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Background This study aims to investigate the current use of pediatric flexible bronchoscopy (PFB) in western China. Methods A cross-sectional survey was conducted in western China between January 1, 2018 to December 30, 2018. Fifty-four centers were invited to answer a questionnaire for seeking information about performance of PFB. The data collected were analyzed to investigate the current status of western China, and hierarchical cluster analysis was conducted to identify developmental level of PFB of cities. Results Forty-seven centers were included in analysis. A total of 22,585 flexible bronchoscopies were carried out in the participating centers from January 1, 2018 to December 30, 2018. Eight centers (17.0%) performed more than 1,000 pediatric flexible bronchoscopies for children, but 20 centers (42.6%) performed less than 100. The median proportion of systematic and professional trained physicians in a single team was 50%, and the pooled rate was 59% (95% CI, 47-70%). Only 10, 8 and 11 centers performed balloon dilatation, thermal ablation and cryoablation, respectively. Obvious cough was the most frequent complication after the PFB procedure, the pooled rate is 24% (95% CI, 18-29%). No one died during and after the PFB procedure. Hierarchical cluster analysis showed that the development of PBF in western China varies, and Chongqing might be the most developed area in PFB use in western China. Conclusions Flexible bronchoscopy in children is now a mature and safe procedure, while the development of PFB varies in western China, especially for the advanced bronchoscopic intervention.

The atomic structure, interfacial charge distribution, bonding nature, and interfacial electronic states of a 4H–SiC/TiN interface are systematically investigated to understand the Ohmic contact formation mechanisms of TiN to 4H–SiC. The experiment results clearly demonstrate that the well-arranged TiN (111)-oriented lattice planes are parallel to the (0001) SiC-oriented substrate, which is in line with the XRD results. In addition, the interface is coherent without any secondary phase layers, amorphous layers, or transition regions, which confirms the direct contact of TiN to SiC at the atomic scale, exhibiting a linear current–voltage relationship. Quantitatively, first-principle calculations reveal that the Schottky barrier height (SBH) is as low as 0.03 eV and that the band gap nearly vanishes at the interface, indicating an excellent Ohmic contact of TiN to 4H–SiC. Furthermore, the SBH is significantly reduced through the interfacial charge polarization effect and strong coupling of interfacial electronic states, enhancing the quantum electron transport. The present results provide insight into the complicated electronic effects of the Ohmic contact interface and indicate that TiN is a promising SiC Ohmic contact material for advanced next-generation power device applications.

Tuberculosis (TB) is an important health issue in the world. Although the relation of

High-temperature stability of the tungsten/tantalum carbide/silicon carbide (W/TaC/SiC) system was examined and compared to the tungsten/silicon carbide (W/SiC) system. Interfacial reactions, surface morphology, and roughness evolutions on thermal annealing at 1000 °C were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). For the W/SiC system, WC, W2C and W5Si3 phases were observed due to severe chemical reaction after 24 h annealing, which led to an inhomogeneous surface structure with several large craters and small pores, thereby increasing surface roughness greatly. On the other hand, there was no tungsten silicide and/or carbide formation upon annealing with a TaC diffusion barrier. The surface structure remained nearly unchanged, and small changes in surface roughness with annealing time, which could be due to the growth of W grains, were noted. Furthermore, both the as-deposited and the 24 h annealed W/TaC/SiC samples presented an excellent interfacial bonding with a dense uniform interface. The results indicate that TaC is a promising diffusion barrier in the W/SiC system for high temperature applications.

In order to monitor the deflection of bored piles, BOTDA sensing technology is employed to measure the strain and temperature profiles along three bored piles adjacent to a deep excavation. Based on the measured strain, the deflections can be calculated according to the mechanics of materials. Comparison between the deflections measured by traditional inclinometer and strain based measurement method has been fully conducted. A two-dimensional FEM model was constructed to simulate the interaction between excavation and subway tunnel and examine the deflection of the three bored piles during progressive excavation. Finally, the deflection profiles calculated from measured strains and simulated by FEM are comprehensively summarized and analysed. It can be found that the deflection changing trend at the top of the bored piles are consistent with the simulation results with acceptable errors while the deflection calculated from the measure strains has a significant discrepancy with the simulation results.

