Solid Bottom Research Articles

Assessment of light absorption within highly scattering bottom sea ice from under‐ice light measurements: Implications for Arctic ice algae primary production

Primary production estimates of ice algae within the bottommost layers of the Arctic ice cover are commonly derived using irradiance measurements taken immediately below the solid ice bottom. However, radiation absorbed by ice algae is significantly affected by the high‐scattering sea ice environment they are embedded within because scattering increases the pathlength traveled by photons and therefore the probability of photon encounters with algal cells. Failing to account for this enhanced absorption may considerably affect estimates of the timing and magnitude of ice algal production. To demonstrate the effect of scattering and attenuation, multipliers for absorption amplification (Φ) and layer average opacity (χ) were derived from observations of chlorophyll a concentration and the vertical attenuation coefficient over the bottom 2.5 cm of landfast sea ice. Φ reached values over 19 at low chlorophyll a, but became < 2 at high biomass levels, whereas χ became larger as biomass levels increased. Using Φ to construct an apparent photosynthesis vs. irradiance relationship showed that light limitation is greatly reduced relative to the case where scattering is not considered. This highlights an important interaction not previously noted for ice algal production in their high‐scattering environment. Knowledge of this absorption amplification can help explain ice algal phenology during the spring bloom and will improve ice algal production estimates and model parameterizations.

Identifying the Advantages of Using Municipal Solid Waste Bottom Ash in Combination with Rice Husk and Bamboo Biochar Mixtures as Soil Modifiers: Enhancement of the Release of Polyphenols from a Carbon Matrix

Incineration is one of the most popular options used to treat waste in highly populated developed countries. It is crucial to find an environmentally acceptable alternative for the disposal of municipal solid waste incineration bottom ash (MSWIBA). The main objective of this study is therefore to investigate the value of biochar and MSWIBA mixtures as soil modifiers and determine their effects on plant growth, root yield, and the dry biomass weight of corn (Zea mays L.). Two different feedstocks (rice husks and bamboo) were used to produce the biochars applied in this test. Water-soluble phenol-based macromolecules (polyphenols) from woody raw materials would be enhanced to leach out metals under an alkali environment. In addition, extraction of polyphenols from a BA-mixed matrix and Z. mays L. dry biomass was performed. Polyphenol content was shown to increase when fertilizer was applied, inhibiting plant growth, root yield, and plant biomass dry weight. After applying fertilizer, the polyphenol content increased to 45-55 mg=L. Without the application fertilizer, however, the polyphenol content was 5-25 mg=L. A combination of BA and biochars added to soil seems to have the potential to improve the growth and yield of corn without the application of any chemical fertilizer. In addition, the BA-enhanced biochar degradation could be achieved through the results of this study. DOI: 10.1061/(ASCE)HZ.2153-5515.0000189. © 2013 American Society of Civil Engineers. CE Database subject headings: Bottom ash; Solid wastes; Mixtures; Recycling; Soil treatment. Author keywords: Municipal solid waste bottom ash; Incineration; Biochar; Polyphenols.

On the effect of “Dead Water” in a stratified liquid on a solid bottom

The influence of a solid bottom on the “dead water” effect for gravitational and fluctuation waves (having the same dispersion law), as well as capillary waves, is calculated in a linear statement. It is found that the presence of a solid bottom aggravates the dead water effect.

On the structure of waves at the charged interface between two viscous liquids at the solid bottom

The solutions to the equation describing the wave motion in a bilayer system of immiscible liquids are obtained in the first order of the theory of approximations. The hydrodynamic potentials, current functions, generatrix of the shape, and electrostatic potential of the charged interface between two viscous liquids, one of which conducts current and the other being a dielectric, on the solid bottom, are determined. It is shown that in the case when the density of the upper medium is three or more orders of magnitude lower than that of the lower liquid or when the kinematic viscosity of the upper medium is negligibly low as compared to that of the lower medium, the effect of the upper medium on the flow of the liquid in the lower medium is negligibly small. The structure of the wave motion generated by the interface between the two media is analyzed.

