Experimental Study of Ultra Shallow Floor Beams (USFB) with Perforated Steel Sections

ABSTRACT: In modern building construction design, floor spans are becoming longer. Hence, steel framed structures have become more competitive when compared with traditional reinforced concrete framed buildings. In order to minimise the structural section of the composite sections, and for economic reasons, steel perforated beams are designed to act compositely with the floor slab. When the concrete slab lies within the steel flanges, as in the Ultra Shallow Floor Beam (USFB), there is an additional benefit when considering fire resistance. The aim of this study is to investigate the contribution of the concrete in composite cellular beams in the case where the concrete slab lies between the beam flanges of a steel section, when resisting vertical shear forces. The concrete between the flanges enhances the load-carrying capacity by providing a load path to transfer the shear force. Four specimens of steel-concrete composite beams with web openings in the steel section were tested in this study. One bare steel section with web openings was also tested as a comparison. This is the first such investigation of the failure mode under shear resistance (Vierendeel action) of the Ultra Shallow Floor Beam. In the test specimens, the web opening diameter is 76% of the beam depth, which is the largest currently available. This represents the worst case in terms of Vierendeel bending forces generated in the vicinity of the web openings. The smaller the hole is, the easier it is for the trapped concrete between the flanges to transfer shear across the opening. The results from the composite beam tests show a significant increase in shear resistance. The percentage of the shear capacity improvement of the particular case is presented herein as well as the failure mode of the composite beams. The shear enhancement demonstrated in this study has been utilised software that is used in design practice

Physical Constraints to Aquatic Plant Growth in New Zealand Lakes

The nature of aquatic plant communities often defines benthic habitat within oligotrophic and mesotrophic lakes and lake management increasingly recognizes the importance of maintaining plant diversity in order to sustain biological diversity and capacity within lakes. We have developed simple statistical relationships between key physical and vegetation variables that define the habitat requirements, or “habitat-templates”, of key vegetation types to facilitate management of plant communities in New Zealand lakes. Statistical relationships were derived from two datasets. The first was a multi-lake dataset to determine the effects of water level fluctuation and water clarity. The second dataset was from a comprehensive shoreline survey of Lake Wanaka, which allowed us to examine within-lake variables such as beach slope and wave action. Sufficient statistical relationships were established to develop a habitat template for each of the major species or assemblages. The relationships suggested that the extent and diversity of shallow-growing species was related to a combination of the extent of water level fluctuation and wave exposure. (PDF contains 9 pages.

An examination of fathers\u27 satisfaction with the legal system: Exploring the concept in relation to fathers\u27 experience with the Family Law Court of Western Australia

Although the importance of fathers\u27 post divorce contact with their children has been linked with a better outcome for the children and is valued by society, studies in the United States and Australia have suggested that up to 30 percent of fathers do not maintain regular contact with their children post divorce. To date, the literature has focused mainly on demographic variables and some personal characteristics of the father. An area, which has been neglected, is the influence of fathers\u27 perception of legal proceedings and rules on their contact with their children post divorce. This study aimed to explore the underlying concepts of satisfaction and examine fathers\u27 perception of satisfaction in relation to their experience with the Family Court of Western Australia. This was done by utilising qualitative research methodology. Twenty·four fathers were interviewed using an interview schedule adapted from Tyler (1988). Results from the present study indicated that fathers\u27 satisfaction was primarily influenced by a favourable outcome in relation to contact with their children. Factors found to result in dissatisfaction included fathers’ feelings that their father role had been eroded, a perceived bias by the family law system in favour of the mother, and a lack of legal assistance and limited availability of legal personnel. In order to clarify a number of issues, a subset often fathers from the original sample were re-interviewed. Further analysis confirmed that fathers\u27 unresolved issues in relation to their separation; strong emotions including anger and distress during the court process; and unrealistic expectations in relation to contact with their children, made dissatisfaction with the legal system, and in particular court outcomes, more likely. This research suggests that early intervention for fathers is needed to allow them to address any unresolved issues surrounding their separation, and the emotions such as anger and grief that often follow separation. Services, which provide legal assistance and direction prior to entering and during legal proceedings, also appear to be necessary

Book Review: The Culture Factory by Stanley K. Schultz

Unreal expectations, and why. A Book review of Stanley K. Schultz\u27s The Culture Factory: Boston Public Schools, 1789-1860

An Examination of Standards-Based Education Relative to Research-Based Practices in Instruction and Assessment

Public schools in the United States face constant political efforts to reform our educational system. One of the major reforms, standards-based education, links all aspects of classroom instruction and assessment with identified , measureable , learning targets. Currently, there is a lack of empirical evidence that standards-based education results in improved student achievement. Explanations for that are: a wide variation in implementation across states, regions, districts, schools, and classrooms; the lack of a clear and consistent purpose and understanding of standards-based instruction; and the fact that reporting practices do not always translate into adjustments to classroom instruction

Nonperturbative Vertices in Supersymmetric Quantum Electrodynamics

We derive the complete set of supersymmetric Ward identities involving only two- and three- point proper vertices in supersymmetric QED. We also present the most general form of the proper vertices consistent with both the supersymmetric and U(1) gauge Ward identities. These vertices are the supersymmetric equivalent of the non supersymmetric Ball-Chiu vertices.Comment: seventeen pages late

Traffic State Estimation via a Particle Filter with Compressive Sensing and Historical Traffic Data

In this paper we look at the problem of estimating traffic states within segments of road using a particle filter and traffic measurements at the segment boundaries. When there are missing measurements the estimation accuracy can decrease. We propose two methods of solving this problem by estimating the missing measurements by assuming the current measurements will approach the mean of the historical measurements from a suitable time period. The proposed solutions come in the form of an l1 norm minimisation and a relevance vector machine type optimisation. Test scenarios involving simulated and real data verify that an accurate estimate of the traffic measurements can be achieved. These estimated missing measurements can then be used to help to improve traffic state estimation accuracy of the particle filter without a significant increase in computation time. For the real data used this can be up to a 23.44% improvement in RMSE values

Location and Orientation Optimisation for Spatially Stretched Tripole Arrays Based on Compressive Sensing

The design of sparse spatially stretched tripole arrays is an important but also challenging task and this paper proposes for the very first time efficient solutions to this problem. Unlike for the design of traditional sparse antenna arrays, the developed approaches optimise both the dipole locations and orientations. The novelty of the paper consists in formulating these optimisation problems into a form that can be solved by the proposed compressive sensing and Bayesian compressive sensing based approaches. The performance of the developed approaches is validated and it is shown that accurate approximation of a reference response can be achieved with a 67% reduction in the number of dipoles required as compared to an equivalent uniform spatially stretched tripole array, leading to a significant reduction in the cost associated with the resulting arrays

Confidentiality Protection in the 2020 US Census of Population and Housing

In an era where external data and computational capabilities far exceed statistical agencies' own resources and capabilities, they face the renewed challenge of protecting the confidentiality of underlying microdata when publishing statistics in very granular form and ensuring that these granular data are used for statistical purposes only. Conventional statistical disclosure limitation methods are too fragile to address this new challenge. This article discusses the deployment of a differential privacy framework for the 2020 US Census that was customized to protect confidentiality, particularly the most detailed geographic and demographic categories, and deliver controlled accuracy across the full geographic hierarchy.Comment: Version 2 corrects a few transcription errors in Tables 2, 3 and 5. Version 3 adds final journal copy edits to the preprin