Amount Of Splash Research Articles

Fire resistance evaluation of a steel roller shutter with water-film cooling system

The full-scale fire evaluations with a large-scale door/wall refractory furnace are conducted to investigate the fire-protection performance of a non-heat-resistant fireproof steel roller shutter with a water-film cooling system. There are two methods in the water-film design, one is formed on “unexposed surface” and another is formed on “exposed surface” of the shutter slat. The main findings indicate that the water-film system combined with the steel roller shutter can effectively improve the heat resistance and the temperature of the shutter slat surface can be controlled to around 100 °C. While the water film formed on “unexposed surface” of the shutter slat cannot control the temperature inside the roller box, it is not suitable for actual applications because of the amount of splash and steam generated. In contrast, compared with the former one, the water film formed on “exposed surface” of the shutter slat with two rows of perforated pipes in the roller box can decrease lots of drawbacks. It not only fulfills to resist the intensive radiation in a fire but also extends the heat-resistance period beyond 120 min. Furthermore, no matter which side of the roller shutter is exposed to fire, a good fire resistance rating can be achieved by the proposed water-film system in this study.

Effects of Rainfall Intensity and Slope Angle on Splash Erosion in Makurdi, Benue State

Soil erosion is a critical global environmental problem, especially in the developing countries including Nigeria. In the humid and sub-humid tropics, splash erosion resulting from intense rainfall and slope degree pose severe land degradation problems. The objective of this study is to assess the effects of some rainfall parameters and slope on directional components of splash erosion in the Makurdi area of Benue State. Data were collected on rainfall amount and duration in an experimental station in Benue State University, Makurdi for a period of one rainy season in 2007. Sediment collectors attached to soil trays placed at angles 5, 15, 25 and 35 degrees were used to collect the amount of splash at the end of every rain day. The soils were oven dried and measured. The amount of soil splashed was statistically analyzed after weighing to verify the slope effects on splash. The results showed that slope has a significant effect on the downslope and upslope components of the splash. Downslope component increased with slope while the upslope component decreased, reflecting variations of raindrop impacting forces and ponding depth with slope. Total splash increased with slope angle to a peak at 150 and then decreased with increasing angle. Factors of slope angle, rainfall amount, and intensity, and total kinetic energy were regressed against directional components of splash. The result showed that 70% of variations in the downslope splash is explained by these factors. Further research is recommended on slope orientations at different wind directions and rate of rain capture on erodibility. KEYWORDS: Splash, erodibility, slope, erosivity, Modeling.

Splash erosion under natural rainfall on three soil types in NE Spain

Splash detachment and transport of soil particles by raindrops impacting a soil surface are the initiating mechanisms of water erosion. The amount of splash depends on rainfall characteristics (mainly kinetic energy and intensity) and soil properties. Experimental results of rainfall and splash monitoring in three soil types under natural rainfall in NE Spain are presented. Some 27 rainfall events were evaluated, during which high rates of soil splash were measured (≤6.06g per splash cup), stressing its importance as an erosion process on bare soils. Sources of variation of soil splash were analyzed by a linear mixed-effects (LME) model. Significant relationships were found between the splash erosion rates and the rainfall erosivity index EI30. No significant differences in erosion were found among the soil types analyzed. The LME model explained 55% of variance in the erosion rates, and most of the residual variability (≤74%) was due to differences between splash cups within a single soil type and event, i.e., random effects.

