Influence Of Water Environment Research Articles

Space Construction of Meihua Fortress Coastal Defense Settlement in Fujian in Ming Dynasty Under the Influence of Water Environment

Space Construction of Meihua Fortress Coastal Defense Settlement in Fujian in Ming Dynasty Under the Influence of Water Environment

Influence of water environment on paint removal and the selection criteria of laser parameters

Laser paint removal in a water environment does not diffuse ablation pollution products into air. Characteristics of water, such as high specific heat and heat flux, generate different effects of the laser paint removal than in an air environment. In this study, the effects of air and water environments on the mechanism and effect of laser paint removal are analyzed and compared experimentally and theoretically. In air, thermodynamic ablation causes removal of paint, whereas in water, stress coupled with plasma shock waves cause tear and splash removal of paint layers after fracture and damage. Fracture and pressure thresholds of the paint and substrate, respectively, indicate the optimum energy density range for laser paint removal in water, providing a reference for engineering applications.

Underwater Laser Welding of Pure Ti: Oxidation and Hardening Behaviors

The local dry underwater laser welding of cp-Ti, with air as an assisting gas, and in a simulated underwater facility was researched, aiming to find a viable and economical method for repairing titanium alloy underwater vehicles in situ in the future. Macro-morphology, microstructure, and microhardness of the cp-Ti laser welds, as a function of welding parameters, were experimentally characterized. The oxidation and hardening behaviors of the welds were also studied in detail. It was found that local dry underwater laser welding with air assisted blowing is feasible for obtaining a complete and glossy weld. Compared with a weld in atmosphere, the cross-section morphology of the weld was almost unaffected by the special underwater welding environment. The weld presented a three-layer structure. High temperature and high pressure water vapor and local blowing are the direct causes of weld oxidation, and porosity defects further aggravate the oxidation behavior. The oxygen-enriched areas were mostly concentrated in the top area of the weld center and near the fusion zone, because of the higher number of grain boundaries and phase boundaries. In addition, the partial oxidation caused by local blowing and water vapor atmosphere, and also the higher strength acicular martensite caused by the rapid cooling effect of water, will lead to weld hardening. However, adjusting the welding process parameters, such as increasing the welding speed, can effectively reduce the microhardness of the weld. Our findings can provide an understanding of the influence of water environment on underwater laser welding, and verify the feasibility of a more economical method for the in situ repair of large underwater facilities.

Influence of water environment on wet underwater manual self-propagating high-temperature synthesis welding

Manual SHS welding is a kind of quick welding technique for emergency maintenance. In this paper, influence of water environment on the welding quality and performance has been studied. Results showed that water had significant influence on the welding. The visibility for welding was significantly reduced, which increased the difficulty of welding operation. The brightness of weld pool in wet welding were darker than that in land welding and the shape of combusting arc was compressed significantly. The highest temperature of weld pool in underwater welding was obviously lower than that in land welding, and the cooling rate of HAZ was faster. The welding quality was worsen remarkably by water. The weld seam was irregular and discontinuous, and a lot of gas pores and inclusions existed in the weld metal. And the amount of deposited metal was obviously reduced. Microstructure analysis showed that the matrix of weld metal was α-Cu solid solution, with Fe-rich second phase distributing orderly on it, which was same as that of land welding. But water caused many apparent inclusions and pores in the weld metal. The tensile strength of weld joints for underwater welding was obviously lower than that of weld joints for land welding.

Research and Application of Underwater Wet Welding Technology

Underwater wet welding has the characteristics of simple equipment and flexible operation. This paper introduces the basic principle of underwater wet welding, focusing on wet welding by welding materials, welding methods and the influence of water environment.

Structural Response of the Metro Tunnel under Local Dynamic Water Environment in Loess Strata

The reasons, prevention, and control of loess disaster are of great concern in practice. In recent years, Xi’an city, China, has taken the leadership in large-scale construction of subway lines in the loess strata. To study the structural response of the tunnel in loess region under local hydrodynamic environment, an experimental testing in 1g as well as a numerical simulation were performed, in which the achieved results were verified and were found to be in good agreement. Furthermore, the results showed that when the water outlet point is above the lining, the overall stress of the lining is “peanut shell,” as the water pressure of the outlet point decreases, the tensile stress of the top and bottom of the lining increases, while the compressive stress on both sides decreases; the channel form of the flow to the lining changes with the variation of the position of the water outlet point. It is worth mentioning that in the process of water gushing, the closer to the water source, the greater surface subsidence is, and there is a positive correlation between water pressure and surface subsidence. This study is of significant benchmark for the construction, maintenance, and prevention of tunnel in loess strata under the influence of water environment.

