Metal-Mold Reactions in CMSX-4 Single Crystal Superalloy Castings

Metal-mold reaction (MMR) layers are often found on the surface of as-cast CMSX-4 single-crystal alloy parts. These layers cannot be removed prior to solution heat treatment of cast parts because of the sensitivity of the single-crystal castings to recrystallization (RX) defect formation. Removal of the reaction layer after solution heat treatments is very costly, as the layer is very hard, and requires abrasive water jet and pressure (grit) blasting processes. To address this manufacturing concern, it was desirable to understand the mechanisms of reaction layer formation and hardening after solution heat treatment. With this understanding, we developed methods for minimizing the reaction layer formation, which will potentially bring a big cost saving for the CMSX-4 casting processes.In this work, we confirmed experimentally that silica (SiO2) reacts with Al, Hf, and Ti, facilitating surface oxidation and formation of a tenacious surface eutectic phase. To avoid this, elimination of the Si is desired. However, Si is present in many of the refractory and pattern materials used in the casting system, which can transfer into the alloy during the solidification process in both liquid and solid state. A two-path solution was investigated: 1) eliminate all Si sources, and 2) create surface diffusion barriers to prevent reaction of the SiO2 with the metal. Potential sources of silica/silicon in the casting system include: the CMSX-4 charge material (nominal Si content less than 400 ppm), thermocouple protection quartz tube (100% silica), crucible (4% silica), bushing (80% silica), funnel (if used-60% silica), ash in pattern waxes, mold release (silicone-based), binder for facecoating (includes nanoscale silica-4% in facecoat), and cores (when used-80% silica).For a diffusion barrier, an yttria slurry (short lifetime and high cost of fine yttria flour), was replaced with an yttria aerosol spray coating, applied directly to the wax pattern before normal zircon primary facecoating. This was followed by an yttria binder washing and soaking, applied on top of the spray coating shell after dewaxing for strengthening. This process showed good bonding in casting trials in an argon atmosphere Bridgman casting furnace. Optical microscopy, SEM/EDS, AES and XPS techniques were employed for characterization of MMR interfaces of both the CMSX-4 casting and the shell mold. These characterization methods revealed MMR layers with oxidation, Si and Hf rich features.In this study, the yttria spray (alone) slightly reduces the amount of MMR of CMSX-4, but when the yttria spray was combined with the binder wash, the reaction was further reduced

Fecal microbiota transplantation from HUC-MSC-treated mice alleviates acute lung injury in mice through anti-inflammation and gut microbiota modulation

IntroductionAcute lung injury (ALI) is a severe respiratory tract disorder facilitated by dysregulated inflammation, oxidative stress and intestinal ecosystem. Fecal microbiota transplantation (FMT) is a rapid method for gut microbiota (GM) reconstruction. Furthermore, our previous studies have confirmed that human umbilical cord mesenchymal stromal cells (HUC-MSCs) can alleviate ALI by improving GM composition. Therefore, we aimed to explore the efficacy and mechanism of FMT from HUC-MSCs-treated mice on ALI.MethodsIn brief, fresh feces from HUC-MSCs-treated mice were collected for FMT, and the mice were randomly assigned into NC, FMT, LPS, ABX-LPS, and ABX-LPS-FMT groups (n = 12/group). Subsequently, the mice were administrated with antibiotic mixtures to deplete GM, and given lipopolysaccharide and FMT to induce ALI and rebuild GM. Next, the therapeutic effect was evaluated by bronchoalveolar lavage fluid (BALF) and histopathology. Immune cells in peripheral blood and apoptosis in lung tissues were measured. Furthermore, oxidative stress- and inflammation-related parameter levels were tested in BALF, serum, lung and ileal tissues. The expressions of apoptosis-associated, TLR4/NF-κB pathway-associated, Nrf2/HO-1 pathway related and tightly linked proteins in the lung and ileal tissues were assessed. Moreover, 16S rRNA was conducted to assess GM composition and distribution.ResultsOur results revealed that FMT obviously improved the pathological damage of lung and ileum, recovered the immune system of peripheral blood, decreased the cell apoptosis of lung, and inhibited inflammation and oxidative stress in BALF, serum, lung and ileum tissues. Moreover, FMT also elevated ZO-1, claudin-1, and occludin protein expressions, activating the Nrf2/HO-1 pathway but hindering the TLR4/NF-κB pathway. Of note, the relative abundances of Bacteroides, Christensenella, Coprococcus, and Roseburia were decreased, while the relative abundances of Xenorhabdus, Sutterella, and Acinetobacter were increased in the ABX-LPS-FMT group.ConclusionFMT from HUC-MSCs-treated mice may alleviate ALI by inhibiting inflammation and reconstructing GM, additionally, we also found that the TLR4/NF-κB and Nrf2/HO-1 pathways may involve in the improvement of FMT on ALI, which offers novel insights for the functions and mechanisms of FMT from HUC-MSCs-treated mice on ALI

Model and performance analysis of coupled heat and moisture transfer of the roadbed slope

The soil samples of the roadbed slope of the Datong-Xi'an high-speed railway section are taken as the research object. The frost-heave property of the fiber soil of the roadbed slope under a single freeze-thaw cycle is studied, where the fiber's content is taken into account. The distributions of temperature and humidity fields inside the slope are numerically studied, and the coupling transfer of heat and moisture is revealed. The results are helpful for the optimal design of the roadbed slop

