Evolution of Local Structural Ordering and Chemical Distribution upon Delithiation of a Rock Salt–Structured Li1.3Ta0.3Mn0.4O2 Cathode

Lithium‐rich disordered rock‐salt oxides have attracted great interest owing to their promising performance as Li‐ion battery cathodes. While experimental and theoretical efforts are critical in advancing this class of materials, a fundamental understanding of key property changes upon Li extraction is largely missing. In the present study, single‐crystal synthesis of a new disordered rock‐salt cathode material, Li_1.3Ta_0.3Mn_0.4O₂ (LTMO), and its use as a model compound to investigate Li concentration–driven evolution of local cationic ordering, charge compensation, and chemical distribution are reported. Through the combined use of 2D and 3D X‐ray nanotomography, it is shown that Li removal accompanied by oxygen oxidation is correlated with the development of morphological defects such as particle cracking. Chemical heterogeneity, quantified by subparticle level distribution of Mn valence state, is minimal during Mn redox, which drastically increases upon the formation of cracks during oxygen redox. Density functional theory and bond valence sum mismatch calculations reveal the presence of local short‐range ordering in the pristine oxide, which gradually disappears along with the extraction of Li. The study suggests that with cycling the transformation into true cation–disordered state can be expected, which likely impacts the voltage profile and obtainable energy density of the oxide cathodes.     

Time-dependent crashworthiness of polyurethane foam

Mechanics of Time-Dependent Materials - Time-dependent stress–strain relationship as well as crashworthiness of polyurethane foam was investigated under constant impact energy with different...     

Jig-free laser welding of Eagle XG glasses by using a picosecond pulsed laser

We have performed the jig-free laser welding on the alkaline earth boro-aluminosilicate glass (Eagle XG, Corning), which is commonly used in the display devices, by using a picosecond pulsed laser. Two sheets of Eagle XG glasses with 0.5 mm thickness each were placed one on top of the other. Due to the jig-free laser welding, there was a very thin air gap between the two glasses, and the experiment proceeded by line scanning. The welding performance was evaluated by observing the optical images from the top view and the bottom view and comparing the line images. We could bond the two glass surfaces on the laser spot, and achieve the successful welding of such glasses in the scanning speeds from 10 mm/s to 50 mm/s with the laser irradiance from 50 TW/cm²(500 J/cm²) to 83 TW/cm² (830 J/cm²). We demonstrated the feasibility of jig-free laser welding on the Eagle XG glass with the welding strength up to 50 MPa.

     

Screen printing for support-pillar placement for vacuum glazing and the effects of pillar spacing on strength properties

Maintaining a vacuum between the two glasses to maximize the heat insulating performance, it is indispensable to array the pillar for the vacuum glazing to maintain the vacuum gap. In this paper, to investigate the effect of the spacing of the pillars arranged using the screen printing method on the strength of the glass, a bending strength test was carried out by design and fabricating a ROR bending strength test jig based on the Euro standard. In the strength test results, the experimental results were analyzed using the Weibull distribution, which is a statistical analysis method mainly used for evaluating the breaking strength of brittle material. Based on the analysis results, the placement spacing of the pillars proved validity for maintaining the vacuum glass gaps.     

Genetic Deficiency and Pharmacological Stabilization of Mast Cells Ameliorate Pressure Overload-Induced Maladaptive Right Ventricular Remodeling in Mice

Although the response of the right ventricle (RV) to the increased afterload is an important determinant of the patient outcome, very little is known about the underlying mechanisms. Mast cells have been implicated in the pathogenesis of left ventricular maladaptive remodeling and failure. However, the role of mast cells in RV remodeling remains unexplored. We subjected mast cell-deficient WBB6F1-KitW/W-v (Kit^W/Kit^W-v) mice and their mast cell-sufficient littermate controls (MC^+/+) to pulmonary artery banding (PAB). PAB led to RV dilatation, extensive myocardial fibrosis, and RV dysfunction in MC^+/+ mice. In PAB Kit^W/Kit^W-v mice, RV remodeling was characterized by minimal RV chamber dilatation and preserved RV function. We further administered to C57Bl/6J mice either placebo or cromolyn treatment starting from day 1 or 7 days after PAB surgery to test whether mast cells stabilizing drugs can prevent or reverse maladaptive RV remodeling. Both preventive and therapeutic cromolyn applications significantly attenuated RV dilatation and improved RV function. Our study establishes a previously undescribed role of mast cells in pressure overload-induced adverse RV remodeling. Mast cells may thus represent an interesting target for the development of a new therapeutic approach directed specifically at the heart.     