Motion dynamics of dropped cylindrical objects in flows after water entry

The investigation on the phenomena of objects falling into water is of great significance to protect the underwater equipment in offshore industry. The dropped objects into water are found to be affected by many factors such as drop angle, drop height, its physical properties, etc. This study mainly focuses on considering the influence of water environment (currents and waves) on the dropped cylindrical objects after water entry by modifying the three-dimensional (3D) theory (Xiang et al., 2017) and integrating the effects of currents and waves into DROBS. Current is added as a uniform steady flow. The waves will bring a non-uniform unsteady flow field based on 3D airy wave theory. Thus, analytic expressions for the hydrodynamic forces and moments are modified by adding inertial terms from waves. The drag forces are revised by rewriting the relative cylinder to water particle velocities. By the comparison between the simulated trajectory of the cylinder under currents and corresponding recorded trajectory in the experiments, the simulations agree well with the experimental data. The effects of speed and heading of the currents associated with the cylinder's initial speed are studied in DROBS and found to influence the trajectory and motions of the dropped cylindrical objects. Also, the dynamics of a dropped cylinder moving in the field of a progressive regular wave is investigated for different wave amplitudes, wave frequencies, and for different ratios of cylinder to water mass density.

Hydrophobic core structure of macromomycin – the apoprotein of the antitumor antibiotic auromomycin – fuzzy oil drop model applied

Abstract The fuzzy oil drop model was applied to analyze the structure of macromomycin, the apoprotein of the antitumor antibiotic auromomycin, revealing the differentiation of β-structural fragments present in β-sandwich. The seven-stranded antiparallel β-barrel and two antiparallel β-sheet ribbons represent the highly ordered geometry of the structure. However, participation in hydrophobic core formation appears different. The structure of the complete domain represents the status of the irregular hydrophobic core; however, some β-structural fragments appear to represent the hydrophobicity density distribution accordant with the idealized distribution of hydrophobicity as expected using the fuzzy oil drop model. Four β-structural fragments generating one common layer appear to be unstable in respect to the general structure of the hydrophobic core. This area is expected to be more flexible than other parts of the molecule. The protein binds the ligand – chromophore, two 2-methyl-2,4-pentanediol – in a well-defined cleft. The presence of this cleft makes the general structure of the hydrophobic core irregular (as it may be interpreted using the fuzzy oil drop model). Two short loops generated by two SS bonds fit very well to the general distribution of hydrophobicity density as expected for the model. No information about the potential amyloidogenic character of this protein is given in the literature; however, the specificity of the hydrophobicity distribution profile is found to be highly similar to the one observed in transthyretin (Banach M, Konieczny L, Roterman I. The fuzzy oil drop model, based on hydrophobicity density distribution, generalizes the influence of water environment on protein structure and function. J Theor Biol 2014;359:6–17), suggesting a possible tendency to turn to the amyloid form. A detailed analysis of macromomycin will be given, and a comparable analysis with other proteins of β-sandwich or β-barrel will be presented.

The fuzzy oil drop model, based on hydrophobicity density distribution, generalizes the influence of water environment on protein structure and function

In this paper we show that the fuzzy oil drop model represents a general framework for describing the generation of hydrophobic cores in proteins and thus provides insight into the influence of the water environment upon protein structure and stability. The model has been successfully applied in the study of a wide range of proteins, however this paper focuses specifically on domains representing immunoglobulin-like folds. Here we provide evidence that immunoglobulin-like domains, despite being structurally similar, differ with respect to their participation in the generation of hydrophobic core. It is shown that β-structural fragments in β-barrels participate in hydrophobic core formation in a highly differentiated manner. Quantitatively measured participation in core formation helps explain the variable stability of proteins and is shown to be related to their biological properties. This also includes the known tendency of immunoglobulin domains to form amyloids, as shown using transthyretin to reveal the clear relation between amyloidogenic properties and structural characteristics based on the fuzzy oil drop model.

Underwater Spatial Distribution of UVC Radiant Intensity in Different Water Environment for Ballast Water Treatment

UV radiation, as an effective method for bacteria inactivation, has been applied popularly on ballast water treatment. However, the inactivation efficiencies of UV radiation greatly depend on the UV intensity which distributed unevenly in water and can be deeply affected by the suspending particles in water. For better understanding of the spatial distribution of UV radiation, a 16W UVC lamp was measured underwater to detect the radiant intensity over horizontal and vertical distance. The distribution tendency of UV radiant intensity was probed behind large amounts of experimental data. In addition, four types of different water including tap water, clean seawater, seawater mixed with suspending substances (SS), and seawater mixed with typical algae, were studied to identity the influence of water environment on UV transmission. The impacting significances were compared among different water quality, to optimize the ballast water treatment methods combining with UV radiation.

Embankment Settlement Calculation Based on the Unsaturated Soils Theory

Based on the one-dimensional constitutive relationship of unsaturated soils, this thesis has established the calculation model for embankment settlement with lateral deformation and without lateral deformation in accordance with the mechanic characteristics and in consideration of the influence of water environment. In addition, the thesis has provided the calculation methods for embankment settlement under various working situations (like under the situations of external load function, self-weight effect, increasing of the groundwater level, the invasion effect of rain water and the comprehensive effect of various working conditions) and used the settlement deformation results from the experiments of embankment models to check the calculation method. The method put forward in this thesis could not only be used in the calculation of the settlement deformation under load, but also could be used for the calculation of the deformation caused by the changes of water content in the embankment.

