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Bitter melon vine (an agricultural waste product with high fiber content) is difficult to treat and has caused problems in the environment. This research aims to produce biochar through low-temperature pyrolysis assisted by non-polluting steam explosion. The physical and chemical properties of the biochar were characterized using scanning electron microscopy (SEM) images, specific surface area measurements (BET), X-ray diffraction patters (XRD), elemental analysis (EA), and Fourier transform infrared spectroscopy (FTIR). Next, the adsorption mechanism of methylene blue (MB) on the steam-exploded bitter melon vine biochar pyrolyzed at 200 °C (qBC200) and the effects of adsorption time, pH, initial concentration, adsorption temperature, and adsorbent dosage on the adsorption effect were investigated. Steam explosion destroyed the dense structure of the plant, increased the number of oxygen-containing surface functional groups, and improved the adsorption performance of the material. Therefore, qBC200 more effectively adsorbed MB than untreated biochar, reaching a saturated adsorption capacity of 267.72 mg/g. The MB adsorption kinetics and isothermal adsorption process of qBC200 align with the pseudo-second-order kinetic model and Langmuir isothermal equation (monolayer adsorption), respectively. The thermodynamic results show that MB adsorbs via a spontaneous, entropy-increasing exothermic reaction. The adsorption mechanism involves electrostatic attraction, hydrogen bonding, and π–π interactions. The prepared biomass with high fiber content is a promising new material for wastewater treatment. [ABSTRACT FROM AUTHOR]

To overcome the deficiency of large numbers of nonlinear time history analysis for seismic fragility assessment of complex bridge structures, a fragility analysis method based on endurance time method (ETM) is proposed for rapid assessment of bridge fragility. Firstly, several endurance time accelerations (ETA) are synthesized according to ETM and combined with probabilistic seismic demand model. Subsequently, a sample library of finite element model for a long-span steel-truss deck arch bridge is established by using OpenSEES software with the consideration of bridge model uncertainties. ETM and incremental dynamic analysis (IDA) methods are employed to carry out nonlinear time history of the bridge models to obtain the fragility curves of typical components, and the applicability of ETM is validated by comparing the results of the two methods above. Results show that the relative error between ETM and IDA is basically controlled within 5%, indicating that the fragility method based on ETM can effectively take into account both analysis efficiency and calculation accuracy; Under the action of longitudinal earthquake, the seismic indexes (i. e., 0.597g and 0.972g) of approach pier and junction pier of steel-truss deck arch bridge with 50% moderate damage probability are much smaller than that of other components, illustrating that concrete piers are the most vulnerable members. The failure probability of arch ribs and columns under earthquake is small while the vault and arch foot are relatively weak. Short columns with fixed supports are susceptive to be damaged subjected to the longitudinal earthquakes, which can be optimized by changing the support layout of columns. [ABSTRACT FROM AUTHOR]

With the development of Western China and urbanization, more and more bridges are close to or even across active faults, which are significantly affected by fault ground motion. In order to simulate the collapse process of a simply supported beam bridge under strong earthquakes, a three-dimensional finite element model of the bridge was established based on LS-DYNA platform. Through the analysis of bridge collapse and seismic response, the damage mechanism of simply supported beam bridge under strong earthquake is studied, and the influence of bearing shear stiffness on the collapse process and seismic response of simply supported beam bridge is analyzed. Research shows: The collapse failure mode of simply supported beam bridge under earthquake is mainly the insufficient bearing capacity of piers caused by the large-area failure of concrete at the bottom of piers, which leads to the collapse of the whole bridge. With the continuous action of seismic load, the piers of simply supported beam bridges go through normal operation stage, damage evolution stage and collapse stage in turn. Increasing the shear stiffness of the bearing will increase the duration of the damage evolution stage of the pier. The increase of the shear stiffness of the support increases the constraint between the beam and the pier, reduces the deformation of the support, and reduces the displacement response of the simply supported beam bridge and the collision effect between the beams. The seismic response of bridges without unit failure is greater than that of bridges with unit failure, and the seismic response of bridges becomes larger and larger with unit failure. [ABSTRACT FROM AUTHOR]

