Search

A major limitation in chemisorptive hydrogen storage in metal hydrides is the long time required for the adsorption reaction during charging. This study investigates how the shape and material of the reaction chamber influences the adsorption and desorption rates. Numerical simulations of hydrogen storage in a cylindrical reaction chamber filled with LaNi5 hydride are conducted for a range of chamber thermal conductivities and aspect ratios. The results show that adsorption and desorption processes are limited by thermal diffusion in the hydride bed and storage chamber. A storage efficiency is proposed based on an ideal isothermal process and used to evaluate the impact of chamber thermal conductivity and aspect ratio on the adsorption and desorption rates. Empirical correlations are proposed for predicting the adsorption and desorption efficiency of cylindrical LaNi5 hydride beds. Finally, a machine-learning based data model for predicting storage efficiency in metal hydride chambers is presented. Comparison against the empirical correlations highlights that the machine learning-based data model can predict the storage efficiency more accurately.

Background Although septal myectomy is a standard strategy for managing patients with hypertrophic obstructive cardiomyopathy (HOCM) and drug-refractory symptoms, so far, only a few experienced myectomy centers exist globally. Mainly, this can be explained by the many technical challenges presented by myectomy. From our clinical experience, applying the mini-invasive surgical instruments during myectomy potentially reduces the technical difficulty. This study reports the preliminary experience regarding transaortic septal myectomy using mini-invasive surgical instruments for managing patients with HOCM and drug-refractory symptoms; also, we evaluate the early results following myectomy. Methods Between March 2016 and March 2019, consecutive HOCM patients who underwent isolated transaortic septal myectomy using the mini-invasive surgical instruments were enrolled in this analysis. Intraoperative, in-hospital and follow-up results were analyzed. Results We included 168 eligible patients (83 males, mean 56.8 ± 12.3 years). The midventricular obstruction was recorded in 7 (4.2%) patients. All patients underwent transaortic septal myectomy with a mean aortic cross-clamping time of 36.0 ± 8.1 min. During myectomy, 9 (5.4%) patients received repeat aortic cross-clamping. Surgical mortality was 0.6%. Notably, 5 (3.0%) patients developed complete atrioventricular block, they needed permanent pacemaker implantation. The median follow-up time was 6 months; however, no follow-up deaths occurred with a significant improvement in New York Heart Association functional status. We reported a sharp decrease in the maximum gradients from the preoperative value (11.6 ± 7.4 mmHg vs. 94.4 ± 22.6 mmHg, p p p Conclusions Mini-invasive surgical instruments may be beneficial in reducing the technical challenges of transaortic septal myectomy procedure. Of note, transaortic septal myectomy using the mini-invasive surgical instruments may present with favorable results.

As usher in Industry 4.0, there has been much interest in the development and research that combine artificial intelligence with automation. The control and operation of equipment in a traditional automated shoemaking production line require a preliminary subjective judgment of relevant manufacturing processes, to determine the exact procedure and corresponding control settings. However, with the manual control setting, it is difficult to achieve an accurate quality assessment of an automated process characterized by high uncertainty and intricacy. It is challenging to replace handicrafts and the versatility of manual product customization with automation techniques. Hence, the current study has developed an automatic production line with a cyber-physical system artificial intelligence (CPS-AI) architecture for the complete manufacturing of soft fabric shoe tongues. The Deep-Q reinforcement learning (RL) method is proposed as a means of achieving better control over the manufacturing process, while the convolutional and long short-term memory artificial neural network (CNN + LSTM) is developed to enhance action speed. This technology allows a robotic arm to learn the specific image feature points of a shoe tongue through repeated training to improve its manufacturing accuracy. For validation, different parameters of the network architecture are tested, and the test convergence accuracy was found to be as high as 95.9 %. During its actual implementation, the production line completed 509 finished products, of which 349 products were acceptable due to the anticipated measurement error. This showed that the production line system was capable of achieving optimum product accuracy and quality with respect to the performance of repeated computations, parameter updates, and action evaluations.

Aiming to investigate the propagation behaviour of distortion-induced fatigue cracks in steel bridge web gaps, multi-scale numerical analysis models were built based on fracture mechanics theory an...

Fatigue and corrosion damage in existing old steel bridges are accumulated continuously in service stage, probably leading to structural failure. One old welded steel bridge and one old riveted ste...

This paper instructs the working principle of the well washing device and its parameter optimization in practical applications. A fluent fluid engineering simulation software was used to establish the calculation model of the bottom flow field. The fluid area inside the well washing device with different orifice diameters at 30, 40, 50, and 60 degrees was simulated, and the gas‐solid two‐phase distribution cloud map and corresponding data were obtained. The results show that the cleaning effect is optimal and with no dead angle when θ = 30° and d = 4 mm. Moreover, the optimization design using simulation technology is reliable and simple. Based on this conclusion, a patent for a cyclone reverse circulation well washing device was invented. Under the same conditions, the above results were also verified by comparison with ordinary washing devices.