Physical modelling of slag splashing in nickel converter

The amount and distribution of slag splashing in nickel converter under various conditions were investigated in a 1∶4 scale water model. The results show that the blowing time and tuyere angle play a significant role in affecting the total amount of splash, while the gas flowrate is of little influence. The proportion of splash on the opposite side of the tuyere line is dramatically reduced from 80 to 5% or so when increasing the tuyere angle from −10 to −30° or the initial bath depth h/D from 0·078 to 0·172. Meanwhile, the splash on the side of the tuyere line and the end side is greatly increased. The height of splashing h2/D takes on a decreasing trend as the tuyere angle or h/D increases. The mode of slag splashing can be defined as injection slag splashing, surging slag splashing and both together. Larger amount of splash and more even distribution on different walls can be acquired by adjusting the tuyere angle for an initial bath depth. The industrial test is in good agreement with the results from the water model and problems such as heavy accretion on tuyere line are also resolved.On a examiné la quantité et la distribution de giclement de laitier du convertisseur de nickel sous des conditions variées avec un modèle aqueux à l’échelle d’un quart. Les résultats montrent que la durée de soufflage et l’angle de la tuyère jouent un rôle important sur la quantité totale de projections, alors que le débit gazeux a peu d’influence. La quantité de projections sur le côté opposé de la ligne de tuyère est réduite dramatiquement de 80% à environ 5% lorsqu’on augmente l’angle de la tuyère de –10° à –30°, ou la profondeur initiale du bain (h/D) de 0·078 à 0·172. Pendant ce temps, les projections sur le côté de la ligne de tuyère et à l’extrémité augmentent beaucoup. La hauteur de giclement (h2/D) a une tendance à décroître à mesure que l’angle de la tuyère, ou h/D augmente. On peut définir le mode de giclement du laitier comme giclement de laitier par injection, giclement de laitier par gonflement, ou les deux ensemble. On peut acquérir une plus grande quantité de projections et une distribution plus égale sur les différentes parois en ajustant l’angle de la tuyère à une profondeur initiale du bain. L’essai industriel est en bon accord avec les résultats du modèle aqueux et l’on résout également des problèmes comme l’accrétion importante sur la ligne de la tuyère.

System for Measuring Splash on Wet Pavements

Vehicles traveling on wet pavements produce splash and spray that reduce driver comfort and safety. The amount of water thrown up by a vehicle's tires depends on many factors such as the type of vehicle and the speed at which it is traveling, the weather conditions, and the pavement surface. Drainage wearing courses and rough macrotexture pavements reduce or completely suppress splash and spray. Nonetheless, the effect of pavement type on splash and spray has yet to be fully elucidated, and there is a need for simple systems that can provide rapid measurements of this phenomenon on real roads. Tests are described with a prototype for a new system consisting of a laser unit and a high-resolution camera that measures splash and shows the effect of pavement surface on the amount of splash produced. Unlike existing systems, which evaluate a single, often nonrepresentative stretch of pavement, the system described can provide continuous measurements over stretches of road. Moreover, the measurement process is sensitive to both water flow and tire speed, and the results analyzed confirm the repeatability of the system and its sensitivity to pavement texture.

Reduction of ultrasonic pad stress and aluminum splash in copper ball bonding

Given the cost and performance advantages associated with Cu wire, it is being increasingly seen as a candidate to replace Au wire for making interconnections in first level microelectronics packaging. A Cu ball bonding process is optimized with reduced pad stress and splash, using a 25.4 μm diameter Cu wire. For ball bonds made with conventionally optimized bond force and ultrasonic settings, the shear strength is ≈140 MPa. The amount of splash extruding out of bonded ball interface is between 10 and 12 μm. It can be reduced to 3–7 μm if accepting a shear strength reduction to 50–70 MPa. For excessive ultrasonic settings, elliptical shaped Cu bonded balls are observed, with the minor axis of the ellipse in the ultrasonic direction and the major axis perpendicular to the ultrasonic direction. To quantify the direct effect of bond force and ultrasound settings on pad stress, test pads with piezoresistive microsensors integrated next to the pad and the real-time ultrasonic force signals are used. By using a lower value of bond force combined with a reduced ultrasound level, the pad stress can be reduced by 30% while achieving an average shear strength of at least 120 MPa. These process settings also aid in reducing the amount of splash by 4.3 μm.

