This paper provides a brief review on modeling of composite structures. Composite structures in this paper refer to any structure featuring anisotropy and heterogeneity, including but not limited to ...their traditional meaning of composite laminates made of unidirectional fiber-reinforced composites. Common methods used in modeling of composite structures, including the axiomatic method, the formal asymptotic method, and the variational asymptotic method, are illustrated in deriving the classical lamination theory for the composite laminated plates. Future research directions for modeling composite structures are also pointed out.
A new failure criterion for fiber tows (i.e. yarns) is developed based on a micromechanical model using the mechanics of structure genome (MSG) and a deep learning neural network model. The proposed ...failure criterion can be applied to yarns in mesoscale textile composites modeling while capturing the failure initiation at the fiber and matrix level. A plain weave fiber reinforced composite material example is used to compute the initial failure strength constants of a woven lamina based on the proposed yarn failure criterion. To study the accuracy and efficiency of the failure criterion, a comparison to a meso-micro coupled model explicitly capturing the failure initiation at fiber and matrix level is performed. Moreover, the differences between the mesoscale modeling results based on the proposed criterion and other yarn failure criteria (i.e. maximum stress, Tsai-Wu, and Hashin) are studied. Lastly, the failure envelope analysis of the mesoscale plain weave example is carried out using the MSG solid model to further demonstrate the accuracy and efficiency of the new yarn failure criterion under combined loading conditions.
•B20 and diesel exhibit similar spray tip penetration and angle.•Change in orientation of spray shapes observed with different fuels.•B100 shows poor air fuel mixing compared to B20 and ...diesel.•Diesel shows higher equivalence ratio compared to B20 and B100.
In this study, the fuel spray characteristics and air-fuel mixing process of waste cooking oil biodiesel (B100) and its blend with diesel (B20) were investigated and compared with diesel fuel. Spray characteristics such as spray tip penetration, spray angle, spray velocity and spray morphology were investigated under high injection and ambient pressure conditions using a constant volume spray chamber. The air-fuel mixing process was analysed using empirical relations like fuel volume, mass of air entrained within the spray and equivalence ratio. The results shows that B100 has higher spray tip penetration and velocity but narrow spray angles due to high viscosity and large momentum possessed by B100 compared to B20 and diesel fuels. The deviation in spray tip penetration reduces under high ambient pressure. The spray angle shows no change under various injection pressures; however it increases significantly under high ambient pressure. The spray shape is affected by the cavitation inside the injector nozzle holes. The fuel volume and amount of air entrainment within the spray showed that B100 exhibits poor air-fuel mixing compared to B20 and diesel fuels. Nevertheless, the equivalence ratio along the axial direction of spray reveals that the B100 has lean equivalence ratio compared to B20 and diesel fuel due to the presence of inherent oxygen content in its structure. A numerical simulation was conducted using new hybrid spray model implemented in KIVA4 and found that the results obtained from the simulation were in good agreement with the empirical results calculated from the experiments.
Despite neoadjuvant/conversion chemotherapy, the prognosis of cT4a/bN+ gastric cancer is poor. Immune checkpoint inhibitors (ICIs) and antiangiogenic agents have shown activity in late-stage gastric ...cancer, but their efficacy in the neoadjuvant/conversion setting is unclear. In this single-armed, phase II, exploratory trial (NCT03878472), we evaluate the efficacy of a combination of ICI (camrelizumab), antiangiogenesis (apatinib), and chemotherapy (S-1 ± oxaliplatin) for neoadjuvant/conversion treatment of cT4a/bN+ gastric cancer. The primary endpoints are pathological responses and their potential biomarkers. Secondary endpoints include safety, objective response, progression-free survival, and overall survival. Complete and major pathological response rates are 15.8% and 26.3%. Pathological responses correlate significantly with microsatellite instability status, PD-L1 expression, and tumor mutational burden. In addition, multi-omics examination reveals several putative biomarkers for pathological responses, including RREB1 and SSPO mutation, immune-related signatures, and a peripheral T cell expansion score. Multi-omics also demonstrates dynamic changes in dominant tumor subclones, immune microenvironments, and T cell receptor repertoires during neoadjuvant immunotherapy. The toxicity and post-surgery complications are limited. These data support further validation of ICI- and antiangiogenesis-based neoadjuvant/conversion therapy in large randomized trials and provide candidate biomarkers.
•One of the first numerical studies on the effect of unsaturation degree of biodiesel.•Higher unsaturated biodiesel exhibits shorter ignition delay.•Higher unsaturated biodiesel produces higher soot ...and NO emissions.•CO emission declines with the DU value increasing.
Biodiesel from different feedstocks has different physicochemical properties. As one of the most important properties, the degree of unsaturation (DU), which is characterized by the number of double bonds in biodiesel composition, could significantly affect its combustion and emission formation process in diesel engines. This study adopted the definition of the degree of unsaturation and aimed to investigate its effect on combustion and emissions in a diesel engine fueled by different biodiesels with different DU. Methyl decanoate (MD), methyl-9-decenoate (MD9D) and n-heptane were adopted as the surrogate fuels to model biodiesel fuels in this study. The different DU in different biodiesel is represented by varying the relative fraction of those three surrogate components when coupling the reaction mechanism into CFD KIVA4-CHEMKIN codes. Numerical modeling was performed to predict the differences in combustion process and the soot, NO and CO emissions in a diesel engine fueled with five typical types of biodiesel under 10%, 50%, and 100% engine loads. The results show that the DU value has a tangible impact on the ignition delay and the emission formation of biodiesel fuels at all engine loads while a negligible impact on the total heat release and the in-cylinder pressure profile at medium-high engine load. The increase of biodiesel unsaturation level alters the viscosity, oxygen contents of fuel, thereby leading to better fuel-air mixing, higher local temperature, and thus promoting the NO emission production while reducing the CO emission. Furthermore, higher unsaturated biodiesel with more carbon double bond also exhibits shorter ignition delay and produces more soot precursor formation, hence more soot emission.
