Assessment of metal contamination in surface sediments of Jiaozhou Bay, Qingdao, China

An assessment of metal contamination in surface sediments of the Jiaozhou Bay, Qingdao, one of the rapidly developing coastal economic zones in China, is provided. Sediments were collected from 10 stations and a total of 15 heavy metals were analyzed. Concentrations of metals show significant variability and range from 210 to 620 ppm for Ti, 2.7 to 23 ppm for Ni, 4.2 to 28 ppm for Cu, 5.2 to 18 ppm for Pb, 12 to 58 ppm for Zn, 0.03 to 0.11 ppm for Cd, 5 to 51 ppm for Cr, 1.5 to 9.9 ppm for Co, 5.3 to 19 ppm for As, 12 to 32 ppm for Se, and 19 to 97 ppm for Sr. Based on concentration relationships and enrichment factor (EF) analyses, the results indicate that sediment grain size and organic matter played important roles in controlling the distribution of the heavy metals in surface sediments of the Jiaozhou Bay. The study shows that the sediment of the Jiaozhou Bay has been contaminated by heavy metals to various degrees, with prominent arsenic contributing the most to the contamination. The analysis suggests that the major sources of metal contamination in the Jiaozhou Bay are land-based anthropogenic ones, such as discharge of industrial waste water and municipal sewage and run-off. Notably, the elevated heavy metal concentrations of the Jiaozhou Bay sediments could have a significant impact on the bay's ecosystem. With the rapid economic development and urbanization around the Jiaozhou Bay, coastal management and pollution control should focus on these contaminant sources, as well as provide ongoing monitoring studies of heavy metal contamination within the bay.

Characters of Surface Deformation and Surface Wave in Thermal Capillary Convection

In the field of fluid mechanics, free surface phenomena is one of the most important physical processes. In the present research work, the surface deformation and surface wave caused by temperature difference of sidewalls in a rectangular cavity have been investigated. The horizontal cross-section of the container is 52 mmx42 mm, and there is a silicon oil layer of height 3.5 mm in the experimental cavity. Temperature difference between the two side walls of the cavity is increased gradually, and the flow on the liquid layer will develop from stable convection to un-stable convection. An optical diagnostic system consisting of a modified Michelson interferometer and image processor has been developed for study of the surface deformation and surface wave of thermal capillary convection. The Fourier transformation method is used to interferometer fringe analysis. The quantitative results of surface deformation and surface wave have been calculated from a serial of the interference fringe patterns.The characters of surface deformation and surface wave have been obtained. They are related with temperature gradient and surface tension. Surface deformation is fluctuant with time, which shows the character of surface wave. The cycle period of the wave is 4.8 s, and the amplitudes are from 0 to 0.55 mu m. The phase of the wave near the cool side of the cavity is opposite and correlative to that near the hot side. The present experiment proves that the surface wave of thermal capillary convection exists on liquid free surface, and it is wrapped in surface deformation.

Combined effect of surface tension, gravity and van der Waals force induced by a non-contact probe tip on the shape of liquid surface

Aiming at understanding how a liquid film on a substrate affects the atomic force microscopic image in experiments, we present an analytical representation of the shape of liquid surface under van der Waals interaction induced by a non-contact probe tip. The analytical expression shows good consistence with the corresponding numerical results. According to the expression, we find that the vertical scale of the liquid dome is mainly governed by a combination of van der Waals force, surface tension and probe tip radius, and is weekly related to gravity. However, its horizontal extension is determined by the capillary length.

Effects of Surface Microtopology and Membrane Stiffness on Kinetics of Selectin/Ligand interactions by a Modified BFP

More and more evidences come out to support that the functionality of adhesion molecules are influenced by the surface microtopology of cell carrier or substrate. Adhesive molecules usually express on the microvilli of a cell, providing a well-defined spatial configuration to mediate the adhesions to the counterpart molecules on the apposed surface.

Assessment of Microscale Test Methods of Peeling and Splitting along Surface of Thin-Film/Substrates

Peel test methods are assessed through being applied to a peeling analysis of the ductile film/ceramic substrate system. Through computing the fracture work of the system using the either beam bend model (BB model) or the general plane analysis model (GPA model), surprisingly, a big difference between both model results is found. Although the BB model can capture the plastic dissipation phenomenon for the ductile film case as the GPA model can, it is much sensitive to the choice of the peeling criterion parameters, and it overestimates the plastic bending effect unable to capture crack tip constraint plasticity. In view of the difficulty of measuring interfacial toughness using peel test method when film is the ductile material, a new test method, split test, is recommended and analyzed using the GPA model. The prediction is applied to a wedge-loaded experiment for Al-alloy double-cantilever beam in literature.

Experimental Study of Surface Deformation and Flow Pattern on Buoyant-Thermocapillary Convection

Free surface deformation is one of the most important physical phenomena in fluids with free surface. In the present paper, convection and surface deformation caused by thermocapillary effect in a rectangular cavity were investigated. In ground experiments, the convection was also affected by gravity. The cavity has a horizontal cross section of 52mm×42mm and the thikkness of the liquid layer is 4mm. Temperature difference between two sides of the liquid layer was increased gradually, and the flow in liquid layer will develop from steady to unstable convection. An optical diagnostic system consisting of a revised Michelson interferometer with image processor was developed to study fluid surface deformation in convection, and the displacements of free surface oscillation were determined. PIV technique was adopted to observe the evolution of flow pattern, and the velocity fields were obtained quantitatively. The present experiments demonstrate that surface deformation is quite distinct in buoyant-thermocapillary convection. in order to understand the mechanism of buoyant-thermocapillary convection, not only the hydrothermal wave instability but also the surface wave instability should be discussed.

