No description available.

No description available.

The goals of minimizing emissions and lowering operating costs by monitoring and controlling fuel efficiency have been a growing concern in the mining and construction industries. The largest single contributor of energy consumption in an open pit mining operation is haul trucks. At Goldstrike Mine, haul trucks accounted for approximately 67% of fuel used in 2010. By examining haul trucks in their operating environment, strategic changes in critical parts of the truck cycles can result in fuel savings. This project was a subproject of the Mine Traffic Optimization (MTO) project and is funded by MITACS and Barrick Gold Corporation. One objective of the MTO project was to examine how mine traffic affects fuel efficiency. Certain components of the haulage profile result in inefficient use of fuel, which results in increased operating costs and a larger environmental footprint. Monitoring the trucks in real time allows for the examination of various ways to modify truck’s behaviours in order to improve fuel efficiency. One critical component of the haulage cycle is intersections. An analysis was performed to gain a better understanding of efficient intersection layouts and travel speeds. Cycle time analysis was conducted to ensure that alterations to the haulage cycle would result in minimal impact to the overall productivity of the mine. Modifications to operating practices and simple coding changes to the dispatching program suggest possibilities for potential fuel savings, reduced mechanical degradation, and improved operation efficiency. / Thesis (Master, Mining Engineering) -- Queen's University, 2013-09-30 19:22:29.328

Circadian mitotic rhythms in epithelial cells of human epidermis (Schevirg, 1959), rat cornea (Scheving,1967) and intestinal epithelium of the mouse (Sidgestad,1972) have been reported in the literature. It is the attempt of this investigation to determine the presence of a circadian rhythm governing the mitotic activity of hair follicle cells in neonatal white mice. The animals used were reared under closely controlled conditions of temperature, humidity, lighting and food. A total of forty-eight, three to four day old mice were used, with eight animals being sampled every four hours over a twenty-four hour period. Skin sections were removed and fixed in Bouins fluid. The tissues were dehydrated in alcohols, cleared in xylol and infiltrated and embedded in paraffin. The sectioned tissues were placed on glass slides, rehydrated and stained with hematoxylin and eosin. To assess the mitotic activity over the twenty-four hour period, cell counts within the follicles were made from the slides. For each animal, 1000 hair follicle cells were counted. Cells undergoing mitosis were identified and specific stages were tallied. These stages were 1) prophase, 2) metaphase, 3) anaphase-telophase and 4) unidentifiable cells. Photomicrographs were made to record the histology and demonstrate the mitotic activity.When the data was statistically analyzed, an analysis of variance test failed to show a significant difference among the mean values of dividing cells from animals sampled during the different time periods. However, the F value for metaphase favorably approaches the table F value for the conditions of this study.By far, the strongest data to support the existence of a circadian rhythm within the hair follicle cells of mice is demonstrated when the mean values for each of the mitotic cell categories are plotted against time for the twenty-four hour period. Metaphase shows peaks in activity at 6:00 a.m. and 10:00 p.m. A similar pattern is also seen for the unidentifiable cells. The peak mitotic activities for prophase, and anaphase-telophase was seen to occur at 10:00 p.m.

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Low recovery rates of fertiliser N in tree biomass are frequently reported due to the inefficiency of N fertilisers in afforested ecosystems. At Culloden (North East Scotland), only 13&'37 of 15N-urea fertiliser applied to Sitka spruce could be recovered in the above-ground tree biomass two years after fertilisation. Fertiliser N not taken up by trees was largely 'locked-up' in stable organic forms of N within the LFH layers of the soil profile. 15N-labelled litter was used in both field and microcosm experiments, the release and fate of litter-derived-N (LDN) being traced over the course of two growing seasons. In both experiments, the microbial biomass acted as a major sink for LDN. Measurement of soil microbial biomass was calibrated for Culloden soil samples by determination of a kEN-factor. Tree uptake of LDN, in the field, occurred within one month of labelled-litter application, with the foliage being the largest sink for LDN. Approximately 30&'37 of the N within the labelled-litter layer was taken up by the trees over the course of two growing seasons and was equivalent to 5.4 kg LDN ha-1 y-1. There was considerable mixing of the LFH and peat layers in Sitka spruce microcosm soil profiles. This was probably due to elevated soil animal population densities. After 18 months, approximately 83&'37 of LDN had been redistributed to other N pools in the microcosm. Uptake of LDN by seedlings accounted for 15.7&'37 of LDN after 12 months, the largest sink being the foliage, equivalent to 6.16 kg LDN ha-1 y-1. Again, the microbial biomass was a major sink for LDN. Measurement of availability (NH4+) N in Culloden soil samples incubated at different matric potentials and temperatures, appeared not to reflect N mineralisation rates. There was a strong interaction between temperature and soil matric potential, seedling uptake of N being greatest at 15oC and -16.0 kPa. The rate of turnover of the microbial biomass pool was identified as the key determinant of the rate of processing of LDN in forest soils.

