scholarly journals Numerical simulation of the impact of an integrated renovation project on the Maowei Sea hydrodynamic environment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cui Wang ◽  
Ling Cai ◽  
Yaojian Wu ◽  
Yurong Ouyang
Keyword(s):  
Water Exchange ◽  
Land Reclamation ◽  
Three Dimensional ◽  
Exchange Capacity ◽  
Reclamation Project ◽  
Hydrodynamic Environment ◽  
Sea Area ◽  
Water Quality Models ◽  
The Impact ◽  
Main Factor

AbstractIntegrated renovation projects are important for marine ecological environment protection. Three-dimensional hydrodynamics and water quality models are developed for the Maowei Sea to assess the hydrodynamic environment base on the MIKE3 software with high resolution meshes. The results showed that the flow velocity changed minimally after the project, decreasing by approximately 0.12 m/s in the east of the Maowei Sea area and increasing by approximately 0.01 m/s in the northeast of the Shajing Port. The decrease in tidal prism (~ 2.66 × 106 m3) was attributed to land reclamation, and accounted for just 0.86% of the pre-project level. The water exchange half-life increased by approximately 1 day, implying a slightly reduced water exchange capacity. Siltation occurred mainly in the reclamation and dredging areas, amounting to back-silting of approximately 2 cm/year. Reclamation project is the main factor causing the decrease of tidal volume and weakening the hydrodynamics in Maowei Sea. Adaptive management is necessary for such a comprehensive regulation project. According to the result, we suggest that reclamation works should strictly prohibit and dredging schemes should optimize in the subsequent regulation works.

Numerical Simulation of Breakwaters for Land Reclamation

2009 ◽  
Author(s):  
Jian-Min Zhang ◽  
Jianhong Zhang ◽  
Gang Wang ◽  
Yang Chen
Keyword(s):  
Land Reclamation ◽  
Southern China ◽  
Soft Soil ◽  
Three Dimensional ◽  
Marine Clay ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Reclamation Project ◽  
The Moment ◽  
Three Dimensional Finite Element

This paper highlights some practical considerations of soil structure interactions in the design of the breakwater for a land reclamation project at Da Ya Bay, Southern China sea, through three-dimensional finite element analysis. A pile-breakwater-foundation system is evaluated during its construction and after construction has been completed. The maximum deflections and moments of the piles take place in the soft marine clay underneath the breakwater. The deformation of the soft soil imposes great impact on the slender pile. Based on the study, it is considered inadequate to solely increase the density and stiffness of the piles, as it will not effectively reduce the deformation of the foundation as well as the moment of the pile. On the contrary, the increased stiffness results in significant increase of the stresses in the pile. Consequently, the deformation of pile should be evaluated in terms of interactions between soil and pile. Improvement of the soft marine clay is also of great importance.

Discussion on Marine Eco-Compensation Standard of Land Reclamation from Sea: A Case Study of Dadeng Sea Area, Xiamen, China

2012 ◽  
Vol 524-527 ◽  
pp. 3365-3370
Author(s):  
Ping Ting Lian ◽  
Wei Qi Chen ◽  
Luo Ping Zhang
Keyword(s):  
Ecosystem Services ◽  
Land Reclamation ◽  
Coastal Ecosystem ◽  
Classification Framework ◽  
Reclamation Area ◽  
Compensation Standard ◽  
Reclamation Project ◽  
Sea Area

This paper chooses a land reclamation project of Dadeng sea area, Xiamen as a case, and put emphasis on discussing how to calculate the marine eco-compensation standard of land reclamation from sea based on the losses of ecosystem services. It starts with the classification of coastal ecosystem services and the analysis of adverse impacts caused by the reclamation project, and then builds the relevant valuation models of ecosystem service losses under the above classification framework and estimates the losses of coastal ecosystem services incurred by the project. On the basis of these, the paper puts forward a method for calculating the theoretical compensation standard and applies it to the case study. The results show that, the total loss of ecosystem services caused by the land reclamation project amounts to 40.88 million yuan/a, in which the loss of space resources (i.e. mariculture space) in provisioning services is the largest, amounting to 30.71 million yuan/a, and the loss of per unit sea area is about 4.19 yuan/m2a. The estimated compensation standards are 209.6 yuan/m2 with discounting rate of 2% and 93.2 yuan/m2 with discounting rate of 4.5%, respectively. It is proposed that the compensation amount can be determined through bargaining between compensators and compensation receivers in practice, based on the theoretical compensation standard as well as the compensation receivers’ willingness to accept, the economic level of land reclamation area, and the local cultures et al.

