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Engineering topics

Li, Ming

Publications and source records attributed to Li, Ming.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Evolution of Non-metallic Inclusions and Precipitates in Oriented Silicon Steel

The evolution of inclusions in oriented silicon steel during the manufacturing process was carried out by chemical composition analysis, non-aqueous electrolytic corrosion, and thermodynamic calculation. The morphology, composition, and size of inclusions were analyzed introducing field emission scanning electron microscope. The oxides were mainly formed during the secondary refining, and the nitrides, sulfides, and compounds were formed during the solidification and cooling of steel in the processes of continuous casting and hot rolling.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Electrochemical Dissolution of Tungsten Carbide in NaCl-KCl-Na{sub 2}WO{sub 4} Molten Salt

Tungsten carbide was utilized as anode to extract tungsten in a NaCl-KCl-Na{sub 2}WO{sub 4} molten salt, and the electrochemical dissolution was investigated. Although the molten salt electrochemical method is a short process method of tungsten extraction from tungsten carbide in one step, the dissolution efficiency and current efficiency are quite low. In order to improve the dissolution rate and current efficiency, the sodium tungstate was added as the active substance. The dissolution rate, the anode current efficiency, and the cathode current efficiency were calculated with different contents of sodium tungstate addition. The anodes prior to and following the reaction, as well as the product, were analyzed through X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. The results demonstrated that the sodium tungstate could improve the dissolution rate and the current efficiency, due to the addition of sodium tungstate decreasing the charge transfer resistance in the electrolysis system. Due to the fact that the addition of sodium tungstate could remove the carbon during electrolysis, pure tungsten powders with 100 nm diameter were obtained when the content of sodium tungstate was 1.0 pct.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Study of In-Trap Ion Clouds by Ion Trajectory Simulations

Gaussian distribution has been utilized to describe the global number density distribution of ion cloud in the Paul trap, which is known as the thermal equilibrium theory and widely used in theoretical modeling of ion clouds in the ion traps. Using ion trajectory simulations, however, the ion clouds can now also be treated as a dynamic ion flow field and the location-dependent features could now be characterized. This study was carried out to better understand the in-trap ion cloud properties, such as the local particle velocity and temperature. The local ion number densities were found to be heterogeneously distributed in terms of mean and distribution width; the velocity and temperature of the ion flow varied with pressure depending on the flow type of the neutral molecules; and the “quasi-static” equilibrium status can only be achieved after a certain number of collisions, for which the time period is pressure-dependent. This work provides new insights of the ion clouds that are globally stable but subjected to local rf heating and collisional cooling. .

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

FPPS mediates TGF-β1-induced non-small cell lung cancer cell invasion and the EMT process via the RhoA/Rock1 pathway

Highlights: • FPPS expression is significantly correlated with TNM stage and metastasis of non-small cell lung cancer. • Inhibition or knockdown of FPPS blocks TGF-β1-induced cell invasion and EMT. • FPPS expression is induced by TGF-β1. • FPPS mediates TGF-β1-induced lung cancer cell invasion and EMT via the RhoA/Rock1 pathway. Farnesyl pyrophosphate synthase (FPPS), a key enzyme in the mevalonate pathway, was recently shown to play a role in cancer progression. However, its role in non-small cell lung cancer (NSCLC) metastasis and the underlying mechanism remain unclear. In this study, FPPS expression was significantly correlated with TNM stage, and metastasis. Inhibition or knockdown of FPPS blocked TGF-β1-induced cell invasion and epithelial-to-mesenchymal transition (EMT) process. FPPS expression of FPPS was induced by TGF-β1 and FPPS promoted cell invasion and EMT via the RhoA/Rock1 pathway. In conclusion, FPPS mediates TGF-β1-induced lung cancer cell invasion and EMT via the RhoA/Rock1 pathway. These findings suggest new treatment strategies to reduce mortality associated with metastasis in patients with NSCLC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

