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The effect of CO2 on the rheology and filtration loss of high-density potassium polysulfonate drilling fluid systems were studied, as well as the law of the contamination and the mechanism of contamination, on the performance of the systems after they are contaminated by CO2 in the one of natural gas area in southwest China and run out of control. The results show that there is a critical value of CO2 contamination: 5 932 mg/L for CO32- and 7 874 mg/L for HCO3-. When it is less than the critical value, CO2 can precipitate Ca2+ and promote hydration and dispersion, the clay dispersion state changes from coarse dispersion to fine dispersion, the particles become smaller, the Zeta potential increases, and the colloid stability of the drilling fluid is enhanced. After passing the critical value, the viscous shear increases sharply and the filtration loss becomes severely out of control. It has been shown that excessive CO2 pollution causes clay particles to aggregate, shifting from a fine dispersion state to a flocculation state, large clay particles form card-house structures, filter cake leakage channels increase, and colloid stability becomes worse. [ABSTRACT FROM AUTHOR]

Parameterisation-based methods for planning tool paths on mesh surfaces have been developing for years. The issue of existing mapping deformation which results in machining error has not been sufficiently addressed. And it still needs particular 3D geometric operations when planning iso-scallop tool path. To handle these, an effective approach to directly generating the iso-scallop paths on the parametric domain utilising anisotropic mapping stretch factors is proposed. The conformal parameterisation algorithm, Angle Based Flattening, is first implemented for the mapping between the spatial mesh and the planar mesh. Then a general method to convert 3D path parameters into 2D, which involves the direction mapping and length mapping based on the mapping deformation analysis, is presented. After that, a non-uniform offsetting method is proposed for retrieving the valid 2D offset paths. Finally, the iso-scallop paths on the parametric domain can be generated using the converted 2D path parameters and the present non-uniform offsetting method, and then the corresponding tool paths are obtained by inverse mapping. Simulation and experimental results are given to validate the feasibility and effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Soil internal forces can affect aggregate breakdown, and then impact splash detachment and transport of aggregate fragments. However, currently, the processes of soil splash detachment and transport under different soil internal forces are still not fully understood. Thus, to determine the effects of soil internal forces on the splash transport process, two soils (Binxian soil and Keshan soil) in the Mollisols (black soil) of Northeast China were selected to analyse the detachment and transport characteristics of aggregate fragments under different splash distances (0–10, 10–20, 20–30, 30–40 and 40–50 cm) through simulated rainfall experiments. Different concentrations of KCl electrolyte (from 1 to 10−5 mol L−1) were employed as rainfall materials to regulate soil internal forces. The results revealed that the net pressure of soil internal forces and splash amount presented the same trend with decreasing electrolyte concentration, that is, increased initially (from 1 to 10−2 mol L−1), followed by levelling off (from 10−2 to 10−5 mol L−1). The splash amount and net pressure had an exponential relationship (p < 0.01). Under the same electrolyte concentration, Binxian soil had a higher net pressure and splash amount than Keshan soil. The splash amount for the two soils was mostly distributed at a splash distance of 0–20 cm, and it exponentially decreased with increasing splash distance (p < 0.01). An empirical expression in our study was developed to predict the splash amount (M) based on the net pressure (N) and splash distance (S). The size distribution of splashed aggregates could be affected by the net pressure of soil internal forces, the greater the net pressure, the smaller size aggregates splashed. At each splash distance, the highest mass percentage was observed for the fragments <0.053 mm and accounted for 35.5% to 82.1% of the total splash amount. This study provides valuable information to better understand the processes and mechanisms of rainfall splash erosion in the Chinese Mollisol region. Highlights: The distribution characteristics of aggregate fragments under different soil internal forces were tested.Relations between soil internal forces and soil aggregate detachment were determined.The distribution of splashed aggregates size was greatly affected by soil internal forces.Soil internal forces had important effects on splash erosion in the Mollisols of Northeast China. [ABSTRACT FROM AUTHOR]