An Electromagnetic-Driven Microshutter Array in a Field-of-View Gated Image System for All-Time Star Sensors

Aiming at the application requirements of a field of view (FOV) gated imaging system for all-time star sensors, a key device of a microshutter array with large unit size, high duty cycle, and fast response speed based on the electromagnetic actuation is designed. The proposed microshutter array adopts the principle that the current-carrying coil is subjected to the magnetic force in the magnetic field. The coil element is deflected by the loading current and acts as a light barrier in realizing the optical switch function. The effects of the coil element parameters on the magnetic force torque, torsion beam resistance torque, and switch response time are analyzed, and the structural parameters of the coil element are determined. A sample of the proposed microshutter array based on the electromagnetic actuation with a 4-mm period and a 2.8-mm aperture is fabricated and tested. The test results demonstrate the good switching function of the proposed microshutter array and show that the switch response time of the microshutter element is approximately 2.5 ms. This proposed microshutter array is used to gate an instantaneous small FOV to suppress the sky’s background radiation and make a FOV-gated imaging system realize the multi-stars detection by switching the gated FOV rapidly. This will solve the problem that only one star can be detected within the FOV by a traditional all-time star tracker and promote the all-time star sensor to realize star pattern recognition and autonomous astronomical navigation in the daytime

Influence of building topography around high-speed railway foundation on wind environment and thermal comfort

The influence of the surrounding building topography of the Datong-Xi’an high-speed railway foundation on the wind environment and the thermal comfort is studied, especially the outdoor wind environment and indoor air-flow organization of the surrounding buildings are analyzed numerically, and the building terrain and the indoor temperature and the wind’s speed distribution are systematically evaluated. The results show that the surrounding terrain of the roadbed has a significant effect on the wind environment of the site, affecting the natural ventilation in summer and wind-proof and energy-saving in winter. The terrain surrounding of the building in summer reduces the wind speed by 30.5%, and it increases in winter by 31.6%; the wind speed in the indoor personnel activity area of the building around the roadbed is less than 0.35 m/s, leading to a comfortable body feeling

Waste Heat Recovery and Utilization of Cement Rotary Kiln Based on Biomass Energy

A rotary kiln is a central piece of equipment for the calcination of clinker in the  production of cement. Biomass energy has been applied to rotary kilns, and solar energy has been introduced to assist the energy supply. Coupled optimization results for biomass energy and solar energy applications are compared to the single fossil energy used in the base period. A field survey and statistical analysis and integration of cement clinker production sites in China’s Central Plains Economic Zone revealed a negative linear correlation between the consumption of raw coal in the cement production process and the environmental temperature and humidity parameters of the production lines.  The energy consumption is large and the energy utilization of the system is low, with goodness of fit of R=0.962.  Coupled solar and biomass energy use in the audit period and single energy use in the base period comparison revealed a 19.5% reduction in electricity consumption, a 25.4% reduction in coal consumption and a 4.39% increase in heavy oil consumption. From 2017 to 2020, the average annual consumption cost of electricity and raw coal decreased, while the average annual consumption cost of heavy fuel oil slowly increased. After verification during the audit period, compared with the base period, the total production cost of the case enterprise can be reduced approximately 5.17%, in which the energy cost decreased 0.9%

RAGE genetic polymorphisms are associated with risk, chemotherapy response and prognosis in patients with advanced NSCLC.

AIM: To explore the association between genetic polymorphisms of the receptor for advanced glycation end-products (RAGE) and susceptibility, chemotherapy response rate and prognosis of non-small cell lung cancer (NSCLC). METHOD: This is a prospective study in which 562 patients with NSCLC and 764 healthy controls were enrolled. Three RAGE genetic polymorphisms, namely, -429T/C, -374T/A and 82G/S were genotyped. Platinum-based chemotherapy was given to 432 subjects with advanced inoperable NSCLC and their responses to chemotherapy were evaluated. RESULTS: All the polymorphic genotypes of RAGE polymorphisms were associated with susceptibility for NSCLC. Only the 82G/S polymorphisms denoted a significant difference between responders and non-responders to chemotherapy. The 82SS genotype and 82S allele distribution not only increased the NSCLC risk, but also was associated with a lower chemotherapy response rate and poor prognosis, indicated by overall survival and progression free survival. CONCLUSION: The 82G/S genetic polymorphism of RAGE gene might be used as a genetic marker to screen for patients sensitive to thermotherapy and to predict the prognosis of NSCLC

Simulation of Cattle Stomach Processes Applied to the Fermentation of Mixed Manure and Straw

The cattle stomach was considered as the basis for simulating a proposed operation. Microenvironmental degradation mechanisms are understood to be key to the efficient utilization of straw and other resources. Through dynamic tracking of the change law of heat generated by microbial degradation of straw in the cattle stomach, this study used an orthogonal test to explore the optimal ratio of feeding feed, the degradation mechanism in the microenvironment, and the characteristics of cattle manure and straw anaerobic fermentation. The results showed that the number of days of fermentation and the ratio of straw and cattle manure had a significant impact on methane gas production, and the mixture ratio was 1:3, at 26 °C; within 20 days, the cumulative gas production was up to 78.9 L. The results also showed that rumen microorganisms, cattle manure, and mixed straw fermentation can be used at different ratios to obtain the change of methane production, and determine the best ratio to achieve the maximum gas production

Summarized the clinical characteristics of NSCLC cases and controls.

<p>Summarized the clinical characteristics of NSCLC cases and controls.</p