GBP3 promotes glioma cell proliferation via SQSTM1/p62-ERK1/2 axis

Highlights: • GBP3, an interferon-inducible large GTPase, is highly elevated in human glioma tumors. • GBP3 promotes glioma cell growth in vitro and in vivo through the SQSTM1/p62-ERK1/2 pathway. • GBP3 expression predicts poor outcome of glioma patients. Guanylate binding proteins (GBPs) are interferon-inducible large GTPases and play a crucial role in cell-autonomous immunity. However, the biology function of GBPs in cancer remains elusive. GBP3 is specifically expressed in adult brain. Here we show that GBP3 is highly elevated in human glioma tumors and glioma cell lines. Overexpression of GBP3 dramatically increased glioma cell proliferation whereas silencing GBP3 by RNA interference produced opposite effects. We further showed that GBP3 expression was able to induce sequestosome-1(SQSTM1, also named p62) expression and activate extracellular signal-regulated kinase (ERK1/2). The SQSTM1-ERK1/2 signaling cascade was essential for GBP3-promoted cell growth because depletion of SQSTM1 markedly reduced the phosphorylated ERK1/2 levels and GBP3-mediated cell growth, and inhibition of mitogen-activated protein kinase/ERK kinase abolished GBP3-induced glioma cell proliferation. Consistently, GBP3 overexpression significantly promoted glioma tumor growth in vivo and its expression was inversely correlated with the survival rate of glioma patients. Taken together, these results for the first time suggest that GBP3 contributes to the proliferation of glioma cells via regulating SQSTM1-ERK1/2 pathway, and GBP3 might represent as a new potential therapeutic target against glioma.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Q482H mutation of procaspase-8 in acute myeloid leukemia abolishes caspase-8-mediated apoptosis by impairing procaspase-8 dimerization

Highlights: • The Q482H mutation of procaspase-8 was identified from AML patients. • The Q482H mutation was associated with poor chemotherapy response in AML patients. • The Q482H mutation abolished procaspase-8 mediated apoptotic signaling cascade. • The Q482H inhibited TRAIL-induced apoptosis. • The Q482H mutation disrupted the dimeriztion of procaspase-8. Certain procaspase-8 mutations are reported to be associated with the progression and prognosis of multiple tumors. However, it remains unclear whether the poor chemotherapy response and frequent relapse after complete remission of patients with acute myeloid leukemia (AML) is also related to procaspase-8 abnormalities.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

MiR-628-5p decreases the tumorigenicity of epithelial ovarian cancer cells by targeting at FGFR2

Highlights: • miR-628-5p decreases the stem like cell percentage of epithelial ovarian cancer cells by inducing their apoptosis. • miR-628-5p decreases the tumourigenecity of epithelial ovarian cancer cells. • miR-628-5p targets at and down regulates the expression of fibroblast growth factor receptor 2. • Fibroblast growth factor receptor 2 expresses higher in ovarian cancer tissues and is correlated with worse prognosis. Micro RNAs (miRNAs) are small non-coding RNAs which are 19–24 nucleotides in length. MiRNAs play a vital role in the whole process of tumour development, but how they influence the tumourigenecity of epithelial ovarian cancer (EOC)cells is rarely researched. In our study, it was verified that miR-628-5p decreased the stem like cell percentage of EOC cells by inducing their apoptosis. The animal experiments showed that miR-628-5p decreased the tumourigenecity of EOC cells. Besides, we found miR-628-5p targeted at and down-regulated the expression of fibroblast growth factor receptor 2 (FGFR2). FGFR2 expressed higher in ovarian cancer tissues and was correlated with worse prognosis. Our findings indicated that miR-628-5pplays an important role in ovarian cancer stem cell driven tumorigenesis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

A New Grain Refiner for Ferritic Steels

A new grain refiner, LaB{sub 6}, was identified for ferritic steels based on the crystallographic calculation using the edge-to-edge matching model. Addition of 0.5 wt pct LaB{sub 6} led to a reduction of the average grain size from 765 to 92 μm and the proportion of the columnar structure from 35 to 8 pct in an as-cast Fe-4Si ferritic alloy. Although LaB{sub 6} was supposed to act as an active inoculant for δ-ferrite, thermodynamic calculation indicated that LaB{sub 6} is not thermodynamically stable in the melt of the Fe-4Si alloy. It was subject to decompose into La and B solutes. Consequently, both La and B reacted with Fe, O and S, forming different compounds. Microstructural examination at room temperature observed La{sub 2}SO{sub 2} and La{sub 2}O{sub 3} particles within the ferrite grains and Fe{sub 2}B along the grain boundaries in the samples. Through EBSD analysis, a reproducible orientation relationship between ferrite and La{sub 2}SO{sub 2} was identified. In addition, the edge-to-edge matching calculation also predicted the high potency for La{sub 2}SO{sub 2} to be an effective nucleant for δ-ferrite. It was considered that the grain refinement of LaB{sub 6} was attributed to the enhanced heterogeneous nucleation of δ-ferrite by La{sub 2}SO{sub 2}, and the solute effect of B due to the high Q-value in ferrite.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Mitigation of tin whisker growth by inserting Ni nanocones

