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Evaluation and validation of the spectral linear wave theory and ‘traditional’ formulae for pulsating wave loads for unimodal and bimodal seas: Comparison to Goda and measurements
No full textFor the design of vertical hydraulic structures pulsating wave forces need to be calculated. The total wave force is a result of every wave component (long waves and short waves) within a wave field. The common formulae are derived for regular or unimodal narrow sea states and use one characteristic wave height and period. Broad-banded spectra like bimodal sea states are present at many locations. Moreover, new hydraulic structures like Panamax or post-Panamax locks do have a large vertical surface exposed to pulsating wave loads. Swell components within the wave spectrum are disproportionally contributing to the total wave force compared to short waves. This depth effect for broad-banded or bimodal wave spectra is not considered by the traditional wave formulae which could result in significant underestimations of wave forces on hydraulic structures.
This paper aims to determine the wave loads of irregular non-breaking wave fields under any wave spectrum: narrow banded, broad-banded, or bimodal. Spectral linear wave theory (LWT) is used to transform any wave spectrum to a wave force spectrum. The wave force or wave pressure at any level can directly be evaluated from the wave force spectrum or wave pressure spectrum for any shape of the wave spectrum considered within this research. Spectral LWT is compared to the outcome of wave flume experiments with bimodal seas and other wave force formulae, like the Goda formula and quasi-regular LWT and the NewWave theory.
This paper gives a description and evaluation of the spectral LWT applied for bimodal wave spectra and a comparison of the accuracy and validity of other wave force formulae. The peak forces and peak pressures distribution obtained by spectral wave theory compare well to the measurements. It appears that the use of a spectral LWT to obtain characteristic extreme forces improves the accuracy of the extreme load more than the use of a second order wave model with a quasi-regular assumption (i.e. where the spectral shape is not considered). For the typical conditions that occur at hydraulic structures (horizontal bed, intermediate to deep water, non-breaking, and uni- and bimodal seas) the often-used Goda formula can both under of overestimate the peak loads. Goda is well applicable for conditions with (breaking) waves narrow wave spectra and values of kph <0.5
Historic Landscape Conservation at the UNC in the early 21st century (2001-2010)
Get PDFBased on the two successive plans of the University of North Carolina (UNC) at Chapel Hill from 2001 to 2010, we review the conservation and planning philosophy of the five landmark landscapes in the master plan, and the historical context, content and aesthetic culture of the plans, with an emphasis on the objectives, principles, methods and implementation of the historic landscape plan. Since its foundation in 1795, the University of North Carolina has gone through five different phases of landscape planning and management, directed by a professor of natural philosophy, a historian, a botanist, a landscape architect and an architect. The spatial form of its campus plan reflects the great changes in the economic development of the United States over 200 years, reflecting the process of American campus construction during that period. It is argued that the guiding principles developed by the University of North Carolina at Chapel Hill for the preservation of historic landscapes reflect the important role that human intervention and the power of restraint play in the preservation of landscape heritage
Jaap Bakema’s Open Society in the Twenty-first Century: A Critical Appraisal of ’t Hool, the Netherlands and Montbau, Spain
Get PDFThe concept of the Open Society appeared in the CIAM discourse of the 1950s as an attempt to create condition in the city for society to prosper. These good intentions at the theoretical level did not always translate into success stories in practice, and some of the consequences of such a gap can be still felt today, amplified by multiple crises (social, economic, environmental, etc.). Often, the consequence is decay and demolition. The availability of vast knowledge and the emergence of different urban theories and tools since the 1950s allows for new possibilities to reinterpret the values underpinning the concept of the Open Society, and to bridge the gap between theory and practice. Our hypothesis is that an historically situated appraisal of the Open Society is necessary to bring it up to date and renew and enrich its legacy towards social, economic, and environmental resilience. Thus, we formulate the question: to what extent is the concept of the Open Society still relevant in contemporary urbanism?This study proposes a two-pronged investigation into the Open Society (both empirical and theoretical). It aims to investigate the discursive and projective validity of the concept as follows: First, critically review the theoretical concept and its implementation from the perspective of global and contemporary frameworks of discourse and policy. Second, empirically review two case studies (’t Hool, the Netherlands and Montbau, Spain) that illustrate the phenomena and patterns that have arisen in the friction between place, Open Society ideals, and resistance generated by users. This research uses a mixed-methods approach (i.e. quantitative and qualitative) and includes critical cartographies to critically and sensitively examine the two case studies and draw conclusions to highlight power relations and the existing materials available for building a more resilient future. In this way, we attempt to bridge the theory-practice gap by providing a methodology that provides a broad and deep understanding of the places, their histories, and their potentials and urgencies