Objectives: Acute type A aortic dissection (aTAAD) is usually lethal without emergency surgery. Although veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is widely used in patients with cardiogenic shock following cardiac surgery, VA-ECMO support following aTAAD surgery has not been well-described. Based on our 6-year experience, we aimed to retrospectively analyze risk factors, application and timing of VA-ECMO, and outcomes in aTAAD patients.Methods: In this retrospective, single-center study, we enrolled adult patients who underwent aTAAD surgery from January 2014 to December 2019 and were supported with VA-ECMO. Patients were divided into two groups according to whether or not they were successfully weaned from VA-ECMO. Preoperative, intraoperative and postoperative variables were assessed and analyzed. Outcomes of the patients were followed up until discharge.Results: Twenty-seven patients who received aTAAD surgery with VA-ECMO support were included in the study. Nine patients (33.3%) were successfully weaned from VA-ECMO. The median VA-ECMO support time and length of hospital stay in the successfully weaned group were significantly longer than in the group could not be successfully weaned (192 [111–327] vs. 55 [23–95] h, p < 0.01; 29 [18–40] vs. 4 [3–8] days, p < 0.01). Overall in-hospital mortality was 81.5%. The main causes of death were bleeding (37%), neurological complications (15%), and multiple organ dysfunction syndrome (15%). Preoperative levels of creatine kinase-MB (CK-MB) were lower in patients who were successfully weaned from VA-ECMO than in the failed group (14 [6–30] vs. 55 [28–138] U/L, p < 0.01). Postoperative peak levels of CK-MB, cardiac troponin T, lactate dehydrogenase, and lactate were significantly lower in the successful group than in the failed group.Conclusion: Postoperative VA-ECMO support was rarely used in aTAAD patients. Our study showed that VA-ECMO can be considered as a salvage treatment in aTAAD patients, despite the high rate of complications and mortality.

Ultra-high performance fiber reinforced cementitious (UHPFRC) and composite reinforcement techniques have great potential in achieving efficient structural resistance recovery and overall ...

A low-cost lumped parameter model (LPM) is developed to simulate hydrogen storage in solid-state materials. The proposed LPM is a zero-dimensional model based on an analogous transient thermal resistance network that considers the whole storage system as a resistor–capacitor (RC) circuit with a current source. Combined with the mass conservation, sorption kinetics, and equation of state, the LPM is capable of predicting key thermofluidic quantities of the storage system, such as the storage bed temperature and pressure, hydrogen fraction and flowrate, and storage tank temperature. To test the applicability of the LPM, chemisorptive (Mg and LaNi5) and physisorptive (activated carbon) solid-state materials are simulated for adsorption and desorption processes. For both material types, LPM achieves predictive accuracies comparable to three-dimensional computational fluid dynamics (CFD) simulations, especially for hydrogen fraction and storage times (with maximum errors less than 9.6%), for a fraction of the computational cost (23,734 times lower memory requirement and 126 times faster calculation time). In addition, several formulations of the bed thermal resistance are proposed and discussed in terms of their impact on the accuracy of the LPM predictions. For slender cylindrical tanks, an equivalent annulus formula achieves the best balance of simplicity and accuracy.

Background Few studies focused on evaluating the impacts of preoperative severe left ventricular dysfunction on clinical outcomes of patients undergoing off-pump coronary artery bypass grafting surgery (OPCAB). This single center retrospective study aimed to evaluate the impacts of severe left ventricular dysfunction on in-hospital and mid-term clinical outcomes of Chinese patients undergoing first, scheduled, and isolated OPCAB surgery. Methods From January 2010 to December 2014, 2032 eligible patients were included in this study and were divided into 3 groups: a severe group (patients with preoperative left ventricular ejection fraction (LVEF) of ≤35%, n = 128), an impaired group (patients with preoperative LVEF of 36-50%, n = 680), and a normal group (patients with preoperative LVEF of >50%, n = 1224). In-hospital and follow-up clinical outcomes were investigated and compared. Results Patients in the severe group compared to the other 2 groups had higher in-hospital mortality and higher incidences of low cardiac output and prolonged ventilation. Kaplan-Meier curves showed a similar cumulative follow-up survival between the severe group and the impaired group (χ2 = 1.980, Log-rank p = 0.159) and between the severe group and the normal group (χ2 = 2.701, Log-rank p = 0.102). Multivariate Cox regression indicated that grouping was not a significant variable related to mid-term all-cause mortality. No significant difference was found in the rate of repeat revascularization between the severe group (2.4%) and the other 2 groups. Conclusions Patients with preoperative LVEF of ≤35% compared to preoperative LVEF of >35% increased the risk of in-hospital death and incidences of postoperative low cardiac output and prolonged ventilation, but shared similar mid-term all-cause mortality and repeat revascularization after OPCAB surgery.

