Three-dimensional analysis of reinforced concrete beam-column structures in fire

This is the author's accepted manuscript. The final published article is available from the link below. Published version copyright @ 2009 ASCE.In this paper a robust nonlinear finite-element procedure is developed for three-dimensional modeling of reinforced concrete beam-column structures in fire conditions. Because of the changes in material properties and the large deflections experienced in fire, both geometric and material nonlinearities are taken into account in this formulation. The cross section of the beam column is divided into a matrix of segments and each segment may have different material, temperature, and mechanical properties. The more complicated aspects of structural behavior in fire conditions, such as thermal expansion, transient state strains in the concrete, cracking or crushing of concrete, yielding of steel, and change in material properties with temperature are modeled. A void segment is developed to effectively model the effect of concrete spalling on the fire resistance of concrete beam-column members. The model developed can be used to quantify the residual strength of spalled reinforced concrete beam-column structures in fire. A series of comprehensive validations have been conducted to validate the model. From this research, it can be concluded that the influence of transient state strains of concrete on the deflection of structures can be very significant. However, there is very little effect on the failure time of a simple structural member. The impact of concrete spalling on both the thermal and structural behaviors of reinforced concrete members is very significant. It is vitally important to consider the prospect of concrete spalling in fire safety design for reinforced concrete buildings

Seasonal dependency of polar cap patches in the high-latitude nightside ionosphere

Observations and a computer simulation were used to investigate the seasonal dependency of the occurrence of polar cap patches in the high-latitude nightside ionosphere together with the relative importance of the driving processes. Measurements were conducted above northern Scandinavia around solar maximum (1999-2001) under conditions predicted to be favourable for observing patches with the EISCAT Svalbard Radar (ESR). The requirements were that the ESR was poleward of the convection reversal boundary, in antisunward cross polar cap flow and that IMF Bz was predominantly negative. The high latitude convection pattern was inferred from the Super Dual Auroral Radar Network (SuperDARN) and the IMF was taken from the Advanced Composition Explorer (ACE) spacecraft. In each study the patch-to-background ratio was calculated and, in most of the winter cases, this ratio was greater than two consistent with a polar cap patch. In summer clear electron density enhancements were seen in the nightside ionosphere, but the patch-to-background ratio was less than two. While these enhancements could not formally be called patches, it was clear that the high-latitude convection pattern was responsible for electron density enhancements. Using a computer simulation the relative importance of the physical processes driving the variation in the patch-to-background ratio was investigated. The dominant factor was changes in the thermospheric composition influencing plasma production and recombination rates

A new design method for industrial portal frames in fire

For single-storey steel portal frames in fire, especially when they are situated close to a site perimeter, it is imperative that the boundary walls stay close to vertical, so that fires which occur are not allowed to spread to adjacent properties. A current UK fire design guide requires either that the whole frame be protected as a single element, or that the rafter may be left unprotected if column bases and foundations are designed to resist the forces and moments generated by rafter collapse, in order to ensure the lateral stability of the boundary walls. This can lead to very uneconomical foundation design and base-plate detailing. In previous studies carried out at the University of Sheffield it was found that a fundamental aspect of the collapse of a portal frame rafter is that it usually loses stability in a “snap-through” mechanism, but is capable of re-stabilising at high deflections, when the roof has inverted but the columns remain close to vertical. Numerical tests performed using the new model show that the strong base connections recommended by the current design method do not always lead to a conservative design. It is also found that initial collapse of the rafter is always caused by a plastic hinge mechanism based on the frame’s initial configuration. If the frame can then re-stabilize when the roof is substantially inverted, a second mechanism relying on the re-stabilized configuration can lead to failure of the whole frame. In this paper, a portal frame with different bases is simulated numerically using Vulcan, investigating the effect of different base strength on the collapse behaviour. The test results are compared with the failure mode assumed by the current design method. A new method for the estimation of re-stabilized positions of single-span frames in fire, using the second failure mechanism, is discussed and calibrated against the numerical test results

The Abundance Parasitoid Populations of Neochrysocharis formosa and Neochrysocharis okazakii (Hymenoptera: Eulophidae) on Liriomyza spp. (Diptera: Agromyzidae) Associated with Vegetable Crop in Bali

The research objective was to determine the population abundance and the level of parasitation of parasitoid of Neochrysocharis formosa and Neochrysocharis okazakii against Liriomyza spp on some vegetable crops in Bali (Indonesia) from March 2014 to December 2014. The method used is a survey method; the sampling of Liriomyza spp infected plants was conducted by purposive sampling on the low, medium and high land in Bali.The results showed that the population abundance of N.formosa on planting vegetables in Bali with the highest population respectively in the low, medium and high lands at 642, 409 and 162 populations. N.okazakii in the low, medium and high lands is 243, 99 and 10 populations. N.formosa parasitation highest level was found in the low, medium and highlands respectively on tomatoes, chicories, tomatoes, while N.okazakii on tomato plants. Both parasitoids associated with L.sativae in the lowlands, medium and highlands, with L.huidobrensis only in the medium and highlands. Keywords: Abundance population, N.formosa, N.okazakii, Liriomyza spp., vegetable crop

