scholarly journals Effects of Combined Salt-Damage Resistant Agent on the Shrinkage, Chloride Penetration and Chemical Erosion of Mortar

2019 ◽  
Vol 9 (1) ◽  
pp. 3813-3818
Keyword(s):  
Large Scale ◽  
Sea Water ◽  
Water Environment ◽  
Reduction Rate ◽  
Drying Shrinkage ◽  
Shrinkage Cracking ◽  
Aluminum Salts ◽  
Salt Damage ◽  
Restrained Shrinkage Cracking ◽  
Chlorine Ion

Reinforced concrete structures located on coastal landfill frequently adjoin sea-water environment, and are exposed to sea water and humid environment during construction. Particularly, in the case of large-scale structures like dams, their drying shrinkage is accompanied by fatal cracking, and thus chlorine ion penetration becomes easier. The present study develops a salt damage-resistant agent (SRA) to which aluminum salts, oligomer condensate, and amino alcohol derivatives with the alkyl group are applied as binding inducers. SRA performs the roles of reducing the drying shrinkage of cement composites, binding chlorine ions, and preventing erosion by sulfate ions. This study tests and evaluates its resistance to degradation factors that may occur to structures constructed on coastal landfill and so on. As a result of evaluating shrinkage cracking properties by performing the restrained shrinkage cracking test, SRC showed the shrinkage reduction compared with BSC. As for the performance of resistance to chlorine ion and the chemical sulfate erosion rate, SRC showed the highest resistance performance, followed by BSC and OPC, regardless of the concentration of aqueous solutions for immersion. In addition, as for the rate of mortar weight change by sulfate erosion, the SRA-intermixed SRC mixture showed a weight reduction rate at the level of 1/3 of BSC and 1/6 of OPC, respectively

scholarly journals Impact of the municipal merger on watershed management: a study of Lake Kasumigaura, Japan

2021 ◽  
Author(s):  
Takeshi Mizunoya ◽  
Noriko Nozaki ◽  
Rajeev Kumar Singh
Keyword(s):  
Watershed Management ◽  
Large Scale ◽  
Environmental Changes ◽  
Water Environment ◽  
Reduction Rate ◽  
Oxygen Demand ◽  
Policy Implications ◽  
Pollution Reduction ◽  
Lake Kasumigaura ◽  
The Impact

AbstractIn the early 2000s, Japan instituted the Great Heisei Consolidation, a national strategy to promote large-scale municipal mergers. This study analyzes the impact that this strategy could have on watershed management. We select the Lake Kasumigaura Basin, the second largest lake in Japan, for the case study and construct a dynamic expanded input–output model to simulate the ecological system around the Lake, the socio-environmental changes over the period, and their mutual dependency for the period 2012–2020. In the model, we regulate and control the following water pollutants: total nitrogen, total phosphorus, and chemical oxygen demand. The results show that a trade-off between economic activity and the environment can be avoided within a specific range of pollution reduction, given that the prefectural government implements optimal water environment policies, assuming that other factors constraining economic growth exist. Additionally, municipal mergers are found to significantly reduce the budget required to improve the water environment, but merger budget efficiency varies nonlinearly with the reduction rate. Furthermore, despite the increase in financial efficiency from the merger, the efficiency of installing domestic wastewater treatment systems decreases drastically beyond a certain pollution reduction level and eventually reaches a limit. Further reductions require direct regulatory instruments in addition to economic policies, along with limiting the output of each industry. Most studies on municipal mergers apply a political, administrative, or financial perspective; few evaluate the quantitative impact of municipal mergers on the environment and environmental policy implications. This study addresses these gaps.

Control of Cracking with Shrinkage-Reducing Admixtures

1997 ◽  
Vol 1574 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Surendra P. Shah ◽  
Shashidhara Marikunte ◽  
Wei Yang ◽  
Corina Aldea
Keyword(s):  
Drying Shrinkage ◽  
Plain Concrete ◽  
Type Specimen ◽  
Wire Mesh ◽  
Restrained Shrinkage ◽  
Shrinkage Cracking ◽  
Restrained Shrinkage Cracking ◽  
Tensile Forces ◽  
Parking Garages ◽  
Shrinkage Reducing Admixtures

Shrinkage cracking can be a critical problem in concrete construction, especially for flat structures such as highway pavements, slabs for parking garages, and bridge decks. One way to reduce the shrinkage cracking is to provide reinforcement in the form of wire mesh to resist tensile forces. In recent years, short, randomly distributed fibers have been used to control shrinkage cracking. The efficiency of shrinkage-reducing admixtures (SRAs) in controlling restrained shrinkage cracking of concrete is reviewed. A ring-type specimen was used for restrained shrinkage cracking tests. The SRA selected for this investigation was a propylene glycol derivative, which was used at 1 and 2 percent by weight of cement. Free (unrestrained) shrinkage, weight loss, compressive strength, and fracture toughness were also investigated. The results of SRA concretes were compared with that of plain concrete with the same water-to-cement ratio. A theoretical model based on nonlinear fracture mechanics was developed for predicting transverse cracking of the concrete ring specimen caused by drying shrinkage. The model prediction of time to cracking compared well with the experimental data. The model can be extended to different geometries and dimensions than those considered in this research.