Purpose: Soil nanoparticles (NPs) are active organic-mineral complexes and have an important impact on the migration of nutrients, organic pollutants, and heavy metals. Due to their diversity and heterogeneity, researches have mainly investigated the effect of solution chemistry on the stability of soil NPs, but little attention is paid to the influences of particle properties. Methods: In the present study, NPs were separated from the eluviated cinnamon soil (ECS), typical cinnamon soil (TCS), and carbonate cinnamon soil (CCS), namely ECS-NP, TCS-NP, and CCS-NP. The particle composition, surface-related properties, and the aggregation kinetics of soil NPs were investigated. Correlation analyses between soil NP properties and their critical coagulation concentrations (CCCs) were further discussed. Results: The bulk ECS, TCS, and CCS differed highly in CaCO3 content. While in soil NP fractions, the contents of soil organic matter and illite were more abundant. The particle size, specific surface area, and Hamaker constant of soil NPs followed the order of ECS-NP < TCS-NP < CCS-NP, while the yield, zeta potential (in absolute values), and the CCCs were in the reverse trend. The particle diameter, specific surface area, and zeta potential significantly correlated with the CCCs. Conclusion: The present study revealed the important role of particle properties in dominating the stability (aggregation and dispersion) of soil NPs. Therefore, it is necessary to further systematically explore the composition of soil NPs on dominating their environmental behaviors. [ABSTRACT FROM AUTHOR]

Background: The anatomical dimensions of the lumbar dural sac determine the sensory block level of spinal anesthesia; however, whether they show the same predictive value during continuous epidural anesthesia (CEA) remains undetermined. We designed the present study to verify the efficacy of the anatomical dimensions of the lumbar dural sac in predicting the sensory block level during labor analgesia. Methods: A total of 122 parturients with singleton pregnancies requesting labor analgesia were included in this study. The lumbar dural sac diameter (DSD), lumbar dural sac length (DSL), lumbar dural sac surface area (DSA), and lumbar dural sac volume (DSV) were measured with an ultrasound color Doppler diagnostic apparatus. CEA was performed at the L2-L3 interspace. After epidural cannulation, an electronic infusion pump containing 0.08% ropivacaine and sufentanil 0.4 μg/ml was connected. The sensory block level was determined with alcohol-soaked cotton, a cotton swab, and a pinprick. The analgesic efficacy of CEA was determined with a visual analog scale (VAS). The parturients were divided into two groups, "ideal analgesia" and "nonideal analgesia," and the groups were compared by t test. Pearson's correlation was performed to evaluate the association between the anatomical dimensions of the lumbar dural sac and sensory block level. Multiple linear regression analysis was used to create a model for predicting the sensory block level. Results: In the ideal analgesia group, the height, DSL, DSA, DSV and DSD were significantly smaller, and the body mass index (BMI) was significantly larger (P < 0.05). In addition, the DSL demonstrated the strongest correlation with the peak level of pain block (r = − 0.816, P < 0.0001; Fig. 2A), temperature block (r = − 0.874, P < 0.0001; Fig. 3A) and tactile block (r = − 0.727, P < 0.0001; Fig. 4A). Finally, the multiple linear regression analysis revealed that DSL and BMI contributed to predicting the peak sensory block level. Conclusion: In conclusion, our study shows that the sensory block level of CEA is higher when the DSL, DSA, DSV and DSD of puerperae are lower. DSL and BMI can be treated as predictors of the peak sensory block level in CEA during labor analgesia. [ABSTRACT FROM AUTHOR]

To solve the Earth pressure problems in practical engineering, such as retaining walls and foundation pits, we derive active and passive Earth pressure formulas in accordance with the relationship between intermediate principal stress and excavation under three-dimensional stress states. The formulas are derived on the basis of the Mohr–Coulomb, spatially mobilized plane (SMP), σ 3 SMP, Lade–Duncan, axisymmetric compression- (AC-) SMP strength, and generalized Mises (Gen-Mises) criteria and then extended to clay. We also compare the calculated Earth pressure with the measured data. Results indicate that the Earth pressure considering medium principal stress contribution under a three-dimensional stress state is consistent with the actual engineering. The calculated active Earth pressure in the Mohr–Coulomb strength criterion is larger, and the passive Earth pressure is smaller than the practical one because the intermediate principal stress effect is not considered. The calculated results of the SMP, σ 3 SMP, Lade–Duncan, AC-SMP strength, and Gen-Mises criteria are close to the measured data, among which the result of the Gen-Mises criterion is closer. The Earth pressure calculated using the Lade–Duncan criterion is no longer appropriate to describe the Earth pressure under medium principal stress condition in this study. The results of this study have theoretical significance for retaining structure design under a three-dimensional stress state. [ABSTRACT FROM AUTHOR]