Modelling raindrop impact and splash erosion processes within a spatial cell: a stochastic approach

AbstractA new approach is proposed to simulate splash erosion on local soil surfaces. Without the effect of wind and other raindrops, the impact of free‐falling raindrops was considered as an independent event from the stochastic viewpoint. The erosivity of a single raindrop depending on its kinetic energy was computed by an empirical relationship in which the kinetic energy was expressed as a power function of the equivalent diameter of the raindrop. An empirical linear function combining the kinetic energy and soil shear strength was used to estimate the impacted amount of soil particles by a single raindrop. Considering an ideal local soil surface with size of 1 m × 1 m, the expected number of received free‐falling raindrops with different diameters per unit time was described by the combination of the raindrop size distribution function and the terminal velocity of raindrops. The total splash amount was seen as the sum of the impact amount by all raindrops in the rainfall event. The total splash amount per unit time was subdivided into three different components, including net splash amount, single impact amount and re‐detachment amount. The re‐detachment amount was obtained by a spatial geometric probability derived using the Poisson function in which overlapped impacted areas were considered. The net splash amount was defined as the mass of soil particles collected outside the splash dish. It was estimated by another spatial geometric probability in which the average splashed distance related to the median grain size of soil and effects of other impacted soil particles and other free‐falling raindrops were considered. Splash experiments in artificial rainfall were carried out to validate the availability and accuracy of the model. Our simulated results suggested that the net splash amount and re‐detachment amount were small parts of the total splash amount. Their proportions were 0·15% and 2·6%, respectively. The comparison of simulated data with measured data showed that this model could be applied to simulate the soil‐splash process successfully and needed information of the rainfall intensity and original soil properties including initial bulk intensity, water content, median grain size and some empirical constants related to the soil surface shear strength, the raindrop size distribution function and the average splashed distance. Copyright © 2007 John Wiley & Sons, Ltd.

Crater formation in soils by raindrop impact

AbstractThe process of crater formation by the impact of water drops on soil, sand and various other target material was studied. Craters of various shapes and sizes were observed on different target materials or conditions, ranging from circumferential depression to completely hemispherical shape. Crater shape was dependent upon target material, its flow stress or shear strength and the presence and thickness of water on the surface. Between 5 and 22 per cent of impact energy was spent on cratering, but the relationship between crater volume and kinetic energy of a raindrop was curvilinear, indicating a lower efficiency of impact energy in removing target material as the energy increases. Impact impulse, on the other hand, showed a more linear relationship with crater volume, and the ratio of impulse over crater volume (I/V) remained constant for the entire range of drop sizes, impact velocities, and surface conditions used in this study. Surface shear strength, represented by the penetration depth of fall‐cone penetrometer, appeared to be a key factor involved in this process. An equation was developed which related crater volume to cone penetration depth and impact impulse. Crater volume, which appeared to be a better indicator of the total amount of material dislodged by a raindrop than splash amount, can thus be predicted using this equation. Copyright © 2004 John Wiley & Sons, Ltd.

Splashing mechanism in combined blowing

In combined BOF blowing, lance parameters and the combination of bottom or side wall tuyeres have an influence on splashing behaviour. The aim of this study was to clarify the interaction of the lance jet cavity with the bottom blowing plume and the side wall blowing jet and to determine its effects on splashing. According to the water model tests, three basic axioms existed in the combined blowing. First, when the bottom tuyere (or side wall tuyere) was located exactly beneath the lance jet, the lowered cavity turned the direction of splashes to lower trajectories. Second, the total amount of splashing was constant and the splashing peak was generated on the wall above the bottom plume. Third, both the plume and the side wall jet formed a so called protected zone beyond it. The model experiments showed clearly that the combination of bottom tuyeres and interaction of cavities and plumes play a very important role in splash generation in real converters.

Splashing and Spitting Behaviour in the Combined Blown Steelmaking Converter.

The amount of iron droplets ejected in the BOF affects on metallic yield, refactory wear and the progress of decarburisation. The purpose of this study was to investigate the effect of lance height, lance nozzle angle, lance position, top gas flow rate, bottom blowing and foamy slag on splashing and spitting. A new cold model method for investigating the effects of above-mentioned parameters on the location and quantity of liquid splashed on the walls of the model was utilised. According to the model tests, reduction of the nozzle angle increased the total amount of splashing and spitting considerably. Consequently, reduced productivity due to an increase in metal losses, skulling of the cone and converter mouth and further increased time for skull removal is expected. Introduction of bottom blowing increased splashing significantly on lower parts of the vessel. Lance position has an effect on total amount of splashing when bottom blowing is used. The presence of even minor foam layer on water surface reduced the amount of total splashing significantly.