Numerical studies of included angle effect on turbulent flow and heat transfer in rhombic serpentine heat exchangers are presented for the first time. Five included angles (γ) are examined, i.e. γ = 45-deg, 60-deg, 90-deg, 120-deg, and 135-deg, with rotation numbers ( Ro ) and coolant-to-wall density ratios (Δ ρ/ρ ) ranging from 0 to 0.2 and 0.1 to 0.2, respectively, at a constant Reynolds number ( Re ) of 10,000. The Reynolds-averaged Navier-Stokes (RANS) equations with low- Re realizable k -e model and enhanced wall treatment are solved with the tradeoff between accuracy and computational cost. Code validations are performed through the comparisons with previous measured local Nusselt number ratio ( Nu/Nu ∞ ) and thermal performance factor (TPF) for both stationary and rotating channels. The results show that the value of γ significantly affects the flow fields and heat transfer behaviors in both stationary and rotating cases. In the stationary situation, the Nu/Nu ∞ distributions on leading and trailing walls of the channels with slant walls (γ ≠ 90-deg) are asymmetric. As the channel rotates, there exists a critical rotating number, Ro c , in between Ro = 0.1 and 0.2. Beyond Ro c , f/f 0 decreases with increasing γ. The friction reduction of 135-deg channel to 90-deg channel for Ro = 0.2 and Δ ρ/ρ = 0.1 is about 43%. Furthermore, above Ro c and a critical Δ ρ/ρ around 0.2, the TPF increases with increasing γ, resulting in a 6% TPF augmentation when comparing the 135-deg channel with the 90-deg one.

The flexural behavior and ductility of high performance steel (HPS) girders were investigated experimentally. Thirteen simply supported I-girders of HPS 485W (nominal yield strength, fy = 485 MPa) flanges and webs with different steel grades including Q235 (fy = 235 MPa), Q345 (fy = 345 MPa), and HPS 485W were tested. Five additional girders considering different flange strengths of Q345, Q420 (fy = 420 MPa), and Q500 (fy = 500 MPa) were tested and compared. The test results show that the effectiveness of lateral braces is mainly influenced by the location and number, which in turn affect the expansion of plastic fields. The slenderness of element (flange or web) is the major factor affecting the flexural capacity and ductility of a girder. As the flange slenderness increases, flange local buckling occurs much earlier during the inelastic loading phase and thus reduces the girder ductility. As the web slenderness increases, the deformation in the inelastic stage decreases. Under the three-point loading, the girder appears not losing its capacity when the local element buckles. While, under the four-point loading, the flange local buckling depends on the unloading stage. When the high-strength HPS 485W steel is used for flanges, the web strength is suggested to be no lower than 345 MPa (Q345 steel). Using the same geometrical dimensions, the ductility of member is decrease with the increasing of flange strength, which is mainly affected by the yield stress to ultimate stress ratio (σy/σu) of steel. Hence, more restrictive slenderness limit appears necessary for structural designs using high-strength steel.

Objective To determine and compare the contributions of modifiable risk factors (RFs) with the prevention of dementia in older adults. Design A systematic review and Bayesian network meta-analysis (NMA). The observational group was set as a reference to collect all existing RFs and compare them with each other. Setting and Participants An exhaustive and comprehensive literature search strategy was used to identify relevant prospective cohort studies from several online databases from their inception to May 1, 2019. Participants without dementia were adults aged greater than 50 years. Measures The required data were extracted from the eligible studies to facilitate the Bayesian NMA. Results Forty-three cohort studies with 277,294 participants were included in this NMA. Using the observation group as the reference, all defined RFs, except for antioxidants, were associated with lower risks of all-cause dementia [no sleep disturbances (odds ratio, OR 0.43, 95% credible interval, CrI 0.24–0.62), a high level of education (OR 0.50, 95% CrI 0.34–0.66), no history of diabetes (OR 0.57, 95% CrI 0.36–0.78), nonobese patients (OR 0.61, 95% CrI 0.39–0.83), no smoking history (OR 0.62, 95% CrI 0.45–0.79), living with family members (OR 0.67, 95% CrI 0.45–0.89), participation in physical exercise (OR 0.73, 95% CrI 0.46–0.94), abstinence from drinking (OR 0.78, 95% CrI 0.56–0.99), and no history of hypertension (OR 0.80, 95% CrI 0.65–0.96)]. Conclusions/Relevance The findings provide reliable support for the hypothesis that modifiable somatic and lifestyle factors are strong predictors of all-cause dementia.

