Modal analysis of the triple-tower twin-span suspension bridge in deck unit erection stage

Modal analysis of large span suspension bridge in different construction stages has to be carried out for the aerodynamic instability analysis. Based on the finite element (FE) model of a triple-tower twin-span (TTTS) suspension bridge in the completed stage, the FE models of the tower-cable-deck system corresponding to 0 %, 5 %, 10 %, 20 %, 30 %, and 40 % deck units erection stage are established respectively by a backward dismantling method. Then, the dynamic characteristics of each of the tower-cable-deck systems are analyzed to study the modal properties of TTTS suspension bridge in various deck erection stages. The results demonstrate that the natural frequencies of each erection stage are closely distributed in the low-order range. In the beginning of the deck units erection stage, the tower-cable-dominated modes are the primary modes and the deck-dominated modes come to next. Due to the strong interactions between deck unites and the cables, both the in-plane and out-of-plane vibrations of cables would excite the swing, lifting or torsional modes of the deck units. Both the in-plane and out-of-plane modes including in-phase and out-of-phase modes of the two main cables in the same span or symmetry and anti-symmetry modes of the neighboring-span cables as well as their corresponding combinations can be classified into groups. With more deck unites erected, the main girder is built up gradually, and thus the frequencies of deck-dominated mode would arise. The different frequency variations result in the modal crossover phenomena, which reflect the instability of the dynamic characteristics during the long deck erection period. At last, the aerodynamic stability of the suspension bridge is checked at each early erection stage, and a wind ropes application for the aerodynamic stability enhancement is investigated. The study of dynamic characteristics provides a reference for the wind-resistance analysis of the TTTS suspension bridge during the deck units erection stage

Robust and Efficient Network Reconstruction in Complex System via Adaptive Signal Lasso

Network reconstruction is important to the understanding and control of collective dynamics in complex systems. Most real networks exhibit sparsely connected properties, and the connection parameter is a signal (0 or 1). Well-known shrinkage methods such as lasso or compressed sensing (CS) to recover structures of complex networks cannot suitably reveal such a property; therefore, the signal lasso method was proposed recently to solve the network reconstruction problem and was found to outperform lasso and CS methods. However, signal lasso suffers the problem that the estimated coefficients that fall between 0 and 1 cannot be successfully selected to the correct class. We propose a new method, adaptive signal lasso, to estimate the signal parameter and uncover the topology of complex networks with a small number of observations. The proposed method has three advantages: (1) It can effectively uncover the network topology with high accuracy and is capable of completely shrinking the signal parameter to either 0 or 1, which eliminates the unclassified portion in network reconstruction; (2) The method performs well in scenarios of both sparse and dense signals and is robust to noise contamination; (3) The method only needs to select one tuning parameter versus two in signal lasso, which greatly reduces the computational cost and is easy to apply. The theoretical properties of this method are studied, and numerical simulations from linear regression, evolutionary games, and Kuramoto models are explored. The method is illustrated with real-world examples from a human behavioral experiment and a world trade web.Comment: 15 pages, 8 figures, 4 table

Balance Fatigue Design of Cast Steel Nodes in Tubular Steel Structures

Cast steel nodes are being increasingly popular in steel structure joint application as their advanced mechanical performances and flexible forms. This kind of joints improves the structural antifatigue capability observably and is expected to be widely used in the structures with fatigue loadings. Cast steel node joint consists of two parts: casting itself and the welds between the node and the steel member. The fatigue resistances of these two parts are very different; the experiment results showed very clearly that the fatigue behavior was governed by the welds in all tested configurations. This paper focuses on the balance fatigue design of these two parts in a cast steel node joint using fracture mechanics and FEM. The defects in castings are simulated by cracks conservatively. The final crack size is decided by the minimum of 90% of the wall thickness and the value deduced by fracture toughness. The allowable initial crack size could be obtained through the integral of Paris equation when the crack propagation life is considered equal to the weld fatigue life; therefore, the two parts in a cast steel node joint will have a balance fatigue life

Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs), which are equipped with chemical composition gratings sensors (CCGs). The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE) model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C

