Naoe-foam-sjtu solver for ship flows and ocean engineering flows

Ship and ocean engineering flows is a very complex and highly non-linear problem. Traditional experimental methods and potential flow theory have limitations in predicting the complex flows. A CFD solver naoe-FOAM-SJTU is developed based on the open source platform OpenFOAM with the purpose of simulating various ship and ocean engineering flow problems. In the present paper, the self-developed modules, i.e., wave generation and absorption, 6 degrees of freedom (6DoF) motion, mooring system and overset grid are introduced to illustrate the development of the CFD solver. Furthermore, extensive applications to ship flows and ocean engineering flows using naoe-FOAM-SJTU solver are conducted and validated by available experimental data. It has been proved that the CFD solver naoe-FOAM-SJTU is suitable and reliable in predicting the complex viscous flows around ship and offshore structures. Future development of naoe-FOAM-SJTU solver will focus on further enhancement of accuracy and efficiency for CFD simulations of complex flows in ship and ocean engineering

Two-Layer Predictive Control of a Continuous Biodiesel Transesterification Reactor

A novel two-layer predictive control scheme for a continuous biodiesel transesterification reactor is presented. Based on a validated mechanistic model, the least squares (LS) algorithm is used to identify the finite step response (FSR) process model adapted in the controller. The two-layer predictive control method achieves the steady-state optimal setpoints and resolves the multivariable dynamic control problems synchronously. Simulation results show that the two-layer predictive control strategy leads to a significant improvement of control performance in terms of the optimal set-points tracking and disturbances rejection, as compared to conventional PID controller within a multiloop framework

Calibration on MEPDG Low Temperature Cracking Model and Recommendation on Asphalt Pavement Structures in Seasonal Frozen Region of China

In order to implement the Mechanistic-Empirical Pavement Design Guide (MEPDG) to design and maintain asphalt pavements in China, it is necessary to calibrate transfer functions of distresses in MEPDG with local conditions, including traffics, environment, and materials as well as measured pavement distresses data in field. Comprehensive single factor sensitivity analyses of factors that influence thermal cracking of asphalt pavements were conducted utilizing the MEPDG low temperature cracking (LTC) model. Additionally, multiple factor sensitivity analyses were carried out as well, based on which pavement structures with sound thermal cracking resistance were recommended for seasonal frozen regions in China. Finally, the field data of thermal cracks on typical asphalt pavements in China was utilized to calibrate the LTC model in MEPDG. An improvement was proposed on MEPDG LTC model, after which was applied, the predicted thermal cracking from MEPDG LTC model agrees well with measured thermal cracking in China

Design and Optimization of the Vertical Plate Metering Device for Alfalfa Seeds Precision Based on Engineering Discrete Element Method (EDEM)

The research is financed by China Agriculture Research System (CARS34) Abstract The vertical plate seed metering device enhancement and constraints mass flow rate when added to the device improve mass flow performance of alfalfa vertical plate device. Alfalfa forage crop is a potential feeding nutrient and the backbone of dairy production success in China. Engineering discrete element method EDEM was adopted for simulation computing and analysis of the seed-filling performance of the vertical plate metering device with three cell shapes under desired rotational speeds. The results showed significant differences at P< 0.05 of seed filing performance in relation to the rotational speed and cell shapes. Triangular cell shape had indicated the lower mass flow at 8x10-5 kg/s compared to the V-shape of 12x10-4 kg/s and U-shape of 8x10-3 kg/s, 20 to 30% reduction, respectively. The rotational velocity of the vertical plate exceeded 30rpm the cell units reach the optimum seed filling efficiency resulted in 30% decrease of the mass flow rate, the results indicated more seeds disturbance, reduces seed filling by enhancing seeds accessibility and falling, from cells. Furthermore, the T-shape had a lower seed filling and higher seeds releasing in comparison to the V-shape and U-shape cells. The lower seed filling found to be the higher filling efficiency while the higher seed filling leads to the lower filling efficiency. Keywords: Alfalfa seed model, cell, filling performance, mass flow, simulation EDE

Deciphering of interactions between platinated DNA and HMGB1 by hydrogen/deuterium exchange mass spectrometry