Highlights: • Tin whisker growth is mitigated effectively by inserting Ni nanocones. • Ni nanocones impede Sn dynamic recrystallization by blocking dislocation motions. • The inhibition method and mechanism are important to the study of tin whisker. - Abstract: An innovative controllable way has been proposed to mitigate tin whisker growth by inserting Ni nanocones prepared by electrodeposition. The results reveal that, after inserting Ni nanocones, tin whisker formation is mitigated effectively for 1.6 μm Sn coating but there is no inhibition effect for 4.5 μm Sn coating. The coatings are characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer and electron backscatter diffraction (EBSD). The EBSD results show that Sn grain size without Ni nanocones increases significantly after indentation test compared with Sn grains with Ni nanocones. The inhibition effect of Ni nanocones on whisker growth can be ascribed to its specific structure which prevents dynamic recrystallization and produces horizontal grain boundaries of Sn grains. The structural inhibition method and mechanism proposed are of great importance to the research of tin whisker.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2017

Development of a bayesian belief network model for the software reliability assessment of nuclear digital I and C safety systems - 206

Since the digital instrumentation and control systems are expected to play an important role for the safety systems in nuclear power plants (NPPs), the need has emerged to not only establish a basis for incorporating software behavior into digital I and C system reliability models, but also to quantify the failure probability of the software used in NPP digital protection systems. In this study, a Bayesian belief network (BBN) model is developed to quantitatively assess software reliability by estimating the number of faults in a software program considering its software development life cycle (SDLC). The model structure and parameters are established based on the information applicable to NPP safety-related systems and the evidence used to construct and quantify the BBN model was collected from three stages of expert elicitation. The software failure probability is estimated from the number of residual defects in a software program at the end of SDLC phase. As a case study, the BBN model was applied to quantify the software reliability of a typical digital protection software having the size of 50 function points and having the Medium development and validation and verification (V and V) qualities. The developed model can be applied to estimate the failure probability for both developing and deployed safety-related NPP software, and such results can be used to evaluate the quality of the digital I and C systems in addition to estimating potential reactor risk due to software failure. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2017

Application of a bayesian belief network model to reliability assessment of nuclear safety-related software - 207

As the instrumentation and control (I and C) systems in nuclear power plants (NPPs) have been replaced with digital-based systems, the need to incorporate software failures into NPP probabilistic risk assessments has arisen. In order to assess the probability of software failure on demand, a Bayesian belief network (BBN) model was developed which estimates the number of defects and the resulting probability of software failure on demand in nuclear safety-related software. To assess the feasibility of the BBN framework, the BBN model was applied to the prototype Integrated Digital Protection System-Reactor Protection System (IDiPS-RPS) to estimate the number of remaining faults and the software failure probability of a target software. The developmental- and V and V-activities carried out during the IDiPS-RPS development process were evaluated based on the well-defined checklist derived by the V and V team and were estimated based on expert elicitation. In addition, the attribute evaluations and the number of FPs of the target software is provided as the inputs for the BBN model. The application results showed the feasibility of using BBNs for quantifying software failure probabilities and several insights were gained from the applications of the BBN model. The proposed BBN framework can be applied to estimate the software failure probability for other safety-related NPP software and provide an insight on modeling the software development process that involves iterations between different development phases. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2017

