Strength model for end cover separation failure in RC beams strengthened with near-surface mounted (NSM) FRP strips

As an alternative to externally bonded FRP reinforcement, near-surface mounted (NSM) FRP reinforcement can be used to effectively improve the flexural performance of RC beams. In such FRP strengthened RC beams, end cover separation failure is one of the common failure modes. This failuremode involves the detachment of the NSM FRP reinforcement together with the concrete cover along the level of the tension steel reinforcement. This paper presents a new strength model for end cover separation failure in RC beams strengthened in flexure with NSM FRP strips (i.e. rectangular FRP bars with asectional height-to-thickness ratio not less than 5), which was formulated on the basis of extensive numerical results from a parametric study undertaken using an efficient finite element approach. The proposed strength model consists of an approximate equation for the debonding strain of the FRP reinforcement at the critical cracked section and a conventional section analysis to relate this debondingstrain to the moment acting on the same section (i.e. the debonding strain). Once the debonding strain is known, the load level at end cover separation of an FRP-strengthened RC beam can be easily determined for a given load distribution. Predictions from the proposed strength model are compared with those of two existing strength models of the same type and available test results, which shows that the proposed strength model is in close agreement with test results and is far more accurate than the existing strength models.

Analytical model for bar-end cover separation failure in RC beams strengthened with near-surface mounted FRP

The flexural performance of RC beams can be improved using the near-surface mounted (NSM) FRP strengthening technique. A likely failure mode of such FRP-strengthened RC beams is bar-end cover separation which involves the detachment of the NSM FRP reinforcement together with the concrete cover along the level of the steel tension reinforcement. This paper presents a new analytical strength model for this failure mode. The proposed strength model and two existing strength models for this failure mode are compared with test results to demonstrate the superior performance of the new analytical model.

Strengthening timber beams with near surface mounted carbon fiber reinforced polymer rods

Many timber structures may require strengthening due to either decay and aging or an increase of load. This paper presents an experimental study in which eleven timber beams were tested, including three unstrengthened reference beams and eight beams strengthened with NSM CFRP bars. The test parameters include the position of NSM (tensile face or the bottom of the sides), the number of CFRP bars (1 or 2), and additional anchorage of NSM CFRP bars (steel wire U anchors or CFRP U strips). The test results show that the ultimate flexural strength of the timber beams were increased by 14%∼85% with an average of 47% due to NSM CFRP bar strengthening. Their deflection corresponding to the peak load was increased by 33% in average.

Initial insights on the biodiversity potential of biosolar roofs: A London Olympic Park green roof case study

Cities dominated by impervious artificial surfaces can experience myriad negative environmental impacts. Restoration of green infrastructure has been identified as a mechanism for increasing urban resilience, enabling cities to transition towards sustainable futures in the face of climate-driven change. Building rooftops represent a viable space for integrating new green infrastructure into high density urban areas. Urban rooftops also provide prime locations for photovoltaic (PV) systems. There is increasing recognition that these two technologies can be combined to deliver reciprocal benefits in terms of energy efficiency and biodiversity targets. Scarcity of scientific evaluation of the interaction between PVs and green roofs means that the potential benefits are currently poorly understood. This study documents evidence from a biodiversity monitoring study of a substantial biosolar roof installed in the Queen Elizabeth Olympic Park. Vegetation and invertebrate communities were sampled and habitat structure measured in relation to habitat niches on the roof, including PV panels. Ninety-two plant species were recorded on the roof and variation in vegetation structure associated with proximity to PV panels was identified. Almost 50% of target invertebrate species collected were designated of conservation importance. Arthropod distribution varied in relation to habitat niches on the roof. The overall aim of the MPC green roof design was to create a mosaic of habitats to enhance biodiversity, and the results of the study suggest that PV panels can contribute to niche diversity on a green roof. Further detailed study is required to fully characterise the effects of PV panel density on biodiversity.

Using recycled aggregates in green roof substrates for plant diversity

Extensive green roofs are becoming a popular tool for restoring green infrastructure in urban areas, particularly biodiverse habitats such as post-industrial/brownfield sites. This study investigated the use of six recycled lightweight aggregates and combinations of them in green roof growing substrate, to determine their effectiveness for enhancing plant abundance and species diversity. In two separate experiments, we examined the roles of substrate type and depth on the establishment of a perennial wildflower mix over a 15-month period. We found that some of the alternative substrates are comparable to the widely used crushed red brick aggregate (predominantly found in commercial green roof growing substrate) for supporting plant establishment. For some materials such as clay pellets, there was increased plant coverage and a higher number of plant species than in any other substrate. Substrates that were produced from a blend of two or three aggregate types also supported higher plant abundance and diversity. Generally, increasing substrate depth improved plant establishment, however this effect was not consistent across substrates. We conclude that recycled materials may be viable constituents of growing substrate for green roofs and they may improve green roof resilience, through increased plant cover and diversity. The results could provide evidence to support the construction of mosaic habitat types on single roofs using various substrate blends.