In order to study the influence of seismic wave, fundamental period of bridge structure and damping model on input energy of seismic, damping energy and hysteresis energy, four working conditions are established according to different height of the pier based on the seismic energy method with reference to the lead rubber bearing isolated continuous girder beam bridge, and three damping models are used for the calculation of damping. According to the ratio of seismic wave peak velocity (PGV) to peak acceleration (PGA), six seismic waves are selected from PEER. The numerical mechanics model is established by using finite element software, and seismic response analysis of nonlinear dynamic time history is carried out. Study results are obtained as follows: the value of /PGV/PGA/ of seismic wave has a great influence on input energy, damping energy and hysteresis energy; the fundamental period of bridge structure has a little influence on input energy, but certain influence on damping and hysteresis energy; the hysteresis energy of isolation bearings of bridge structure with lower fundamental period is more obvious; the damping model has a little influence on seismic input energy, but great influence on damping and hysteresis energy. Therefore, the calculation of damping with Rayleigh damping is more conducive to protect piers when the energy method is used for seismic analysis of isolated continuous girder beam bridge; and seismic wave should not be selected randomly, but selected according to the type of site and the seismic fortification intensity. [ABSTRACT FROM AUTHOR]

The objective of this study is to present a novel fragility analysis method that combines principal component analysis (PCA) and the K-means clustering algorithm for a probability assessment of seismic damage in high-pier bridges undergoing pulse-like ground motions. Firstly, the method uses the correlation coefficient and the condition number as judgment indices to eliminate those seismic intensity measures (IMs) with weak correlation and multicollinearity from all 29 of the initial candidate seismic IMs, the optimal combination of IMs that satisfies the requirements for the PCA method is determined. Secondly, the method utilizes PCA to reduce the dimensionality of the optimal combination of IMs to obtain the principal components, after which the K-means algorithm is applied to classify the original group of selected pulse-like ground motions into four classes. Thirdly, a 3D finite element model of the exemplary high-pier bridge is developed via OpenSees, while incremental nonlinear dynamic time-history analyses are conducted to record the maximum cross-section curvatures of high piers under the influence of various categories of ground motions. Finally, based on the analytical procedures used in the increment dynamic analysis (IDA) method, this study develops and compares the fragility curves for the various classes of pulse-like ground motions. The results indicate the necessity of utilizing the PCA and K-means approach for classifying pulse-like ground motions in the seismic fragility analysis of high-pier bridges. This approach also significantly improves the precision and accuracy of damage probability analysis. [ABSTRACT FROM AUTHOR]

This study aims to analyse the risk factors of Peristomal Moisture‐Associated Skin Damage (PMASD) in colorectal cancer patients, construct a prediction model, and verify its effect. A total of 375 patients who underwent rectal cancer stoma surgery at the Liaoning Cancer Hospital between January and December 2020 were selected according to the inclusion and exclusion criteria. The clinical data were retrospectively analysed for modelling and internal validation (modelling group). According to the same criteria, the clinical data of 242 patients from January and June 2021 were retrospectively analysed for external validation (validation group). Baseline patient data were recorded. Patients in the modelling group were divided into those with and without PMASD based on the occurrence of PMASD during hospitalisation. Logistic regression analysis was used to examine the factors of PMASD and the PMASD nomogram model of colorectal cancer. Internal model validation was performed with the Bootstrap method, using the ROC and H‐L goodness of fit test to evaluate the differentiation and calibration of the model. Last, external validation of the model was performed. In the modelling group, 212 patients with colorectal cancer developed PMASD. According to the results of the logistic regression analysis, high fasting plasma glucose and fasting blood glucose (FPG), a history of radiotherapy, the height of the stoma opening (i.e., flat or lower than the skin surface), and skin folds around the stoma are risk factors for PMASD (OR > 1, P < 0.05). The stool shaping and colostomy are protective factors for PMASD in patients with colorectal cancer (OR < 1, P < 0.05). To establish the prediction of colorectal cancer, patient development of PMASD line, graph model, and internal verification was carried out using the Bootstrap method: H‐L test P = 0.846, area under curve, area under the ROC curve (0 > 0.75, 95% CI: 0.778–0, AUC = 0.820). The external validation included the H‐L test (P = 0.137, AUC [0.862] > 0.75, 95% CI: 0.815–0.909), with the maximum value of the Youden index as the best cut‐off value for the model. The ROC curve had a Youden index of 0.559, a sensitivity of 0.877, and a specificity of 0.657. The prompt model area showed good calibration and discrimination. The PMASD in patients with colorectal cancer is affected by defecation traits, the stoma opening height, stoma type, FPG, skin folds around the stoma, and previous radiotherapy history. The nomogram model can provide an effective means to reasonably predict the risk of PMASD in patients with colorectal cancer. [ABSTRACT FROM AUTHOR]