Between Tradition and Modernity: Western urban planning and street improvement projects in Hankou (1889-1937)
Get PDFThis article examines street improvement projects in Hankou\u27s case for unearthing the contribution of Chinese political elites and planers in exchanging planning concepts and technologies from the West to China. Aiming to realize the Modern Metropolis, which Sun Yat-sen proposed in the fundamentals of national reconstruction, Chinese political elites and planers selected, borrowed, and imported western planning ideas to transform traditional Hankou city by implementing street improvement projects. Using the case of street improvement of Hankou during the Late Qing period(1889-1911), Early Republic China period(1911-1926), and Municipal Government period(1926-1937) as case studies, this article examines street improvement projects which authorities developed for Hankou in three different periods. By analyzing planning concepts, street plans(both realized and planned), and management regulations of these projects, the paper argues that improvement projects aimed to develop economic and industrial and improve public hygiene. Furthermore, the Chinese political and planning elites imported European and American design principles and practiced them in the Hankou local context for their own needs. In conclusion, the built environment showed hybridization features after implementing continuous planning schemes
A Study on the Spatial Structure of Jinan in the Qing Dynasty
Get PDFTaking Jinan as the research object, this paper attempts to construct the spatial structure of Jinan in the Qing dynasty through documentary research and historical map transfer. The study was conducted on the following three levels: macro, meso and micro. Specifically, in macro-level, the study attempted to construct the spatial structure by sorting out the natural environment and transport elements, Qing dynasty administrative divisions and urban functions within the city limits. In meso-level, the study focused on the interaction of mountain and river with urban siting and urban axes. In micro level, the study focused on the organisation of space within the city. The study found that the eight counties within the city limits of the Qing Dynasty were all centres of defence, political, economic, cultural, and educational functions, together forming a multi-centre network structure. Among the 8 counties, Licheng County was located between mountains and rivers, and used the natural elements to establish an effective defence system. The city formed five main axes with the mountains and rivers, creating a harmonious and close connection with the surrounding environment. Inside the city, the space was organised through lishe, forming a spatial structure with the north-south road as the skeleton. By establishing the spatial structure of the entire administrative region and its multiple layers, the study hopes to provide historical advice to current planning practice
Towards a future sustainable housing stock: Assessment of the energy performance of dwellings of non-profit housing
Get PDFThis thesis examines the energy performance of dwellings of Dutch non-profit housing associations towards a future sustainable housing stock. Improving the energy performance of dwellings aims to improve the quality of dwellings and therewith to lower the actual energy consumption. Lowering the actual energy consumption of dwellings contributes to the battle against climate change. This thesis addresses four studies. Study 1 assesses the energy performance progress of over two million dwellings of Dutch non-profit housing associations between 2017 and 2020. It gives insights into the development of the housing stock, the effect of changes of and within the stock, the effect of characteristics of housing associations and it relates the improvement of the energy performance to the sectoral goal. Study 2 assesses advanced models to improve estimations of actual energy consumption of dwellings and therewith to better estimate the effect of renovation measures on actual energy savings. Study 3 assesses the energy performance of dwellings with heat pumps. It gives insights into the energy performance of dwellings with heat pumps as a promising renovation measure towards a future sustainable housing stock. Study 4 assesses the process to create a model to benchmark the energy performance in a changing policy context. The four studies contribute to the understanding of the improvement of the energy performance of dwellings of non-profit housing associations towards a future sustainable housing stock
Evolution and Permanence in Coimbra’s Urban Form: The Emergence of Urban Planning in Portugal at the Turn of the Twentieth-Century
Get PDFAcross Europe, the 19th century was a period of radical transformation and the time of the emergence of urban planning as a science. In Portugal, a peripheral country, devastated by civil war and political and economic instability, these transformations emerged with some delay and on a smaller scale. After the creation in 1852 of the Ministry of Public Works, responsible for planning and construction of modern infrastructure and the road and railway network that would connect the main cities and the country with Europe, the first concerns with cities’ health and urban beautification arose. Thus in 1864, the first urban legislation introducing the general improvement plan, mandatory for the two main Portuguese cities, Lisbon and Porto emerged, but it was also applicable to other cities. Coimbra, a medium-sized city, but then the only Portuguese university city, one of the cities that tried to draw up a general improvement plan to ensure the city\u27s beautification planning. This paper analyses these efforts and a set of plans and projects, their relations with European models, and intends to understand the innovation of these first plans in the light of the emergence of urban planning as a mandatory public policy in Portugal. 