Mud filtrate invasion is a complex and time-dependent process. During the process, a zone of finite size around the wellbore (invasion zone) in which a portion of the initial pore fluids have been displaced by the mud filtrate is gradually generated. As a result, the petrophysical and fluid properties of the formation in this zone will be inevitably altered, and sometimes tend to be quite different from their initial values. Petrophysicists and logging analysts have long considered mud filtrate invasion as a nuisance due to its troublesome effect on formation properties and logging measurements, especially on resistivity logging measurements. Note that even deep reading resistivity logging may not see deep enough (beyond the invasion zone), and need to be corrected. Therefore, simulation of mud filtrate invasion under near reservoir conditions is crucial for an in-depth understanding of its physics and effects on logging measurements, and hence for logging interpretation and formation evaluation. Otherwise, this will produce substantial errors in determining initial formation properties, and estimating hydrocarbon reserves and well productivity. To date, most researchers have done a number of works on mud filtrate invasion on the basis of physical simulation at core plug scale. However, conducting invasion experiment on core plug has intrinsic limitations. Firstly, the cylindrical shape of core plug determines that the seepage form of mud filtrate within it (horizontal linear flow) is completely different from that (plane radial flow) in the actual downhole environment, thereby causing a poor representation of the filtration law observed in the experiment. Secondly, due to the small size of core plug, it is almost impossible to monitor the radial resistivity variation for reflecting the dimension and geometry of the invasion zone. To overcome the limitations, a large-sized formation module (sectorial block structure, 55.9 cm in radial depth, and 10 cm in thickness) made by sandstone outcrop was introduced in this paper. Compared with core plug, as a novel type of experimental equivalent, the formation module is larger in size, greater in saturation capacity, and much more similar to the in-situ formation. Its structure can ensure the seepage form of mud filtrate within it is exactly the same as that in the actual downhole environment. Its large size is able to provide enough space and radial distance to follow the entire invasion process from beginning to dynamic equilibrium. The dynamic processes of long-term water-based mud filtrate (WBMF) invasions were duplicated realistically in laboratory. During the whole experimental period, the dynamic invasion data (including radial formation resistivity profile and filtration rate) can be uninterruptedly real-time acquired, thereby investigating and comparing the phenomenon of WBMF invasion in the formation modules with different physical properties. Finally, by combining physical and numerical simulation, the invasion characteristics of WBMF in high-permeability and tight sandstone reservoirs under in-situ formation conditions were quantified. The results obtained in this paper provide an experimental basis and theoretical support for enlightening novel simulation methodologies of mud filtrate invasion, revealing invasion mechanisms, and establishing invasion correction model for electric logging, etc.

Background: Tuberculosis (TB) is an important health issue in our world. It is reported that various factors may effect on its pathogenesis. In this current study, we aimed to investigate the association between SLC11A1 polymorphism and the risk of TB among 510 TB patients and 508 healthy controls.Methods: Agena MassARRAY platform was conducted for genotyping. Odds ratios (ORs) and 95% confidence intervals (CIs) were analyzed through unconditional logistic regression adjustment confound factors, such as age and gender.Results: The results suggested that the allele and genotype frequencies of polymorphisms in SLC11A1 were not observed associated with TB risk. Subsequently, stratified analysis by age and gender confirmed that rs7608307 “A/A” and “C/T-T/T” genotypes were related with increased TB risk in age ≤ 41 group (p = 0.021) and males (p = 0.013), respectively. Besides, rs13062 “A/A” genotype was reduced TB risk in age > 41 group (p = 0.043). In addition, we observed that the “C/C” genotype of rs4674301 was noteworthy correlated with increased TB risk in females (p = 0.043). Conclusion: Our results demonstrated the relationship between SLC11A1 polymorphism and TB risk and confirmed for the first time that the correlation was restricted to age and gender in northwest Chinese population.

The effect of high-temperature annealing on tungsten (W) films deposited on silicon carbide (SiC) with and without a titanium nitride (TiN) diffusion barrier was examined as a function of time. Evolutions in phase composition, surface morphology, and roughness from annealing at 1273 K were investigated for up to 24 h. Without a TiN diffusion barrier, solid state reactions between the W film and SiC substrate led to the formation of W5Si3, W2C, and WC species and the rise of an inhomogeneous surface structure that was initially web-like and later discontinuous. Severe roughening on the order of the initial film thickness was observed. Incorporation of a 100 nm TiN diffusion barrier suppressed the formation of W5Si3 and W2C and only trace WC could be detected due to species diffusion through TiN grain boundaries. Changes in the surface structure and roughness were minimal. The results of this work warrant consideration of TiN as an effective diffusion barrier for W on SiC systems where structural stability at high temperatures is highly desired.

