Test Set-Up for Irregular Vertical Hydraulic Transport in Deep Ocean Mining

2011 ◽  
Author(s):  
Arno M. Talmon ◽  
Cees van Rhee
Keyword(s):  
Fine Particles ◽  
Deep Ocean ◽  
Ocean Surface ◽  
Processing Plant ◽  
Coarse Particles ◽  
Hydraulic Transport ◽  
Test Set ◽  
Sea Floor ◽  
High Concentrations ◽  
Set Up

The mining of scarce minerals from the sea-floor at the depths of several kilometers and bringing them to a processing plant at the ocean surface requires new techniques. Seafloor Massive Sulphide (SMS) deposits are known to have an extremely rich mineral content, and are considered technically-economically-environmentally feasible to explore. Vertical hydraulic transport is the link between the sea-floor mining and the maritime vessel where the first processing stage will take place. Clogging of any part of the vertical transport system is an absolute disaster. Fine particles are conveyed faster than coarse particles. High concentrations of fines cannot bypass high concentrations of coarse particles, hence these particle fractions accumulate, potentially blocking the pipe. Fundamental research into yet unexplored physics is necessary. Besides numerical flow simulations, it is necessary to conducted experiments on the transport over large vertical distances. Such tests aim to investigate the dynamic development of density waves consisting of different particle diameters and clogging phenomenon thereof. Different particle size fractions have to be followed in real time as they overtake each other, and change their shape, merge and segregate. It is however impossible to back-scale the prototype riser to a one-pass laboratory test set-up, but the process can be simulated by repeated flow through an asymmetric vertical pipe loop, where slurry flow in the upward leg represent vertical hoist conditions and the slurry is returned quickly via the downward leg. The particle accumulation process is allowed to take place in the upward leg whereas in the downward leg the restoring process is nearly neutralized. The development of accumulations in time (= distance traveled to the ocean surface) can be followed upon multiple passes of the solids batches through the upward leg. The novelty of the described testing method is that the essentials of fundamental processes occurring in long vertical stretches are quantified in a specially designed laboratory setup. Via subsequent implementation of the results in a numerical flow simulation, reliable transport scenarios can be delineated.

Flow Pattern and Pressure Drop in Highly Concentrated Slurries Transportation Pipelines

2011 ◽  
Vol 281 ◽  
pp. 179-182
Author(s):  
Hai Lu ◽  
Jun Yin ◽  
Yi Xing Yuan ◽  
Biao Wang ◽  
Hong Wei Chen ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Particle Concentration ◽  
Fine Particles ◽  
Pipe Wall ◽  
Flow Patterns ◽  
Coarse Particles ◽  
Pressure Drops ◽  
Frictional Losses ◽  
High Concentrations

Flow pattern and pressure drop in highly concentrated slurries transportation pipelines were discussed. The particles are settling, and tend to settle down to the bottom of pipes due to the action of gravity force forming different flow patterns which can be indicated by particle concentration profile. Three distinct flow patterns can be observed for different particle size distribution at different velocities: fully stratified, partially stratified and fully suspended flow patterns. As for pressure drop, it is well known that pressure drops in pipeline flows of slurries are strongly dependent on the flow pattern developed in a pipeline. Furthermore, fine particles suspended in water make the water more viscous, and increase the friction. In case of coarse particles, having larger volume, they have the tendency to contact with the pipe wall and with the other coarse particles more times, which increase the friction of flow. Meanwhile, coarse particles are lifted by the pressure difference generated as they rotate in the liquid preventing the coarse particles from settling down which results in less friction. The mixture of particles of different sizes is helpful to reduce pressure drop in pipeline flow slurries. Narrow grading particles tend to have high frictional losses, while broad grading particles have low frictional losses at high concentrations.

scholarly journals The Trend of Trace Elements (Cd, Ni, Pb) from PM2.5 and PM10 Aerosols and its Effect on Human Health in Bucharest, Romania

2001 ◽  
Vol 71 (3) ◽  
pp. 433-439 ◽  
Author(s):  
Katalin Bodor ◽  
Zsolt Bodor ◽  
Robert Szep
Keyword(s):  
Trace Elements ◽  
Particulate Matter ◽  
Fine Particles ◽  
Average Concentration ◽  
Coarse Particles ◽  
Exposure Pathway ◽  
Adults And Children ◽  
High Concentrations ◽  
One Year ◽  
Pm2.5 And Pm10

The comprehensive investigation of the elemental characteristics in fine and coarse particles at Bucharest was carried out. The daily samples of PM2.5 and PM10 particulate matter were collected at eight monitoring stations for a one-year period, and concentrations of Cd, Ni, Pb elements were analyzed. The results show that PMs and trace elements were present in high concentrations in Bucharest. The annual concentrations of PM10 and PM2.5 were 31.57 μg/m3 and 21.30 μg/m3, respectively. In Bucharest, the average concentration ratio of fine (PM2.5) and coarse particulates (PM10) was 0.67. Trace elements concentration carried by the PM2.5 was higher than the concentration detected from PM10. The Cd, Ni, and Pb accumulation was higher by 55.16%, 37.46% and 29.14% in fine particles than in coarse particles. The annual mean trace element concentration from PM2.5 and PM10 was in the case of Cd 0.22/0.24 ng/m3, for Ni 3.28/3.14 ng/m3 and for Pb 5.61/6.44 ng/m3, respectively. The highest Spearman correlation was found between Cd and Ni with correlation coefficient of 0.62 in PM2.5 and 0.48 in PM10, which suggests that they share common sources. The health risk indexes were estimated for both adults and children thanks to the trace elements from the particulate matter (PM), and the results revealed that inhalation was the major exposure pathway in both cases.

