social change of Civil Rights attacked the social order of White Resistance that supported the state superstructure. The public schools were a place for the discovery of identity for Blacks. The integrated on of the schools caused many Whites to leave rather than be integrated with Blacks. Desegregation of schools was also a slow process because the local and state government could not enforce the decisions of the US Courts, leading Blacks to realize their place in American society could only be secured through individual action. ^ This work explains the role of schooling during the integration of the Holly Springs Separate School System. The process of forging a new identity by local Blacks is examined against the forces of social change and resistance. I addition, this work examines the perils for the Blacks as they faced the uncertainty of change in the crucial Civil Rights years between 1964 and 1974. ^ This work analyzes how the Black community dealt with the problems triggered by the desegregation of the school system in Holly Springs, of a constructed social condition, a psychological state of being, the realities of racism and segregation, and the change and resistance between the individual and the collective. It is based on six months of field work investigation. Although the schools were a crucial aspect of community life for Blacks and Whites, Blacks did form their identity in them. Other institutions, such churches were more crucial. Second, the aspect of politeness and belief in law made the experience in Holly Springs unique to that place, and thus, warrants further study to determine its place within the Civil Rights Movement. Finally, while the political and economic control of Holly Springs remained with Whites, desegregation led to the resegregation of the public schools: as Whites left to private schools. ^

Lateral load distribution for curved steel I -girder bridges

Lateral load distribution factor is a key factor for designing and analyzing curved steel I-girder bridges. In this dissertation, the effects of various parameters on moment and shear distribution for curved steel I-girder bridges were studied using the Finite Element Method (FEM). The parameters considered in the study were: radius of curvature, girder spacing, overhang, span length, number of girders, ratio of girder stiffness to overall bridge stiffness, slab thickness, girder longitudinal stiffness, cross frame spacing, and girder torsional inertia. The variations of these parameters were based on the statistical analysis of the real bridge database, which was created by extracting data from existing or newly designed curved steel I-girder bridge plans collected all over the nation. A hypothetical bridge superstructure model that was made of all the mean values of the data was created and used for the parameter study. ^ The study showed that cross frame spacing and girder torsional inertia had negligible effects. Other parameters had been identified as key parameters. Regression analysis was conducted based on the FEM analysis results and simplified formulas for predicting positive moment, negative moment, and shear distribution factors were developed. Thirty-three real bridges were analyzed using FEM to verify the formulas. The ratio of the distribution factor obtained from the formula to the one obtained from the FEM analysis, which was referred to as the g-ratio, was examined. The results showed that the standard deviation of the g-ratios was within 0.04 to 0.06 and the mean value of the g-ratios was greater than unity by one standard deviation. This indicates that the formulas are conservative in most cases but not overly conservative. The final formulas are similar in format to the current American Association of State Highway and Transportation Officials (AASHTO) Load Resistance and Factor Design (LRFD) specifications. ^ The developed formulas were compared with other simplified methods. The outcomes showed that the proposed formulas had the most accurate results among all methods. ^ The formulas developed in this study will assist bridge engineers and researchers in predicting the actual live load distribution in horizontally curved steel I-girder bridges. ^

A branch and efficiency algorithm for the optimal design of supply chain networks

Supply chain operations directly affect service levels. Decision on amendment of facilities is generally decided based on overall cost, leaving out the efficiency of each unit. Decomposing the supply chain superstructure, efficiency analysis of the facilities (warehouses or distribution centers) that serve customers can be easily implemented. With the proposed algorithm, the selection of a facility is based on service level maximization and not just cost minimization as this analysis filters all the feasible solutions utilizing Data Envelopment Analysis (DEA) technique. Through multiple iterations, solutions are filtered via DEA and only the efficient ones are selected leading to cost minimization. In this work, the problem of optimal supply chain networks design is addressed based on a DEA based algorithm. A Branch and Efficiency (B&E) algorithm is deployed for the solution of this problem. Based on this DEA approach, each solution (potentially installed warehouse, plant etc) is treated as a Decision Making Unit, thus is characterized by inputs and outputs. The algorithm through additional constraints named “efficiency cuts”, selects only efficient solutions providing better objective function values. The applicability of the proposed algorithm is demonstrated through illustrative examples.

Seismic Response Analysis of a Full-Scale Base-Isolated Structure via Measurements and Modeling

The full-scale base-isolated structure studied in this dissertation is the only base-isolated building in South Island of New Zealand. It sustained hundreds of earthquake ground motions from September 2010 and well into 2012. Several large earthquake responses were recorded in December 2011 by NEES@UCLA and by GeoNet recording station nearby Christchurch Women's Hospital. The primary focus of this dissertation is to advance the state-of-the art of the methods to evaluate performance of seismic-isolated structures and the effects of soil-structure interaction by developing new data processing methodologies to overcome current limitations and by implementing advanced numerical modeling in OpenSees for direct analysis of soil-structure interaction.

