Structural load monitoring of floating mooring column and its application on optimal regulation for water conveyance system operation of sea shiplock

Due to the sea water intrusion and the development trend of using large-scale ships, more stringent requirements are put forward for the safety of water delivery process and the mooring equipment operation for the sea shiplock. The maximum loads for the mooring equipment of sea shiplock, i.e., floating mooring column (FMC), are generally occurred at the end of water delivery. The superimposed effect of turbulent flow and marine corrosive environment can accelerate the failure of the floating mooring column structure for the sea shiplock, which leads to the safety incidents, including the structural damage of FMC and the breakage of mooring lines for the ship, etc. The safety of the FMC is mostly influenced by three factors, including the ship’s tonnage, the water flow environment of the locked room, and the lock operation technologies; among these, the water flow environment can be considered the most significant. In practice, because the mooring load of an FMC due to water delivery from the shiplock is very complicated, there is currently no mature approach to condition monitoring. This investigation aims to address a large sea shiplock, and the optimal regulation approach for water delivery of shiplock is established based on a load monitoring methodology for FMCs. The detection accuracy of the FMC mooring loads is controlled by simulation verification with errors less than 10%. During the optimized water delivery process, the exerted loads on the FMCs are noticeably reduced to be lower than the maximum design rating. The innovative approach is essentially based on an inversion calculation of the load response model for obtaining the mooring loads of FMCs, with the monitored load results used to regulate and optimize the water delivery process of the shiplocks. The research results can fill a part of the research gap of FMC mooring load condition monitoring method in shiplock water delivery, and provide technical support for the safety of shiplock water delivery process and mooring equipment operation

Cloning and expression characterization of elongation of very long-chain fatty acids protein 6 (elovl6) with dietary fatty acids, ambient salinity and starvation stress in Scylla paramamosain

Introduction: Elongation of very long-chain fatty acids protein 6 (ELOVL6) played crucial roles in regulating energy expenditure and fatty acid metabolism. Many studies have performed to investigate the physiological roles and regulatory mechanisms of elovl6 in fish and animals, while few studies were reported in crustaceans.Methods: Here we reported on the molecular cloning, tissue distribution and expression profiles in response to dietary fatty acids, ambient salinity and starvation stress in Scylla paramamosain by using rapid amplification of cDNA ends (RACE) and quantitative real-time PCR.Results: Three elovl6 isoforms (named elovl6a, elovl6b and elovl6c) were isolated from S. paramamosain in the present study. The complete sequence of elovl6a was 1345 bp, the full-length sequence of elovl6b was 1419 bp, and the obtained elovl6c sequence was 1375 bp in full length. The elovl6a, elovl6b and elovl6c encoded 287, 329 and 301 amino acids respectively, and exhibited the typical structural features of ELOVL protein family members. Phylogenetic analysis showed that the ELOVL6a from S. paramamosain clustered most closely to ELOVL6 from Portunus trituberculatus and Eriocheir sinensis, while the ELOVL6b and ELOVL6c from S. paramamosain gathered alone into a single branch. Quantitative real-time PCR exhibited that the relatively abundant expression of elovl6b was observed in intestine and stomach, and the elovl6a and elovl6c were highly expressed in hepatopancreas. In addition, studies found that replacing fish oil with soybean oil could significantly increase the transcriptional levels of three elovl6 in hepatopancreas of S. paramamosain, and the expression of elovl6a and elovl6c in hepatopancreas were more sensitive to dietary fatty acids than the elovl6b. Compared with the normal sea water group (27‰), the expression of sterol-regulatory element binding protein1c (srebp-1), elovl6a, elovl6b and elovl6c were upregulated in the low salinity groups, particularly in 7‰. On the contrary, the starvation stress suppressed the expression of srebp-1, elovl6a, elovl6b and elovl6c.Discussion: These results may contribute to understand the functions of elovl6 in fatty acid synthesis and regulatory mechanisms in crustaceans