DEVELOPMENT OF INTEGRATED MONITORING NETWORK FOR MEASURING SALINITY OF SEA WATER

2018 ◽  
pp. 18-26
Author(s):  
Sima Ajdar qizi Askerova
Keyword(s):  
Surface Waters ◽  
Sea Water ◽  
Water Environment ◽  
Monitoring Network ◽  
Monitoring Networks ◽  
The Caspian Sea ◽  
Integrated Monitoring ◽  
Ecological Control ◽  
Different Depths ◽  
Optimal Construction

Monitoring of sea water condition is one of major requirements for carrying out the reliable ecological control of water environment. Monitoring networks contain such elements as sea buoys, beacons, etc. and are designated for measuringvarious hydrophysical parameters, including salinity of sea water. Development of specialized network and a separate buoy system for measuring thesea water salinity at different depths makes it possible to determine major regularities of processes of pollution and self-recovery of the sea waters. The article describes the scientific and methodological basics for development of this specialized network and questions of its optimal construction. It is well-known that at a depth of 30-45 m of the Caspian Sea salinity decreases and then at a depth of 45-60 m salinity is fully recovered. The mentioned changes of salinity at the relatively upper layer of sea waters is of special interest for studying the effect of ocean-going processes on the climate forming in the Caspian area. In terms of informativeness of measurements of surface waters salinity, the most informative is a layer ata 30-60 m depth, where inversion and recovery of salinity take place. It is shown that in most informative subrange of measurements, i. e. at a depth of 30-60 m optimization of regime of measurements complex should be carried out in order to increase the effectiveness of held researches. It is shown that at a depth of 35-50 m choice of the optimum regime of measurements makes it possible to obtain the maximum amount of information.

MEASURES FOR ENVIRONMENT CONSERVATION IN ENCLOSED COASTAL SEAS

2017 ◽  
Author(s):  
Keizo Negi ◽  
Keizo Negi ◽  
Takuya Ishikawa ◽  
Takuya Ishikawa ◽  
Kenichiro Iba ◽  
...  
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Water Mass ◽  
Sea Water ◽  
Red Tide ◽  
Water Environment ◽  
Quality Standard ◽  
Tokyo Bay ◽  
View Point ◽  
High Concentration

Japan experienced serious water pollution during the period of high economic growth in 1960s. It was also the period that we had such damages to human health, fishery and living conditions due to red tide as much of chemicals, organic materials and the like flowing into the seas along the growing population and industries in the coastal areas. Notable in those days was the issues of environment conservation in the enclosed coastal seas where pollutants were prone to accumulate inside due to low level of water circulation, resulting in the issues including red tide and oxygen-deficient water mass. In responding to these issues, we implemented countermeasures like effluent control with the Water Pollution Control Law and improvement/expansion of sewage facilities. In the extensive enclosed coastal seas of Tokyo Bay, Ise Bay and the Seto Inland Sea, the three areas of high concentration of population, we implemented water quality total reduction in seven terms from 1979, reducing the total quantities of pollutant load of COD, TN and TP. Sea water quality hence has been on an improvement trend as a whole along the steady reduction of pollutants from the land. We however recognize that there are differences in improvement by sea area such as red tide and oxygen-deficient water mass continue to occur in some areas. Meanwhile, it has been pointed out that bio-diversity and bio-productivity should be secured through conservation/creation of tidal flats and seaweed beds in the view point of “Bountiful Sea” To work at these challenges, through the studies depending on the circumstances of the water environment in the enclosed coastal seas, we composed “The Policy of Desirable State of 8th TPLCS” in 2015. We have also added the sediment DO into the water quality standard related to the life-environmental items in view of the preservation of aquatic creatures in the enclosed water areas. Important from now on, along the Policy, is to proceed with necessary measures to improve water quality with good considerations of differences by area in the view point of “Beautiful and bountiful Sea”.