Today, the problem of energy shortage and climate change has urgently motivated the development of research engaged in improving the fuel efficiency of internal combustion engines (ICEs). Although ...many constructive alternatives—including battery electric vehicles (BEVs) and low-carbon fuels such as biofuels or hydrogen—are being put forward, they are starting from a very low base, and still face significant barriers. Nevertheless, 85–90% of transport energy is still expected to come from combustion engines powered by conventional liquid fuels even by 2040. Therefore, intensive passion for the improvement of engine thermal efficiency and decreasing energy loss has driven the development of reliable approaches and modelling to fully understand the underlying mechanisms. In this paper, literature surveys are presented that investigate the relative advantages of technologies mainly focused on minimizing energy loss in engine assemblies, including pistons and rings, bearings and valves, water and oil pumps, and cooling systems. Implementations of energy loss reduction concepts in advanced engines are also evaluated against expectations of meeting greenhouse gas (GHG) emissions compliance in the years to come.
Kaolinite (Kln) is ubiquitous in weathering crust, rivers, groundwater, and oceans, and plays an important role in controlling the migration of rare earth elements (REEs). Phosphate forms strong ...complexes with REEs in aqueous environments, but it remains unclear whether phosphate influences the sorption and fractionation of REEs onto Kln. In this study, the characteristics of the sorption of phosphate, REEs, and phosphate plus REEs onto Kln and the mechanisms of these processes were investigated through batch sorption experiments and model-based computation. Under both weakly acidic and neutral conditions, the sorption isotherms of phosphate and REEs, respectively, were well fitted with a Langmuir model, suggesting that they underwent monolayer sorption onto Kln. The sorption capacity of Kln increased with pH. At pH 4.0, the sorption mechanism of phosphate involved electrostatic attraction and surface complexation, whereas that of REEs mainly involved electrostatic attraction without apparent fractionation. Although pre-sorption of phosphate generated more binding sites on Kln, most REEs were sorbed via electrostatic attraction, which did not affect the fractionation of REEs into light REEs (LREEs) and heavy REEs (HREEs). At pH 6.5, the sorption mechanism of phosphate was only surface complexation, whereas that of REEs involved electrostatic attraction and surface complexation, with slight fractionation. Pre-sorbed phosphate formed ternary surface complexes with REEs, thereby increasing sorption of HREEs, which had a greater complexation ability than LREEs. The above-described results account for the reported effect of phosphate on the enrichment and fractionation of REEs in the supergene environment, and thus improve our understanding of the transfer characteristics of REEs on Earth's surface.
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•Batch sorption experiments and model-based computation were adopted.•Phosphate promoted the sorption of REEs on kaolinite surface at pH 4 and 6.5.•At pH 4, phosphate did not cause the fractionation of REEs.•At pH 6.5, phosphate and REEs formed ternary surface complexes on kaolinite.•At pH 6.5, phosphate promoted the preferential sorption of heavy REEs.
Abstract
N
6
-methyladenosine (m
6
A) is the most common epigenetic RNA modification with essential roles in cancer progression. However, roles of m
6
A and its regulator METTL3 on non-coding RNA in ...gastric cancer are unknown. In this study, we found elevated levels of m
6
A and METTL3 in gastric cancer. Increased METTL3 expression indicated poor outcomes of patients and high malignancy in vitro and in vivo. Mechanically, m
6
A facilitated processing of pri-miR-17-92 into the miR-17-92 cluster through an m
6
A/DGCR8-dependent mechanism. The m
6
A modification that mediated this process occurred on the A879 locus of pri-miR-17-92. The miR-17-92 cluster activated the AKT/mTOR pathway by targeting
PTEN
or
TMEM127
. Compared with those with low levels of METTL3, METTL3-high tumors showed preferred sensitivity to an mTOR inhibitor, everolimus. These results reveal a perspective on epigenetic regulations of non-coding RNA in gastric cancer progression and provide a theoretical rationale for use of everolimus in the treatment of m
6
A/METTL3-high gastric cancer.
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Hierarchically porous TS-1/modified-diatomite composites with high removal efficiency for methylene blue (MB) were prepared via a facile in situ hydrothermal route. The surface charge ...state of the diatomite was modified to enhance the electrostatic interactions, followed by in situ hydrothermal coating with TS-1 nanoparticles. The zeolite loading amount in the composites could be adjusted by changing the hydrothermal time. The highest specific surface area and micropore volume of the obtained composites were 521.3m2/g and 0.254cm3/g, respectively, with an optimized zeolite loading amount of 96.8%. Based on the synergistic effect of efficient adsorption and photocatalysis resulting from the newly formed hierarchically porous structure and improved dispersion of TS-1 nanoparticles onto diatomite, the composites’ removal efficiency for MB reached 99.1% after 2h of photocatalytic reaction, even higher than that observed using pure TS-1 nanoparticles. Moreover, the superior MB removal kinetics of the composites were well represented by a pseudo-first-order model, with a rate constant (5.28×10−2min−1) more than twice as high as that of pure TS-1 nanoparticles (2.43×10−2min−1). The significant dye removal performance of this novel TS-1/modified-diatomite composite indicates that it is a promising candidate for use in waste water treatment.
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