According to potential safety hazards of unreasonable ventilation and overrun dust concentration caused by the high degree of mechanization and the quick tunneling speed in the “long-distance & full-section” working face used in Daliuta coal mine of Shenhua coal group corporation limited, this paper studied the FPNA (far pressing near absorption ventilation) ventilation dedusting technology to solve the problems. This technology includes measures of simulation analysis on dust distribution, reasonable selection of the dust removal fan, adopting dynamic hanging technology to extending blower to the front of tunneling working face, setting up dust preventing board in front of tunneling machine and dust suppression by spraying. Field practice shows that the average dust concentration of working face is reduced by more than 50%, and achieved good results. The improved ventilation dedusting technology has been promoted and applied in Shenhua coal group corporation limited.

The aim of this study was to determine how older age and co-morbidities affect the treatment decision-making and long-term survival in elderly patients with symptomatic severe valvular heart diseases.A total of 181 elderly patients (mean age, 78.4 ± 3.4 years) hospitalized between January 2003 and June 2012 with symptomatic severe valvular heart diseases were enrolled. Cardiac and geriatric factors associated with treatment decision-making were analyzed. Survival outcomes were investigated.Surgical treatment was performed in 116 (64%) patients (surgical group) and 65 patients (36%) were treated conservatively (conservative group). The most common [62% (40/65)] reason for refusing surgical treatment was high operative risk as assessed by the physicians who initially cared for the patients. Multivariate logistic regression analysis identified female gender, chronic renal insufficiency, older age, pneumonia, and emergent status as independent predictors of the conservative treatment. Patients with isolated aortic valve disease tended to undergo an operation. Overall 5-year survival in the surgical group was 76.8% versus 42.9% in the conservative group (P < 0.0001). After matching using the propensity score, the surgical group still had a better long-term survival than the conservative group (P = 0.001). Cox regression analysis revealed conservative treatment as the single risk factor associated with poor long-term survival in all series.Approximately 40% of the elderly patients with symptomatic severe heart valve disease were treated conservatively despite a definite indication for surgical intervention. Cardiac and geriatric co-morbidities profoundly affect the treatment decision-making. Interdisciplinary discussion should be encouraged to optimize therapeutic options for elderly patients with valvular heart disease.

The main aim of this paper is to improve the control efficiency of the sewage treatment system, by analyzing the various control parameters of sewage treatment system and comparing different ways of automatic control, Siemens S7-200 Programmable Logic Controller(PLC) is applied to the system. We designed the control flow charts of coarse grid and dewatering system, compiled the total manual program and automatic control program of aerated grit chamber by using STEP 7-Micro/WIN 32 software, and realized the related equipment automatic control in the sewage treatment system which can run the coarse grid machine that runs for 20 minutes and stops for 2 hours alternately et cetera. The results show that the controllability of sewage treatment system is enhanced and the efficiency is improved.

In order to achieve the automatic control of electrostatic precipitator (ESP) more efficiently and accurately, an ESP system combining hardware and software is designed. According to the requirement of the ESP system,the Electronic Design Automation (EDA) is introduced to the ESP control system and the system is divided into four modules.These sub-modules are designed and the simulation waveform of the system is ananalyzed,based on the Very-High-Speed Integrated Circuit Hardware Description Language (VHDL) programming language and Quartus software.The results show that the security, flexibility and reliabity of the system is improved by using EDA as the control ,which is a great value for generalization.

Daqing oilfield ASP flooding drive target gradually changes from the first reservoir to the second and third reservoir,which leads to the unequal of the reservoirs producing extent, and seriously affects the developing for ASP flooding molecule weight. On the basis of that, we optimum the Molecule Weight Adjusting Mechanism of low permeability reservoir, and use the method of control variables to change the nozzle angle of diffuser section, cylinder length, diffuser angle, nozzle angle to establish 81 models. At the same time, we simulate flow field characteristics of these models with the help of Fluent. Ultimately, the models of low pressure drop and high stick loss rate could be found. Through analyzing and contrasting large of models, we found that shrinkage angle is 30 degree models under the same pressure drop condition the stick loss rate relativity high. Simultaneously, these models are suitable for the field requirements, and can provide theoretical basis for molecular weight adjusting and optimizing structure.

In the oil field development process, oil wells production capacity has been severely affected by clogged wells. There are many ways to relieve clogged wells, due to easy to operate, on the lifting of the blockage formation, the pressure pulse plugging technology has good prospects, but the current theory remains to be further studied, so the pressure pulse plugging process was simulated necessarily. The task to pressure pulses pulse tube plugging device as the research object, the establishment of its three-dimensional structure model to study the internal structure of the chamber, to analyze the impact of the flow field structure size rule. Establish its simplified model two-dimensional flow field, the compiler can achieve the state of motion of the sphere device UDF, application dynamic mesh of the pulse tube through Fluent unsteady flow was simulated. By convection field pressure, velocity and import-sectional physical monitoring equipment installation depth research and analysis, work flow, pressure relief device structure and the formation process of the pressure shocks field were investigated. Reveal the pulse tube working mechanism, and promote understanding of the pressure pulse plugging the nature of technology, optimize the structure of the pulse tube design basis and direction for the pressure pulse plugging technology and its theoretical foundation dynamics simulations.

