The Change of Stress on Marine Concrete Covered with Barnacles

2014 ◽  
Vol 584-586 ◽  
pp. 1031-1034
Author(s):  
Gen Li Wang ◽  
Zheng Mao Ye ◽  
Bin Wu
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Concrete Surface ◽  
Simplified Model ◽  
Marine Structures ◽  
Marine Fouling ◽  
Marine Concrete ◽  
Fouling Organisms

Barnacle is a major creature in marine fouling organisms, it increases static load and dynamic load of marine structures. In this paper, the change of stress on marine concrete surface covered with barnacles is studied. Moreover, a simplified model is established. The result shows that the stress of seawater increases by 0.53 times on the concrete surface, which is covered with barnacles.

Moray Firth marine fouling communities

1986 ◽  
Vol 91 ◽  
pp. 213-220 ◽  
Author(s):  
Gordon B. Picken
Keyword(s):  
Shallow Water ◽  
Depth Range ◽  
Soft Corals ◽  
Fouling Communities ◽  
Algal Cover ◽  
Marine Fouling ◽  
Moray Firth ◽  
Hanging Chain ◽  
Fouling Organisms

SynopsisFouling communities typical of shallow water inshore sites were found at three locations in the Moray Firth. At each, an initial background cover of solitary tubeworms and barnacles was overgrown by secondary fouling organisms. On the piles of Nigg jetty, overgrowth consisted of mussels in the depth range 0–6 m and hydroids, sponges, soft corals and anemones from 6–26 m. Buoys in the approaches to Cromarty Firth were completely covered by a mixture of algae and mussels. Sunlit areas of the float cleaned annually bore a diverse algal cover, whereas uncleaned shaded areas and the freely hanging chain had three-year-old mussels up to 7 cm long. Mussel fouling extended down the chain to within 1 m of the seabed at 26 m depth. Concrete anchor blocks on the seabed were covered with solitary tubeworms and hydroids. Steel piled platforms in the Beatrice Field were completely fouled after four years. Mussels and seaweeds were abundant from 0–5 m. In the depth range 8–35 m the background calcareous layer was overgrown by soft corals up to 10 cm long and hydroids. From 35 m to the seabed at 46 m, soft overgrowth was provided mainly by hydroids and ascidians, with only a few small corals.

Novel Approach for Biofouling-Release Materials with Interpenetrating Polymer Networks

2005 ◽  
Vol 897 ◽  
Author(s):  
Kenji Mori ◽  
Masanobu Naito ◽  
Takashi Nakai ◽  
Michiya Fujiki ◽  
Takuma Kawabe
Keyword(s):  
Blue Mussel ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Repellent Activity ◽  
Marine Fouling ◽  
3 Dimensional ◽  
Blue Mussels ◽  
Novel Approach ◽  
Specific Fraction ◽  
Fouling Organisms

AbstractEnvironmentally friendly organic-inorganic hybrid materials with repellent activity against marine fouling organisms, such as blue mussel, have been developed using interpenetrating polymer networks (IPNs), composed of a 3-dimensional siloxane matrix of tetraethoxysilane (TEOS) and poly(vinylacetate) (PVAc). Facile bioassay using blue mussels allowed screening the adequate proportions of those components. The repellent activity of IPN with PVAc/silica reached approximately 90% at a specific fraction, relative to that of tributyl tin oxide (TBTO). On the other hand, poly(methylmethacrylate)(PMMA) /silica composite did not show marked repellent activity against blue mussel, even though chemical structure of MMA is similar to that of vinylacetate.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

Modeling the operation of structures made of dispersed-reinforced concrete with an alternating dynamic load of high intensity

2021 ◽  
Vol 14 (3) ◽  
pp. 36-44
Author(s):  
S. Nikolenko ◽  
Svetlana Sazonova ◽  
Viktor Asminin
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Load ◽  
High Intensity ◽  
Concrete Beam ◽  
Static Load ◽  
Dynamic Compression ◽  
Experimental Studies ◽  
Reinforced Concrete Beam ◽  
Beam Elements ◽  
Laminated Structures