Optimizing locally linear classifiers with supervised anchor point learning

Kernel SVM suffers from high computational complexity when dealing with large-scale nonlinear datasets. To address this issue, locally linear classifiers have been proposed for approximating nonlinear decision boundaries with locally linear functions using a local coding scheme. The effectiveness of such coding scheme depends heavily on the quality of anchor points chosen to produce the local codes. Existing methods usually involve a phase of unsupervised anchor point learning followed by supervised classifier learning. Thus, the anchor points and classifiers are obtained separately whereas the learned anchor points may not be optimal for the discriminative task. In this paper, we present a novel fully supervised approach for anchor point learning. A single optimization problem is formulated over both anchor point and classifier variables, optimizing the initial anchor points jointly with the classifiers to minimize the classification risk. Experimental results show that our method outperforms other competitive methods which employ unsupervised anchor point learning and achieves performance on par with the kernel SVM albeit with much improved efficiency

Discontinuous phase diagram of amorphous carbons

The short-range order and medium-range order of amorphous carbons demonstrated in experiments allow us to rethink whether there exist intrinsic properties hidden by atomic disordering. Here we presented six representative phases of amorphous carbons (0.1-3.4 g/cm3), namely, disordered graphene network (DGN), high-density amorphous carbon (HDAC), amorphous diaphite (a-DG), amorphous diamond (a-D), paracrystalline diamond (p-D), and nano-polycrystalline diamond (NPD), respectively, classified by their topological features and microstructural characterizations that are comparable with experiments. To achieve a comprehensive physical landscape for amorphous carbons, a phase diagram was plotted in the sp3/sp2 versus density plane, in which the counterintuitive discontinuity originates from the inherent difference in topological microstructures, further guiding us to discover a variety of phase transitions among different amorphous carbons. Intriguingly, the power law, log(sp3/sp2) proportional to rho n, hints at intrinsic topology and hidden order in amorphous carbons, providing an insightful perspective to reacquaint atomic disorder in non-crystalline carbons. A phase diagram for amorphous carbons was plotted in the sp3/sp2 versus density plane, where counterintuitive discontinuity originates from inherent differences in topological microstructures, further guiding us to discover various phase transitions

Development of Fuel Performance Analysis Code for Liquid Metal Cooled Fast Reactor Based on MOOSE Platform

The liquid metal cooled fast reactor has significant strategic significance for the innovative development of nuclear energy, and the development of fuel performance analysis programs suitable for liquid metal cooled fast reactors is of great significance for the design and safety analysis of fast reactors. Fuel elements are one of the most fundamental components of nuclear reactors, and analyzing their performance is one of the most challenging tasks in reactor development. The fuel element performance analysis program LoongCALF based on the multi-physics coupling platform MOOSE was developed in this paper. This program aimed to simulate the long-term service performance evolution of fuel elements under steady-state conditions, providing scientific basis for the design, service life prediction, and safety evaluation of LMFR fuel elements. The program was aimed at metal cooled fast reactor fuel elements, and based on finite element method and JFNK method, solved the thermal mechanical coupling equation of nuclear reactor fuel, and obtained the spatial distribution and temporal variation of physical quantities such as temperature, stress, strain, and fission gas release. The program used a 1.5-dimensional modeling method to perform multi-physics field coupling calculations on fuel rods. In addition, the program supported one-dimensional, two-dimensional, and three-dimensional mesh modeling calculations to meet the construction requirements of fuel element models of different sizes and shapes. The program adopted a modular design with separate material modules. Currently, the fuel types supported by the program include UO2 and MOX, the cladding materials include HT9 and 1515Ti, and the coolant materials supported sodium, lead, and lead bismuth. To verify the accuracy of the program, two benchmark examples were designed for numerical simulation and calculation in this paper. Example 1 used UO2 as the core material and 1515Ti as the cladding material; Example 2 used MOX as the core material and HT9 as the cladding material. By comparing and calculating with the Fiber-Oxide program of the Chinese Institute of Atomic Energy, it is found that the two programs show good consistency in key parameters such as core cladding temperature, displacement, stress, and fission gas release fraction. Although there are certain differences in the handling of repositioning and fracture models, resulting in some deviation in the initial calculation results, considering the limitations of the empirical models used in fuel performance analysis programs, this difference is still within an acceptable range. In summary, the LoongCALF program can accurately simulate the fuel behavior and key parameter evolution inside fuel elements under steady-state operating conditions of liquid metal cooled fast reactors. In the future, we will rely on more practical measurement cases to conduct deeper verification and optimization of the LoongCALF program, to ensure its accuracy and reliability in fast reactor design and safety analysis