Groundwater seepage stimulates the growth of aquatic macrophytes

Summary1. The impact of groundwater seepage on the growth of submerged macrophytes was investigated in experiments on the isoetid Littorella uniflora and the elodeid Myriophyllum alterniflorum both in the laboratory and in the field. Isoetids rely mostly on sediment‐derived CO2 and nutrients via root uptake, whereas elodeids acquire their inorganic carbon and nutrients from the water column. We thus hypothesised that L. uniflora would respond positively to seeping ground water as it should improve both CO2 and nutrient supply.2. Laboratory experiments were conducted by percolating vegetated cores containing natural sediment or technical sand with artificial ground water of high CO2 concentrations and with either high or low levels of nutrients. Field experiments were conducted in the oligotrophic Lake Hampen, Denmark, with custom‐built seepage‐growth chambers that permitted a near‐natural flow‐through of seeping ground water. Chambers with a solid bottom, and thus no flow‐through of seeping ground water, served as controls in both laboratory and field experiments. In the field, seepage chambers were installed at a site with relatively high seepage fluxes (ground water from forest catchment), at a site with much lower seepage fluxes but with higher nutrient concentrations (ground water from agricultural catchment) and at a reference site with no net discharge or recharge of ground water.3. Positive growth responses were observed in the field at transects with high groundwater discharge compared to the control chambers with no seepage. No growth response was observed at the reference transect with low or alternating direction of groundwater seepage. The growth rates of L. uniflora in the field were significantly higher in seepage treatments compared to control treatments, and final plant mass was up to 70% higher than that for plants where seepage was excluded. In areas with high groundwater discharge, a strong positive correlation was found between groundwater seepage fluxes, growth rates, and final plant mass for L. uniflora, while there was no such relationship at the reference transect. The growth of M. alterniflorum was also significantly affected by groundwater seepage, but to a lesser degree than L. uniflora. Laboratory experiments generally showed the same trend for both L. uniflora and M. alterniflorum, and the positive influence of seeping ground water was apparently related to increased inorganic carbon supply and, to a lesser degree, improved nutrient availability.4. Groundwater discharge results in enhanced growth of isoetids and to some extent elodeids inhabiting a groundwater‐fed softwater lake. We propose that the shallow dense vegetation present where most of the discharge takes place acts as a biological filter that retains nutrients that otherwise would end up in the water column and could result in increased algal growth.

Co-gasification of municipal solid waste and material recovery in a large-scale gasification and melting system

This study evaluates the effects of co-gasification of municipal solid waste with and without the municipal solid waste bottom ash using two large-scale commercial operation plants. From the viewpoint of operation data, there is no significant difference between municipal solid waste treatment with and without the bottom ash. The carbon conversion ratios are as high as 91.7% and 95.3%, respectively and this leads to significantly low PCDD/DFs yields via complete syngas combustion. The gross power generation efficiencies are 18.9% with the bottom ash and 23.0% without municipal solid waste bottom ash, respectively. The effects of the equivalence ratio are also evaluated. With the equivalence ratio increasing, carbon monoxide concentration is decreased, and carbon dioxide and the syngas temperature (top gas temperature) are increased. The carbon conversion ratio is also increased. These tendencies are seen in both modes.Co-gasification using the gasification and melting system (Direct Melting System) has a possibility to recover materials effectively. More than 90% of chlorine is distributed in fly ash. Low-boiling-point heavy metals, such as lead and zinc, are distributed in fly ash at rates of 95.2% and 92.0%, respectively. Most of high-boiling-point heavy metals, such as iron and copper, are distributed in metal. It is also clarified that slag is stable and contains few harmful heavy metals such as lead. Compared with the conventional waste management framework, 85% of the final landfill amount reduction is achieved by co-gasification of municipal solid waste with bottom ash and incombustible residues. These results indicate that the combined production of slag with co-gasification of municipal solid waste with the bottom ash constitutes an ideal approach to environmental conservation and resource recycling.

Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with adjustable resonance frequencies have been designed—one with a solid bottom and one with membrane on the bottom. The resonance frequencies of the resonators were matched to the complementing piezoelectric harvesters during harvesting. The aim of the presented work is a feasibility study on using packaged piezoelectric energy harvesters with Helmholtz resonators for airflow energy harvesting. The maximum energy we were able to obtain was 42.2 µW at 20 m s−1.

Influence of Organic Matters on the Elution of Chroline in Municipal Solid Waste Bottom Ash

Influence of Organic Matters on the Elution of Chroline in Municipal Solid Waste Bottom Ash

On calculating the oscillations of a viscous liquid layer over a solid spherical core in terms of the boundary layer theory

The theory of a boundary layer near the periodically oscillating free surface of a spherical viscous liquid layer over a solid core (bottom) is modified. Two boundary layers are considered to adequately describe a liquid viscous flow in the system: one at the free surface of the liquid and the other at the solid bottom. The thicknesses of the boundary layers are estimated, which provide any given discrepancy between an exact solution to the model problem and a solution obtained in the small viscosity approximation. Taking into account the boundary layer near the solid bottom is shown to be significant only for lower oscillation modes. For higher modes, the flow near the core can be considered potential. In the case of lower modes and shallow liquid, the surface and bottom boundary layers overlap and an eddy flow occupies the entire volume of the liquid.