This dissertation presents a novel method for recovering force-displacement relations within the isolators of building structures with unknown nonlinearities from sparse seismic-response measurements of floor accelerations. The method requires only direct matrix calculations (factorizations and multiplications); no iterative trial-and-error methods are required. The method requires a mass matrix, or at least an estimate of the floor masses. A stiffness matrix may be used, but is not necessary. Essentially, the method operates on a matrix of incomplete measurements of floor accelerations. In the special case of complete floor measurements of systems with linear dynamics, real modes, and equal floor masses, the principal components of this matrix are the modal responses. In the more general case of partial measurements and nonlinear dynamics, the method extracts a number of linearly-dependent components from Hankel matrices of measured horizontal response accelerations, assembles these components row-wise and extracts principal components from the singular value decomposition of this large matrix of linearly-dependent components. These principal components are then interpolated between floors in a way that minimizes the curvature energy of the interpolation. This interpolation step can make use of a reduced-order stiffness matrix, a backward difference matrix or a central difference matrix. The measured and interpolated floor acceleration components at all floors are then assembled and multiplied by a mass matrix. The recovered in-service force-displacement relations are then incorporated into the OpenSees soil structure interaction model.

Numerical simulations of soil-structure interaction involving non-uniform soil behavior are conducted following the development of the complete soil-structure interaction model of Christchurch Women's Hospital in OpenSees. In these 2D OpenSees models, the superstructure is modeled as two-dimensional frames in short span and long span respectively. The lead rubber bearings are modeled as elastomeric bearing (Bouc Wen) elements. The soil underlying the concrete raft foundation is modeled with linear elastic plane strain quadrilateral element. The non-uniformity of the soil profile is incorporated by extraction and interpolation of shear wave velocity profile from the Canterbury Geotechnical Database. The validity of the complete two-dimensional soil-structure interaction OpenSees model for the hospital is checked by comparing the results of peak floor responses and force-displacement relations within the isolation system achieved from OpenSees simulations to the recorded measurements. General explanations and implications, supported by displacement drifts, floor acceleration and displacement responses, force-displacement relations are described to address the effects of soil-structure interaction.

Room for Writing: moving from abstract to extended abstract

An developmental exercise to help grow the superstructure of a report. A paper by Repko discussing common ground is included, you are also advised to look at the set text, Chapter 11, Page 271

The Keokuk & Hamilton Bridge : Keokuk, Iowa - Hamilton, Illinois, 1982

The Keokuk & Hamilton Bridge is one of three remaining in Iowa that were designed by Ralph Modjeski, one of this country's premier early 20th century bridge engineers. The eleven-span, double-deck steel superstructure was built in 1915-1916 on piers retained from an earlier (1869-1871) structure, to meet greater loading requirements from railroads that operated across the Mississippi at this point.

Between path dependency and contingency: new challenges for the geography of port system evolution.

Seaports play a critical role as gateways and facilitators of economic interchange and logistics processes and thus have become crucial nodes in globalised production networks andmobility systems. Both the physical port infrastructure and its operational superstructure have undergone intensive evolution processes in an effort to adapt to changing economic environments, technological advances,maritime industry expectations and institutional reforms. The results, in terms of infrastructure, operator models and the role of an individual port within the port system, vary by region, institutional and economic context. While ports have undoubtedly developed in scale to respond to the changing volumes and structures in geographies of trade (Wilmsmeier, 2015), the development of hinterland access infrastructure, regulatory systems and institutional structures have in many instances lagged behind. The resulting bottlenecks reflect deficits in the interplay between the economic system and the factors defining port development (e.g. transport demand, the structure of trade, transport services, institutional capacities, etc. cf. Cullinane and Wilmsmeier, 2011). There is a wide range of case study approaches and analyses of individual ports, but analyses from a port system perspective are less common, and those that exist are seldom critical of the dominant discourse assuming the efficiency of market competition (cf. Debrie et al., 2013). This special section aims to capture the spectrum of approaches in current geography research on port system evolution. Thus, the papers reach from the traditional spatial approach (Rodrigue and Ashar, this volume) to network analysis (Mohamed-Chérif and Ducruet, this volume) to institutional discussions (Vonck and Notteboom, this volume; Wilmsmeier and Monios, this volume). The selection of papers allows an opening of discussion and reflection on current research, necessary critical analysis of the influences on port systemevolution and,most importantly, future directions. The remainder of this editorial aims to reflect on these challenges and identify the potential for future research.

Engenharia ferroviária: traçado e materiais de via

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil - Área de Especialização em Vias de Comunicações e Transportes

Dimensionamento de um pavilhão metálico para armazenamento de paletes de madeira

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Estruturas