A Review of Durability Issues of Reinforced Concrete Structures Due to Coastal Soda Residue Soil in China

Soda residue soil (SRS) is a man-made engineering foundation soil formed by soda residue; it is mainly distributed in coastal areas in China. SRS is rich in a variety of corrosive salts, among which the concentrations of chloride ions are about 2–3 times that of seawater. These highly concentrated chloride ions migrate and diffuse in reinforced concrete (RC) structures built on coastal SRS through multiple transport mechanisms. However, current research on the durability of RC structures exposed to the coastal SRS environment has not led to the publication of any reports in the literature. SRS may be classified by analyzing the quantitative relationships among the corrosive ions it contains. In this paper, the deterioration of RC structures due to the corrosive saline-soil environment in China is discussed, and advances in RC structure durability under such circumstances are reviewed. Our findings show that a corrosive environment, especially when this is a result of coastal SRS, has a significant influence on the deterioration of RC structures, greatly threatening such buildings. A series of effective measures for enhancing the durability of RC structures in saline soil, including improvements in concrete strength, reductions in the water–binder ratio, the addition of mineral admixtures and fiber-reinforcing agents, etc., could provide a vital foundation for enhancing the durability of RC structures which are at risk due to coastal SRS. Vital issues that must be investigated regarding the durability of RC structures are proposed, including the transport mechanism and a prediction model of corrosive ions, dominated by chloride ions (Cl−), in SRS and RC structures, the deterioration mechanism of RC materials, a long-term performance deduction process of RC components, durability design theory, and effective performance enhancement measures. The findings of this paper provide some clear exploration directions for the development of basic theories regarding RC structure durability in coastal SRS environments and go some way to making up for the research gap regarding RC structure durability under corrosive soil environments

Fabrication of TiO2/CdS/TiO2 Nanotube/Ti Mesh Electrode and Application in Photoelectrocatalytic Cell System for Degradation of Methylene Blue under Visible Light Illumination

A TiO2/CdS/TiO2 nanotube/Ti mesh composite structure photoelectrocatalyst was fabricated by decorating the anodized TiO2 nanotubes (TNT) on Ti mesh with CdS nanoparticles via successive ionic layer adsorption and reaction and subsequently coated with a TiO2 protection layer via a vacuum dip-coating process. For the photoelectrocatalysts severed as the photoanodes, the transient photocurrent (i(ph)) and linear sweep voltammetry (LSV) were investigated in a three-electrode system and the photoelectrocatalytic performance was evaluated in a photoelectrocatalytic cell (PEC) system for degradation of methylene blue under visible light illumination. The results show that the TiO2 nanotube arrays are decorated with relatively uniform CdS nanoparticles on the tube wall. Owing to the protection of TiO2 layer, the TiO2/CdS/TiO2 nanotube/Ti mesh electrode shows a stable and superior photoelectrocatalytic performance. The superimposition of mesh electrode can remarkably increase the photoelectrocatalytic efficiency for the degradation of methylene blue

SCATTERING CORRECTION FOR IMAGE RECONSTRUCTION IN FLASH RADIOGRAPHY

Scattered photons cause blurring and distortions in flash radiography, reducing the accuracy of image reconstruction significantly. The effect of the scattered photons is taken into account and an iterative deduction of the scattered photons is proposed to amend the scattering effect for image restoration. In order to deduct the scattering contribution, the flux of scattered photons is estimated as the sum of two components. The single scattered component is calculated accurately together with the uncollided flux along the characteristic ray, while the multiple scattered component is evaluated using correction coefficients pre-obtained from Monte Carlo simulations. The arbitrary geometry pretreatment and ray tracing are carried out based on the customization of AutoCAD. With the above model, an Iterative Procedure for image restORation code, IPOR, is developed. Numerical results demonstrate that the IPOR code is much more accurate than the direct reconstruction solution without scattering correction and it has a very high computational efficiency