The plate shaped gravity installed anchor (GIA) provides a potential alternative to deepwater mooring systems as its dynamic installation and diving behavior. However, the anchor final penetration depth in seabed soils, especially in soils with high strength gradient, is relatively shallow due to the limited impact velocity and large contact area between the anchor and the surrounding soil. An innovative booster concept is put forward in this study to increase the anchor final penetration depth by increasing the kinetic energy during free fall in water and gravitational energy during dynamic penetration within seabed. The booster is attached to the rear of the anchor during installation and can be retrieved after installation for reuse. The present study performed model tests with the aim of investigating the working efficiency of booster on the impact velocity of the GIA during free fall in the water column. A mini motion tracing device (MTD) is developed to record the anchor free fall history in water. The hydrodynamic characteristics, including the terminal velocity, drag coefficient and directional stability, for the GIA were studied. A series of experimental cases were subsequently conducted to study the effects of the adding booster on the impact velocity and directional stability of the GIA. The testing results demonstrated that both the directional stability and the release height can be improved for the GIA with a booster, thus the anchor impact velocity is increased. The anchor kinetic energy is significantly increased due to the additional mass and increased impact velocity by the booster, which ensures the anchor to be embedded deeper within seabed.

The suction caisson is commonly a top-closed cylindrical steel structure with large diameter, short length and much thinner skirt wall thickness. The resistance to penetrating is calculated as the ...

Based on the analytical solutions for wave-induced soil response in an unsaturated anisotropic seabed of finite thickness, an elliptical, i.e., noncircular rotation stress path is proven to be a more common state in a soil element with the cyclic shear stresses due to the traveling linear wave. The influence of an elliptical stress path on the characterization of failure strength is analyzed using three new parameters representing the shape, size, and the orientation of the ellipse. A series of cyclic rotational shear tests on the reconstituted specimens of Chinese Fujian Standard Sand have been performed to investigate the effect of elliptical stress path. A strength function in term of failure cycles is derived to quantify the failure strength of a given sand within a seabed subjected to regular wave loading. The results provide a basis for the evaluation of liquefaction potential of seabed but also point to a unique backbone cycle shear strength curve for soil under principal stress rotation.

Vertically loaded anchors offer an attractive alternative for mooring systems because of their relatively high efficiency and low cost. The bridle shank is an important feature of these anchors because its reconfiguration significantly affects their performance. A plasticity model considering a bridle shank is introduced to investigate the mechanism of the system. Model-based parametric studies on the effects of the bridle length, drag distance and anchor line angle are also conducted. These studies establish a new, more rational analytical model for these anchors, as well as contribute to the understanding of the mechanism of them in research and practice.

The principal stress rotation is one of the most important features of the stress state in a seabed subjected to wave loading. Most prior investigations focused their attention on the cyclic behaviour of soil deposits under the circular rotation stress path based on the analytical solutions for a seabed of infinite thickness. In this paper, the nonstandard elliptical, i.e., non-circular, rotation stress path is shown to be a more common state in the soil sediments of a finite seabed with an alternating changeover in stress due to a travelling regular wave. Then an experimental investigation in a hollow cylinder triaxial-torsional apparatus is conducted into the effect of the nonstandard elliptical stress path on the cyclic strength. A special attention is placed on the difference between the circular rotation stress path and the elliptical rotation stress path. The results and observations show that the shear characteristics for the circular rotation stress path in the literature are not applicable for analyzing the cyclic strength of sand in a finite seabed, and also indicate that due to the influence of three parameters about the size and the shape of a nonstandard ellipse, the cyclic strength under a nonstandard elliptical rotation stress path is evidently more complex and diversified as compared with that under a circular rotation stress path. Especially the influence of the initial phase difference on the cyclic strength is significant.

Three-dimensional (3D) nanohierarchical Ni nanomace (Ni NM) array was fabricated on copper substrate by only one step with electroplating method, the unique structure was covered with Au film (Ni/Au NM) without changing its morphology, and in the following step, it was sintered with silver nanoparticle (Ag NP) paste. The structure of the Ni NM array and its surface morphology were characterized by X-ray diffraction, scanning electron microscope (SEM), and atomic force microscope. The sintered interface was investigated by SEM, transmission electron microscopy, and energy-dispersive X-ray spectroscopy to analyze the sintering mechanism. The results showed that a metallurgical bond was successfully achieved at 250 °C without any gas or vacuum shield and extra pressure. The Cu substrate with Ni/Au NM array was able to join with the Ag NP paste without obvious voids. Due to the compatible chemical potential between Ag NPs and Ni/Au NM array, the Au element was able to diffuse into the Ag layer with about 800 nm distance. Based on the excellent 3D nanohierarchical structure, the shear strength of Ni/Au NM array was 6 times stronger than the flat Ni/Au coated substrate. It turned out that the substrate surface played a crucial role in improving the shear strength and sintering efficiency. The 3D Ni NM array had achieved an excellent bonding interface and had great potential application in the microelectronics packaging field.

Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides. Currently, commercial calculation programs such as BING have limitations in simulating underwater soil movements. All of these processes can be consistently simulated through a smoothed particle hydrodynamics (SPH) depth integrated model. The basis of the model is a control equation that was developed to take into account the effects of soil consolidation and erosion. In this work, the frictional rheological mode has been used to perform a simulation study of submarine landslides. Time-history curves of the sliding body’s velocity, height, and length under various conditions of water depth, slope gradient, contact friction coefficient, and erosion rate are compared; the maximum sliding distance and velocity are calculated; and patterns of variation are discussed. The findings of this study can provide a reference for disaster warnings and pipeline route selection.

This paper presents the results of physical modelling tests carried out in a geotechnical drum centrifuge to investigate the impact forces of submarine slide at debris flow stage acting on pipelines with various incident angles. The UK kaolin clay was used and normally consolidated clay samples were prepared at 40 g level. For each incident angle condition, the impact velocity was changed from 0.23 to 94.2 mm/s, and the influence of impact velocity and impact angle at low Re value are discussed. The present tests data were analyzed by geotechnical approach proposed by Randolph and White (2012). Then, a failure envelope was fitted to describe the impact force on pipeline caused by oblique debris flow. It was found that the normal bearing factor calculated by the present envelope was much lower than the result calculated by existing CFD envelope. While the frictional factor calculated by the present envelope was slightly higher than that of existing CFD envelope. By comparing the slide conditions of CFD calculations and present centrifuge tests, it should be noted that the present envelope was more appropriate to evaluate the impact force on pipeline due to slide with low impact velocity. When the Reynolds number was higher than 3, the existing CFD envelope was maybe more appropriate to evaluate the impact force on pipeline.

Tunnel debris used as coarse aggregate in concrete can reduce the amount of disposal effectively. And can ease the insufficient sand and stone. This study compared the effects of coarse aggregate on the durability of concrete from gneiss and limestone scrap. (1) C50 concrete prepared from gneiss gravel and limestone gravel has no significant difference in its antifreeze properties. That is, the lithology of the coarse aggregate does not affect the frost resistance of the concrete. (2) Concrete prepared from gneiss gravel and limestone gravel has no significant difference in the corrosion resistance of chloride ions. That is, the lithology of the coarse aggregate does not affect the corrosion resistance of the concrete. (3) Concrete prepared from gneiss gravel and from limestone gravel have little relationship with the crushing value of coarse aggregate, when the antifreeze properties and corrosion resistance of chloride ions are studied.

Recently, nanosilver pastes have emerged as one of the most promising high temperature bonding materials for high frequency and high power applications, which provide an effective lead-free electronic packaging solution instead of high-lead and gold-based solders. Although nanosilver pastes can be sintered at lower temperature compared to bulk silver, applications of nanosilver pastes are limited by long-term sintering time (20–30 min), relative high sintering temperature (>250 °C), and applied external pressure, which may damage chips and electronic components. Therefore, low temperature rapid sintering processes that can obtain excellent nanosilver joints are anticipated. In this regard, we present a review of recent progress in the rapid sintering of nanosilver pastes. Preparation of nanosilver particles and pastes, mechanisms of nanopastes sintering, and different rapid sintering processes are discussed. Emphasis is placed on the properties of sintered joints obtained by different sintering processes such as electric current assisted sintering, spark plasma sintering, and laser sintering, etc. Although the research on rapid sintering processes for nanosilver pastes has made a great breakthrough over the past few decades, investigations on mechanisms of rapid sintering, and the performance of joints fabricated by pastes with different compositions and morphologies are still far from enough.

Background Numerous studies have explored the association between pretreatment prognostic nutritional index (PNI) and prognosis in lung cancer (LC), but the results are still inconclusive. We systematically evaluated the prognostic value of pretreatment PNI in LC patients by conducting a meta-analysis. Methods A comprehensive literature search was performed by retrieving PubMed, EMBASE, and Web of Science, Wan Fang and CNKI databases. We used hazard ratios (HRs) and their 95% confidence intervals (CIs) to assess the associations of PNI with overall survival (OS), disease-free survival/recurrence-free survival (DFS/RFS) and progression-free survival (PFS) in LC patients. Results A total of 21 studies were enrolled into this meta-analysis, with 17 about no-small cell lung cancer (NSCLC) and 4 about on small-cell lung cancer (SCLC). The results indicated that NSCLC patients with low PNI had shorter OS (HR: 1.59, 95% CI: 1.28–1.96, P = 0.001), DFS/RFS (HR = 1.74, 95% CI = 1.08–2.80, P = 0.017), and PFS (HR = 1.52, 95% CI = 1.26–1.83, P = 0.002) than patients with high PNI. The robustness of these pooled results were verified by our stratified analysis and sensitivity analysis. Besides, a pooled analysis of 4 studies about SCLC suggested that low PNI was closely associated with worse OS in SCLC patients as well. Conclusion Low PNI predicts poor survival in LC patients.

