The effect of polypropylene fibres within concrete with regard to fire performance in structures

Purpose – The purpose of this paper is to examine the effect of various polypropylene fibre additions (types and volume) to concrete with regard to explosive spalling when subject to high temperatures similar to those experienced in building or tunnel fires. Design/methodology/approach – Medium strength concrete was manufactured with varying proportions of polypropylene fibres. Plain control samples were used to determine the original concrete strength and this was used as a benchmark following high temperature heat tests to evaluate the surface condition and final compressive strength. A pilot study was used to determine an appropriate heat source for the test. This was three Bunsen burners, however sufficient heat could not be generated within 150mm concrete cubes and the concrete was shown to be a significant insulator and fire protection for structural members. The concrete test cubes were tested in a saturated condition which may reflect conditions where concrete is used in an external environment and thus is subject to soaking. Findings – One hundred and fifty millimetre concrete cubes with and without fibres were placed into a furnace at 1,000°C. Explosive spalling was shown to be reduced with the use of polypropylene fibres but the final compressive strength of concrete was significantly reduced and had little residual structural value after a two hour period of heating. Research limitations/implications – As the concrete tested was saturated, this condition provided a worst case scenario with regards to the build up of hydrostatic and vapour pressure within the cube. A range of percentage moisture contents would produce a more evenly balanced view of the effects of fibres in concrete. A single grade of concrete was used for the test. As the permeability of concrete influences the rate at which steam can escape from the interior of a saturated concrete cube, testing a range of concrete strengths would show this aspect of material performance with regard to spalling and final residual strength. Further research is recommended with regard to moisture contents, strengths of concrete and a range of temperatures

Status and Enhancement of \u3cem\u3eTrissolcus japonicus\u3c/em\u3e (Ashmead) (Hymenoptera: Scelionidae) for Biological Control of \u3cem\u3eHalyomorpha halys\u3c/em\u3e (Stål) (Hemiptera: Pentatomidae) in Northern Utah

The invasive brown marmorated stink bug (BMSB) is a major insect pest that invades human structures causing nuisance issues and attacks numerous fruit and vegetable crops in Northern America. As this pest threatens $23 billion worth of specialty and agricultural crops in the U.S. and is difficult to manage due to insecticide resistance, control practices such as the use of biological control through egg parasitoid wasps are critical. In its native range of Asia, BMSB populations are controlled primarily by members of the Trissolcus genus such as the samurai wasp, but U.S. native wasps have demonstrated low success of BMSB egg parasitism. An introduced population of the samurai wasp was detected in Utah in 2019, and early research suggests this wasp may provide effective biological control of BMSB. This research focuses on the status and enhancement of the samurai wasp and native parasitoids in northern Utah. Chapter II explores the range of the exotic samurai wasp and native parasitoids in northern Utah’s urban and agricultural areas and factors affecting their prosperity. The samurai wasp exhibited a strong association with BMSB, following its patterns of seasonality, orchard groundcover preference, and reliance on urban landscape resources. Samurai wasps accounted for only a small proportion of total Trissolcus parasitoid detections, and more native wasps were captured in orchards with floral groundcover as compared to those with non-floral groundcover. Chapter III assesses the attractiveness of kairomone lures to the samurai wasp in field and laboratory conditions. In the field, samurai wasp attacked lab-reared BMSB egg masses at almost an equal rate to a native Trissolcus species but had much higher emergence success from egg masses. Laboratory trials compared specific chemical blends for attractiveness to the samurai wasp. Finally, Chapter IV investigates the role of BMSB parasitoids in a state previously unsurveyed for the samurai wasp. Reported is the first record of samurai wasp in the state of Idaho and details about its population size and geographic locations. Overall, population sizes were very low, but collection of wild egg masses proved samurai wasp is taking an active role in the suppression of BMSB populations