Many existing steel bridges in China were strengthened or retrofitted recently to improve the load-carrying capacity or to extend the service life span. The effectiveness of these measures is investigated by evaluation of fatigue life of a strengthened highway continuous steel truss bridge in order to ensure continued safe use and to gain knowledge on repair or replacement. Three-dimensional finite element models of the structure before and after strengthening are established through calibration with in situ measured stresses and displacement. The traffic condition of the bridge is investigated, and the stress histogram and stress spectrum are simulated by the Monte Carlo method. The fatigue life and damage of all fracture-critical tension members before and after strengthening of the structure is calculated using S–N curves and by adopting a fracture mechanics model. Finally, the effectiveness of the strengthening is evaluated and a maintenance strategy evolved on the basis of the results of eval...

A probabilistic method named discovery process modeling is described for estimating the quantity of undiscovered oil and gas resources in Aral sea area in the North Ustrurt basin. In this model, the pool size distribution was demonstrated, and the numbers and sizes of undiscovered pools were estimated. The most likely remaining plays potential in Area sea area is 3447.2 Billions of standard cubic meters of gas in place. The eastern Jurassic-Cretaceous play bears 2901.5 Billions of standard cubic meters of undiscovered gas in place, and 17 gas pools are yet to be discovered; the paleogene-Neogene play bears 545.7 Billions of standard cubic meters of undiscovered gas in place, and 13 gas pools are yet to be discovered. Based on resources analysis, the Aral sea area is a prospecting exploration area for gas, and the emphasis should be strengthened on the eastern Jurassic-Cretaceous play.

This article presents a general framework for sensor-driven structural health prognosis and its application to probabilistic maintenance scheduling. Continuously collected sensor data is used to update the parameters of the stochastic structural degradation model. Uncertainty in sensor data (i.e. measurement error) is explicitly modelled as an evolving stochastic process. The proposed framework utilises Bayesian theorem and Markov Chain Monte Carlo (MCMC) sampling to calculate the posterior distributions of stochastic parameters of the structural degradation model. Bayesian updating allows the use of dynamic diagnostic information with prior knowledge for improved prognosis including risk analysis and remaining useful life (RUL) estimation. Although the proposed sensor-driven structural health prognosis procedure is illustrated with a fatigue-related example, it is applicable to more general applications such as corrosion and pavement cracking. A case study of the fatigue details found in a prototype stee...

Existing schemes have been firstly analyzed for secure routing protocol in Ad hoc networks. Then we present a new scheme for secure routing protocol base on AODV. Security features in the routing protocol include threshold authentication mechanism based on elliptic curve cryptosystem algorithm and improved the process of authentication without relying on the availability of a certificate authority center. Furthermore, the neighbor supervising mechanism combining with reputation mechanism are adopted to strengthen the management and supervision to network nodes, make the whole process of routing protocol under administration and supervision.

In this paper, fatigue damage and life prediction of laser lap joints were investigated based on natural frequency as the damage variable. At each fatigue stage, damage degree of laser welded specimen was monitored by the fatigue test and dynamic response tests. The results show that in the fatigue process during the increase in the number of fatigue cycles, each order natural frequency of test specimen decreased at different rate. There was almost no damage before the number of cycles reached 60% of the fatigue life, and then cracks began to initiate. When the number of cycles reaches 80% of the life, macroscopic cracks appeared and the predicted damage degree reached to 50%. Based on relation between the change rate of the natural frequency and the fatigue damage, a new fatigue life prediction model was established. The results from experimental tests were consistent with the fatigue life prediction model.

Trough-to-deck plate joints in steel orthotropic deck are very sensitive to fatigue. A full-scale fatigue test of steel orthotropic deck was conducted to study the fatigue performance of trough-to-deck plate joints between two diaphragms. The test panel has three spans of 1.0m+3.5m+1.0m in the longitudinal direction and five troughs with the width of 3.0m in the transverse direction. At the end of the fatigue test, the cycles of the fatigue load reached to six million and no fatigue cracks were found by naked eye at the trough-to-deck plate joints. Based on the failure criteria of the measured stresses with a sudden change, it is confirmed that the fatigue strength of trough-to-deck plate welded joints with deck plate failure is similar to design category 71 in the Eurocode using the measured stresses at a distance of ten millimeters from the weld toe.

