Fluidised bed drying is currently receiving much attention as a dewatering option after the beneficiation of fine coal (defined in this study as between 1mm and 2mm particles). The aim of this study was to investigate the removal of moisture from fine coal by using air at relatively low temperatures of between 25°C and 60°C within a controlled environment by lowering of the relative humidity of air. The first part of the experimental work was completed in a controlled climate chamber with the coal samples in a static non-fluidised state. Drying in the second part was carried out using a fluidised bed with conditioned air as the fluidising medium. Introduction of airflow to the system led to a lower moisture content in the coal samples and it also proved to have the ability to increase the drying rate. It was determined that the airflow had the ability to remove more free moisture from the filter cake. In addition more inherent moisture could also be removed by using upward flowing air, resulting in a lower equilibrium moisture content. It was proven that the airflow rate and relative humidity of the drying air contributed to faster drying rates. The effect of temperature was not as significant as expected, but higher temperatures did increase the drying rate at higher airflow and lower humidity conditions. The larger surface areas of particles create surface and capillary forces that prevent the moisture from leaving the finer coal particles. It was found that the rate of drying is independent of the moisture content in the coal sample. Just in terms of the fastest drying time and drying rate in the fluidised bed, it was concluded that the most efficient conditions is airflow above minimum fluidisation point causing vigorous mixing and maximum contact with the drying air. In addition to the high airflow it was concluded that 30% relative humidity and 55°C resulted in the fastest drying time. All the drying processes at all the airflow rates, temperature and relative humidity conditions were energy efficient. This process was shown to be energy positive, resulting in an overall energy gain. The overall energy consumption for the fluidised bed is lower than for all the dryer systems compared to and it compared favourably with other thermal drying technologies. It was therefore shown that this is a viable technology for the dewatering of fine coal. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2014

Fluidised bed drying is currently receiving much attention as a dewatering option after the beneficiation of fine coal (defined in this study as between 1mm and 2mm particles). The aim of this study was to investigate the removal of moisture from fine coal by using air at relatively low temperatures of between 25°C and 60°C within a controlled environment by lowering of the relative humidity of air. The first part of the experimental work was completed in a controlled climate chamber with the coal samples in a static non-fluidised state. Drying in the second part was carried out using a fluidised bed with conditioned air as the fluidising medium. Introduction of airflow to the system led to a lower moisture content in the coal samples and it also proved to have the ability to increase the drying rate. It was determined that the airflow had the ability to remove more free moisture from the filter cake. In addition more inherent moisture could also be removed by using upward flowing air, resulting in a lower equilibrium moisture content. It was proven that the airflow rate and relative humidity of the drying air contributed to faster drying rates. The effect of temperature was not as significant as expected, but higher temperatures did increase the drying rate at higher airflow and lower humidity conditions. The larger surface areas of particles create surface and capillary forces that prevent the moisture from leaving the finer coal particles. It was found that the rate of drying is independent of the moisture content in the coal sample. Just in terms of the fastest drying time and drying rate in the fluidised bed, it was concluded that the most efficient conditions is airflow above minimum fluidisation point causing vigorous mixing and maximum contact with the drying air. In addition to the high airflow it was concluded that 30% relative humidity and 55°C resulted in the fastest drying time. All the drying processes at all the airflow rates, temperature and relative humidity conditions were energy efficient. This process was shown to be energy positive, resulting in an overall energy gain. The overall energy consumption for the fluidised bed is lower than for all the dryer systems compared to and it compared favourably with other thermal drying technologies. It was therefore shown that this is a viable technology for the dewatering of fine coal. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2014

For the successful reclamation of disturbed land, the reduction of initial erosion risk must be balanced with later vegetation establishment. A combination of erosion control and revegetation practices was researched using commercial (full-sized) equipment on a semi-desert grassland site in southern Arizona, USA. Two soils with different parent materials were used to add a 30 cm cap on sites at two elevations: 1646 and 1403 m asl. There were two surface roughness treatments: smooth and rough. Three straw mulch treatments were applied: no mulch, mulch incorporated into the surface soil, and mulch tackified onto the surface. Plots were planted with a 10 species native mix dominated by perennial grasses. After two growing seasons, the incorporated mulch treatment resulted in significantly more seeded grass aboveground biomass than the no mulch treatment while the no mulch treatment had more forb and volunteer biomass than the surface mulch treatment. There was significantly higher erosion on the rough surface treatment compared to the smooth surface. Increasing perennial grass biomass was correlated with reduced erosion while forb and volunteer biomass showed no relationship with erosion. The smooth surface with surface mulch best established perennial grasses, minimized weeds, and reduced erosion. This combination of practices both minimized erosion as well as maximized vegetation establishment. (C) 2016 The Authors. Published by Elsevier B.V.