In the ironmaking process, the addition of an organic binder to replace a portion of bentonite has the potential to improve the performance of pellets. The interaction between original bentonite (OB) and organic binder was investigated. Results indicated that the micromorphology of organic composite bentonite (OCB) became porous and the infrared difference spectrum exhibited a curved shape. In addition, the residual burning rates of OB and organic binder were determined to be 82.72% and 2.30%, respectively. Finally, the influence of OCB on the properties of pellets was investigated. The compressive strength of OCB-added green pellets (14.7 N per pellet) was better than that of OB-added pellets (10.3 N per pellet). Moreover, the range of melting temperature of OCB-added green pellets (173°C) was narrower than that of OB-added pellets (198°C). The compressive strength of OCB-added green pellets increased from 2156 to 3156 N per pellet with the increase in roasting temperature from 1200 to 1250°C. [ABSTRACT FROM AUTHOR]

We investigated the effect of Al2O3 content on the viscosity of CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3 (mass ratio of CaO/SiO2 is 1.0, and Al2O3 content is 17wt%–29wt%) slags. The results show that the viscosity of the slag increases gradually with increases in the Al2O3 content in the range of 17wt% to 29wt% due to the role of Al2O3 as a network former in the polymerization of the aluminosilicate structure of the slag. With increases in the Al2O3 content from 17wt% to 29wt%, the apparent activation energy of the slags also increases from 180.85 to 210.23 kJ/mol, which is consistent with the variation in the critical temperature. The Fourier-transform infrared spectra indicate that the degree of polymerization of this slag is increased by the addition of Al2O3. The application of Iida's model for predicting the slag viscosity in the presence of Cr2O3 indicates that the calculated viscosity values fit well with the measured values when both the temperature and Al2O3 content are at relatively low levels, i.e., the temperature range of 1673 to 1803 K and the Al2O3 content range of 17wt%–29wt% in CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3 slag. [ABSTRACT FROM AUTHOR]

A low MgO content in sinter is conducive to reduce the MgO content in blast furnace slag. This study investigated the effect of MgO content in sinter on the softening—melting behavior of the mixed burden based on fluxed pellets. When the MgO content increased from 1.31wt% to 1.55wt%, the melting temperature of sinter increased to 1521°C. Such an increase was due to the formation of the high-melting-point slag phase. The reduction degradation index of sinter with 1.31wt% MgO content was better than that of others. The initial softening temperature of the mixed burden increased from 1104 to 1126°C as MgO content in sinter increased from 1.31wt% to 1.55wt%, and the melting temperature decreased from 1494 to 1460°C. The permeability index (S-value) of mixed burden decreased to 594.46 kPa·°C under a high MgO content with 1.55wt%, indicating that the permeability was improved. The slag phase composition of burden was mainly akermarite (Ca2MgSiO7) when the MgO content in sinter was 1.55wt%. The melting point of akermarite is 1450°C, which is lower than other phases. [ABSTRACT FROM AUTHOR]

Soil labile organic carbon (LOC) responds rapidly to environmental changes and plays an important role in carbon cycle. In this study, the seasonal fluctuations in LOC, the activities of carbon-cycle related enzymes, and the bacterial and fungal communities were analyzed for soils collected from two forests, namely Betula albosinensis (Ba) and Picea asperata Mast. (Pa), in the Qinling Mountains of China. Results revealed that the seasonal average contents of microbial biomass carbon (MBC), easily oxidized organic carbon (EOC), and dissolved organic carbon (DOC) of Pa forest soil were 13.5%, 30.0% and 15.7% less than those in Ba soil. The seasonal average enzyme activities of β-1,4-glucosidase (βG), and β-1,4-xylosidase (βX) of Ba forest soils were 30.0% and 32.3% higher than those of Pa soil while the enzyme activity of cellobiohydrolase (CBH) was 19.7% lower. Furthermore, the relative abundance of Acidobacteria was significantly higher in summer than in winter, whereas the relative abundance of Bacteroidetes was higher in winter. Regarding the fungal communities, the relative abundance of Basidiomycota was lowest in winter, whereas Ascomycota predominated in the same season. In addition, the soil LOC was significantly positively correlated with the CBH, βG and βX activities. Changes in LOC were significantly correlated with Acidobacteria, Bacteroidetes and Basidiomycota. We conclude that the seasonal fluctuations in forest soil LOC fractions relied on carbon cycle-associated enzymatic activities and microorganisms, which in turn were affected by climatic conditions. [ABSTRACT FROM AUTHOR]