The gray system theory modified by Kalman filtering method is used in the inconsistent between the observed and theoretical values of the segment’s deflection in bridge cantilever construction process. Firstly, get the statistically optimal estimatations of the observed value using Kalman filtering theory, then making it as the initial value, the gray system theory is used to predict the deflection of the next segment, and the formwork elevation of next stage is fixed. As a project example, a prestressed continuous girder bridge in Zhongshan City, Guangdong Province is put forward, respectively using the gray system theory and the gray system theory modified by Kalman filtering method to predict the deflection. According to the comparison from above two methods as well as the closure precision, the conclusion is the gray system theory modified by Kalman filtering can be more effective to reduce the deviation of observed and theoretical values, that means a better bridge linear control.

The long-term ground severe deformation and destruction induced by open pit and underground mining can badly affect the safety of surrounding environment. This problem is different from ground deformation and destruction induced by single mining. Based on chronological relationship between two kinds of mining and its corresponding deformation law under a practical engineering, the main reasons for long-term deformation and the deformation mechanism were revealed in this paper. Starting with the displacement mechanism, a method of horizontal movement coefficient was put forward to distinguish the movement property. Therefore, the impacts on two components of displacement vector can be distinguished, and then the basis for the proper analysis of ground deformation would be reached. At the same time, the ground deformation zone and the failure zone caused by subsequent open pit mining would be predicted, and the range of the failure zone would be gotten, providing a basis for safety decision.

The monitor system architecture in ternary optical computer (TOC) was discussed. There were some important modules, such as the client, network communication module (NCM), data preprocess module (DPM), operation-request scheduling module (ORSM), optical processor allocation module (OPAM) and the embedded system in the architecture. And the communication protocols between these modules were analyzed and designed. At the same time, the functions of the modules were introduced.

Through modern nondestructive inspection (NDI) techniques, fatigue cracks can be detected with varying accuracies in steel bridge structures, and consequently assessment and updating of fatigue reliability can be performed. A probabilistic fracture mechanics method based on the Bayes theorem using information from NDI has been demonstrated to update the relevant parameters of crack growth models effectively. Using the probabilistic characteristics of the NDI techniques, the probabilistic fatigue failure method, and the Bayes theorem, a procedure for assessing and updating the fatigue reliability of existing steel bridge components is presented. Data collected from two steel bridges, the Zhejiang Street Bridge and Ganjiang River Bridge, are used to illustrate the fatigue reliability assessment and updating method. In the case study, the suspender β‐T curves of the Zhejiang Street Bridge and Ganjiang River Bridge are determined after inspection and updating. It is found in this research that the fat...

The Yao Zhou downlink Viaduct damaged in a fire accident was repaired using steel plate and concrete composite strengthening (SPCCS) technique. After strengthening and servicing normally for 1.5 years, two loading tests, meanwhile, a three-day traffic information observation and dynamic strain monitoring were carried out. The static loading test and monitoring results all showed that the Yao Zhou downlink Viaduct had good service condition since reinforcement, which satisfying the safety requirement. In order to evaluate the effectiveness of the SPCCS technique in-depth, structural behaviour under the ultimate limit state (ULS) and the serviceability limit state (SLS) were analyzed. The SLS and ULC of the key sections before and after reinforcement were calculated using the simplified formula and the finite element models calibrated by filed test results. The post-evaluation results showed that the behaviour of the spans damaged in fire accident could be improved obviously under the SLS using SPCCS technique, as well as the bridge stiffness enlarged than the original bridge structure. The ultimate bearing capacity (UBC) of the key sections was improved about 75% using SPCCS technique, which was two times as the most disadvantageous load effect combinations. Whats more, the fatigue life of fire damaged box girders strengthened using SPCCS technique was evaluated based on monitoring strain data, and the further bridge maintenance suggestions were proposed based on the assessment results.

Induced forces in secondary steel bridge members such as diaphragms and cross-bracing can cause out-of-plane distortion in webs that may lead to fatigue cracking. Such cracking is most likely to occur if the distortion must be accommodated in a short length of the web, such as in the gap between the end of transverse stiffeners and girder flanges, thats because the web gap is subject to double curvature. In this paper, the numerical analysis models of the curved continue steel bridges were established using ANSYS software to calculate the fatigue stress at the web gaps. The numerical analysis results show that both the bottom web gap at middle span area and the top web gap at supported were poor fatigue details, and web thickness and web gap depth give the great affection on the out-of-plane distortion fatigue stress at web gaps of curved steel bridges.