Combined blowing with three ‐ hole lance in a sidewall blowing converter

Traditionally, in stainless steelmaking converters, oxygen has been blown by a one‐hole lance (1 HL) and sidewall tuyères. In order to reduce the tap‐to‐tap time, the multi‐hole lance has been used for oxygen blowing. The aim of this work was to develop blowing practise for a multi‐hole lance to reduce the tap‐to‐tap time and minimise metal splashing and spitting in the sidewall blowing converter (chromium converter). In the chromium converter the chemical energy of liquid ferrochrome (which contains 4 % silicon and 7 % carbon) is utilised for scrap melting by oxidising the silicon and the part of carbon.The research has been made by a dynamically scaled water model and full‐scale converter. Used parameters were the gas flowrate from sidewall tuyères and lance, lance height, charge weight and position of multi‐hole lance. Splashing has been measured during blowing from walls (splashing) and mouth of the converter model (spitting). The model tests indicated less splashing and spitting by the three‐hole lance (3 HL) than traditional 1 HL. The 1 HL caused strong skulling of the converter cone. By 3 HL blowing the position of the lance has a remarkable effect on the direction and the amount of splashing and lance life. Because of hot metal‐slag splashes, the life time of the 3 HL was halved by position 1 (compared to 1 HL). With the lance position 2 the splashing decreased by approx. 50% in model tests and lance life time increased by ~ 50% (compared to 1 HL) in the full‐scale converter. The model agreed well with the full‐scale converter. According to the process tests, the nominal productivity of the chromium converter has increased 15 % and depending on the refining practise and the silicon content of ferrochromium the lining life has increased 20 ‐ 30 %. In the future the multi‐hole lance will be tested in the AOD vessel.

Soil loss by splash and wash during rainfall from two loess soils

Physical processes occurring during surface seal formation through a rainstorm are well understood, but limited information is available regarding the quantity and particle size distribution of splash and runoff at certain time intervals. In this study, we evaluated the quantity and particle size distribution of suspensions of both splash and interrill runoff in two loess soils with different mineralogy and aggregate stability, and somewhat different particle size distribution, but similar organic matter content. The soils were subjected to simulated rainstorms of ∼ 40 turn h − 1 and 100 mm h −1 intensities. The amount of splash was about four times higher for the Saskatchewan soil (Typic Haploboroll) with high smectite than for the Grenada soil (Typic Fragiudalf) which is rich in Fe-oxyhydroxides. The amount of splashed material and sediment load increased with increased rainfall intensity for both soils. Splash was decreased after wetting of the soil surface. The decrease in splash rate was more rapid with high rainfall intensity. The amount of clay size particles of the splash was similar to the original soil material. Micromorphological observations confirmed the fluctuations in clay content with time, at the very surface. Soil materials splashed were much higher (10 to 20 times) than the interrill runoff losses. The latter was controlled by the rainfall intensity. The soil material from Saskatchewan, produced more than 11 Mg ha − 1 of interrill runoff with low rainfall intensity. High rainfall intensity produced 10 times more soil loss than low rainfall intensity. High amount of soil loss clearly shows that the Saskatchewan soil would benefit from erosion control measures. Both rainfall intensities removed preferentially more clay from the Saskatchewan B horizon material. This has important agronomic and environmental implications for this soil. Interrill soil losses from the Granada A horizon material were much less, with no clear evidence of preferential removal of clay size particles.

Experimental study of splash generation in a flash smelting furnace

A survey of previous studies of splash formation in metallurgical vessels revealed that little information is available to characterize and describe the processes involved in splash formation. An experimental study of splash formation by top submerged gas injection was carried out in the settler region of the nickel flash smelting furnace at the Kalgoorlie Nickel Smelter (KNS) both to obtain some visualization of the splash mechanisms that occur on a plant scale and to measure the amount of splash being formed. Video images taken of the splashing showed that large sheets of melt were formed by the escaping gas and subsequently thinned into ligaments which then broke up into large splash drops. The video could only resolve a minimum size of 2 cm. The large splash drops visible on video have an initial velocity between 1 and 2 m/s, are unstable, and fall back into the bath after traveling a short distance. The analysis identified two major splash forming mechanisms. First, the gas injected resulted in the bulk movement of the melt to form a cavity and large sheets of melts being thrown around the point of injection. The area affected by this splash mechanism can be predicted successfully by using an energy balance between the removal of the melt in the cavity and the energy of the gas being injected. Second, the slag free surface within the cavity is highly unstable, and through the Kelvin-Helmholtz instability mechanism, small splash droplets are generated which are carried into the furnace’s top space. A model proposed for the formation of the smaller splash droplets predicted that the splash collected decreases exponentially with increasing height above the slag free surface from the point of splashing, and this is in agreement with the experimental results obtained.