A study of the properties of dispersed-reinforced concrete and a study of the effect of dispersed reinforcement on the operation of structures was carried out, mainly with a static load of the same sign. Based on the results of experimental studies, a comparison was made of the work of dispersed-laminated structures under alternating dynamic action of high intensity with the work of reinforced concrete beam elements under similar influences. The results of experimental studies of cubes and prisms for static and dynamic compression are also presented. The results of experimental studies allow us to conclude that there is a significant effect of dispersed reinforcement on the operation of structures under the investigated influences and the feasibility of combined reinforcement of structures. The use of dispersed reinforcement in structures will increase the resistance of structures to such influences.

scholarly journals Study on Occurrence Mechanism of Coal Pillar in L-Shaped Zone during Fully Mechanized Mining Period and Prevention Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zeng-qiang Yang ◽  
Hong-mei Wang ◽  
De-quan Sun ◽  
Xian-jian Ma ◽  
Ming-bao Xu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Burst ◽  
Dynamic Load ◽  
Static Load ◽  
Coal Pillar ◽  
Simulation Software ◽  
In Situ Investigation ◽  
Simulation Results ◽  
Occurrence Mechanism

In order to study the occurrence mechanism of rock burst in L-shaped zone during a fully mechanized mining period, the No. 705 working face which is located in Baojishan Colliery is taken as a typical engineering background. By means of in situ investigation, theoretical analysis, numerical simulation, in situ tests, and relevant monitoring methods, the occurrence mechanism of rock burst and corresponding prevention technology are studied. The results show that a coal pillar with some confining pressure in the L-shaped zone is established by FLAC3D numerical simulation software, and the numerical simulation results indicate that the change in static load has a greater effect than dynamic load on coal pillar unstable failure; the static load plays a role in storing energy, and dynamic load plays a role in inducing rock burst; the bolt-mesh-cable support and high-pressure water jet unloading combined technology is put forward to prevent rock burst in roadways, and the numerical simulation results show that stress distribution of surrounding rock meets the model of strong-soft-strong (3S) structure, and the moment distribution is reasonable. In the follow-up mining, a limit value of coal fines is used to determine that this measure is a reasonable method to prevent rock burst. The study conclusions provide theoretical foundation and new guidance for preventing rock burst by synergistic effect technology in roadways.

The Synthesis and Bioactivities of 2-Hydroxyethyl Benzo[d] Isothiazole-3(2H)-One Marine Antifouling Paints

2013 ◽  
Vol 646 ◽  
pp. 24-29 ◽  
Author(s):  
Jian Xin Yang ◽  
Cheng Hang You ◽  
Xiang Hui Wang ◽  
Qiang Lin
Keyword(s):  
1H Nmr ◽  
Marine Environment ◽  
Aromatic Acid ◽  
Gram Positive ◽  
Fouling Organism ◽  
Antifouling Paints ◽  
Marine Fouling ◽  
Fouling Organisms ◽  
Marine Antifouling

Twenty-one novel compounds were synthesized from the benzo[d]isothiazole-3(2H)-one and aromatic acid, the structures were identified by means of 1H NMR, IR, EA. The intro antibacterial experiment was carried out to evaluate the activities against antibacterial and the marine hanging plate experiment was also carried out to evaluate the activities against marine fouling organism. The results showed that all the compounds were active against the six bacterials, with an inhibiting rate of 90% at the concentration of 32 µg/ml against Gram-positive bacterials, and the antifouling paints couldn’t be attached by marine fouling organisms in the marine environment for more than 3 months.

scholarly journals Experimental Study on City Road Collapse under Vibrating Load

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yuxiao Wang ◽  
Gang Shi ◽  
Xiaowei Tian ◽  
Chaoyue Li ◽  
Huanyu Cheng
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Soil Layer ◽  
Formation Time ◽  
Traffic Load ◽  
Scale Model ◽  
The Road ◽  
Ultimate Failure ◽  
The Stability ◽  
Collapse Process