Med ett naturligt fältexperiment studeras betydelsen av social påverkan för individers benägenhet att skänka pengar. Den dominerande teorin inom nationalekonomin som förklaring till välgörenhet är warm glow altruism. Teorin säger att människor skänker pengar på grund av en kombination av altruism och warm glow. Men det finns även teorier som förutsäger att socialt tryck spelar roll. I experimentet ställdes frågor till pantkunder om deras bidrag till välgörenhet. Individerna i behandlingsgruppen blev tillfrågade innan de började panta och kunnat välja om de ska skänka panten. I kontrollgruppen besvarades frågorna efteråt. Resultatet tyder på att social påverkan spelar stor roll för benägenheten att skänka panten.

For numerical modeling and predictive analysis of warm hydroforming, better understanding of material properties (i.e. Flow curves) is required at elevated temperatures and high strains. Hydraulic bulge testing is a suitable method to obtain this information. However, analysis of the test data is not standardized as there are numerous approaches developed and adopted throughout the years. In this study, first, different approaches for hydraulic bulge analysis were compared with stepwise experiments to determine the best combination of approaches in obtaining accurate flow curves at different temperatures and strain rates. Then, three different grades of stainless steels (AISI 201, 301 and 304) were tested at various hydroforming conditions to determine the effect of pressure, temperature and strain rate on formability (i.e. cavity filling and thinning). These experimental findings were then used to be compared with predicted values from FEA. Results showed that material model works accurately in predicting the formability of materials in warm hydroforming.

The Warm Springs soil series which contained variable amounts of subsoil available (sodium bicarbonate extractable) phosphorus was studied to explain the variability and distribution of the NaHCO3-P in the subsoil. Four pedons ranging in subsoil NaHCO3-P from less than 10 ppm to greater than 30 ppm were selected in an area of less than 200 ha located on a nearly level, low lake terrace east of the Great Salt Lake in Weber County, Utah. The morphology of each pedon was described in the field and samples collected from each genetic horizon or contrasting layer. Each soil sample was analyzed for total phosphorus, NaHCO3-P, water- soluble phosphorus, pH, extractable iron , calcium carbonate equivalent, electrical conductivity and water-soluble sodium. Four horizons were selected from each pedon for anal ysis of parti cle-size distribution, clay-size carbonate and non-carbonate clay. The very fine sand fraction of four horizons from two of the pedons were studied petrographically to determine the amount of apatite present. Thin strata with higher chroma were separated from adjacent layers and analyzed for extractable iron and NaHCO3-P. Cicada casts and their surrounding matrix were separated and analyzed Selected soil samples were shaken with sodiumphosphate solutions and then analyzed for NaHCO3-P to determine the influence of the amount of phosphorus in solution on the amount of phosphorus extracted. NaHCO3-P below the calcic horizons was highly variable, 10 ppm or less in two pedons and up to 40 ppm in the other two. Subsoil horizons with pH values greater than 10.0 and relatively large amounts of water-soluble sodium contained more than 10 ppm NaHCO3-P. Extractable iron and NaHC03-P were concentrated in subsoil strata with higher chroma. The results indicated that large amounts of NaHCO3-P in the subsoil were primarily due to the presence of readily soluble sodium phosphate. Weathering of apatite in the surface horizons did not contribute the NaHCO3-P below the calcic horizons. The most likely source of NaHCO3-P in the Warm Springs subsoil , however, was the sediments deposited in the low lake terraces and river flood plains by the Weber and Bear Rivers. Lateral flow and vertical fluctuations of the water table were suggested as a means by which the NaHCO3-P could be extracted from some areas and concentrated in others. Although certain soil properties might indicate the probable occurrence of more than 10 ppm NaHCO3-P in the subsoil, this study did not provide a method for identifying all subsoils with appreciable amounts of NaHCO3-P.

The air-sea interaction thermodynamics of the western equatorial Pacific, the Earth's largest region of warm SST, is a major component of the global climate system. Along the equator, warm pool thermodynamics and momentum are influenced by equatorial ocean visco-inertial boundary layer dynamics that occur within a few degrees of the equator because of the sign reversal of the Coriolis force. Designed to study this system, COARE Enhanced Monitoring Array (EMA) observations of temperature, salinity, velocity, and surface meteorology were centered at 0, 156°E from February 1992 through April 1994. They sampled variability on the equator over larger space/time-scales than the concurrent Intensive Flux Array (IFA) centered at 2°S, 156°E. The EMA data are examined within the context of the larger scale equatorial Pacific and the El Niño conditions that occurred at that time. There is a structural change in the equatorial Pacific near the dateline resulting from the winds that are strong, steady, and easterly in the east and generally weak, punctuated by westerly wind bursts, in the west. East of the dateline the EUC's speed and transport increases downstream, while in the west it tends to be zonally uniform, consistent with the extra-tropical ocean interior water pathways that tend to converge on the equator east of the dateline. At 0°, 156°E in the western Pacific deep, seasonal upwelling (appearing stronger after the peak of the 1991/92 El Niño than during the following weaker El Niño year) occurs within the thermocline in boreal summer with magnitudes as large as upwelling in the eastern Pacific cold tongue. This large upwelling is associated with large downward turbulent heat flux and large turbulent shear stress. While the inferred mixing is quantitatively inconclusive because of unresolved potential errors, it is consistent with the visco-inertial boundary layer concepts from early theory [e.g. Arthur 1960; Robinson 1960; Stommel 1960; and Charney and Spiegel 1971]. These findings suggest that the equatorial thermodynamics differ from those of the IFA. Further process experimentation is necessary to quantify these results.