We investigate the solar cycle modulation of the quasi-biennial oscillation (QBO) in stratospheric zonal winds and its impact on stratospheric ozone with an updated version of the zonally averaged CHEM2D middle atmosphere model. We find that the duration of the westerly QBO phase at solar maximum is 3 months shorter than at solar minimum, a more robust result than in an earlier CHEM2D study due to reduced Rayleigh friction drag in the present version of the model. The modeled solar cycle ozone response, determined via multiple linear regression, is compared with observational estimates from the combined Solar Backscattered Ultraviolet (SBUV/2) data set for the period 1979–2003. We find that a model simulation including imposed solar UV variations, the zonal wind QBO, and an imposed 11-year variation in planetary wave 1 amplitude produces a lower stratospheric ozone response of ∼2.5% between 0 and 20°S and an upper stratospheric ozone response of ∼1% between 45 and 55 km, in good agreement with the SBUV-derived ozone response. This simulation also produces an (enhancement/reduction) in the (lower/upper) stratospheric temperature response at low latitudes compared to the effects of solar UV variations alone, which are consistent with model vertical velocity anomalies produced by the solar-modulated QBO and imposed changes in planetary wave forcing.

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This thesis developes computer modelling techniques, and their use in the investigation of biochemical systems, principally the photosynthetic Calvin cycle. A set of metabolic modelling software tools, "Scampi", constructed as part of this project is presented. A unique feature of Scampi is that it allows the user to make a particular model the subject of arbitrary algorithms. This provides a much greater flexibility than is available with other metabolic modelling software, and is necessary for work on models of (or approaching) realistic complexity. A detailed model of the Calvin cycle is introduced. It differs from previously published models of this system in that all reactions are assigned explicit rate equations (no equilibrium assumptions are made), and it includes the degradation, as well as the synthesis, of starch. The model is later extended to include aspects of the thioredoxin system, and oxidative pentose phosphate pathway. Much of the observed behaviour is consistent with experimental observation. In particular, Metabolic Control Analysis of the model shows that control of assimilation flux is likely to be shared between two enzymes, rubisco and sedoheptulose bisphosphotase (SBPase), and can readily be transferred between them. This appears to offer an explanation of experimental evidence, obtained by genetic manipulation, that both of these enzymes can exert high control over assimilation. A further finding is that the output fluxes from the cycle (to starch and the cytosol), show markedly different patterns of control from assimilation, and from each other. An novel observation in behaviour of the Calvin cycle model is that, under certain circumstances, particularly at low light levels, the model has two steady-states and can be induced to switch between them. Although this exact behaviour has not been described experimentally, published results show charecteristics suggesting the potential is there in vivo. An explanation of all the observed behaviour is proposed, based upon the topology of the model. If this is correct then it may be concluded that the qualitative behaviour observed in the model is to be expected in vivo, although the quantitative detail may vary considerably.

The discovery of sulphur-deficient agricultural soils has focussed concern on the dynamics of sulphur transformations in soils and on the important role of the soil microbial population in mineralising organic sulphur to forms more available to plants. This thesis reports a study carried out to investigate the dynamics of supply of plant available sulphur from soils and includes development of a method for determination of microbial biomass S, comparison of a perfusion system with a plant bioassay to assess soil S-supply, characterisation of a fertilizer S budget for a crop-soil system and assessment of the role of VA mycorrhizas in plant S uptake. The first experiment was carried out to investigate the factors involved in determination of microbial biomass S in soil in order to develop a more reliable assay. Biomass S-concentrations were determined by chloroform fumigation/direct extraction (with determination of the Ks calibration constant using 35S labelled microorganisms). The effects of period of fumigation, the need for chloroform evacuation, the type of extractant, and the time of extraction were investigated. The optimium values for biomass-S were obtained using a 5 day fumigation period without chloroform evacuation (use of 35S labelled microorganisms demonstrated that there is a vacuum sensitive non-biomass S pool), with CaC12 as an extractant over a 1 h extraction period. The second experiment consisted of a simple, open perfusion system for studying the S-supplying capacity of soils. A range of soils were perfused at frequent intervals and the leachates analysed for inorganic and total sulphur. Results were compared with plant S-offtake from the same soils. Although greater amounts of sulphur were removed in the perfusion system, data from the techniques correlated strongly, suggesting the perfusion system can be effectively used to estimate the S-supplying capacity of soils.