Optimization of Multi-Fidelity Computer Experiments via the EQIE Criterion

<p>Computer experiments based on mathematical models are powerful tools for understanding physical processes. This article addresses the problem of kriging-based optimization for deterministic computer experiments with tunable accuracy. Our approach is to use multi-fidelity computer experiments with increasing accuracy levels and a nonstationary Gaussian process model. We propose an optimization scheme that sequentially adds new computer runs by following two criteria. The first criterion, called EQI, scores candidate inputs with given level of accuracy, and the second criterion, called EQIE, scores candidate combinations of inputs and accuracy. From simulation results and a real example using finite element analysis, our method outperforms the expected improvement (EI) criterion that works for single-accuracy experiments. Supplementary materials for this article are available online.</p

The Design and Analysis for the Icing Wind Tunnel Experiment of a New Deicing Coating

<p>A new kind of deicing coating is developed to provide aircraft with efficient and durable protection from icing-induced dangers. The icing wind tunnel experiment is indispensable in confirming the usefulness of a deicing coating. Due to the high cost of each batch relative to the available budget, an efficient design of the icing wind tunnel experiment is crucial. The challenges in designing this experiment are multi-fold. It involves between-block factors and within-block factors, incomplete blocking with random effects, related factors, hard-to-change factors, and nuisance factors. Traditional designs and theories cannot be directly applied. To overcome these challenges, we propose using a step-by-step design strategy that includes applying a cross array structure for between-block factors and within-block factors, a group of balanced conditions for optimizing incomplete blocking, a run order method to achieve the minimum number of level changes for hard-to-change factors, and a zero aliased matrix for the nuisance factors. New (theoretical) results for D-optimal design of incomplete blocking experiments with random block effects and minimum number of level changes are obtained. Results of the experiments show that this novel deicing coating is promising in offering both high efficiency of ice reduction and a long service lifetime. The methodology proposed here is generalizable to other applications that involve nonstandard design problems. Supplementary materials for this article are available online.</p

Enhanced Hydrogen Production from Sawdust Decomposition Using Hybrid-Functional Ni-CaO-Ca₂SiO₄ Materials

A hybrid-functional material consisting of Ni as catalyst, CaO as CO₂ sorbent, and Ca₂SiO₄ as polymorphic “active” spacer was synthesized by freeze-drying a mixed solution containing Ni, Ca and Si precursors, respectively, to be deployed during sawdust decomposition that generated gases mainly containing H₂, CO, CO₂ and CH₄. The catalytic activity showed a positive correlation to the Ni loading, but at the expense of lower porosity and surface area with Ni loading beyond 20 wt %, indicating an optimal Ni loading of 20 wt % for Ni-CaO-Ca₂SiO₄ hybrid-functional materials, which enables ∼626 mL H₂ (room temperature, 1 atm) produced from each gram of sawdust, with H₂ purity in the product gas up to 68 vol %. This performance was superior over a conventional supported catalyst Ni–Ca₂SiO₄ that produced 443 mL H₂ g-sawdust^–1 under the same operating condition with a purity of ∼61 vol %. Although the Ni-CaO bifunctional material in its fresh form generated a bit more H₂ (∼689 mL H₂ g-sawdust^–1), its cyclic performance decayed dramatically, resulting in H₂ yield reduced by 62% and purity dropped from 73 to 49 vol % after 15 cycles. The “active” Ca₂SiO₄ spacer offers porosity and mechanical strength to the Ni-CaO-Ca₂SiO₄ hybrid-functional material, corresponding to its minor loss in reactivity over cycles (H₂ yield reduced by only 7% and H₂ purity dropped from 68 to 64 vol % after 15 cycles)

Effects of relative humidity and particle type on the performance and service life of automobile cabin air filters