The existing concrete bridges are often required to carry an increasing volume of traffic, higher speed and heavier trucks, so the bridge owners pay more attention to the actual fatigue damage and service safety of such structures. In this paper, Acoustic Emission (AE) sensors are used to monitor and evaluate the fatigue and damage of Yaoxian Bridge, which is the first field AE monitoring using Physical Acoustics Company equipment and sensors in China existing concrete bridge. This AE sensor has fine frequency bandwidth of interest to bridge monitoring, which is applicable to local cracking and damage positions and can monitor fatigue cracks and damage in close-range. In the field inspection, healthy monitoring was conducted at several locations, including the box concrete girder webs, bottom plates and deck plates using AE sensors. Based on AE monitoring data, the fatigue and damage conditions of box concrete girders was analyzed in order to propose theoretical basis and the rational advices for Yaoxian Bridge maintenance.

Removing noise from the original image plays an important role in many important applications involving image-based medical diagnosis and visual material examination for public security, and so on. Among them, there have been several published methods to solve the related problem, however, each approach has its advantages, and limitations. This paper examines a new measure of denosing in space domain based on 2-D kernel regression which overcomes the difficulties found in other measures. The idea of this method mainly let the values of a row or a column from an image are taken as the measured results of a fitting function. The following step is to estimate the weight coefficients using least square method. Finally, we obtain an denoised image by resampling the estimated function, and the variable x denotes the coordinate of an image. Results of an experimental applications of this method analysis procedure are given to illustrate the proposed technique, and compared with the basic wavelet-thresholding algorithm for image denoising.

Under the action of surface-underground unite mining, Slope stability is related to underground mining location and mining space dimension, This paper studies the underground mining of slope outer region on slope stability influence characteristic; With the increase of mining width stability coefficient increases, when mining width reach a certain value stability coefficient tends to constant; With the increase of mining depth stability coefficient increases, when mining depth reaching a certain value stability coefficient began to decrease; this show that the underground mining has a direct effect on slope stability, its size needs a combination of their relative spatial position relation and mining geometric size to determine.

Comparative finite element method (FEM) analyses of resistant spot welding (RSW) and laser beam welding (LBW) on stainless steel railway vehicles to assembly the framework and the side wall penal were conducted. The stress and strain of RSW joint and LBW lap joint were calculated under the same loading conditions by FEM simulation, respectively. The analyses revealed that not only the stress concentration occurred but also the maximum stress existed in the RSW joint compared with LBW lap joint under the same load. In contrast, LBW technique had more advantages than that of RSW technique in joining the car body framework and side wall penal of railway vehicles in the respects such as smaller deformation, better air tightness, and better appearance of car body and higher efficiency of processing.

This paper introduces the composition and usage of the18 luminescence tubes shadowless retractor, the Single-port gasless laparoscopy minimally invasive surgical instrument， which is the national patent products. As for the issue of inadequate illuminating intensity, the 3- lamp cold light Lifting retractor system is presented for the first time in domestic, as well as its designing and manufacturing procedure. It also presents the trial-producing of 3- lamp cold light Lifting retractor and its supporting power box. The system has been tested. It can apply to the disaster relief field and other special conditions, at the same time, it can improve the intensity of illumination with its simple producing procedure.

This paper presents an information-entropy-based integrated model for predicting the burn-through point (BTP) in lead-zinc sintering process. First, a fuzzy T-S prediction model for BTP was established to deal with the uncertainty of the vertical burning speed. Considering the BTP is also affected by process parameters, a neural network (NN) prediction model for BTP was then built. Finally, an integrated model for predicting the BTP was constructed by combining the above two models using the recursive entropy algorithm. The practical running results demonstrate the validity of the proposed integrated predictive model.

In this paper, we investigate the integrated network planning for telecommunications system, which considers adaptive sectorization and a hybrid F/CDMA scheme jointly under quality of service (QoS) constraints. The problem is formulated as a combinatorial optimization formulation in terms of minimizing the cost. We also investigate the viability of using Lagrangean relaxation (LR) to solve the problem. With regard to the computational results, the cost of considering network error states in the planning stage is 45% more than that of non-error. The proposed LR approach outperforms a simple algorithm with a cost improvement of 60%. In addition, the link constraint is more important to the total cost than the node constraint. Given a link constraint, the cost is affected more significantly by a decreasing threshold than by an increasing threshold. The proposed model is not only a valuable reference for network planning in a new field (e.g., a desert scenario), but also fits the planning requirements when some equipment pre-exists (an embedded scenario). We assign constant values to several decision variables, so the model is adaptable to various scenarios.

A full scale model of orthotropic deck panel was designed and fabricated referring to the common steel box girder bridges used in China. Experiment was conducted to test the behavior and fatigue performance of the orthotropic steel bridge deck under the actual truck wheel load. The loading test was conducted on the platform specially prepared. Measurement of the over-all structure and the fatigue sensitive details was made to evaluate the performance of the panel. For each gauge position, the results are presented as the form of influence lines.