Interrill Soil Erosion and Slope Steepness Factors

Interrill erosion models assume a constant slope steepness term as a function of slope angle. To test the hypothesis that the slope steepness term varies with antecedent soil moisture and soil texture, we determined the effect of slope steepness on soil loss for five soils from clay to silt loam in texture with wet or dry antecedent soil water contents. Interrill sediment yield (wash), splash detachment, runoff, and sediment size were measured in laboratory erosion pans under simulated 90-min, 72 mm h -1 rainfall at 9 and 20% slopes. As slope steepness increased, splash decreased for three soil treatments and increased for the other five treatments. Splashed sediment and sediment yield were not correlated. Change in splash with increased slope steepness was correlated (r = 0.96) with change in sediment yield. Mean weight diameter (MWD) of splash was, on the average, about twice the MWD of wash. The MWD of both splash and wash was significantly (r = 0.0001) influenced by soil type and antecedent moisture, but MWD of splash and wash was uncorrelated with amount of splash and wash, respectively. The results emphasize the importance of quantifying terms in erosion equations in relation to specific erosion processes.

Variation in the height to which tracer is moved by splash during natural summer rain in the UK

The relative capacity of rain events to transport material between ground level and a given height can be compared using a splashmeter. This consists of a central pole carrying a sheet of strong absorbent paper, surrounded by a ring of small dishes containing cellulose-reactive ultraviolet fluorescent dye. After rain, the dye coverage on the paper gives a permanent record of the total dye moved to any zone above the reservoirs. Results were comparable when the dishes were 15–25 cm from the central axis, but became more variable at greater distances. Results from replicate splashmeters were concordant, and there appeared to be a linear relationship between the results obtained using an open dye surface and dishes filled with glass fibre. Splashmeters were exposed at Long Ashton near Bristol, from April to August, during the period 1985–1989. The relative amount of splash projected above a given height during an individual rain event had a Weibull (extreme-value) probability distribution. The parameters of this distribution varied systematically with height. This allows, for example, calculation of the extent to which healthy plant tissues at any given height were at risk from splash-dispersed disease propagules produced lower down in a crop.

EFFECT OF ANTECEDENT SOIL MOISTURE ON SPLASH DETACHMENT UNDER SIMULATED RAINFALL

Antecedent soil water content is an important variable affecting soil erosion processes and may be responsible for much of the variation in splash and wash erosion rates. The purpose of this study was to determine the effect of antecedent water content on splash detachment and on soil and hydraulic variables that control splash. Five soils ranging in texture from sandy loam to clay were exposed to simulated rainfall with an intensity of approximately 64 mm h−1 for 1 h. Wash, splash, runoff, and infiltration were measured for near-saturated (-0.5 kilopascal) and air-dried soils in 0.14 m2 Al erosion pans. Changes in the soil surface were monitored with a fall-cone device. Prewetting significantly reduced runoff occurring over a 60-minute rainfall period for the Heiden clay only. Prewetting reduced splash detachment rates for all soils except the Miami silt loam, with the greatest reduction for the Heiden clay. Total splash for the air-dried and prewetted Heiden clay was 770.1 and 169.4 g in 60 minutes, respectively. Prewetting increased soil shear strength following 60 minutes of rainfall for all soils. Development of a surface seal controlled the amount of soil detached from the Miami silt loam. Miami silt loam had the highest final shear strength values for air-dried and prewetted soils and the highest difference between initial and final shear strength (Δτ) among prewetted soils. Prewetted wash and splash sediment size was larger than that for air-dried sediments. Antecedent soil moisture conditions prior to rainfall influenced the amount of splash detachment and the physical processes that control amount of splash.