Inductive Telemetry on a Deep Ocean Surface Mooring.

1995 ◽  
Author(s):  
Daniel Frye ◽  
Alessandro Bocconcelli ◽  
Stephen Liberatore ◽  
Edward Hobart
Keyword(s):  
Deep Ocean ◽  
Ocean Surface

scholarly journals Contribution of Fine Particles to Air Emission at Different Phases of Biomass Burning

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 278 ◽  
Author(s):  
Niloofar Ordou ◽  
Igor E. Agranovski
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Fine Particles ◽  
Combustion Process ◽  
Coarse Particles ◽  
Biomass Smoke ◽  
Smoke Particles ◽  
Air Emission ◽  
Entire Duration ◽  
Diffusion Properties

Particle size distribution in biomass smoke was observed for different burning phases, including flaming and smouldering, during the combustion of nine common Australian vegetation representatives. Smoke particles generated during the smouldering phase of combustions were found to be coarser as compared to flaming aerosols for all hard species. In contrast, for leafy species, this trend was inversed. In addition, the combustion process was investigated over the entire duration of burning by acquiring data with one second time resolution for all nine species. Particles were separately characterised in two categories: fine particles with dominating diffusion properties measurable with diffusion-based instruments (Dp < 200 nm), and coarse particles with dominating inertia (Dp > 200 nm). It was found that fine particles contribute to more than 90 percent of the total fresh smoke particles for all investigated species.

Dynamic characteristics of squeeze-type mount using magnetorheological fluid

2005 ◽  
Vol 219 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Y K Ahn ◽  
J-Y Ha ◽  
Y-H Kim ◽  
B-S Yang ◽  
M Ahmadian ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Analysis ◽  
Vibration Isolation ◽  
Dynamic Behaviour ◽  
Electrical Current ◽  
Magnetorheological Fluid ◽  
Test Set ◽  
Mr Fluid ◽  
Set Up ◽  
Stiffness And Damping

This paper presents an analytical and experimental analysis of the characteristics of a squeeze-type magnetorheological (MR) mount which can be used for various vibration isolation areas. The concept of the squeeze-type mount and details of the design of a squeeze-type MR mount are discussed. These are followed by a detailed description of the test set-up for evaluating the dynamic behaviour of the mount. A series of tests was conducted on the prototype mount built for this study, in order to characterize the changes occurring as a result of changing electrical current to the mount. The results of this study show that increasing electrical current to the mount, which increases the yield stress of the MR fluid, will result in an increase in both stiffness and damping of the mount. The results also show that the mount hysteresis increases with increase in current to the MR fluid, causing changes in stiffness and damping at different input frequencies.

scholarly journals Ambient Particulate Matter Air Pollution in Mpererwe District, Kampala, Uganda: A Pilot Study

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Stephan Schwander ◽  
Clement D. Okello ◽  
Juergen Freers ◽  
Judith C. Chow ◽  
John G. Watson ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Pilot Study ◽  
Fine Particles ◽  
Airborne Particulate Matter ◽  
Personal Exposure ◽  
Ambient Air ◽  
Combustion Products ◽  
Carbonaceous Aerosol ◽  
Coarse Particles

Air quality in Kampala, the capital of Uganda, has deteriorated significantly in the past two decades. We made spot measurements in Mpererwe district for airborne particulate matter PM2.5(fine particles) and coarse particles. PM was collected on Teflon-membrane filters and analyzed for mass, 51 elements, 3 anions, and 5 cations. Both fine and coarse particle concentrations were above 100 µg/m3in all the samples collected. Markers for crustal/soil (e.g., Si and Al) were the most abundant in the PM2.5fraction, followed by primary combustion products from biomass burning and incinerator emissions (e.g., K and Cl). Over 90% of the measured PM2.5mass can be explained by crustal species (41% and 59%) and carbonaceous aerosol (33%–55%). Crustal elements dominated the coarse particles collected from Kampala. The results of this pilot study are indicative of unhealthy air and suggest that exposure to ambient air in Kampala may increase the burden of environmentally induced cardiovascular, metabolic, and respiratory diseases including infections. Greater awareness and more extensive research are required to confirm our findings, to identify personal exposure and pollution sources, and to develop air quality management plans and policies to protect public health.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2014 ◽  
Vol 14 (5) ◽  
pp. 2233-2244 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractionated particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume-weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban North America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, as well as nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium, and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of the HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer, while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal, with two peaks in the bins of < 0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

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