An Improved Open Microfluidic Flow Cell for Measuring Solute Adsorption to Monolayers

We earlier described an apparatus and optical method that permit quantitative measurement of the adsorption of a solute to a gas-liquid interface [K.C. Hoang, D. Malakhov, W.E. Momsen and H.L. Brockman (2006) Anal. Chem. 78, 1657-1664]. The interface may or may not support a protein, lipid or other monolayer. A potential limitation to such a flow cell, being probed optically through the monolayer, is concomitant solute adsorption to the solid trough bottom, which is parallel to but displaced from the monolayer being studied. To circumvent this unwanted adsorption we introduced a flowing sucrose solution under the flowing solute solution that supports the monolayer. In this way solute is prevented from reaching the trough bottom and any solute which might adsorb to or diffuse through the sucrose-solute solution interface is rapidly moved from the optical path by flow to the trough drain. Eliminating the need to chemically modify the trough bottom by introducing a sucrose layer allows trough dimensions to be reduced, allows robust and fully automated cleaning between experiments and improves reproducibility of solute adsorption measurements. An additional feature of the new configuration is control of the thickness of the solute solution layer, which conserves reagents and enhances the sensitivity of solute adsorption measurements. The apparatus was used to characterize the interaction of a fluorescent protein antigen with an antibody monolayer and to the initial rate of adsorption of bovine serum albumin to phospholipid-diacylglycerol monolayers of differing lipid compositions but approximately constant surface pressure. Supported by USPHS HL-49180 and the Hormel Foundation.

Solvability of the free boundary value problem of the Navier-Stokes equations

In this paper, we study the incompressible Navier-Stokes equations on a moving domain in $\mathbb{R}^{3}$ of finite depth, bounded above by the free surface and bounded below by a solid flat bottom. We prove that there exists a unique, global-in-time solution to the problem provided that the initial velocity field and the initial profile of the boundary are sufficiently small in Sobolev spaces.

Nonlinear interaction of internal and surface gravity waves in a two-layer fluid with free surface

A new nonlinear model of the propagation of wave packets in the system “liquid layer with solid bottom–liquid layer with free surface” is considered. With the use of the method of multiple-scale expansions, the first three linear approximations of the nonlinear problem are obtained. Solutions of problem of the first approximation are constructed and analyzed in detail. It is shown that there exist internal and surface components of the wave field, and their interaction is analyzed.

Rotation of a weakly conducting liquid in crossed electric and magnetic fields

Two problems of rotation of a liquid in crossed electric and magnetic fields are formulated and solved as applied to the study of the principles of the interaction between external electric and magnetic fields and weakly conducting water type liquids (running water, sea water) and their solutions ((10-2-102) 1 m-1). In the first problem, the liquid is contained in the gap of a vertical cylindrical capacitor, while the second problem deals with the liquid in a rectangular cuvette, two lateral vertical walls of which are used as armatures of a plane-parallel capacitor. In either case, a constant vertical magnetic field is applied to the liquid, while a constant voltage is maintained between the armatures of the capacitor. Three sets of boundary conditions are considered in the first case: the capacitor is of infinite length (throughout the height); the capacitor is confined by a solid bottom from below and has a free boundary with the atmosphere at the top; the capacitor has closed ends and the liquid occupies the entire capacitor gap. The results can be used in various practical applications, for example, for pumping of weakly conducting liquids.

Three-dimensional numerical simulation of thermocapillary flow in a shallow cylindrical pool

In order to understand the characteristics of thermocapillary flow, we conducted a series of unsteady three-dimensional (3D) numerical simulations of thermocapillary flow for fluids with Prandtl number Pr = 0.011 and 1.0 in a shallow cylindrical pool with an azimuthal temperature non-uniform, an adiabatic solid bottom and free surface. The simulation results indicate that thermocapillary flow is steady 3D flow at the small temperature non-uniform. When temperature non-uniform exceeds some critical value, the flow will undergo a transition to 3D oscillatory flow, which is characterized by traveling oscillatory wave reversely along the flow direction on the free surface and diffusing to two sides at the same time. Further, the critical conditions for the flow transition are determined.