Resistance to flow in sand channels

CER65EVR27.June, 1965.Includes bibliographical references (pages 77-81).In partial fulfillment of the requirements for the Degree of Doctor of Philosophy in Civil Engineering.A theoretical and laboratory investigation was made of resistance to flow in sand-bed channels. The objectives were to determine the type of flow and energy dissipation in sand-bed channels and develop equations and relations for predicting resistance to flow and mean velocity. The types of flow, energy dissipation and, thus resistance to flow in sand-bed channels is extremely variable because (1) the configuration of the boundary, (2) the properties of the fluid, and (3) the characteristics of the turbulence are functions of the flow, fluid, and sand characteristics and of the geometry of the channel. The boundary configurations that form in a sand bed are ripples, ripples on dunes, dunes, plane bed, antidunes or chutes-and-pools. The type of flow in a sand channel with constant discharge and average energy gradient may be steady or unsteady and uniform or nonuniform, depending on the boundary configuration. With the array of boundary configurations found in sand channels, the dissipation of energy may result from grain roughness, form roughness, acceleration of the flow, breaking waves or any combinations of them. With variable boundary configuration, type of flow and energy dissipation, it is impossible to determine a general equation to predict resistance to flow and mean velocity for all flow conditions. However, if the boundary configuration is known, specific relations and equations are developed for predicting resistance to flow. For steady uniform flow, the equations are based on integrating the Reynolds equation for turbulent flow. The coefficients in the integrated equation were determined from a study of the velocity distribution and verified using the mean flow variables. For nonuniform and (or) unsteady flow, resistance to flow is determined by applying a correction term to the equation developed for flow over a plane bed. The correction term compensates for the increase in energy dissipation resulting from form roughness, flow acceleration and breaking waves. The study of the velocity profiles for plane bed flow when there is considerable bed-material movement, determined that there is an inner and outer flow zone. In the inner zone, the slope A and intercept B in the relation u = A ln y + B are variable. The variation of the slope and intercept are functions of the size and concentration of suspended sediment in the inner zone. In the outer zone , the slope and intercept are constant

The bacteriology of the Bantu food-handler: Enterobacteriaceae

No Abstract

Resisting disablism in the gym: a narrative exploration of the journey from disabled client to disabled instructor

It is imperative that individuals with physical impairments maintain an active lifestyle to enhance various aspects of well-being and overall quality of life. This population, however, are also one of the most sedentary in society. One identified reason for this is the ableism which exists in many fitness establishments that promotes acceptance of one particular body; the strong, physically athletic, muscular body is given value. Individuals who do not align to his particular physical reality may be subject to discrimination which can have a detrimental effect on their psycho-emotional well-being and deter them from exercising. Surprisingly, there is an increasing number of disabled individuals who are becoming gym instructors and further integrating themselves into a space which is deemed to oppress them. The purpose of this PhD is to explore these individuals' journey from gym clients to gym instructors. Framed by interpretivism and with particular focus on narrative inquiry, various qualitative analysis techniques were applied to explore 1) participants experiences exercising in the gym, 2) participants' motivations to be gym instructors, 3) how participants made sense of their gym instructor training and, 4)what impact participants perceived they had in the gym as instructors. This thesis has made original contributions to the literature by crafting a deep understanding of disabled people s experiences in the gym and why people enact social missions. For example, this thesis contextualizes disability in the gym and identifies that despite the numerous health benefits disabled people experience by exercising in this space, the psycho-emotional disablism they are subject to acts as a barrier for individuals to exercise here. Importantly, although disablism acted as a barrier to continued exercise for participants, it was also a facilitator in their decision to become a gym instructor. Essentially, participants described their own negative gym experiences as fuelling their desires to enact positive change in this space and do social missions in the gym. To be a gym instructor, participants went through a training programme specifically designed to train disabled people to embody this role. At this training, participants initially experienced a sense of validation and belonging through peer group exercise and were able to craft a collective story which allowed them to resist the oppressive disablism they experienced in the gym. However, as training continued and evolved so too did the narratives participants crafted to make sense of their experiences. Instead of one united story, participants crafted two conflicting narratives which redefined their relationship with each other and InstructAbility, and ultimately determined why some participants continued their training and others did not. For those who did continue to become fully qualified gym instructors, they felt they had a positive influence in promoting inclusion, exercise and diversity in the gym. In light of these findings, there are several practical recommendations for exercise practitioners, rehabilitation specialists, gym managers and those prescribing exercise to disabled people. Implications are aimed at improving exercise promotion and experiences of exercise in the gym for disabled people. For example, disabled gym instructors could be a way to bridge the perceived experiential gap between disability and the gym as they exhibit an alternate way of being which is accepted in this space. Through their experiential knowledge of disability and practical knowledge of exercise, these individuals can also relate to disabled clients in a way that non-disabled instructors cannot. Disabled gym instructors, however, can educate non-disabled gym instructors in how to train someone with an impairment. Equally, a more critical attitude to promoting exercise to disabled people is called for. Specifically, to steer away from disabling expectations and narratives of disabled people s motivations to exercise and move towards more realistic, enabling strategies and narratives to facilitate disabled peoples exercise behaviour