Background: Hearing loss (HL) is a common sensory disorder in humans characterized by extreme clinical and genetic heterogeneity. In recent years, next‐generation sequencing (NGS) technologies have proven to be highly effective and powerful tools for population genetic studies of HL. Here, we analyzed clinical and molecular data from 21 Chinese deaf families who did not have hotspot mutations in the common deafness genes GJB2, SLC26A4, GJB3, and MT‐RNR1. Method: Targeted next‐generation sequencing (TGS) of 127 known deafness genes was performed in probands of 12 families, while whole‐exome sequencing (WES) or trio‐WES was used for the remaining nine families. Results: Potential pathogenic mutations in a total of 12 deafness genes were identified in 13 probands; the mutations were observed in GJB2, CDH23, EDNRB, MYO15A, OTOA, OTOF, TBC1D24, SALL1, TMC1, TWNK, USH1C, and USH1G, with eight of the identified mutations being novel. Further, a copy number variant (CNV) was detected in one proband with heterozygous deletion of chromosome 4p16.3‐4p15.32. Thus, the total diagnostic rate using NGS in our deafness patients reached 66.67% (14/21). Conclusions: These results expand the mutation spectrum of deafness‐causing genes and provide support for the use of NGS detection technologies for routine molecular diagnosis in Chinese deaf populations. [ABSTRACT FROM AUTHOR]

We prove that the irreducible components of the moduli space of polarized Calabi–Yau pairs are projective. [ABSTRACT FROM AUTHOR]

Purpose: To determine the postoperative effects of radiotherapy (PORT) on the local recurrence‐free survival (LRFS) and overall survival (OS) of stage III‐N2 non‐small‐cell lung cancer (NSCLC). Materials and Methods: 183 patients with resected stage III‐pN2 NSCLC from Hunan Cancer Hospital between 2013 and 2016 were divided into two groups for postoperative chemotherapy (POCT) (n = 105) or combination chemotherapy and radiotherapy (POCRT) (n = 78). The LRFS and OS were compared and the factors affecting local recurrence were illustrated in these two groups. The sites of failure based on the lobe of the primary tumor in two groups were described. Results: PORT leads to a strikingly lower risk for local recurrence and brought superior OS benefit. For different pN2 Subclassification, Patients with multiple‐station pN2 ± pN1 disease had the worst LRFS (11 months) and single‐station pN2 + multiple station pN1 disease had a relatively short LRFS (24 months) in group POCT. Short LRFS is correlated with multiple‐station pN2, older age (Y > 55), patients with a high positive LN ratio > 1/3 and a poor tumor histological differentiation degree. In group POCT, the most frequent failure site occurs at the ipsilateral hilum (21.0%), the bronchial stump (20.0%), followed by LNs4R (19.0%), LNs4L (18.1%), LNs7 (15.2%), most of left‐sided tumors more frequently involved the contralateral mediastinum, whereas the ipsilateral recurrences dominated for right‐sided tumors, especially for LNs4R. In group POCRT, the highest failure site was the bronchial stump (11.5%), followed by LNs4L (8.97%), LNs1 (7.69%), the ipsilateral hilum (6.41%) and LNs4R (6.41%). Conclusion: PORT remarkably reduced local recurrence and improved OS in stage III‐pN2 NSCLC, especially in the multiple‐station pN2 group. [ABSTRACT FROM AUTHOR]