Die ontwikkeling van die menslike bewussyn: Teorieë oor die ontwikkeling van menslike bewussyn – die ontdekking van die ‘misterie van die siel’

The development of the human consciousness: Theories of the development of human consciousness – discovering the ‘mystery of the soul’ A number of theories on the development of human consciousness have tried to incorporate all views on the subject into one integral theory. However, Ken Wilber is the fi rst philosopher who managed to combine the external with the internal fi elds of study. Using Wilber’s integral theory, a number of researchers developed their own theories in their fi eld of speciality. Jim Marion used Wilber’s development theory to show the evolution of consciousness from a Christian perspective.Steve McIntosh, an integral philosopher, takes Wilber’s ideas further, and even criticises him on a few points. Another important researcher following Wilber is Andre Marquis, who developed an integral questionnaire to help pastors gauge clients’ problems. James Fowler, Clare Graves and Bill Plotkin also researched the evolution of human consciousness. This article examines each of these researchers, and concludes with a glance at several viewpoints on the soul and the mystical union with God

Die ontwikkeling van die menslike bewussyn: Kan die postmodernekerk ruimte bied vir ‘mitologie’? Ken Wilber se bydrae tot die pastoraat

The development of the human consciousness: Can a ‘postmodern church’ accommodate ‘mythology’? Ken Wilber’s contribution to pastoral care Postmodern theologians like Hal Taussig are not very optimistic about the future of Christianity. To them, the theistic (mythological) understanding of God is of little use in the postmodern world of the 21st century. Taussig prefers the grassroots Christianity, which has room for persons of all sexual orientations, and advocates ecological sensitivity. The question is: What do the followers of this spirituality teach their children about God? The solution is what Wilber calls ‘the conveyer belt’ and God’s ‘Kosmic address’. Everyone starts at square one, ‘traditional’ and grassroots Christians alike, and move along this conveyer belt. Along the way, there are seven stages and three perspectives, i.e. the first, second and third-person perspective, through whichhuman consciousness could evolve. That means that any given person could have one of 21 different possible understandings and experiences of God. A questionnaire could assist pastors to determine at which stage or level of evolution an individual is, as well as the ‘Kosmic address’ that God has for that individual. Through spiritual exercises, pastors could then support the individual’s further growth towards mature human consciousness

Die ontwikkeling van die menslike bewussyn: Ken Wilber se AQAL-teorie

The development of the human consciousness: Ken Wilber’s AQAL theory Kenneth Earl Wilber III, an integral philosopher, psychologist and mystic with an intelligence quotient of 160, was born on 31 January 1949 in Oklahoma City, Oklahoma, in the United States ofAmerica, and is considered by some as one of the most important philosophers of the 21st century. He developed his integral philosophy over 30 years, which can be divided into five phases. The most important aspects of his philosophy for the purposes of this article are the AQAL integral map of reality, and the evolution of consciousness. AQAL stands for ‘all quadrants, all levels, lines and stages’. Wilber divides reality into singular and plural interiors and exteriors; or art,morals and science. Also deriving ideas from Developmental Psychology, he sees the evolution of consciousness unfolding in seven stages: archaic, magic, mythic, rational, pluralistic, holisticand transpersonal. This theory could add value to pastoral care by enabling pastors to support believers’ own spiritual growth in pursuit of the kingdom of heaven

Die ontwikkeling van die menslike bewussyn: Die postmoderne vraag na God

The development of the human consciousness: The postmodern quest for God This article critically reflects upon ‘emerging Christians’ – those who have departed from a premodern (theistic) and modernist (secular) view of reality, and have rather embraced postmodernity in response to the cognitive dissonance they experience due to a clash of  epistemological paradigms. The article discusses psychological theories on the development of human consciousness, and describes seven levels or stages of such development, namely the archaic, magical, mythological, rational, pluralistic, holistic and transpersonal levels. The article focuses on Ken Wilber’s integral psychological theory, better known as AQAL (All Quadrants, All Levels and All Lines), which also covers the internal and external dimensions of human consciousness, including an integral view on the so-called ‘states of human consciousness’. In doing so, the article aims to contribute to that aspect of pastoral care that focuses on psychological theory

Hypertension: The Cardiovascular Risk Continuum

Hypertension is established modifiable risk factor for cardiovascular diseases (CVD) and should ....