During the past few decades, silicon carbide (SiC) has emerged as the most promising wide-bandgap semiconductor for high-temperature, high-frequency, and high-power applications. All its attractive properties depend critically on and are often limited by the formation of Ohmic contacts to SiC. Although impressive progress has been made, improvements to further reduce the specific contact resistance without lowering the stability of Ohmic contacts during long-term aging are still indispensable. In this regard, we present a review of recent progress in Ohmic contacts to n- and p-type SiC reported in literature. The mechanism of Ohmic contact to SiC, surface preparation methods, and performance of Ohmic contacts are discussed. Emphasis is placed on the thermal stability of Ohmic contacts to SiC. To date, extremely low specific contact resistance values (10−7 Ω cm2 to 10−6 Ω cm2) have been obtained after high-temperature (>800°C) annealing. Moreover, great efforts have been made to achieve good Ohmic contact performance (10−6 Ω cm2 to 10−5 Ω cm2) under low-temperature annealing (

Pr 0.6 Sr 0.4 Cu 0.2 Fe 0.8 O 3−δ -Ce 0.8 Sm 0.2 O 2−δ (PSCF-SDC) (70:30 wt.%), a new cobalt-free composite cathode, is investigated for BaZr 0.3 Ce 0.5 Y 0.2 O 3−δ -based proton-conducting solid oxide fuel cells (H-SOFCs). The influence of firing temperature on cathode microstructure and electrochemical performance of fuel cells is researched and analyzed. These results show that the optimum sintering temperature of PSCF-SDC composite cathode is 800 °C. The low polarization resistance of 0.14 Ω cm 2 and the maximum power density of 456 mW cm −2 are achieved at 650 °C. Cell performance is further enhanced when the BaZr 0.3 Ce 0.5 Y 0.2 O 3−δ electrolyte is replaced by BaZr 0.1 Ce 0.7 Y 0.2 O 3−δ with higher proton conductivity; resulting in an improved maximum power density of 556 mW cm −2 at 650 °C.

New mixed ionic conductors, BaCe 0.7 In 0.3 O 3− δ –Gd 0.1 Ce 0.9 O 2− δ (BCI–GDC, weight ratio, 3:7, 5:5 and 7:3), were synthesized via a one-step citric acid–nitrate gel combustion method as electrolyte materials for solid oxide fuel cells (SOFCs). X-ray diffraction patterns of BCI–GDC indicated that there was no impurity phase formed after sintering at high temperature up to 1400 °C. Scanning electron microscopic study of BCI–GDC depicted dense grain morphology. Single fuel cells were prepared and the corresponding electrochemical performances were tested. The sintering temperature of the dense composite electrolyte membranes decrease as the BCI content increases because of the sintering aids of In element. All samples with the composite electrolyte showed higher open circuit voltage (OCV) values than the single phase GDC. In addition, Electrical conductivity of the composite electrolyte under different atmospheres at different temperatures confirmed that the BCI–GDC exhibited high mixed oxygen ionic and protonic conduction. The test results indicated that the conductivity and OCV values of the composite electrolyte enhanced as the GDC content increases, and the optimum performance was found to be BCI3–GDC7 compared with the pure BCI and GDC electrolyte. The possible interface effects were suggested to explain this phenomenon. Our results not only provide one new promising composite electrolyte material for intermediate-temperature SOFCs but the composition dependence can actually provide a guide for the material design, optimization.

Principal stress axes rotation influences the stress-strain behavior of sand under wave loading. A constitutive model for sand, which considers principal stress orientation and is based on generalized plasticity theory, is proposed. The new model, which employs stress invariants and a discrete memory factor during reloading, is original because it quantifies model parameters using experimental data. Four sets of hollow torsion experiments were conducted to calibrate the parameters and predict the capability of the proposed model, which describes the effects of principal stress orientation on the behavior of sand. The results prove the effectiveness of the proposed calibration method.