Sorption of organic phosphates- myo-inositol hexakisphosphate (IHP) and glycerol phosphate (GP) and its effects on the early stage of hematite aggregation kinetics were investigated at different pH and electrolyte composition. KHPO (KP) was taken as an inorganic P source for comparison. Results indicated that for all types of P, the sorption amounts decreased with increasing solution pH. Sorption amount of IHP was almost two times that of KP, while those of GP and KP were close. Both organic P and inorganic P interacted with hematite via ligand exchange through their phosphate groups, which conveyed negative charges to mineral surface and significantly decreased the zeta potential of hematite. In Na solution, critical coagulation concentrations (CCCs) of hematite suspensions increased with increasing P concentration and followed the order of KP < GP < IHP at pH 5.5. Compared with KP, the organic P could more effectively stabilize the hematite suspension not only through increasing the negative charges and electrostatic repulsive force, but also through steric repulsion between P-sorbed hematite nanoparticles. When the pH was increased from 5.5 to 10.0, the CCCs of the hematite suspensions with GP and IHP decreased mainly because of the great reductions in organic P sorption amounts and consequent decreases in electrostatic and steric repulsive forces. However, enhanced aggregation was observed in the presence of IHP at pH 4.5 and above in low Ca solutions. The precipitation of calcium phytate formed net-like structure, which served as bridges to bind hematite nanoparticles and resulted in enhanced aggregation. These results have important implications for assessing the fate and transport of organic P and hematite nanoparticles in soil and aquatic environments. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the present study is to examine the effect of phosphate on the aggregation kinetics of hematite and goethite nanoparticles. Materials and methods: The dynamic light scattering method was used to study the aggregation kinetics of hematite and goethite nanoparticles. Results and discussion: Specific adsorption of phosphates could promote aggregation through charge neutralization at low P concentrations, stabilize the nanoparticle suspensions at medium P concentrations, and induce aggregation through charge screening by accompanying cations at high P concentrations. Two critical coagulation concentration (CCC) values were obtained in each system. In NaHPO, the goethite CCC at low phosphate concentrations was smaller than hematite and vice versa at high phosphate concentrations. Stronger phosphate adsorption by goethite rapidly changed the zeta potential from positive to negative at low phosphate concentrations, and the zeta potential became more negative at high phosphate concentrations. The clusters of hematite nanoparticles induced by phosphate adsorption had an open and looser structure. Solution pH and the phosphate adsorption mechanisms in NaHPO, KHPO, and NaPO solutions affected zeta potential values and controlled the stability of hematite suspensions during aggregation. High pH and preference for non-protonated inner-sphere complexes in NaPO solution decreased the zeta potential of positively charged hematite and promoted aggregation. Activation energies followed the order NaHPO > KHPO > NaPO at low P concentrations. K was more effective than Na in promoting hematite aggregation due to the non-classical polarization of cations. Conclusions: Phosphate can enhance or inhibit the aggregation of hematite and goethite nanoparticles in suspensions by changing surface charge due to specific adsorption onto the particles. The phosphate-induced aggregation of the nanoparticles mainly depended on the initial concentration of phosphate. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to investigate the effect of clay mineralogy on aggregate stability under the consideration of soil particle surface electric field in electrolyte solution. Materials and methods: Aggregates of montmorillonite, kaolinite, and their compounds in different mass ratio were used as experimental materials. The degree to which the aggregates broke down under different electrolyte concentrations was evaluated both qualitatively and quantitatively. The aggregate breakdown process was observed with a video microscope. Furthermore, the percentage of particles (micro-aggregates and single particles) in diameter of <10, <5, and <2 μm to the total sample mass were measured based on Stokes equation. Results and discussion: Different electrolyte concentrations correspond to different surface potential values around the particle surface. (1) The amount of released small particles for aggregate of clay compounds was several times higher than that for montmorillonite aggregate after breakdown. (2) Under high surface potential conditions, aggregate breakdown in a way of explosion was observed, and the critical surface potential values for the explosion increased with the increase of kaolinite content in aggregates. (3) The content of released particles for clay compound aggregates with high kaolinite content was much higher than that for aggregates with low kaolinite content under high surface potential values. Conclusions: The coupling effects of electric field and clay mineralogy determined the aggregate stability of montmorillonite and clay compounds. This indicated that soil aggregates with relatively high silt content would be less stable than those with relatively high clay content under heavy rainfall; the most erosive soil might not be clay soils, but the silt soils, especially those under sudden storm after long-time drought. [ABSTRACT FROM AUTHOR]