The Surface- And Size-Dependent Elastic Moduli Of Nanostructures

A theoretical model is presented to investigate the size-dependent elastic moduli of nanostructures with the effects of the surface relaxation surface energy taken into consideration. At nanoscale, due to the large ratios of the surface-to-volume, the surface effects, which include surface relaxation surface energy, etc., can play important roles. Thus, the elastic moduli of nanostructures become surface- and size-dependent. In the research, the three-dimensional continuum model of the nanofilm with the surface effects is investigated. The analytical expressions of five nonzero elastic moduli of the nanofilm are derived, and then the dependence of the elastic moduli is discussed on the surface effects and the characteristic dimensions of nanofilms.

Competitive adsorption of collagen and bovine serum albumin - effect of the surface wettability

The competitive adsorption of collagen and bovine serum albumin (BSA) on surfaces with varied wettability was investigated with imaging ellipsometry, and ellipsometry. Silane modified silicon surfaces were used as substrates. The results showed that surface wettability had an important effect on protein competitive adsorption. With the decrease of surface wettability, the adsorption of collagen from the mixture solution of collagen and BSA decreased, while the adsorption of BSA increased. (C) 2003 Elsevier B.V. All rights reserved.

Atomistic investigation of the effects of temperature and surface roughness on diffusion bonding between Cu and Al

Molecular dynamics (MD) simulations are carried out to analyze the diffusion bonding at Cu/Al interfaces. The results indicate that the thickness of the interfacial layer is temperature-dependent, with higher temperatures yielding larger thicknesses. At temperatures below 750 K, the interface thickness is found to increase in a stepwise manner as a function of time. At temperatures above 750 K, the thickness increases rapidly and smoothly. When surface roughness is present, the bonding process consists of three stages. In the first stage, surfaces deform under stress, resulting in increased contact areas. The second stage involves significant plastic deformation at the interface as temperature increases, resulting in the disappearance of interstices and full contact of the surface pair. The last stage entails the diffusion of atoms under constant temperature. The bonded specimens show tensile strengths reaching 88% of the ideal Cu/Al contact strength. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The Influence of Viscosity and Surface Tension on Atomization of Water/Methanol and Diesel Emulsions

This paper shows the result of experimental studies of the influence of viscosities, surface tensions on atomization characteristics of water/methanol and diesel emulsions. Three emulsifying agents Y01, Y02 and Y03, with viscosity of 1.32 ～ 1.5 Pa·s and HLB values of 5.36, 4.83 and 4.51 respectively was produced by Span 80 and Tween 60. In the W/O emulsions, the aqueous phase is between 10% and 50%; the agent concentration added is 0.8 ～ 8.0%. The viscosity of the emulsions is 0.003 ～ 0.02 Pa·s, and the surface tension is 0.04 ～ 0.1 N/m. The types and concentrations of agents and the aqueous phase ( < 50%) significantly influence the viscosity of the emulsions and the Sauter Mean Diameter, measured by Malvern Particle Analyzer SERIES 2600.

The surface- and size-dependent elastic moduli of nanostructures

A theoretical model is presented to investigate the size-dependent elastic moduli of nanostructures with the effects of the surface relaxation surface energy taken into consideration. At nanoscale, due to the large ratios of the surface-to-volume, the surface effects, which include surface relaxation surface energy, etc., can play important roles. Thus, the elastic moduli of nanostructures become surface- and size-dependent. In the research, the three-dimensional continuum model of the nanofilm with the surface effects is investigated. The analytical expressions of five nonzero elastic moduli of the nanofilm are derived, and then the dependence of the elastic moduli is discussed on the surface effects and the characteristic dimensions of nanofilms.

Coupling between elytra of some beetles: Mechanism, forces and effect of surface texture

Lightweight materials, structures and coupling mechanisms are very important for realizing advanced flight vehicles. Here, we obtained the geometric structures and morphologies of the elytra of beetles and ascertained its coupling zone by using the histological section technique and SEM. We set up a three-dimensional motion observing system to monitor the opening and closing behaviour of elytra in beetles and to determine the motion mechanism. We constructed a force measuring system to measure the coupling forces between elytra. The results show that elytra open and close by rotating about a single axle, where the coupling forces may be as high as 160 times its own bodyweight, the elytra coupling with the tenon and mortise mechanism, surface texture and opening angle between elytra heavily influence the coupling forces. These results may provide insights into the design mechanism and structure for future vehicles of flight.

Biotransfer of persistent organic pollutants from a large site in China used for the disassembly of electronic and electrical waste

Samples of groundwater, river water, river sediment, paddy soil, rice seeds, hen eggs, fish, umbilical cord blood, and newborn meconium were collected from October 2002 to October 2003 near a large site in China used for the disassembly of obsolete transformers and other electronic or electrical waste. Six indicator PCB congeners, three non-ortho dioxin-like PCB congeners, and six organochlorine pesticides were determined in the samples by GC with electron capture detector. The results demonstrated that the local environment and edible foods had been seriously polluted by toxic PCBs and organochlorine pesticides. The actual daily intakes (ADIs) of these pollutants were estimated for local residents living in the area. The intake data showed that the contents of PCBs in these local residents were substantial, as the ADI estimates greatly exceed the reference doses set by the World Health Organization and the United States Agency for Toxic Substances and Disease Registry. The presence of the indicator PCB congeners in the cord blood and the meconium samples, as well as significant correlations (r(2) > 0.80, p < 0.05) between these levels, suggests a potential biotransfer of these indicators from mothers to their newborns. This preliminary study showed that obsolete transformers and other electronic or electrical waste can be an important source for the emission of persistent organic pollutants into the local environment, such as through leakage, evaporation, runoff, and leaching. Contamination from this source appears to have reached the level considered to be a serious threat to environmental and human health around the disassembly site.