Instability development on the charged free surface of a horizontal liquid layer with thermal convection

The instability of the charged free surface of a horizontal liquid layer heated from the solid bottom against excess electric charge is studied theoretically for the case in which this type of instability is combined with thermal-convective instability. The structure of the total spectrum of unstable wave flows and physical parameters influencing the structure of the spectrum are determined.

Modelling propeller and rudder induced forces acting on deep drafted vessels in muddy navigation areas

To assess the navigability of deep drafted vessels in muddy navigation areas a mathematical model has been built that takes into account the characteristics of the mud layer. This was achieved with the introduction of a fluidization parameter which determines the corresponding hydrodynamically equivalent depth above a solid bottom. As a result, the under keel clearance dependency of a given mathematical manoeuvring model can be reformulated in such way that the effect of any realistic muddy condition is included. In this article the modelling of the propeller and rudder induced forces and the implementation possibilities of the model will be discussed. It is concluded that the mathematical model, initially formulated for a 6,000 TEU container carrier, provides reliable predictions of the behaviour of larger container carriers and even fuller deep drafted ships.

Prediction of the forces acting on container carriers in muddy navigation areas using a fluidization parameter

To assess the safety of navigation in muddy areas, a comprehensive captive manoeuvring model test program was executed. Based on the results of this experimental program, a four-quadrant manoeuvring model was built with a separate set of coefficients for each combination of under-keel clearance and mud layer characteristics. The disadvantage of this model is that only conditions corresponding with the experimental ones can be simulated. A more consolidated mathematical model was needed. This was achieved with the introduction of a fluidization parameter that determines the corresponding hydrodynamically equivalent depth above a solid bottom. As a result, the under-keel clearance dependency of a given mathematical manoeuvring model can be reformulated in such way that the effect of any realistic muddy condition is included. In this article, the modelling of the hull forces, the propeller thrust and torque, and the forces acting on the rudder will be discussed.

Flow pattern due to capillary-gravitational waves in a charged layer of a viscous conducting liquid on a solid support

Analytical solutions for the time evolution of a capillary-gravitational wave in a charged layer of a viscous conducting liquid on a solid support are found. It is shown that the velocity field eddy component of the wave-induced liquid flow arises not only near the free surface of the liquid, but also at the solid bottom. The ratio between the amplitudes of these eddy components depends on the relationship between the thickness of the layer and the wavelength. If the wavelength far exceeds the thickness, the eddy flow amplitude near the bottom exceeds that near the free surface and the eddy flow occupies the whole volume of the liquid.

Engineering and Environmental Characterization of Municipal Solid Waste Bottom Ash as an Aggregate Substitute Utilized for Asphalt Concrete

The preferred management option for the municipal solid waste bottom ash (MSW-BA) around the world is utilization rather than landfilling, but the current environmental quality criteria for bottom ash to be utilized in bulk quantities are rather strict. The purpose of this paper is to analyze the physical and environmental properties of asphalt mixtures containing different amounts of MSW-BA used as an aggregate substitute. The Marshall mix design method, water sensitivity, and wheel track rutting tests were conducted on MSW-BA asphalt mixtures to evaluate the engineering properties of the mix. Leach tests were performed to measure the concentration of heavy metals. The MSW-BA asphalt mixture had relatively lower rutting resistance when compared with the conventional one. The results of the water sensitivity test showed that the MSW-BA asphalt mixtures had a lower tensile strength ratio compared with the conventional asphalt mixtures. It is recommended that the use of the MSW-BA ash in asphalt concrete mixtures be limited to be 20% ash, by total weight of the mix, in binder or base course and 10% in surface mix to ensure satisfactory pavement performance. The test results obtained from the toxicity characteristic leaching procedure testing indicated that, after being mixed with asphalt binder, the concentration of heavy metals and the levels of toxicity were significantly reduced. The concentrations of MSW-BA all along were below regulation limits.

Theoretical and numerical investigations of the acoustic field excited by submarine explosion

This paper simulates and analyzes numerically the dispersion characteristics of the waves propagating in the shallow-ocean overlying a semi-infinite elastic solid. The analytical solution of the acoustic field in the shallow-ocean, excited by an explosive point source in the solid bottom, is derived by using the theories for sound propagation in liquid and solid. The time-domain waveforms of transient acoustic field are simulated with the above analytical solution. The dispersion characteristics of the transient acoustic field are analyzed by using the smoothed pseudo Wigner-Ville distribution.