In this work, hydrogen permeation properties of Ni–La0.5Ce0.5O2−δ (LDC) asymmetrical cermet membrane are investigated, including hydrogen fluxes (JH2) under different hydrogen partial pressures, the influence of water vapor on JH2 and the long-term stability of the membrane operating under the containing-CO2 atmosphere. Ni-LDC asymmetrical membrane shows the best hydrogen permeability among LDC-based hydrogen separation membranes, inferior to Ni–BaZr0.1Ce0.7Y0.2O3−δ asymmetrical membrane. The water vapor in feed gas is beneficial to hydrogen transport process, which promote an increase of JH2 from 5.64 × 10−8 to 6.83 × 10−8 mol cm−2 s−1 at 900 °C. Stability testing of hydrogen permeation suggests that Ni-LDC membrane remains stable against CO2. A dual function of combining hydrogen separation and generation can be realized by humidifying the sweep gas and enhance the hydrogen output by 1.0–1.5 times. Ni-LDC membrane exhibits desirable performance and durability in dual-function mode. Morphologies and phase structures of the membrane after tests are also characterized by SEM and XRD.

Bilayered electrolyte membranes composed of BaZr 0.1 Ce 0.7 Y 0.2 O 3 −δ (BZCY) and Ce 0.8 Sm 0.2 O 2 −δ (SDC) were evaluated for solid oxide fuel cells (SOFCs), and the influence of the membrane architecture on the cell performance was investigated. The electrochemical testing results showed that the electron-blocking ability of BZCY layer depends on its exact location in the fuel cell. The partial internal short circuit was nearly totally eliminated for the cell with BZCY layer located at the anode side, and the corresponding cell exhibited a high open circuit voltage (OCV) of 1.0 V at 700 °C. In contrast, the cell with BZCY layer located at the cathode side still exhibited significant internal short-circuit behavior. The different electron-blocking ability can be ascribed to the atmosphere-dependent charge transport behavior of BZCY. The present results demonstrate that the bilayered BZCY/SDC membrane with BZCY layer located at the anode side is a promising electrolyte for highly efficient low-temperature SOFCs. Besides, the BZCY layer should be as thin as possible to achieve desirable power performance for the fuel cell.

Chemically stable composite BaZr0.8Y0.2O3−δ–Ni (BZY–Ni) was proposed and evaluated as the anode for solid oxide fuel cells (SOFCs) based on Ce0.8Sm0.2O2−δ (SDC) electrolyte. A thin electron-blocking interlayer was formed in situ at the anode/electrolyte interface when the anode-supported half cell was prepared via a high-temperature sintering process. Raman spectra and high-resolution TEM (HRTEM) results revealed that the electron-blocking interlayer consisted of Ce0.8Sm0.2O2−δ@Ba(Ce, Zr)1−x(Sm, Y)xO3−δ core/shell-like grains. The Ba(Ce, Zr)1−x(Sm, Y)xO3−δ shell protected SDC grains from reduction and consequently the electronic conduction through the SDC electrolyte film was nearly completely eliminated in the new structured fuel cell. The fuel cell exhibited significantly improved open circuit voltages (OCVs), high power densities as well as good operating durability, demonstrating that BZY–Ni is a promising anode for CeO2-based SOFCs operating at a higher efficiency. These findings also imply that doped CeO2@doped Ba(Ce, Zr)O3 core/shell composite is a promising electrolyte with high ionic transport number, which directs a new strategy to design novel electrolyte materials for SOFCs.

In order to obtain chemically stable hydrogen-permeable cermet membranes against CO2 and H2O, the composite membranes consisting of Ni and Ba(Zr0.7Pr0.1Y0.2)O3−δ (BZPY) are fabricated by the dry-press technique and reducing atmosphere sintering process. SEM results show that the cermet membrane is extremely dense and metal nickel is randomly distributed in BZPY oxide matrix. Hydrogen permeation properties of the Ni-BZPY membranes are systemically studied including the influence of the operating temperature, H2 concentration in feed stream, humidification degree and membrane thickness. The Ni-BZPY membrane presents good chemical stability in humid condition or CO2-containing environments and is potential candidates for hydrogen separation.

Acceptor-doped barium cerate is considered as one of the state-of-the-art high temperature proton conductors (HTPCs), and the proton conductivity of such HTPCs is heavily dependent on the dopant. In this work, a codoping strategy is employed to improve the electrical conductivity and sinterability of BaCeO3-based HTPC. BaCe0.8Sm(x)Y(0.2-x)O(3-δ) (0 ≤ x ≤ 0.2) powders are synthesized by a typical citrate-nitrate combustion method. The XRD and Raman spectra reveal all the compounds have an orthorhombic perovskite structure. The effects of Sm and/or Y doping on the sinterability and electrical conductivity under different atmospheres are carefully investigated. The SEM results of the sintered BaCe0.8Sm(x)Y(0.2-x)O(3-δ) pellets indicate a significant sintering enhancement with increasing Sm concentration. BaCe0.8Sm0.1Y0.1O(3-δ) exhibits the highest electrical conductivity in hydrogen among the BaCe0.8Sm(x)Y(0.2-x)O(3-δ) pellets. Anode-supported BaCe0.8Sm0.1Y0.1O(3-δ) electrolyte membranes are also fabricated via a drop-coating process, and the corresponding single cell exhibits desirable power performance and durability at low temperatures. The results demonstrate that BaCe0.8Sm0.1Y0.1O(3-δ) is a promising proton conductor with high conductivity and sufficient sinterability for proton-conducting solid oxide fuel cells operating at reduced temperatures.