Underground pipeline seepage and traffic load are the important factors causing city road collapse. In this paper, eight groups of indoor scale model experiments are used to study the road collapse caused by pipeline seepage, taking into account the load type, pipeline buried depth, the distance between pipeline and loss channel, the relative position of pipeline and loss channel, and the formation time of loss channel. The results show that when the erosion channel was formed later, the underlying erosion cavity was ellipsoid, while the other erosion cavities were funnel shaped. When only the static load is applied, the time to reach the ultimate failure is longer than that when only dynamic load is applied. The smaller dynamic load can increase the stability of the soil above the seepage pipeline, while the larger dynamic load can accelerate the collapse process. With the formation time of the erosion channel increasing, the erosion void size is larger and the surface is easier to collapse. With the increase of the distance between the loss passage and the pipeline, the damage time of the road surface is also increased. The larger the thickness of the soil layer above the pipeline, the smaller the size of the underground cavity and the surface subsidence.

Australian Bryozoa Volume 1

2018 ◽  
Keyword(s):  
Invasive Species ◽  
Natural History ◽  
Ocean Acidification ◽  
Marine Biology ◽  
Freshwater Species ◽  
Aquatic Animals ◽  
Marine Fouling ◽  
Biology Students ◽  
The World ◽  
Fouling Organisms

Bryozoans are aquatic animals that form colonies of connected individuals. They take a variety of forms: some are bushy and moss-like, some are flat and encrusting and others resemble lace. Bryozoans are mostly marine, with species found in all oceans from sublittoral to abyssal depths, but freshwater species also exist. Some bryozoans are of concern as marine-fouling organisms and invasive species, while others show promise as sources of anticancer, antiviral and antifouling substances. Written by experts in the field, Australian Bryozoa Volume 1: Biology, Ecology and Natural History is the first of two volumes describing Australia’s 1200 known species of bryozoans, the richest diversity of bryozoans of any country in the world. It contains chapters on the discovery of bryozoans, their morphology, classification and fossil history, their roles in biosecurity and marine benthic environments, and potential uses in biotechnology and ocean acidification. It provides an authoritative reference for biology students, academics and others interested in marine biology.

scholarly journals Research on Fault Activation Law in Deep Mining Face and Mechanism of Rockburst Induced by Fault Activation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Lyu Pengfei ◽  
Bao Xinyang ◽  
Lyu Gang ◽  
Chen Xuehua
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Coal Pillar ◽  
Fault Structure ◽  
Fault Activation ◽  
Fault Type ◽  
Stress Behavior ◽  
Mining Face ◽  
And Control ◽  
The Impact

To effectively monitor and control the severe mining-induced rockburst in deep fault area, the fault activation law and the mechanical essence of rockburst induced by crossing fault mining were studied through theoretical analysis, microseismic monitoring, field investigation, and other methods; numerical simulation was employed to verify the obtained fault activation law and the mechanical nature. First, the distribution of microseismic sources at different mining locations and the fault activation degree were analyzed. According to the microseismic frequency and the characteristics of the energy stage, the fault activation degree was divided into three stages: fault stress transfer, fault pillar stress behavior, and fault structure activation. It was determined that the impact disaster risk was the strongest in the stage of the fault pillar stress behavior. Based on the periodic appearance law of microseisms in fault area, three types of conceptual models of fault-type rockburst were proposed, and the rockburst carrier system model of “roof-coal seam-floor” in the fault area was established. The mechanical essence of fault-type rockburst was obtained as follows: under the action of fault structure, the static load of the fault coal pillar was increased and superimposed with the active dynamic load of the fault, leading to high-strength impact disaster. Finally, the prevention and treatment concepts of fault-type rockburst were proposed. The monitoring and prevention measures of fault-type rockburst were taken from two aspects: the monitoring and characterization of fault rockburst and weakening control of the high static load of the fault coal pillar and dynamic load of fault activation. The proposed concepts and technical measures have been verified in the working face 14310 of Dongtan Coal Mine with sound results. The research results have a guiding significance for the prevention and control of rockburst in a similar mining face under crossing fault mining.

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