Engineering the Winter Soldier: A study of an advanced bionic arm
Get PDFThe Winter Solider, better known as James Buchanan “Bucky” Barnes, possesses a highly advanced prosthetic arm that provides enhanced levels of strength, endurance, and toughness to the biologically enhanced solider. This paper covers some of the engineering aspects behind his advanced prosthetic. First, the origin of the Winter Solider is discussed with a review of the abilities of his prosthetic arm. These abilities are used to assess the essential characteristics of the arm. An assessment of the anatomical damage suffered by Barnes is presented with this dictating the functionality needed for his prosthetic arm. Some basic assumptions are then made to estimate the material composition of his arm, and thus help identify the real materials that could be used to actually make his arm. This analysis process indicates that early versions of the arm were most likely made from a ferroalloy with a depleted uranium/titanium alloy and tungsten carbides being highly suitable. This is followed by an engineering assessment that breaks down the core aspects of the arm (mechanical structure, actuators, sensors, a power source, and a control system) with discussion on past, present, and future engineering solutions of these core aspects
Modelling the relationship between covid-19 restrictive measures and mobility patterns across Europe using time-series analysis
Get PDFSince early 2020, strict restrictions on non-essential movements were imposed globally as countermeasures to the rapid spread of COVID-19. The various containment and closures strategies, taken by the majority of countries, have directly affected travel behavior. This paper aims to investigate and model the relationship between covid-19 restrictive measures and mobility patterns across Europe using time-series analysis. Driving and walking data, as well as confinement policies were collected from February 2020 to February 2021 for twenty-five European countries and were implemented into Seasonal AutoRegressive Integrated Moving Average with eXogenous regressors (SARIMAX) time-series models. Results reveal a significant number of models in order to estimate mobility during pandemic almost in every country of the study. School closing was found to be the most important exogenous factor for describing driving or walking, while “Stay at home” orders had not a significant effect on the evolution of people movements. In addition, countries which suffered the most due to the pandemic indicated a strong correlation with the restrictive measures. No time-series models were found to describe the countries which implemented weak confinement policies
The border effect in European air transport
Get PDFThis article deals with the analysis of the border effect in European air transport. The border effect measures how trade or transport flows are diminished when they cross a national border. This topic has attracted a great deal of attention within trade, but it is still little studied within transport. Existing studies have estimated that the border effect diminished air passenger transport flows by a factor of five to six. However, there have been many changes in the European economy and transport since those studies. Our estimate based on a new data set suggested the existence of a border effect in European passenger air traffic flows, albeit with a lower value of around two. A possible reason for the lower value is the growing integration of the European economy and the development of low-cost carriers in Europe between 2000 and 2019. Our econometric analysis also found differences in border effects among European countries. No significant border effect was detected for France, but we did find high and significant effects for Germany, Spain, and Poland. These differences can be attributed to different intensities of intermodal competition on domestic routes
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