Submarine pipelines that transport crude oil and natural gas are often in a complex marine geological environment and may become unstable and fail upon impact by submarine landslides. Previous research has mostly focused on the impact forces exerted by submarine landslides on suspended pipelines, but the impact of submarine landslides on pipelines laid on the seafloor at various impact angles, θ, have been relatively infrequently discussed, and the effects of suspended height, H, on the impact forces exerted by submarine landslides on pipelines have not been thoroughly investigated. In this study, based on the Herschel–Bulkley model, the impact forces exerted by a submarine landslide on laid-on or suspended pipelines at various impact angles θ were simulated using the computational fluid dynamics (CFD) approach. Equations for calculating the axial and normal drag coefficients of a submarine pipeline were proposed. The CFD numerical simulation results were rearranged based on the soil mechanics approach. By comparing the parameters, an essentially corresponding relationship was found between the soil mechanics and CFD approaches when the equations were used to calculate the impact forces exerted by a submarine landslide on a pipeline. In addition, a semi-analytical expression for the failure envelope was provided. Furthermore, the effects of H on the forces on a pipeline were discussed, and an equation for calculating the acting forces on a pipeline along the flow direction of a submarine landslide that comprehensively accounts for the effects of θ and H was proposed. The lift force was discussed preliminarily and the results provide a basis for further investigation. The achievement of this study is applicable for selecting locations of submarine pipeline routes and for designing submarine pipelines.

Vertically loaded anchors offer an attractive alternative for mooring system because of their relatively high efficiency and low costs. Predicting the ultimate embedment depth (UED) of anchor is important as it essentially determines the holding capacity. By analyzing the shank's mechanism, an analytical method is established to determine the ultimate state of the reconfigurable bridle shank. Thus, based on this method, a new form of analytical solution for the ultimate embedment depth of a vertically loaded anchor is proposed using the plasticity approach. Parametric studies on the effects of shank dimensions, yield surface and chain parameters are also conducted. A series of criteria are proposed to optimize the bridle ratio. A proper range for the bridle ratio is presented.

Iron-stabilized lanthanum nickelate oxide with a perovskite structure, LaNi 0.6 Fe 0.4 0 3− δ (LNF), was prepared by a citrate–nitrate process and evaluated as the cathode component of a proton-conducting SOFC based on a Ba(Zr 0.1 Ce 0.7 Y 0.2 )O 3− δ (BZCY) electrolyte. XRD analysis shows that LNF reacts with BZCY to form a K 2 NiF 4 -type phase in the course of cathode calcination, but remains chemically well compatible with BZCY at the operating temperature. A single cell was assembled and tested using humidified hydrogen as fuel gas and atmospheric air as the oxidant. The matching thermal expansion coefficient (TEC), high conductivity and good catalytic activity of the LNF cathode enable the cell to generate high power densities and low polarization resistances. At 700 °C, the peak power density is 668 mW cm −2 and the polarization resistance is 0.046 Ω cm 2 . This work confirms that LNF may be a prospective cathode material for BZCY proton-conducting electrolytes.

Pile-cap-soil interaction is important to understand the load transfer mechanisms of pile foundations. However, studies on pile-cap-soil interactions are quite limited. This article reports a series of small-scale model tests in laboratory that was carried out on the single piles with and without pile caps. Transparent soils made of fused quartz and refractive index–matching fluids are employed to represent natural angular sand. Pile cap effects, diameter effects, and pile length effects are investigated. Elastic load limits are found to increase linearly with pile cap area, pile length, and pile diameter for the tested pile models. Soil deformation around the pile head is greatly influenced by the pile cap size, pile diameter, and pile length. Soil deformation at the pile head can be described by Terzaghi’s bearing capacity failure theory. The soil particles below the pile cap next to the pile body move downward, which might reduce the shaft friction or induce the negative shaft friction. All the loading tests show that the pile cap can increase the pile’s bearing capacity. For small-diameter model piles, soil deformation is centered below the pile base, no sliding surfaces are formed at the pile base when settlement S = 4 mm. For large-diameter piles, it is possible that a bearing capacity failure forms two sliding surfaces on the left and right of the pile base. This study indicates that the appropriate usage of the bearing resistance of soils below the pile cap can increase the bearing capacity of pile foundations. This study reveals the soil deformation below the pile cap, which benefits the utilization of the bearing resistance of pile caps. The soil deformation zone at the pile head and around the pile base is also investigated.