Relationship of Soil Crust Morphology to Inter‐rill Erosion Parameters

AbstractResearch on soil surface sealing and crust formation has taken two approaches: (i) measurement of common soil erosion parameters such as infiltration, permeability, detachment, and strength and (ii) observation of seal or crust morphology using both microscopic and submicroscopic techniques. The purpose of this research was to combine the two approaches to extend our knowledge of surface sealing and crusting and its role in the erosion process. Eight soils with exchangeable sodium percentages (ESP) <1 and with textures ranging from sandy loam to clay were exposed in the laboratory to simulated rainfall with an intensity of 63 mm h−1 for 1 h. Seal and crust formation were investigated by measuring splash and wash erosion, single waterdrop splash, and fall‐cone strength and by observing scanning electron microscope (SEM) and thin‐section photographs. Medium‐textured soils (five silt loams and a silty clay loam) developed homogeneous, silty surface seals of high strength ranging from 14 to 43 kPa and low splash detachment. Splash amounts for single drop impact ranged from 0.8 to 1.8 mg soil per drop, and for multiple raindrops in erosion pans, from 9 to 26 g soil during the final 5 min of a 60 min rain. For a clay soil, no morphological evidence of crusting was observed; strength of the seal was low (6.4 kPa) and splash amount was high (40.0 g in 5 min). For a sandy loam soil, splash was high (41.8 g) and strength, low (10.8 kPa). Crust morphology indicated slight crusting. The subjective nature of interpreting SEM and thin section photographs makes it difficult to draw conclusions about erosion processes or rates.

Effect of Soil Surface Sealing on Splash from a Single Waterdrop

AbstractMost soil erosion prediction models do not account for surface sealing and soil crusting effects on soil detachment. The objective of this research was to evaluate surface seal formation and subsequent drying effects on amount of soil detached by single waterdrop impact. Twenty soils ranging in texture from sand to clay were tested. Single drop splash and fall‐cone strength determinations were made on each soil in an uncrusted condition, in a crusted condition immediately following 1 h of simulated rainfall (63 mm/h), and after 2 to 4 weeks of drying. Splash for the uncrusted condition ranged from 8.9 to 61.0 mg/drop and from 0.8 to 13.7 mg/drop for the crusted condition. Subjecting crusted soils to one drying cycle did not significantly alter splash amount. Splash was correlated with soil strength for both uncrusted and crusted conditions for finertextured soils; however, for sands and sandy loams additional research is required for soil strength‐based splash model for crusted conditions.

Detachment of Soil Aggregates by Simulated Rainfall

AbstractSharpsburg silty clay loam was separated into 11 aggregate fractions with the following diameters: 9,250–4,760µ, 4,760–3,360µ, + … +, 297–210µ, and <210µ. Krilium solution was added to half of each aggregate fraction to make the aggregates more water‐stable. The aggregate fractions were packed into splash‐cups and exposed to simulated rainfall intensities from 2 to 12 cm/hr. Raindrops were 5.1 mm in diameter and fell 11.33 m onto the surface of soil materials. Splash of soil particles and aggregates was caught, oven‐dried, and weighed.The amount of detachment of aggregates was linearly related to the rainfall intensity.Detachment of non‐treated aggregates exposed to rainfall increased from 76 mg of particles per cm3 of water to a maximum amount of 172 mg/cm3 as the aggregate diameters decreased from 9,250–4,760µ to 2,360–1,680µ. Then, the amount of detachment decreased with decreasing diameter to aggregate to 78 mg/cm3 for aggregates < 210µ diameter.The addition of Krilium to aggregates reduced the amount of detachment of aggregates >420µ in diameter exposed to simulated rainfall. The amount of splash increased with decreasing diameter of Krilium treated aggregates until 297–210µ diameter was reached (138 mg/cm3), then it decreased (101 mg/cm3) for aggregates < 210µ diameter.

Experiments on the Amount of Splash from the Wind Shield of a Rain Gauge

Experiments on the Amount of Splash from the Wind Shield of a Rain Gauge