Dynamic Consolidation Ground Reclamation Vibration Transmission Mechanism and Impact Studies on Composite Foundation

2014 ◽  
Vol 587-589 ◽  
pp. 1125-1131
Author(s):  
Yan Feng Li ◽  
Jing Juan Zhang ◽  
Yuan Ming Dou ◽  
Zeng Guo
Keyword(s):  
Theoretical Basis ◽  
Land Reclamation ◽  
Composite Foundation ◽  
Transmission Mechanism ◽  
Foundation Design ◽  
Vibration Transmission ◽  
Coastal Reclamation ◽  
Dynamic Consolidation ◽  
Reclamation Project ◽  
The Impact

Combined with dynamic consolidation Caofeidian area of land reclamation project examples, Vibration transmission mechanism of dynamic consolidation and reclamation of the foundation were explored, obtaining acceleration attenuation law, and studying and analyzing the impact of strong vibrating composite foundation. Research provide important theoretical basis to guide Dynamic Consolidation coastal reclamation foundation design and construction.

scholarly journals Impacts of Human Activities on Hydrodynamic Structures during the Dry Season in the Modaomen Estuary

2021 ◽  
Vol 9 (12) ◽  
pp. 1327
Author(s):  
Changjie Liu ◽  
Ziyue Zhong ◽  
Yiqing Xiao ◽  
Xiaoqi Chen ◽  
Minghui Yu
Keyword(s):  
Human Activities ◽  
Large Scale ◽  
Land Reclamation ◽  
Three Dimensional ◽  
Dry Season ◽  
Hydrodynamic Characteristics ◽  
Tidal Dynamics ◽  
Modaomen Estuary ◽  
The Pearl River ◽  
The Impact

Over the past few decades, the topography and river-tide-salt dynamic characteristics of the Pearl River Delta (PRD) have undergone a myriad of changes due to the unnatural evolution process induced by diverse human activities, such as dam construction, land reclamation, sand excavation, and dredging for navigation. To investigate the impact of human activities on hydrodynamic structures in the PRD of the Modaomen Estuary (ME) during the dry season, a three-dimensional river-tide-salt dynamic model was used to simulate the hydrodynamic characteristics of the ME for different historical periods. The model results indicate that large-scale land reclamation weakened the tidal dynamics and mixing effects in the ME, promoting gravity circulation with opposite velocity directions at the surface and bottom within 15 km downstream of the estuary. Additionally, riverbed downcutting enhanced the tidal dynamics, which intensified saltwater intrusion, leading to the spatial scale-of-gravity circulation expanding 1–2 times. The enhancement of riverbed downcutting on the tidal dynamics in the ME was significantly greater than the weakening effect of land reclamation. Hence, due to the comprehensive influence of human activities between the 1970s and 2010, the hydrodynamic structures in the ME changed from a state of atypical gravity circulation, with nonobvious stratification, to a state of highly stratified and large-scale gravity circulation. The pollutant diffusion in the ME under different scenarios is also discussed in this paper. The results show that reclamation results in weakening of tidal dynamics, which is not conducive to the mixing and diffusion of pollutants in the estuary. However, the narrowed estuary due to land reclamation is conducive to the rapid entry of pollutants into the open sea.

IMPACTS OF DREDGING AND RECLAMATION PROJECTS

2016 ◽  
Vol 78 (7-3) ◽  
Author(s):  
Norpadzlihatun Manap ◽  
Kavitha Sandirasegaran
Keyword(s):  
Human Activities ◽  
Coastal Erosion ◽  
Land Reclamation ◽  
Geotechnical Engineering ◽  
Dredged Sediments ◽  
Excavation Process ◽  
Reclamation Project ◽  
The Impact

Dredging works are commonly described as removal of sediments from underwater which involving excavation process. Soil and rocks are excavated for channel and harbor deepening and for land reclamation. Land reclamation is defined as usage of dredged sediments to construct or build new land in the sea. This research aims to investigate the impact of dredging and reclamation projects as dredging and reclamation are one of the geotechnical engineering elements. Human activities such as dredging and reclamation may lead to geo-hazards such as coastal erosion, landslides, flooding and etc. In this research, 157 villagers from Teluk Rampang and Langkah Baik, Pengerang, Kota Tinggi in Malaysia has been selected as respondents to answer the distributed questionnaire. As a result, the analysis shows that villagers become victims due to the reclamation project executed to construct petroleum hub in Pengerang, Kota Tinggi. The impact can be reduced with a proper monitoring and management by the project stakeholders’.

Analyzing the Impact of X-Ray Tomography on the Reliability of Integrated Circuits

2015 ◽  
Author(s):  
Halit Dogan ◽  
Md Mahbub Alam ◽  
Navid Asadizanjani ◽  
Sina Shahbazmohamadi ◽  
Domenic Forte ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
3D Imaging ◽  
Three Dimensional ◽  
Serial Sectioning ◽  
Promising Technique ◽  
Flash Memories ◽  
X Ray ◽  
3D Information ◽  
The Impact