Traduzir Teatro no Estado Novo: Gata em Telhado de Zinco Quente (1959), tradução de Sérgio Guimarães, do original Cat on a Hot Tin Roof (1955), de Tennessee Williams

À luz da viragem cultural dos Estudos de Tradução ocorrida nos anos 80 e tendo em conta a interdisciplinaridade abordada nos campos literário, cultural e histórico pela Manipulation School (Lefevere, Bassnett, Lambert, Hermans e Toury), na esteira de Itamar Even-Zohar com a Teoria dos Polissistemas (1979), a presente dissertação pretende analisar a tradução portuguesa da peça Cat on a Hot Tin Roof (1955), da autoria de Tennessee Williams, intitulada Gata em Telhado de Zinco Quente (1959), de Sérgio Guimarães. Este pode ser um caso representativo de como a tradução para teatro actua na cultura receptora numa perspectiva diatópica, antevendo a dimensão intercultural da tradução para o palco. É ao tradutor que cabe a tarefa de transferir a peça de um sistema linguístico e cultural para outro, conhecendo, se possível, o grau de representabilidade da mesma e o contexto cultural de chegada. Deste modo, é evidenciada a competência artístico-criativa do tradutor teatral que trabalha com o intuito de manter, fidus interpres, as intenções do autor da obra original. No período em que Cat on a Hot Tin Roof foi escrita, ensombrado pelo controlo sociopolítico do Macartismo nos E.U.A. e o contexto em que a tradução foi concretizada, sob a vigência da Ditadura de Salazar, a (auto)censura desempenha um papel fundamental ao moldar a produção literária nos dois sistemas culturais. Numa época em que, mais do que nos dias de hoje, traduzir consistia numa actividade subserviente e secundária, Vasco Morgado, detentor do monopólio de teatros em Lisboa encomendou a Sérgio Guimarães a tradução de uma peça de Tennessee Williams. Com base na teoria desenvolvida por Lawrence Venuti em The Translator’s Invisibility (1995), não é despiciente problematizar, neste estudo de caso, a invisibilidade do tradutor/mediador entre o texto e a representação, abordando simultaneamente as estratégias então necessárias para a peça ser aprovada e posta em cena.

H Block Roof

The interesting ventilation system on the roof of the Science Complex.

Receipt from E. Priddle for measurement of slate roof

Receipt from E. Priddle for measurement of slate roof, June 24, 1876.

Province of Upper Canada Grant (paper mounted on canvas) to the Honorable Peter Russell of the Township of Newark

Province of Upper Canada Grant (paper mounted on canvas) to the Honorable Peter Russell of the Township of Newark. He is granted 10 acres in the Township of Newark in the County of Lincoln. This document is mounted on canvas. This was entered in the auditor’s office Sept.29, 1797. Part of the paper document is missing but this does not affect the text, Sept. 1, 1797.

Province of Upper Canada Grant (paper mounted on canvas) to William Dickson

Province of Upper Canada Grant (paper mounted on canvas) to William Dickson. He is granted 24 acres with allowance for roads in the Town of Newark in the County of Lincoln. This was entered in the auditor’s office on June 12, 1798. Parts of the paper are missing. This affects the text slightly, Nov. 10, 1797.

Province of Upper Canada Grant (paper mounted on canvas) to Alexander McDonell

Province of Upper Canada Grant (paper mounted on canvas) to Alexander McDonell. He is granted 400 acres in the Town of York, Lots numbered 12 and 13 in the 3rd Concession and part of Lot no. 16 in the 4th Concession. This was entered in the auditor’s office Dec 31, 1798, Dec. 31, 1798.

Under the roof and the pen of Elizabeth Willing Powel. Material culture, sociability, and letters in revolutionary and early republican Philadelphia

Ce mémoire a pour toile de fond Philadelphia à la fin du dix-huitième siècle et couvre les périodes de la Révolution américaine et les débuts de la République. Trois thèmes s’y entrelacent: la culture matérielle, la sociabilité, et l’agentivité des femmes. Ces trois thèmes sont explorés au travers de Elizabeth Willing Powel, une femme éduquée faisant partie de l’élite de Philadelphie, et des moyens avec lesquels elle s’auto-projetait auprès de la société au travers l’environnement matériel de sa maison – la Powel House – and au travers de sa correspondance. Elizabeth Powel était reconnue pour son intelligence, son art de la conversation et ses qualités d’hôtesse. Ce projet explore les interactions entre une femme de l’élite et son environnement matériel durant les périodes révolutionnaires et postrévolutionnaires. Le but est d’observer comment la culture matérielle représentait des positions sociales, culturelles et politiques. Ce mémoire observe les interactions sociales et les façons dont Elizabeth Powel se représente en société par une analyse de sa correspondance, analyse qui porte une attention particulière aux discours de Elizabeth sur les questions du rôle des femmes en société, de l’éducation des femmes. Enfin, ce mémoire explore comment la culture matérielle et l’écriture épistolaire étaient des vecteurs d’agentivité pour Elizabeth, des moyens de participer aux important changements qui transformaient la société américaine de la fin du dix-huitième siècle.

Optimal Design of a Surface Mounted Permanent-Magnet BLDC Motor for Spacecraft Applications

This paper presents the optimal design of a surface mounted permanent-magnet (PM) Brushless direct-current (BLDC) motor meant for spacecraft applications. The spacecraft applications requires the choice of a motor with high torque density, minimum cogging torque, better positional stability and high torque to inertia ratio. Performance of two types of machine configurations viz Slotted PMBLDC and Slotless PMBLDC with Halbach array are compared with the help of analytical and finite element (FE) methods. It is found that unlike a Slotted PMBLDC motor, the Slotless type with Halbach array develops zero cogging torque without reduction in the developed torque. Moreover, the machine being coreless provides high torque to inertia ratio and zero magnetic stiction

Spatial calibration of an optical see-through head-mounted display

We present here a method for calibrating an optical see-through Head Mounted Display (HMD) using techniques usually applied to camera calibration (photogrammetry). Using a camera placed inside the HMD to take pictures simultaneously of a tracked object and features in the HMD display, we could exploit established camera calibration techniques to recover both the intrinsic and extrinsic properties of the~HMD (width, height, focal length, optic centre and principal ray of the display). Our method gives low re-projection errors and, unlike existing methods, involves no time-consuming and error-prone human measurements, nor any prior estimates about the HMD geometry.