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A new compound was synthesized by chemical combination of (3-mercapto)propyl-heptaisobutyl polyhedral oligomeric silsesquioxane (POSS-SH) and 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS) via epichlorohydrin while hydroxyl groups were still retained in the product POSS-DMDBS. The prepared POSS-DMDBS was introduced into isotactic polypropylene (iPP) to improve crystallization behaviors of iPP and obtain nanocomposites with suitable mechanical properties. Crystallization and mechanical properties of iPP/POSS-DMDBS were systematically investigated by wide-angle X-ray diffraction, polarization microscopy, atomic force microscopy, differential scanning calorimetry, and tensile tests. The spherulite size of the modified iPP was obviously decreased with the addition of POSS-DMDBS, while the crystallization temperature was increased by 5[degrees]C to 9[degrees]C depending on the content of POSS-DMDBS incorporated. POSS-DMDBS exhibited relatively higher nucleating efficiency on iPP which is similar to that of DMDBS, confirmed by the increased crystallization temperature. It was also found that the tensile modulus of iPP after adding POSS-DMDBS increased significantly with respect to pristine iPP, but the elongation values decreased. Introduction of POSS-DMDBS in content less than 1 wt% could bring about effective influence on the crystallization behaviors of iPP, demonstrating its potential applications. POLYM. ENG. SCI., 57:357-364, 2017. [C] 2016 Society of Plastics Engineers, INTRODUCTION As a kind of hybrid organic-inorganic compounds, polyhedral oligomeric silsesquioxanes (POSS) received dramatic attention in recent years for development of polymer nanocomposites [1-3]. Different from other inorganic modifiers, POSS [...]

To address the problem of dissolution damage during the long-term service of concrete hydraulic buildings, the concrete dissolution damage degree D and contact dissolution loss model with time were proposed by combining the results of indoor concrete dissolution tests. A mathematical model of the evolution of concrete parameters with time was developed. In the context of an underground concrete culvert project, a numerical analysis model of concrete dissolution deterioration was established, according to which the effects of different damage locations on the stress and displacement of concrete culverts were analyzed. The results show that the settlement value of the surface and the soil pore pressure value increase more when the bottom of the culvert is damaged by dissolution, and the settlement of the surface from the bottom damage is about 1.07~1.16 times of that from the top damage. When the damage position deviates from the center line of the culvert, the maximum point of vertical displacement in the transverse settlement trough of the ground surface deviates from the centerline of the culvert by about 3~5 m in the horizontal direction. At the bottom of the culvert, the concrete permeability coefficient reaches 6.957 × 10−8 m/s~8.354 × 10−8 m/s in about 13~16 years after the occurrence of dissolution damage, and local leakage occurs, causing a significant increase in the pore pressure of the soil near the leakage location. The overall settlement and uneven settlement resulting from the dual action of dissolution deterioration of concrete and infiltration pressure can have a serious impact on the upper channel buildings. [ABSTRACT FROM AUTHOR]

Low-density polyethylene (LDPE)/barium sulfate (BaSO4) composites with different contents of BaSO4 nanoparticles after modification by stearic acid (SA) were prepared. Characterizations of morphology, thermal, and mechanical properties of the LDPE/SA-BaSO4 composites were systematically performed by scanning electron microscope, thermal gravimetric analysis, tensile and flexural tests. Specially, the X-ray radiographic and developable properties were examined by the X-ray fluoroscopy test and the ageing resistant properties were analyzed by the simplified protocol of accelerated aging. It was found that the Young's modulus and tensile strength of the composites were increased by 24.6 and 11.0% while flexural modulus and flexural strength were increased by 10.8 and 14.0%, respectively, together with the elongation at break of 455.1% ± 26.3% which was 74.4% of LDPE when the SA-BaSO4 content reached 25 wt%. By contrast, when accelerated ageing for 5 years, the retention ratios of Young's modulus, tensile strength and elongation remained at 89.3, 69.5, and 69.6%, respectively. In addition, X-ray radiographic and developable properties of the composites were also improved by the addition of SA-BaSO4, making it possible to achieve some applications in medical devices such as intrauterine devices and body brackets which could be easily implanted into human bodies and enable accurate external monitoring using an X-ray medical diagnostic machine. POLYM. COMPOS., 37:1396-1406, 2016. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