Abstract X-ray tomography is a promising technique that can provide micron level, internal structure, and three dimensional (3D) information of an integrated circuit (IC) component without the need for serial sectioning or decapsulation. This is especially useful for counterfeit IC detection as demonstrated by recent work. Although the components remain physically intact during tomography, the effect of radiation on the electrical functionality is not yet fully investigated. In this paper we analyze the impact of X-ray tomography on the reliability of ICs with different fabrication technologies. We perform a 3D imaging using an advanced X-ray machine on Intel flash memories, Macronix flash memories, Xilinx Spartan 3 and Spartan 6 FPGAs. Electrical functionalities are then tested in a systematic procedure after each round of tomography to estimate the impact of X-ray on Flash erase time, read margin, and program operation, and the frequencies of ring oscillators in the FPGAs. A major finding is that erase times for flash memories of older technology are significantly degraded when exposed to tomography, eventually resulting in failure. However, the flash and Xilinx FPGAs of newer technologies seem less sensitive to tomography, as only minor degradations are observed. Further, we did not identify permanent failures for any chips in the time needed to perform tomography for counterfeit detection (approximately 2 hours).

scholarly journals Mechanical Behavior of Hydroxyapatite-Chitosan Composite: Effect of Processing Parameters

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 213
Author(s):  
Hamid Ait Said ◽  
Hassan Noukrati ◽  
Hicham Ben Youcef ◽  
Ayoub Bayoussef ◽  
Hassane Oudadesse ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Bone Repair ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Composite Effect ◽  
Solid Liquid ◽  
The Impact

Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field.

scholarly journals Spatio-Temporal Variation Characteristics of Snow Depth and Snow Cover Days over the Tibetan Plateau

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 307
Author(s):  
Chi Zhang ◽  
Naixia Mou ◽  
Jiqiang Niu ◽  
Lingxian Zhang ◽  
Feng Liu
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
Snow Depth ◽  
Feedback Effect ◽  
Effect Of Temperature ◽  
The Tibetan Plateau ◽  
Reanalysis Dataset ◽  
Spatio Temporal ◽  
The Impact ◽  
Main Factor

Changes in snow cover over the Tibetan Plateau (TP) have a significant impact on agriculture, hydrology, and ecological environment of surrounding areas. This study investigates the spatio-temporal pattern of snow depth (SD) and snow cover days (SCD), as well as the impact of temperature and precipitation on snow cover over TP from 1979 to 2018 by using the ERA5 reanalysis dataset, and uses the Mann–Kendall test for significance. The results indicate that (1) the average annual SD and SCD in the southern and western edge areas of TP are relatively high, reaching 10 cm and 120 d or more, respectively. (2) In the past 40 years, SD (s = 0.04 cm decade−1, p = 0.81) and SCD (s = −2.3 d decade−1, p = 0.10) over TP did not change significantly. (3) The positive feedback effect of precipitation is the main factor affecting SD, while the negative feedback effect of temperature is the main factor affecting SCD. This study improves the understanding of snow cover change and is conducive to the further study of climate change on TP.

scholarly journals Impact of inter-reader contouring variability on textural radiomics of colorectal liver metastases

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Francesco Rizzetto ◽  
Francesca Calderoni ◽  
Cristina De Mattia ◽  
Arianna Defeudis ◽  
Valentina Giannini ◽  
...  
Keyword(s):  
Liver Metastases ◽  
Hausdorff Distance ◽  
Intraclass Correlation ◽  
Three Dimensional ◽  
Liver Lesion ◽  
Dice Coefficient ◽  
Rf Values ◽  
Enhanced Computed Tomography ◽  
Relative Change ◽  
The Impact

Abstract Background Radiomics is expected to improve the management of metastatic colorectal cancer (CRC). We aimed at evaluating the impact of liver lesion contouring as a source of variability on radiomic features (RFs). Methods After Ethics Committee approval, 70 liver metastases in 17 CRC patients were segmented on contrast-enhanced computed tomography scans by two residents and checked by experienced radiologists. RFs from grey level co-occurrence and run length matrices were extracted from three-dimensional (3D) regions of interest (ROIs) and the largest two-dimensional (2D) ROIs. Inter-reader variability was evaluated with Dice coefficient and Hausdorff distance, whilst its impact on RFs was assessed using mean relative change (MRC) and intraclass correlation coefficient (ICC). For the main lesion of each patient, one reader also segmented a circular ROI on the same image used for the 2D ROI. Results The best inter-reader contouring agreement was observed for 2D ROIs according to both Dice coefficient (median 0.85, interquartile range 0.78–0.89) and Hausdorff distance (0.21 mm, 0.14–0.31 mm). Comparing RF values, MRC ranged 0–752% for 2D and 0–1567% for 3D. For 24/32 RFs (75%), MRC was lower for 2D than for 3D. An ICC > 0.90 was observed for more RFs for 2D (53%) than for 3D (34%). Only 2/32 RFs (6%) showed a variability between 2D and circular ROIs higher than inter-reader variability. Conclusions A 2D contouring approach may help mitigate overall inter-reader variability, albeit stable RFs can be extracted from both 3D and 2D segmentations of CRC liver metastases.

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