Predictions of turbulent boundary-layer developments using a two-equation model of turbulence

Imperial Users onl

Pile Setup, Dynamic Construction Control, and Load and Resistance Factor Design of Vertically-Loaded Steel H-Piles

Because of the mandate imposed by the Federal Highway Administration (FHWA) on the implementation of Load Resistance Factor Design (LRFD) in all new bridge projects initiated after October 1, 2007, research on developing the LRFD recommendations for pile foundations that reflect local soil conditions and construction experiences for the State of Iowa becomes essential. This research focuses on the most commonly used steel H-pile foundation. The research scope is to (1) characterize soil-pile responses under pile driving impact loads, and (2) understand how the generated information could be used to improve design and construction control of piles subjected to vertical loads in accordance with LRFD. It has been understood that efficiency of the pile foundation can be elevated, if the increase in pile resistance as a function of time (i.e., pile setup) can be quantified and incorporated into the LRFD. Because the current pile foundation practice involves different methods in designing and verifying pile performances, the resulting discrepancy of pile performances often causes an adjustment in pile specifications that incurs incremental construction costs, significant construction delays, and other associated scheduling issues. Although this research focuses on the most advanced dynamic analysis methods, such as Pile Driving Analyzer (PDA), Wave Equation Analysis Program (WEAP), and CAse Pile Wave Analysis Program (CAPWAP), the accuracy of these methods in estimating and verifying pile performances is highly dependent upon the input selection of dynamic soil parameters that have not been successfully quantified in terms of measured soil properties. To overcome these problems and due to the limited data available from the Iowa historical database (PILOT), ten full-scaled field tests on the steel H-piles (HP 250 y 63) were conducted in Iowa. Detailed in-situ soil investigations using the Standard Penetration Test (SPT) and the Cone Penetration Test (CPT) were completed near test piles. Push-in pressure cells were installed to measure total lateral earth and pore water pressures during the life stages of the test piles. Soil characterization and consolidation tests were performed. Pile responses during driving, at the end of driving (EOD), and at restrikes were monitored using PDA. PDA records were used in CAPWAP analysis to estimate the pile performances. In addition, hammer blow counts were recorded for WEAP analysis. After completing all restrikes, static load tests were performed to measure the pile resistance. The information collected from the tests provided both qualitative and quantitative studies of pile setup. Unlike the empirical pile setup methods found in the literature, analytical semi-empirical equations are developed in terms of soil coefficient of consolidation, SPT N-value, and pile radius to systematically quantify the pile setup. These proposed equations do not require the performance of pile restrikes or load tests; both are time consuming and expensive. The successful validation of these proposed equations provides confidence and accuracy in estimating setup for steel H-piles embedded in cohesive soils. For the similar study on large displacement piles, the results indicate that the proposed methods provide a better pile setup prediction for smaller diameter piles. Based on statistical evaluations performed on the available database, field tests, and sources found in the literature, it was determined that different uncertainties were associated with the estimations of the initial pile resistance at the EOD and pile setup resistance. To account for this difference, a procedure for incorporating the pile setup in LRFD was established by expanding the First Order Second Moment (FOSM) method, while maintaining the same target reliability level. The outcome of the research provides a methodology to determine resistance factors for both EOD and setup resistances based on any regional database. Therefore, the practical implementation of pile setup can now be included in a pile design, which has not been provided in the latest American Association of State Highway and Transportation Officials (AASHTO) Bridge Design Specifications. Combining the PILOT database with the field test results, regionally calibrated resistance factors for bridge deep foundations embedded in clay, sand, and mixed soil profiles were established for the dynamic analysis methods. This regional calibration generated higher resistance factors and improved the efficiency of pile performances when compared with those recommended by the latest AASHTO Bridge Design Specifications. Furthermore, using these calibrated results of the dynamic analysis methods that serve as the construction control methods, the resistance factors of the Iowa in-house method (Iowa Blue Book) that serves as the design method were enhanced through the development of a construction control procedure. Construction control consideration minimizes the discrepancy between design and field pile resistances, and integrates the construction control methods as part of the design process. An improved CAPWAP signal matching procedure was developed to provide a better quantification of the dynamic soil damping factor and quake value with respect to different soil properties along the shaft and at the toe of a pile. Correlation studies resulted in the development of several empirical equations for quantifying the dynamic soil parameters using the measured SPT N-value. In addition, the results reveal the influences of pile setup and pile installation on the dynamic soil parameters. The application of these estimated dynamic soil parameters was validated through the improvement of a CAPWAP signal match quality

Ornamentation in Marin Marais' Pieces de Viole

Ornamentation In Marin Marais’ Pièces de Viole This thesis sets out to uncover the ornamentation practices of French violist-composer Marin Marais (1656–1728). Marais wrote almost nothing about the execution of his ornaments in his music; in the avertissement of his first book of viol pieces, Pièces à une et à deux violes (Paris, 1686), he listed all the ornaments and their corresponding symbols, but provided no realisations and little explanation of how they are to be performed. While a historical violist could simply visit the master to learn how to properly perform his ornaments, the modern performer has little choice but to consult other historical musical works and treatises to gain a better understanding of the subject. In this thesis, I argue that the ornamentation practices in Marais’ music have largely been misunderstood because these historical works have not been properly examined. This study begins with a brief historical background of Marais, underpinning his significance as a major composer of the French Baroque era, thus showing that his style of ornamentation can be regarded as one of the prevailing methods of the day. The study then focuses on the modern writings that deal with issues that are relevant to Marais’ music, demonstrating how modern writers have sometimes overlooked historical sources, and how this results in their misunderstanding of Marais’ ornamentation practices. Lastly, the practices of historical violists and writers are analysed. The findings of this study offer a range of interpretive possibilities for Marais’ ornaments such as the tremblement, batement, port de voix, coulé de doigt and pincé or flatement. This information provides a basis on which modern performers will be able to apply appropriate historical ornamentation in performing the music of Marais and his contemporaries today. Keywords: France, French, Baroque, viol, viola da gamba, ornamentation, Marin Marais