Concrete Strength and Deformation Property under Sea Water Erosion Environment

2012 ◽  
Vol 446-449 ◽  
pp. 2554-2559 ◽  
Author(s):  
Jian Jun Cai ◽  
Feng Zhang ◽  
Wei Cui ◽  
Shou Shan Chen ◽  
Pu Lun Liu
Keyword(s):  
Large Scale ◽  
Failure Modes ◽  
Deformation Property ◽  
Sea Water ◽  
Dynamic Stiffness ◽  
Concrete Strength ◽  
Strain Curve ◽  
Water Erosion ◽  
Strength And Deformation ◽  
Erosion Environment

In order to effectively assess the concrete strength and deformation property under sea water erosion environment, concrete stress and strain curve was researched with the number of wet and dry cycle of 0 times, 10 times , 20 times, 30 times, 40 times, 50 times and 60 times based on the large-scale static and dynamic stiffness servo test set. The stress - strain curves of concrete was tested for the lateral pressure 10.8MPa, 14.4MPa, and 18.8MPa at different dry-wet cycles, The failure modes and superficial cracking characteristics of specimens are reported at different dry-wet cycles. Concrete elastic modulus and compressive strength were researched. Based on concrete mechanical theory , the classic Kufer-Gerstle strength criteria of concrete was used, a large number of test samples of multivariate data were nonlinear regressed, a biaxial concrete strength criterion was established taking into account the stress ratio and the number of dry-wet cycles.

scholarly journals Energy-Efficient Routing Control Algorithm in Large-Scale WSN for Water Environment Monitoring with Application to Three Gorges Reservoir Area

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuanchang Zhong ◽  
Lin Cheng ◽  
Liang Zhang ◽  
Yongduan Song ◽  
Hamid Reza Karimi
Keyword(s):  
Three Gorges Reservoir ◽  
Large Scale ◽  
Water Environment ◽  
Maximum Energy ◽  
Base Station ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Environment Monitoring ◽  
Cluster Heads ◽  
Node Energy

The typical application backgrounds of large-scale WSN (wireless sensor networks) for the water environment monitoring in the Three Gorges Reservoir are large coverage area and wide distribution. To maximally prolong lifetime of large-scale WSN, a new energy-saving routing algorithm has been proposed, using the method of maximum energy-welfare optimization clustering. Firstly, temporary clusters are formed based on two main parameters, the remaining energy of nodes and the distance between a node and the base station. Secondly, the algorithm adjusts cluster heads and optimizes the clustering according to the maximum energy-welfare of the cluster by the cluster head shifting mechanism. Finally, in order to save node energy efficiently, cluster heads transmit data to the base station in single-hop and multihop way. Theoretical analysis and simulation results show that the proposed algorithm is feasible and advanced. It can efficiently save the node energy, balance the energy dissipation of all nodes, and prolong the network lifetime.

scholarly journals Spectral Minutiae Fingerprint Recognition System

2014 ◽  
pp. 103-108
Author(s):  
S. Shanawaz Basha ◽  
N. Musrat Sultana
Keyword(s):  
Large Scale ◽  
Reduction Rate ◽  
Principal Component ◽  
Rejection Rate ◽  
Recognition System ◽  
Feature Reduction ◽  
Fingerprint Recognition ◽  
Identification System ◽  
Behavioral Characteristics ◽  
Template Size

Biometrics refers to the automatic recognition of individuals based on their physiological and/or behavioral characteristics, such as faces, finger prints, iris, and gait. In this paper, we focus on the application of finger print recognition system. The spectral minutiae fingerprint recognition is a method to represent a minutiae set as a fixedlength feature vector, which is invariant to translation, and in which rotation and scaling become translations, so that they can be easily compensated for. Based on the spectral minutiae features, this paper introduces two feature reduction algorithms: the Column Principal Component Analysis and the Line Discrete Fourier Transform feature reductions, which can efficiently compress the template size with a reduction rate of 94%.With reduced features, we can also achieve a fast minutiae-based matching algorithm. This paper presents the performance of the spectral minutiae fingerprint recognition system, this fast operation renders our system suitable for a large-scale fingerprint identification system, thus significantly reducing the time to perform matching, especially in systems like, police patrolling, airports etc,. The spectral minutiae representation system tends to significantly reduce the false acceptance rate with a marginal increase in the false rejection rate.

scholarly journals STUDY ON DRYING SHRINKAGE CRACKING PROPERTIES OF FLY ASH MORTAR UNDER DIFFERENT DRYING CONDITIONS

2017 ◽  
Vol 71 (1) ◽  
pp. 386-393
Author(s):  
Satoshi YOSHIKAWA ◽  
Yoshiaki SATO ◽  
Toshihiro OTANI ◽  
Kenji UEDA
Keyword(s):  
Fly Ash ◽  
Drying Shrinkage ◽  
Shrinkage Cracking ◽  
Drying Conditions
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