A high mobility group box 1 (HMGB1) protein has been reported to recognize both 1,2-intrastrand crosslinked DNA by cisplatin (1,2-cis-Pt-DNA) and monofunctional platinated DNA using trans-[PtCl2(NH3)(thiazole)] (1-trans-PtTz-DNA). However, the molecular basis of recognition between the trans-PtTz-DNA and HMGB1 remains unclear. In the present work, we described a hydrogen/deuterium exchange mass spectrometry (HDX-MS) method in combination with docking simulation to decipher the interactions of platinated DNA with domain A of HMGB1. The global deuterium uptake results indicated that 1-trans-PtTz-DNA bound to HMGB1a slightly tighter than the 1,2-cis-Pt-DNA. The local deuterium uptake at the peptide level revealed that the helices I and II, and loop 1 of HMGB1a were involved in the interactions with both platinated DNA adducts. However, docking simulation disclosed different H-bonding networks and distinct DNA-backbone orientations in the two Pt-DNA-HMGB1a complexes. Moreover, the Phe37 residue of HMGB1a was shown to play a key role in the recognition between HMGB1a and the platinated DNAs. In the cis-Pt-DNA-HMGB1a complex, the phenyl ring of Phe37 intercalates into a hydrophobic notch created by the two platinated guanines, while in the trans-PtTz-DNA-HMGB1a complex the phenyl ring appears to intercalate into a hydrophobic crevice formed by the platinated guanine and the opposite adenine in the complementary strand, forming a penta-layer π–π stacking associated with the adjacent thymine and the thiazole ligand. This work demonstrates that HDX-MS associated with docking simulation is a powerful tool to elucidate the interactions between platinated DNAs and proteins

Effects of Moisture Content on Selected Physical and Mechanical Properties of Alfalfa Seeds

Alfalfa is one of the most widely planted forage legume in the world and that because of its tolerance, adaptation, high yield and nutritious value. Physico-mechanical properties of alfalfa seed are very crucial in the machine designing and processing operations. In this study, some of the physical and mechanical properties of alfalfa seed cultivar were investigated under laboratory condition, as desired for the design of a metering device.  Seven moisture contents were introduced to the initial content of 7.98%, d.b. The geometric and gravimetric characteristics were determined. Correlation equation models were developed based on the function of moisture contents. The means average parameter values of the length, width, thickness, aspect ratio, seed mass, arithmetic, geometric mean diameter, true and bulk density, porosity seed volume, and surface area ranged between 2.356 to 2.718mm, 1.390 to 1.473mm, 1.071 to 1.345mm, 0.68 to 0.776%, 1.7968 to 2.295g, 1.466 to 1.589mm, 1.141 to 1.517mm and 1.466 to 1.589g/cm31.199 to 0.830g/cm3, 0.10 to 0.44%, 0.7383 to 0.79426, and 6.305 to 7.2438mm2, respectively. While, the plywood surface had the highest value of the coefficient of friction as the roughest, followed by polished steel and rubber, glass the least surface roughness. However, the germination rate (%) increased as seed damages decreased, as the coefficient of internal friction decreases from 0.127 to 0.095, while the cohesion increasing from 2.11 to 5.95. The angle of repose resulted in a non-linear increase from 27.05o to 28.68o, 28.86o to 29.86o, 31.49o to 32.35o, and 32.47o to 33.21o as moisture content increased from7.98 to 22.12% d.b. Keywords: alfalfa seed, moisture content, mechanical property, physical propert

Enhancing Robust Representation in Adversarial Training: Alignment and Exclusion Criteria

Deep neural networks are vulnerable to adversarial noise. Adversarial Training (AT) has been demonstrated to be the most effective defense strategy to protect neural networks from being fooled. However, we find AT omits to learning robust features, resulting in poor performance of adversarial robustness. To address this issue, we highlight two criteria of robust representation: (1) Exclusion: \emph{the feature of examples keeps away from that of other classes}; (2) Alignment: \emph{the feature of natural and corresponding adversarial examples is close to each other}. These motivate us to propose a generic framework of AT to gain robust representation, by the asymmetric negative contrast and reverse attention. Specifically, we design an asymmetric negative contrast based on predicted probabilities, to push away examples of different classes in the feature space. Moreover, we propose to weight feature by parameters of the linear classifier as the reverse attention, to obtain class-aware feature and pull close the feature of the same class. Empirical evaluations on three benchmark datasets show our methods greatly advance the robustness of AT and achieve state-of-the-art performance.Comment: 10 pages, 9 figures, Submitted to TIF