<p>Cabin air filters are the main barrier for protecting automobile passengers from on road particulate matter. There are many studies about the evaluation of their performance in terms of filtration efficiency. However, the knowledge about the loading capacity of them is still lacking. Meanwhile, there has been no quantitative method to estimate the proper filter service life time. This study focuses on testing the loading capacity of different types of cabin air filters under the conditions of different relative humidity values and particle types. The results indicate that when the relative humidity increases, the activated carbon coated filters can adsorb significant amounts of water with no significant increase of the pressure drop. The normal fibrous filters show in contrast negligible water adsorbance. Compared with the filters loaded by Arizona road dust only, loading the filters by Arizona road dust and soot particles simultaneously will result in the steeper loading curves as well as the shift of most penetrating particle size to the smaller diameter. Finally, a new method to estimate the proper service life time of the cabin air filters is suggested based on the loading curves.</p> <p>© 2016 American Association for Aerosol Research</p

Polyethylenimine-Grafted Cellulose Nanofibril Aerogels as Versatile Vehicles for Drug Delivery

Aerogels from polyethylenimine-grafted cellulose nanofibrils (CNFs-PEI) were developed for the first time as a novel drug delivery system. The morphology and structure of the CNFs before and after chemical modification were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Water-soluble sodium salicylate (NaSA) was used as a model drug for the investigation of drug loading and release performance. The CNFs-PEI aerogels exhibited a high drug loading capability (287.39 mg/g), and the drug adsorption process could be well described by Langmuir isotherm and pseudo-second-order kinetics models. Drug release experiments demonstrated a sustained and controlled release behavior of the aerogels highly dependent on pH and temperature. This process followed quite well the pseudo-second-order release kinetics. Owing to the unique pH- and temperature-responsiveness together with their excellent biodegradability and biocompatibility, the CNFs-PEI aerogels were very promising as a new generation of controlled drug delivery carriers, offering simple and safe alternatives to the conventional systems from synthetic polymers

Light-Triggered Pyroelectric Nanogenerator Based on a pn-Junction for Self-Powered Near-Infrared Photosensing

A nanogenerator, as a self-powered system, can operate without an external power supply for energy harvesting, signal processing, and active sensing. Here, near-infrared (NIR) photothermal triggered pyroelectric nanogenerators based on pn-junctions are demonstrated in a p-Si/n-ZnO nanowire (NW) heterostructure for self-powered NIR photosensing. The pyroelectric-polarization potential (pyro-potential) induced within wurtzite ZnO NWs couples with the built-in electric field of the pn-junction. At the moment of turning on or off the NIR illumination, external current flow is induced by the time-varying internal electric field of the pn-heterostructure, which enables a bias-free operation of the photodetectors (PDs). The NIR PD exhibits a high on/off photocurrent ratio up to 10⁷ and a fast photoresponse component with a rise time of 15 μs and a fall time of 21 μs. This work provides an unconventional strategy to achieve active NIR sensing, which may find promising applications in biological imaging, optoelectronic communications, and optothermal detections

DataSheet_1_Laminin-bound integrin α6β4 promotes non-small cell lung cancer progression via the activation of YAP/TAZ signaling pathway.zip

Laminin is an extracellular matrix multidomain trimeric glycoprotein, that has a potential role in tumor progression. Here, we studied the effects of non-small cell lung cancer (NSCLC) cells interaction on laminin and explored the underlying mechanism of laminin associated NSCLC progression. Culture of A549 and NCI-1299 cells on 2D collagen gels (containing laminin) significantly promoted the proliferative and tumorigenic characteristics, as well as cell invasion of tumor cells in vitro. Consistently, comparing the clinical NSCLC tumor tissues, a poor overall survival was observed in patients with high laminin expression. Mechanistically, the expression of integrin α6β4 was required for the pro-tumor effects of laminin. Meanwhile, we showed that the downstream signaling of integrin α6β4, involved the focal adhesion kinase (FAK)/Yes-Associated Protein (YAP)/TAZ signaling pathway. The activation of FAK/YAP/TAZ signaling pathway induced by laminin was validated in tumor tissues from NSCLC patients. Suppression of integrin α6β4/FAK/YAP/TAZ signaling pathway efficiently suppressed the laminin-induced tumor growth, and strengthened the anticancer effects of chemotherapy, describing a novel target for NSCLC treatment.</p

Effects of Drying Methods on Wet Chemistry Synthesis of Al-Stabilized CaO Sorbents for Cyclic CO₂ Capture