Performance of two shrouded probes for the collection of liquid aerosols in a wind tunnel optimized for high air speeds

Abstract

A combination of type A (high flow model) or B (low flow model) shrouded probe and appropriate isokinetic air-sampler (IAS) was tested in a wind tunnel that was optimized for high air speed testing using computational flow modeling. Liquid uranine aerosols (LUA) with AED (aerodynamic equivalent diameter) of 10?μm were generated at a constant flow rate using a vibrating orifice aerosol generator. The monodispersed aerosols were introduced into a wind tunnel at speeds of 5, 10, 15 and 20?m/s. The high flow (A) or low flow (B) model shrouded probe and the appropriate isokinetic air-sampler (IAS) was co-located to collect the LUA simultaneously during each treatment. After the test, the LUA deposited on the filters and inside the walls of the two air-samplers were collected and analyzed for fluorescence intensity units to determine the wall loss, transmission and aspiration ratios. While the type B shrouded probe had 20% (at 10?m/s) and 14.3% (at 15?m/s) higher wall loss ratios than model A, it had 16.1% (at 10?m/s) and 11.6% (at 15?m/s) higher transmission ratios compared to model A. Similarly, probe B had 17.6% (at 10?m/s) and 14.6% (at 15?m/s) higher aspiration ratios than probe A at similar air velocities. Overall, the wall loss, transmission and aspiration ratios of 10?µm AED ULA measured with two types of shrouded probes at 5, 10, 15 and 20?m/s air velocities in the optimized wind tunnel had good agreement with the range of standard data.

Copyright © 2020 American Association for Aerosol Research     

Supply chain data analytics for predicting supplier disruptions: a case study in complex asset manufacturing

Although predictive machine learning for supply chain data analytics has recently been reported as a significant area of investigation due to the rising popularity of the AI paradigm in industry, there is a distinct lack of case studies that showcase its application from a practical point of view. In this paper, we discuss the application of data analytics in predicting first tier supply chain disruptions using historical data available to an Original Equipment Manufacturer (OEM). Our methodology includes three phases: First, an exploratory phase is conducted to select and engineer potential features that can act as useful predictors of disruptions. This is followed by the development of a performance metric in alignment with the specific goals of the case study to rate successful methods. Third, an experimental design is created to systematically analyse the success rate of different algorithms, algorithmic parameters, on the selected feature space. Our results indicate that adding engineered features in the data, namely agility, outperforms other experiments leading to the final algorithm that can predict late orders with 80% accuracy. An additional contribution is the novel application of machine learning in predicting supply disruptions. Through the discussion and the development of the case study we hope to shed light on the development and application of data analytics techniques in the analysis of supply chain data. We conclude by highlighting the importance of domain knowledge for successfully engineering features.     

Two-step sintering technique for enhancing mechanical and oxygen permeation properties of dual-phase oxygen transport membranes

The present work involved the application of a two-step sintering (TSS) technique for typical Ce_0.9Gd_0.1O_2?δ–La_0.6Sr_0.4Co_0.2Fe_0.8O_3–δ (GDC–LSCF) composites and its effect on the microstructure and resultantly mechanical and O₂-permeating properties. The samples obtained by conventional sintering (CS) performed at 1100, 1250, and 1400 °C for 3 h exhibited maximum flexural strength and hardness values of 142 MPa and 8.71 GPa, respectively. However, the application of a TSS procedure produced fine-grained microstructures with improved mechanical properties. In particular, with the use of a typical 1250/1200 TSS protocol, increases of approximately 31 % and 7% in the flexural strength and hardness values, respectively, were observed compared to those obtained using the CS method. Moreover, thick-film (～ 60 μm) GDC–LSCF membrane prepared by tape casting and the TSS technique showed remarkably 1.5–2 times higher oxygen permeation flux than membrane sintered by CS method. The results are discussed and explained in detail.     

Modeling occupant behavior of the manual control of windows in residential buildings

Window opening and closing is the most preferred behavior for occupants to control their indoor environment in homes. This study aims to identify driving forces for window opening and closing behavior in the home. The additional field survey was carried out for the cooling period after following the previous study. The state of windows and environmental variables for outdoor and indoor were continuously monitored in 23 sample homes over one year. The monitored data provide evidence that there is a statistically significant relationship between window opening behavior and outdoor temperature. The behavior of the occupant's manual control of windows can be described by seasonal effects, occupancy, and time of day. Indoor stimuli, such as such as temperature, humidity, and CO₂, can better account for the window opening behavior than can outdoor stimuli. There are clear differences in driving variables between window opening and closing behavior. The closing behavior is better described when the outdoor and indoor variables are combined. Finally, multivariate logistic regression models were developed to predict typical patterns of window opening and closing as a function of indoor and outdoor variables.     

Stimulation of densification during the reduction of U3O8 to UO2 by atmosphere control

A reduction process in the head-end for pyroprocessing has been adopted to avoid oxidation attack on the molybdenum crucible during sintering. The reduction process is employed to reduce U₃O₈ pellets to UO₂ prior to sintering. This allows elimination of the oxygen source, which causes oxidation attack during sintering, thereby permitting the use of a metallic crucible. However, little densification occurs due to the low reduction temperature limited by the INCONEL crucible. Consequently, the amount of material scraps from the pellets increases, thus creating an additional processing burden due to its high radioactivity. To reduce the amount of scraps, densification should be enhanced. This study suggests a simple atmospheric control strategy and clarifies its effects. With the atmospheric control, a higher bulk density and better attrition resistance were obtained in comparison to without this strategy. This can be explained in terms of O/U ratio dependent diffusion kinetics during the reduction of U₃O₈ to UO₂.