Underwater Wet Weld Seam Tracking Based on Passive Visual Sensor

Weld seam tracking system is urgently needed in weld automation process, but it has not been well studied in underwater weld applications. This paper used visual sensor to automatically monitor the weld seam in underwater wet weld process, and image processing algorithms were developed to remove the influence of water environment on the captured image and automatically obtain the weld torch deviation, and the weld torch was adjusted automatically according to the deviation obtained by the image, experiment results showed that the system could meet the requirements of underwater wet welding process.

Morphological evaluation of hard tissues irradiated by holmium laser under various environments using optical coherence microscopy

In order to investigate the influence of water environment on fiber-guided holmium laser ablation of hard tissues, high-speed photography is performed to accurately record the dynamic evolutions of vaporization bubbles and ablation plumes, and optical coherence microscopy is also used to measure the crater morphology. Experimental results indicate that under the same condition, the ablation performances in air and in water for a single long-pulse laser are comparable when the used fibers are in perpendicular contact with the tissues. But for multiple-pulses ablation, the ablation performances such as ablation efficiency and surface morphology in water become better than those in air because of more and more significant vaporization effect for bigger ablation craters. Optical coherence microscopy is an effective tool for the morphological measurement of craters.

Influence of water environment on holmium laser ablation performance for hard tissues

This study clarifies the ablation differences in air and in water for hard biological tissues, which are irradiated by fiber-guided long-pulsed holmium lasers. High-speed photography is used to record the dynamic characteristics of ablation plumes and vaporization bubbles induced by pulsed holmium lasers. The ablation morphologies and depth of hard tissues are quantitatively measured by optical coherence microscopy. Explosive vaporization effects in water play a positive role in the contact ablation process and are directly responsible for significant ablation enhancement. Furthermore, water layer depth can also contribute to ablation performance. Under the same laser parameters for fiber-tissue contact ablation in air and water, ablation performances are comparable for a single-laser pulse, but for more laser pulses the ablation performances in water are better than those in air. Comprehensive knowledge of ablation differences under various environments is important, especially in medical procedures that are performed in a liquid environment.

Boxers motor actions ranking according to their complexity

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Magneto – hydrodynamic mechanism of the water environment influence on the person

Magneto – hydrodynamic mechanism of the water environment influence on the person

An integrated GIS-based analysis system for water environment influence on the urban system around lake areas

An integrated GIS-based analysis system for water environment influence on the urban system around lake areas was developed in this paper. The IGAS consists of the theoretical assumption, the theoretical model and the GIS-based application module. Lake effect hypothesis and urban spatial structure theory are used to put forward the theoretical assumption and the diffusion model by Bass is developed to explain the influence effects that water environment affects urban system around lake areas. Meanwhile, the buffer zone analysis, nonlinear regression, extreme equation and thematic mapping are used to construct the application module, respectively. A case study implementing the system was performed on the urban system around Poyang Lake areas, China, which is under significant water environment influence.

An explicit solvent quantum chemistry study on the water environment influence on the interactions of fluoride with phenol

The phenol complexes with fluoride in water solution were analyzed for different F⋯O separation distances ranging from 2.6 A up to 4.0 A with 0.2 A intervals. The quenching molecular dynamics runs were followed by hybrid quantum mechanics–molecular mechanics (QM–MM) geometry optimization at B3LYP/6–311+G** level. The analysis of MD trajectories allowed for detailed characteristics of hydration patterns and mobility of fluoride and phenol hydroxyl group. The explicit solvent molecules taken into account in QM–MM studies impose solute geometry changes according to fluctuations of the structure of its nearest neighborhood. Hence, fluctuations of HOMA (harmonic oscillator model of aromaticity index) values were observed corresponding to different conformations of water molecules around the solute. However, the screening role of the water molecules was noticed, which reduces the influence of the fluoride compared with the gas phase. Similarly as in vapor state, also in water solution the formation of hydrogen bond between the fluoride and the hydroxyl group of phenol is energetically favorable.

208 強加工高強度鋼の疲労強度特性に及ぼす水環境効果(OS-1 環境効果)

208 強加工高強度鋼の疲労強度特性に及ぼす水環境効果(OS-1 環境効果)

Effects of environment on the properties of low-density polyethylene composites reinforced with pineapple-leaf fibre

The influence of water environment on the sorption characteristics of low-density polyethylene composites reinforced with short pineapple-leaf fibers (PALF/LDPE) has been studied by immersion in distilled water at 28, 50 and 70°C. The effects of fiber loading, temperature and chemical treatment on the sorption behavior are also evaluated. Water uptake is found to increase with fiber loading owing to the increased cellulose content. Weight change profiles for the composites at high temperature indicated that the diffusion is close to Fickian. All of the treated composites showed lower uptake than the unmodified composites. Parameters like diffusion, sorption and permeability coefficients were determined and activation energies were calculated. The thermodynamic constants such as entropy, enthalpy and first-order kinetic rate constant have been evaluated. A correlation between theoretical and experimental sorption results was evaluated. The effect of water uptake on uniaxial tensile properties has also been studied. Mechanical properties decreased after exposure to water, depending on time of immersion, fiber loading and chemical treatment. Finally, studies were carried out on the flexural properties of PALF/LDPE composites exposed to ultraviolet radiation.