This paper presents a new seepage inversion technique to predict the permeability coefficient of the rock mass with developed fracture or fault. With the measured data of flow and water head of boreholes, the permeability coefficient of the rock masses near the boreholes are obtained by inverse calculation on the basis of unsteady seepage tests. Then, a flexible tolerance method is proposed to invert the permeability coefficient of rock masses in different zones of the reservoir area. This comprehensive inversion analysis method is applied in one actual project of the water supply reservoir. The equivalent permeability coefficient of the rock masses in the range of 0 m to 16.0 m below the road surface near the dam axis on the left bank of the mountain is 1.12 × 10−3 cm/s. The root mean squared error and coefficient of determination of the measured and calculated values are 1.33 × 10−4 m3/s and 0.9976 m3/s, respectively. The rock masses in the reservoir site area have high permeability. The groundwater level in the junction area and the mountains on both sides of Shangmo reservoir is low, and the hydraulic gradient is small. The maximum error between the calculated value of the groundwater level and the measured values is −0.41 m, and the relative error is −4.36%. The recommended anti-seepage scheme can effectively solve the problem of large leakage in the reservoir area. The results show that the innovative approach is appropriate for the seepage analysis of the field with the fractured rock masses and more meaningful from an engineering point of view. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Dalton Transactions: An International Journal of Inorganic Chemistry." It includes various articles and papers on topics such as combatting bacterial infections, rare-earth metal-organic frameworks, and electrochemical capacitor applications. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document provides a brief overview of the articles included in the journal issue. The papers cover a range of topics in chemistry, including the synthesis of stable cyclopropenylvinyl ligands, the properties of metal-organic frameworks, the photocatalytic performance of titanium-oxide clusters, and the adsorption mechanisms of heavy metals on silica. Other topics include the synthesis of coordination polymers, the synthesis of salophen complexes, and the behavior of cyanido-bridged complexes. The papers provide valuable insights into various areas of chemical research. [Extracted from the article]

Background: The predictive value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) metabolic parameters for predicting AIP relapse is currently unknown. This study firstly explored the value of 18F-FDG PET/CT parameters as predictors of type 1 AIP relapse. Methods: This multicenter retrospective cohort study analyzed 51 patients who received 18F-FDG PET/CT prior to treatment and did not receive maintenance therapy after remission. The study collected baseline characteristics and clinical data and conducted qualitative and semi-quantitative analysis of pancreatic lesions and extrapancreatic organs. The study used three thresholds to select the boundaries of pancreatic lesions to evaluate metabolic parameters, including the maximum standard uptake value (SUVmax), mean standard uptake value (SUVmean), total lesion glycolysis (TLG), metabolic tumor volume (MTV), and tumor-to-normal liver standard uptake value ratio (SUVR). Univariate and multivariate analyses were performed to identify independent predictors and build a recurrence prediction model. The model was internally validated using the bootstrap method and a nomogram was created for clinical application. Results: In the univariable analysis, the relapsed group showed higher levels of SUVmax (6.0 ± 1.6 vs. 5.2 ± 1.1; P = 0.047), SUVR (2.3 [2.0–3.0] vs. 2.0 [1.6–2.4]; P = 0.026), and TLG2.5 (234.5 ± 149.1 vs. 139.6 ± 102.5; P = 0.020) among the 18F-FDG PET metabolic parameters compared to the non-relapsed group. In the multivariable analysis, serum IgG4 (OR, 1.001; 95% CI, 1.000–1.002; P = 0.014) and TLG2.5 (OR, 1.007; 95% CI, 1.002–1.013; P = 0.012) were independent predictors associated with relapse of type 1 AIP. A receiver-operating characteristic curve of the predictive model with these two predictors demonstrated an area under the curve of 0.806. Conclusion: 18F-FDG PET/CT metabolic parameters, particularly TLG2.5, are potential predictors for relapse in patients with type 1 AIP. A multiparameter model that includes IgG4 and TLG2.5 can enhance the ability to predict AIP relapse. [ABSTRACT FROM AUTHOR]

In research using heat tracing technology to investigate the lateral hyporheic exchange in the shallow geological body of the riparian zone, the accurate estimation of temperature changes can provide a scientific basis for quantifying the process of lateral hyporheic exchange. To improve the accuracy of estimating temperature changes in the riparian zone, a hydrothermal coupling model considering parameter heterogeneity was established based on existing models of the relationship between thermal conductivity and saturation. The model was verified by temperature data from laboratory experiments, and the effect of the thermal conductivity prediction models was compared with that of the partial differential equation (PDE) modeling approach. The results show that the established hydrothermal coupling model can effectively characterize the temperature changes observed in a generalized laboratory model of the riparian zone, and the model simulation effects vary with the equivalent thermal conductivity models. In addition, several thermal conductivity empirical models are suggested for further application. The model parameter sensitivity analysis indicated that the hydraulic conductivity k s , VG model parameters (α and β) and heat capacity of soil C s have a relatively large effect on the temperature output of the model. The results of this study will provide reference for the selection of equivalent thermal conductivity model for simulating temperature variations in the riparian zone. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to devote to the experimental analysis and modeling on the heat generation of angular contact ball bearings under vibration. Design/methodology/approach: The experiments about vibration effect on bearing temperature are implemented. To explore the causes of bearing temperature rise, the shaft-bearing system is first simplified to a forced vibration model to analyze the bearing loads in vibration. Next, the vibratory-induced additional load is proposed and the spin power loss of balls is re-derived under vibration. The vibration-induced heat is integrated into a novel forecasting model of bearing power loss. For validation, the muti-node model for angular contact ball bearings is referred to create the thermal network of spindle front bearing, and then the contrast and discussion is done. Findings: The simulation and test results both indicate that more energy is expended and more heat is generated with vibration. And the further quantitative comparisons between simulation results and experimental values of bearing temperature demonstrate the rationality and availability of constructed model on bearing heat generation. Originality/value: The vibration-induced additional load is proposed and modeled, and the novel forecasting model for heat generation for high-speed angular contact ball bearings with vibration is constructed and validated. [ABSTRACT FROM AUTHOR]