Al-stabilized CaO sorbents synthesized by wet chemistry methods have demonstrated effectiveness to mitigate CaO sintering during Ca-looping cycles (CaO + CO₂ ⇌ CaCO₃) for CO₂ capture. To further screen the synthesis techniques and recipes, a series of Al-stabilized CaO sorbents, namely, CaO–Ca₉Al₆O₁₈ hybrid materials, derived from cosolutions of calcium acetate and aluminum nitrate were prepared using three different drying methods, i.e., freeze drying, spray drying, and evaporation drying. These sorbents were then characterized by X-ray diffraction, N₂ physisorption, scanning electron microscopy, and energy dispersive spectrometry. The effects of drying methods on the CO₂ capture performance of the sorbents were analyzed comprehensively. Out of the three drying methods, spray drying enabled the optimal textural property and the hard skeleton with sufficient mechanical strength, resulting in the supreme CO₂ capture capacity. Furthermore, it was found that, by spray drying, the inert spacer Ca₉Al₆O₁₈ could play the most significant role in stabilizing the cyclic sorption reactivity of CaO. For spray dried samples, the SD70 sample with 70 wt % CaO and 30 wt % Ca₉Al₆O₁₈ could well balance the capacity and stability under mild conditions. Its advantage was much more pronounced under severe conditions, where SD70 overtook other samples in CO₂ uptake capacity from the fourth cycle and maintained the highest CaO conversion all through the 30 cycles

Regeneration of Commercial SCR Catalysts: Probing the Existing Forms of Arsenic Oxide

To investigate the poisoning and regeneration of SCR catalysts, fresh and arsenic-poisoned commercial V₂O₅–WO₃/TiO₂ catalysts are researched in the context of deactivation mechanisms and regeneration technology. The results indicate that the forms of arsenic oxide on the poisoned catalyst are related to the proportion of arsenic (As) on the catalyst. When the surface coverage of (V+W+As) is lower than 1, the trivalent arsenic species (As^III) is the major component, and this species prefers to permeate into the bulk-phase channels. However, at high As concentrations, pentavalent arsenic species (As^IV) cover the surface of the catalyst. Although both arsenic species lower the NO_<i>x</i> conversion, they affect the formation of N₂O differently. In particular, N₂O production is limited when trivalent arsenic species predominate, which may be related to As₂O₃ clogging the pores of the catalyst. In contrast, the pentavalent arsenic oxide species (As₂O₅) possess several As–OH groups. These As–OH groups could not only enhance the ability of the catalyst to become reduced, but also provide several Brønsted acid sites with weak thermal stability that promote the formation of N₂O. Finally, although our novel Ca­(NO₃)₂-based regeneration method cannot completely remove As₂O₃ from the micropores of the catalyst, this approach can effectively wipe off surface arsenic oxides without a significant loss of the catalyst’s active components

Table_1_Laminin-bound integrin α6β4 promotes non-small cell lung cancer progression via the activation of YAP/TAZ signaling pathway.docx

Laminin is an extracellular matrix multidomain trimeric glycoprotein, that has a potential role in tumor progression. Here, we studied the effects of non-small cell lung cancer (NSCLC) cells interaction on laminin and explored the underlying mechanism of laminin associated NSCLC progression. Culture of A549 and NCI-1299 cells on 2D collagen gels (containing laminin) significantly promoted the proliferative and tumorigenic characteristics, as well as cell invasion of tumor cells in vitro. Consistently, comparing the clinical NSCLC tumor tissues, a poor overall survival was observed in patients with high laminin expression. Mechanistically, the expression of integrin α6β4 was required for the pro-tumor effects of laminin. Meanwhile, we showed that the downstream signaling of integrin α6β4, involved the focal adhesion kinase (FAK)/Yes-Associated Protein (YAP)/TAZ signaling pathway. The activation of FAK/YAP/TAZ signaling pathway induced by laminin was validated in tumor tissues from NSCLC patients. Suppression of integrin α6β4/FAK/YAP/TAZ signaling pathway efficiently suppressed the laminin-induced tumor growth, and strengthened the anticancer effects of chemotherapy, describing a novel target for NSCLC treatment.</p