Probing the oxidation kinetics of small permalloy particles

The oxidation of permalloys is important to apply in a wide range. The oxidation and diffusion mechanisms of small permalloy particles with different Fe content are studied by using thermal gravimetric analysis (TGA) and microstructure characterizations. Fe{sub 2}O{sub 3}/(Ni, Fe){sub 3}O{sub 4} plays a key role in the morphology evolution and diffusion mechanisms of small NiFe particles upon oxidation. The activation energies of grain boundary diffusion for the NiFe alloys increase from 141 kJ/mol to 208 kJ/mol as the Fe content increases from 0 to ~50 wt%. We have developed a diffusion process resolved temperature programed oxidation (PR-TPO) analysis method. Three diffusion mechanisms have been recognized by using this method: In addition to the grain boundary diffusion and lattice diffusion, our TGA analysis suggests that the phase conversion from Fe{sub 2}O{sub 3} to (Ni, Fe){sub 3}O{sub 4} induces diffusion change and affects the diffusion process at the intermediate temperature. Relevant oxidation kinetics and diffusion mechanisms are discussed. - Graphical abstract: The oxidation mechanisms of small Permalloy particles with different Fe content is studied by using thermal gravimetric analysis (TGA) and microstructure characterizations. The activation energies of grain boundary diffusion for the NiFe alloys increases from 140 kJ/mol to 208 kJ/mol as the Fe content increases from 0 to 50 wt% as determined by TGA. We have developed a diffusion process resolved temperature programed oxidation (DPR-TPO) analysis method, and three diffusion mechanisms have been recognized by using this method: In addition to the well-known grain boundary diffusion and lattice diffusion, we found that the phase conversion from Fe{sub 2}O{sub 3} to (Ni, Fe){sub 3}O{sub 4} will induce diffusion changes and affect the diffusion process at the intermediate temperature. The diffusion processes can be characterized by the corresponding characteristic peak temperatures in temperature programmed oxidation (TPO) analysis. This work not only give insight knowledge about the oxidation and diffusion processes of small permalloy particles, but also, provides a useful tool for analyzing solid-gas reactions of other materials. - Highlights: • The oxidation kinetics of small NiFe particles were studied by using thermoanalysis. • Grain boundary, lattice, and phase conversion induced diffusions were recognized. • The activation energy of oxidation increases with the Fe content in the alloy. • Each diffusion process corresponds to a characteristic temperature in TPO analysis. • NiFe alloys with ~5–10 wt% Fe content have the lowest oxidation rates.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

In-Plane Deformation Mechanics for Highly Stretchable Electronics

Scissoring in thick bars suppresses buckling behavior in serpentine traces that have thicknesses greater than their widths, as detailed in a systematic set of analytical and experimental studies. Scissoring in thick copper traces enables elastic stretchability as large as ≈350%, corresponding to a sixfold improvement over previously reported values for thin geometries (≈60%).

36 MATERIALS SCIENCE↗
DOE OSTI2016

Correlative characterization of primary particles formed in as-cast Al-Mg alloy containing a high level of Sc

Primary particles formed in as-cast Al-5Mg-0.6Sc alloy and their role in microstructure and mechanical properties of the alloy were investigated using optical microscopy (OM), scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and tensile testing. It was found that primary particles due to a close orientation to matrix could serve as the potent heterogeneous nucleation sites for α-Al during solidification and thus impose a remarkable grain refinement effect. Eutectic structure consisted of layer by layer of ‘Al{sub 3}Sc + α-Al + Al{sub 3}Sc + ⋯’ and cellular-dendritic substructure were simultaneously observed at the particles inside, indicating that these particles could be identified as the eutectics rather than individual Al{sub 3}Sc phase. A calculating method, based on EBSD results, was introduced for the spatial distribution of these particles in matrix. The results showed that these eutectic particles randomly distributed in matrix. In addition, the formation of primary eutectic particles significant improved the strength of the Al-Mg alloy in as-cast condition, which is ascribed to the structural evolution from coarse dendrites to prefect fine equiaxed grains. On the other hand, these large-sized particles due to the tendency to act as the microcrack sources could cause a harmful effect in the ductility of Al-Mg-Sc alloy. - Highlights: •Primary particles exhibit an ‘Al{sub 3}Sc + α-Al + Al{sub 3}Sc + ⋯’ multilayer feature with a cellular-dendritic mode of growth. •EBSD analyses the mechanism of grain refinement and the distribution of primary particles in α-Al matrix. •A computational method was presented to calculate the habit planes of primary particles.

36 MATERIALS SCIENCE↗