The prognostic significance of protein tyrosine phosphatase 4A2 in breast cancer

Duanzheng Zhao,1 Libin Guo,2,* Henrique Neves,3,* Hiu-Fung Yuen,4 Shu-Dong Zhang,5 Cian M McCrudden,6 Qing Wen,5 Jin Zhang,2 Qi Zeng,4 Hang Fai Kwok,3,5,6 Yao Lin2 1College of Continuing Education, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, People’s Republic of China; 2College of Life Sciences, Fujian Normal University, Fuzhou, Fujian, People’s Republic of China; 3Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau Special Administrative Region, People’s Republic of China; 4Institute of Molecular and Cell Biology, Biopolis Drive, Proteos, Singapore; 5Center for Cancer Research and Cell Biology, 6School of Pharmacy, Queen’s University of Belfast, Belfast, UK *These authors have contributed equally to this work Abstract: Although PTP4A3 has been shown to be a very important factor in promoting cancer progression, the role of its close family member PTP4A2 is still largely unknown. Recent reports have shown contradicting results on the role of PTP4A2 in breast cancer progression. Considering this, we aimed to investigate the prognostic value of PTP4A2 in five independent breast cancer data sets (minimum 198 patients per cohort, totaling 1,124 patients) in the Gene Expression Omnibus Database. We found that high expression of PTP4A2 was a favorable prognostic marker in all five independent breast cancer data sets, as well as in the combined cohort, with a hazard ratio of 0.68 (95% confidence interval =0.56–0.83; P<0.001). Low PTP4A2 expression was associated with estrogen receptor-negative tumors and tumors with higher histological grading; furthermore, low expression was inversely correlated with the expression of genes involved in proliferation, including MKI67 and the MCM gene family encoding the minichromosome maintenance proteins. These findings suggest that PTP4A2 may play a role in breast cancer progression by dysregulating cell proliferation. PTP4A2 expression was positively correlated with ESR1, the gene encoding estrogen receptor-alpha, and inversely correlated with EGFR expression, suggesting that PTP4A2 may be involved in these two important oncogenic pathways. Together, our results suggest that expression of PTP4A2 is a favorable prognostic marker in breast cancer. Keywords: breast cancer, PTP4A2, survival, prognostic marker, overexpression, minichromosome maintenance proteins&nbsp

Sources of organic matter and paleo-environmental implications inferred from carbon isotope compositions of lacustrine sediments at Inexpressible Island, Ross Sea, Antarctica

The carbon isotopic composition of organic matter (δ13Corg) was determined in two sediment cores (IIL1 and IIL9) recovered from Inexpressible Island, Ross Sea, Antarctica, and analyzed to identify the sources of that organic matter. The δ13Corg values of sediments of IIL9 were found to vary between −14.6‰ and −11.6‰, with a mean of −13.4‰ (n=48). These values were significantly higher than those of IIL1 sediments which varied between −23.2‰ and −20.4‰, with a mean of −21.8‰ (n=55). The variation in δ13Corg values in these two sediment cores indicate different sources of organic matter. The relatively high δ13Corg values in IIL9 are in accordance with a source from algae, while the low δ13Corg values in IIL1 evince significant influence from penguin guano with algae as the secondary source. Compared with the reference data from other high-latitude lake sediments and plants, the δ13Corg values in IIL9 were extremely high, a result likely related to intense competition for CO2 assimilation among algal species during the growing season in this relatively shallow pond. These results indicate that sedimentary δ13Corg is a reliable proxy for paleo-primary productivity in ponds at Inexpressible Island

Measurement of high-temperature strains in superalloy and carbon/carbon composites using chemical composition gratings

This is a text file associated with Ref. [11] from R. Siew, "Practical automated glass selection and the design of apochromats with large field of view," App. Opt. 55, pp. 9232 - 9236 (2016). It lists the lens prescription for the Zemax lens file of Ref. [10] in the above manuscript.  This lens represents a re-optimized state of the prior lens "AUTO GLASS FINISHED.zmx".  The design form is based on the design by A. Yang, X. Gao, and M. Li, "Design of apochromatic lens with large field and high definition for machine vision," App. Opt. 55, 5977 - 5985 (2016)