The purpose of this investigation was to determine the effectiveness of using imagery in eliminating post-rest warm-up decrement (WUD) in the volleyball serve, and to assess whether individual differences in imagery ability mediated any possible reductions in WUD. Thirty-nine State level volleyball players were placed into one of 3 groups, High Imagery, Control, and Low Imagery, based on their scores on the Vividness of Movement Imagery Questionnaire (VMIQ). Players served 15 balls at a designated target area, rested for 10 minutes, and then attempted 5 more serves. During the last 2 minutes of the rest period, the players in the High and Low Imagery groups engaged in imagery of successful serving every 10 seconds, for a total of 12 repetitions. The Control group continued to read a magazine article. To ensure adherence to the imagery instructions, players were evaluated at completion of testing. Results revealed the High Imagery group was significantly better on serving performance post-rest, however there was no significant differences when comparing the mean of the last 3 pre-rest trials with the first post-rest trial. The interaction approached significance (p_= .091) and suggested that the High Imagery group may have benefited from the use of imagery. These findings have implications for the Nacson and Schmidt's (1971) activity-set hypothesis that states that an appropriate task will reduce WUD. It may need to include the effect individual differences, such as imagery ability, may have on the performance of that task.

<p>Med ett naturligt fältexperiment studeras betydelsen av social påverkan för individers benägenhet att skänka pengar. Den dominerande teorin inom nationalekonomin som förklaring till välgörenhet är warm glow altruism. Teorin säger att människor skänker pengar på grund av en kombination av altruism och warm glow. Men det finns även teorier som förutsäger att socialt tryck spelar roll. I experimentet ställdes frågor till pantkunder om deras bidrag till välgörenhet. Individerna i behandlingsgruppen blev tillfrågade innan de började panta och kunnat välja om de ska skänka panten. I kontrollgruppen besvarades frågorna efteråt. Resultatet tyder på att social påverkan spelar stor roll för benägenheten att skänka panten.</p>

Warm forming of aluminum alloys of has shown promising results for increasing the formability of aluminum alloy sheet. Warm forming is a term that is generally used to describe a sheet metal forming process, where part or all of the blank is formed at an elevated temperature of less than one half of the material’s melting temperature. The focus of this work is to study the effects of warm forming on Novelis X926 clad aluminum brazing sheet. Warm forming of clad aluminum brazing sheet, which is commonly used in automotive heat exchangers has not been studied. This work can be split into three main goals: i) to characterize the material behavior and develop a constitutive model, ii) to experimentally determine the effects of warm forming on deep drawing; and, iii) to create and validate a finite element model for warm forming of Novelis X926. For an accurate warm forming material model to be created, a temperature and rate dependant hardening law as well as an anisotropic yield function are required. Uniaxial isothermal tensile tests were performed on 0.5mm thick Novelis X926at 25°C (room temperature), 100°C, 150°C, 200°C, and 250°C. At each temperature, tests were performed with various strain rates between 7.0 E -4 /sec and 7.0 E -2 /sec to determine the strain rate sensitivity. Tensile tests were also performed at 0° (longitudinal), 45° (diagonal), and 90° (transverse) with respect to the material rolling direction in order to assess the anisotropy of the material. It was found that increasing forming temperature increases elongation to failure by 200%, decreases flow stress by 35%, and increases strain rate sensitivity. Barlat’s Yield 2000 yield function (Barlat et al., 2003a) and the Bergström work hardening law (van den Boogaard and Huétink , 2006) were found to accurately method model the material behavior. Warm deep drawing of 101.6 mm (4”) diameter cylindrical cups was performed using specially designed tooling with heated dies and a cooled punch. Deep drawing was performed on 228.6 mm (9“) and 203.2 mm (8”) diameter blanks of 0.5 mm thick Novelis X926. Deep drawing was performed with die temperatures ranging from 25°C to 300°C with a cooled punch. Teflon sheet and Dasco Cast 1200 lubricants were used in experiments. Different punch velocities were also investigated. 228.6 mm diameter blanks, which could not be drawn successfully at room temperature, were drawn successfully using 200°C dies. Increasing the die temperature further to 250°C and 300°C provided additional improvement in formability and reduced tooling loads. Increasing the punch velocity, increases the punch load when forming at elevated temperatures, reflecting the strong material rate sensitivity at elevated temperatures. A coupled thermal mechanical finite element model was developed using the Bergström hardening rule and the Yield 2000 yield surface using LS-DYNA. The model was found to accurately predict punch force for warm deep drawing using Teflon sheet as a lubricant. Results for Dasco Cast 1200 were not as accurate, due to the difficulties in modeling the lubricant’s behavior. Finite element simulations demonstrated that warm forming can be used to reduce thinning at critical locations, compared to parts formed at room temperature.