There exists a critical cyclic stress ratio when sand or clay is subjected to cyclic loading. It is an index distinguishing stable state or failure state. The soil static and dynamic universal triaxial and torsional shear apparatus developed by Dalian University of Technology in China was employed to perform different types of tests on saturated soft marine clay in the Yangtze estuary. Undisturbed samples were subjected to undrained cyclic vertical and torsional coupling shear and cyclic torsional shear after three-directional anisotropic consolidation with different initial consolidation parameters. The effects of initial orientation angle of major principal stress, initial ratio of deviatoric stress, initial coefficient of intermediate principal stress and stress mode of cyclic shear on the critical cyclic stress ratio were investigated. It is found that the critical cyclic stress ratio decreases significantly with increasing initial orientation angle of major principal stress and initial ratio of deviatoric stress. Compared with the effects of the initial orientation angle of major principal stress and initial ratio of deviatoric stress, the effect of initial coefficient of intermediate principal stress is less evident. Under the same consolidation condition, the critical cyclic stress ratio from the cyclic coupling shear test is lower than that from the cyclic torsional shear test, indicating that the stress mode of cyclic shear has an obvious effect on the critical cyclic stress ratio. The main reason is that the continuous rotation in principal stress directions during cyclic coupling shear damages the original structure of soil more than the cyclic torsional shear does.

Acceptor-doped barium cerate is considered as one of the state-of-the-art high temperature proton conductors (HTPCs), and the proton conductivity of such HTPCs is heavily dependent on the dopant. In this work, a codoping strategy is employed to improve the electrical conductivity and sinterability of BaCeO3-based HTPC. BaCe0.8Sm(x)Y(0.2-x)O(3-δ) (0 ≤ x ≤ 0.2) powders are synthesized by a typical citrate-nitrate combustion method. The XRD and Raman spectra reveal all the compounds have an orthorhombic perovskite structure. The effects of Sm and/or Y doping on the sinterability and electrical conductivity under different atmospheres are carefully investigated. The SEM results of the sintered BaCe0.8Sm(x)Y(0.2-x)O(3-δ) pellets indicate a significant sintering enhancement with increasing Sm concentration. BaCe0.8Sm0.1Y0.1O(3-δ) exhibits the highest electrical conductivity in hydrogen among the BaCe0.8Sm(x)Y(0.2-x)O(3-δ) pellets. Anode-supported BaCe0.8Sm0.1Y0.1O(3-δ) electrolyte membranes are also fabricated via a drop-coating process, and the corresponding single cell exhibits desirable power performance and durability at low temperatures. The results demonstrate that BaCe0.8Sm0.1Y0.1O(3-δ) is a promising proton conductor with high conductivity and sufficient sinterability for proton-conducting solid oxide fuel cells operating at reduced temperatures.

A novel CO2-stable and reduction-tolerant Ce0.8Sm0.2O(2-δ)-La0.9Sr0.1FeO(3-δ) (SDC-LSF) dense dual-phase oxygen-permeable membrane was designed and evaluated in this work. Homogeneous SDC-LSF composite powders for membrane fabrication were synthesized via a one-pot combustion method. The chemical compatibility and ion interdiffusion behavior between the fluorite phase SDC and perovskite phase LSF during the synthesis process was studied. The oxygen permeation flux through the dense dual-phase composite membranes was evaluated and found to be highly dependent on the volume ratio of SDC and LSF. The SDC-LSF membrane with a volume ratio of 7:3 (SDC70-LSF30) possessed the highest permeation flux, achieving 6.42 × 10(-7) mol·cm(-2)·s(-1) under an air/CO gradient at 900 °C for a 1.1-mm-thick membrane. Especially, the membrane performance showed excellent durability and operated stably without any degradation at 900 °C for 450 h with helium, CO2, or CO as the sweep gas. The present results demonstrate that a SDC70-LSF30 dual-phase membrane is a promising chemically stable device for oxygen production and CO2 capture with sufficiently high oxygen permeation flux.

Hyper spectral remote sensing has a great application in resources, environment, urban development and ecological balance and other aspects, one of the most important fields is for precise classification of features. Due to the hyper spectral remote sensing data has the characteristics of large data volume, the specific operation in the presence of long processing time problem. This paper focus on SAM algorithm and realize optimization based on the GPU parallel framework, and makes a system experiment on hyper spectral remote sensing images to prove the validity of this method.