Large eddy simulation of a lifted ethylene flame using a dynamic nonequilibrium model for subfilter scalar variance and dissipation rate

Accurate prediction of nonpremixed turbulent combustion using large eddy simulation(LES) requires detailed modeling of the mixing between fuel and oxidizer at scales finer than the LES filter resolution. In conserved scalar combustion models, the small scale mixing process is quantified by two parameters, the subfilter scalar variance and the subfilter scalar dissipation rate. The most commonly used models for these quantities assume a local equilibrium exists between production and dissipation of variance. Such an assumption has limited validity in realistic, technically relevant flow configurations. However, nonequilibrium models for variance and dissipation rate typically contain a model coefficient whose optimal value is unknown a priori for a given simulation. Furthermore, conventional dynamic procedures are not useful for estimating the value of this coefficient. In this work, an alternative dynamic procedure based on the transport equation for subfilter scalar variance is presented, along with a robust conditional averaging approach for evaluation of themodel coefficient. This dynamic nonequilibrium modeling approach is used for simulation of a turbulent lifted ethylene flame, previously studied using DNS by Yoo et al. (Proc. Comb. Inst., 2011). The predictions of the new model are compared to those of a static nonequilibrium modeling approach using an assumed model coefficient, as well as those of the equilibrium modeling approach. The equilibrium models are found to systematically underpredict both subfilter scalar variance and dissipation rate. Use of the dynamic procedure is shown to increase the accuracy of the nonequilibrium modeling approach. However, numerical errors that arise as a consequence of grid-based implicit filtering appear to degrade the accuracy of all three modeling options. Thus, while these results confirm the usefulness of the new dynamic model, they also show that the quality of subfilter model predictions depends on several factors extrinsic to the formulation of the subfilter model itself

Hydraulic model studies

CER62EVR18.Series statement and numbering from publisher's list.Includes bibliographical references (page 13).Stage-discharge relations for two artificial controls were determined in a model study conducted at Colorado State University. The controls are used to measure the discharge at two gaging stations (Cibecue Ridge No. 1 and Cibecue Ridge No. 2), that form a part of an intensive hydrologic investigation of the semi-arid environment of Central Arizona. The gaging stations are located in a remote area where the runoff is infrequent and of brief duration. The model studies were conducted because it was virtually impossible to calibrate the controls in the field. In addition to determining the stage-discharge relation, modifications in the controls are proposed to improve the discharge records for the two stations. A hydraulic jump occurs in the present controls at the section where the stage is measured. The hydraulic jump keeps the controls clear of the large sediment discharge of the streams, but causes large fluctuations of the water surface in the stilling wells. The modified controls eliminate the hydraulic jump, make extensive use of the construction that presently exists, will pass the sediment discharge of the streams, and have a fairly sensitive stage-discharge relation. The recorded elevation of the water surf ace in the stilling well lags the actual elevation of the stream because the connection between the control and the stilling well is too small in relation to the size of the stilling well. The lag can be decreased by replacing the present stilling well with a tube 14 to 20 inches in diameter