A new steel-concrete composite girder which is an I-shaped girder with concrete-filled rectangular tubular flange was proposed in this paper. The web depth of the new composite girder is reduced, and lateral torsion buckling stiffness is improved, which can increase the buckling capacity of the girder. In order to study the bending capacity of concrete-filled rectangular tubular flange composite girders (CFRTFCG), the static tests of CFRTFCG with flat and corrugated webs under concentrate lateral loads had been performed. Based on the test results, the bending limit load capacity and mechanical behavior of the specimens were obtained, the bending failure mechanisms of CFRTFCG were also summarized.

Using truck weigh device, the data of traffic stream was collected from a toll station in Shaanxi province for 24 hours. A standard fatigue truck was developed based on the regular traffic data. Then S-N curves and Palgrem-Miner summation method was introduced in assessing fatigue life of the reinforcement in negative region of one continuous concrete bridge. It was concluded that the welding detail of reinforcement in negative region had long service life under normal traffic state. The fatigue life of reinforcement would be weakened considering overloading vehicles.

In the past ten years, considerable increases in traffic volume and vehicle loads have caused obviously fatigue damage in existing highway reinforced concrete bridges in China. Some highway reinforced concrete bridges were damaged seriously, leading to the whole bridge collapse sometimes because of overloading and oversize trucks. In order to observe the highway load character in Shaanxi province, truck weigh device is set up in highway pavement to measure axle weights and axle spacing. Based on these data, it can be classified and generalized the different classes of vehicles, and drawn out the simplifying fatigue truck model in Shaanxi province. Furthermore, the fatigue truck model was used to evaluate the fatigue life and service safety of typical concrete bridges.

Steel-concrete composite structure has been applied in bridge tower in recent years. In order to investigate the influence of different cross sections on the mechanical behaviors of composite bridge tower, two composite tower models with different cross sections, including rectangle and rectangle with chamfers, were designed and tested under axial compression. Through analysis of the local buckling modes and axial strain of the panels between the two models, it shows that in composite towers, compared with rectangle section, the section of rectangle with chamfers is more favorable in improving the capability of the tower to resist local buckling. For the panels in the chamfer have the smallest width-thickness ratio, so they can supply more advantageous support to their adjacent panels which are not in the chamfer and with the larger width-thickness ratio.

This paper evaluates the shear resistance of hybrid I-beams fabricated by high performance steel and conventional steel. A number of hybrid I-beams are modeled and analyzed to determine their shear failure mechanism characteristics, considering parameters of web slenderness (hw/tw), frame action from end-stiffeners, ratio of flange width to web depth (bf/hw) and panel numbers. The analyses conclude that, in shear resistance calculation, plate beam with inter and slender webs often fail in inelastic or elastic shear buckling while ultimate shear resistance of compact webs is given by the shear strength of the material. What’s more, more rigid stiffeners provide more fixity to flange plates and increase the post-buckling resistance of plate beam. For plate beam with several panels, the shear stress at the ultimate load is similar. Finally, the I-beams with larger flange width to web depth ratio would develop larger shear strengths and then shear deformation cause formation of plastic hinges.

In order to promote the applications of steel and concrete composite girder with concrete-filled tubular up-flange (SCCGCFTF) in practical bridge engineering, some actual issues for SCCGCFTF bridge structures have been discussed. The finite element static and dynamic analysis models of SCCGCFTF and conventional composite I-shape girder (CCIG) bridge structures were established. Then the stiffness, stress and dynamic characteristics of these composite girder bridges were studied and compared. Based on the numerical analysis results, the mechanical characters of SCCGCFTF bridges are obtained, and some design rules for SCCGCFTF bridges are also proposed. The analysis results show that SCCGCFTF bridges have high practical engineering application value.

Steel-concrete composite bridge towers have the advantages of steel and concrete, they have a good prospect in bridge engineering. However, the applications and related researches of composite bridge towers in China are rare. Therefore, in this article, two types of steel-high performance concrete composite bridge tower and pier models, which had none and one row of longitudinal stud connectors, were designed. The axial compression tests were practiced on the two specimens, in order to study the influence of connectors on the mechanical properties of the composite bridge towers and piers. From the tests, the ultimate bearing capacity and failure mode were obtained, and the regularities of strains and deformations were also analyzed. The results show that setting up stud connectors on the composite towers and piers can improve the ductility and the ultimate bearing capacity obviously.

In order to study the bending capacity of steel and concrete composite girder with concrete filled tubular flange (SCCGCFTF), a formula for the ultimate bending capacity of normal section was proposed based on perfected elastic-plastic model for steel and restricted concrete model for inner high performance self-compacted concrete. Analysis result shows that the mechanical behavior under static load can be divided into two phases in accordance with confining effects. Confining effects strength of the concrete-filled steel tube flange was relation to the restriction effect coefficient ξ. The ratios of the calculated value to the experimental ultimate bending capacity were between 0.93 and 0.97. Therefore, the theoretical formula is relatively safe to calculate the ultimate bending capacity.