The hierarchical structure of a firm: a geometric approach

This paper develops a novel, geometric approach to modelling a firm's hierarchical structure. We model the firm''s hierarchy as the sector of a circle, in which the radius represents the height of the hierarchy and the angle of the sector represents the width of the hierarchy. The firm then chooses the height and angle in order to maximise profit. We analyse the impacts of changes in economies of scale, input substitutability and labour productivity on the firm''s hierarchical structure. We find that the firm will unambiguously become more hierarchical as specialisation of its workers increases or as its output price increases. The effect of changes in scale economies is contingent on the level of task specialisation and output price.

The right to spatial development for human flourishing

This paper explores the literature on spatial development for people’s multifaceted well-being and the rights to the city, and argues for people’s right to live with dignity in cities. Nature and people-friendly spatial developments are fundamental to nourishing capabilities of human beings and realising their well-being. However, in reality, spatial developments are determined by legal planning and development regimes and socio-cultural discourses. These allocate different ‘claims, privileges and power rights’ to different stakeholders, and the results may not contribute to human flourishing. This paper attempts to synthesise an evaluation framework to achieve flourishing life with dignity in cities

Sexual Function and Sexual Frequency among Chinese Women in Hong Kong: Implications for Public Health Services

Female sexual dysfunction (FSD) is a public health problem because of its high prevalence and harmful impacts on women’s physical health, psychological well-being, and overall quality of life. The objective of this exploratory study was to identify risk factors of sexual dysfunction and assess the sexual function of Hong Kong Chinese women. Results were compared with findings on American women. A questionnaire survey was conducted to collect data via convenience sampling. Participants of the study (N = 1011) were women (aged 18 or above) from diverse demographic backgrounds. Sexual function of Hong Kong Chinese women was generally adequate, but significantly lower than that of American women. Women of older age (41 years old or above), lower education (primary or below), divorced, in menopause or with oophorectomy were at risk of FSD. Women at risk of FSD also exhibited a decline of sexual frequency which implicated poor sexual health. With the risk factors identified, public health professionals could implement targeted health services that would tackle the problems of FSD in good time and promote the sexual health of women who are distressed by the problems.

Characterization of Nucleosomes Containing Specific Forms of the Histone Variant H2A.Z

H2A.Z is a highly conserved histone variant that replaces canonical histone H2A at specific loci to regulate diverse nuclear processes. Amongst these, the role of H2A.Z in transcriptional regulation is of particular interest due to its enrichment at promoters of most genes in yeast and higher eukaryotes. However, its precise role in regulation is complex, as it has been linked to both repression and activation. One possibility is that H2A.Z activity is regulated by post-translational modifications since H2A.Z can be acetylated or monoubiquitylated in mammals. For example, H2A.Z can be multiply acetylated at several lysine residues at its N-terminus, and such modified form is associated with active promoters. In contrast, our lab has previously shown that a fraction of H2A.Z is monoubiquitylated at its C-terminus, and this form is associated with silent chromatin. One aim of this thesis is to characterize monoubiquitylated H2A.Z-nucleosomes in the context of transcriptional regulation. To this end, we devised a biotinylation-based method to enrich for H2A.ZUb1-mononucleosomes, and further characterized their composition and genomic distribution. In the second chapter, I demonstrate that H2A.ZUb1-enriched mononucleosomes are enriched with the histone post-translational modification H3K27me3, but depleted of H3K4 methylation and other modifications associated with transcriptional activity. H2A.ZUb1-eniched mononucleosomes also preferentially co-purify with proteins typically involved in repression, and with CTCF and cohesin. Consistent with these, ChIP-Seq analysis of H2A.ZUb1-nucleosomes identifies non-expressed genes as sites of H2A.ZUb1 enrichment. In addition to post-translational modification, vertebrate H2A.Z is differentiated into non-allelic isoforms H2A.Z-1 and H2A.Z-2. Previously, we used mass-spectrometry to identify proteins that preferentially associate with H2A.Z-mononucleosomes over H2A-mononucleosomes. In the third chapter, I show that one of these proteins, USP39, is enriched on mononucleosomes containing H2A.Z-1 over those containing H2A.Z-2, and that this selectivity can be mapped to an isoform-specific residue in its C-terminal tail. USP39 is a component of the U4/U6.U5 tri-snRNP, and consistent with a functional link between H2A.Z-1 and USP39, we identify a subset of shared alternative splicing events. Altogether, these data support functional diversification of H2A.Z through monoubiquitylation and isoform-specific amino acid substitution, and collectively, contribute to our understanding of biological pathways converging on H2A.Z