Modeling only constitutes one aspect of decision making. The prevailing limitation of applying modeling to practice is the absence of explicit consideration of uncertainties. This review paper covers ...uncertainty quantification (soil properties, stratification, and model performance) and uncertainty calculation with a focus on how it enhances the role of modeling in decision making (reliability analysis, reliability-based design, and inverse analysis). The key output from a reliability analysis is the probability of failure, where “failure” is defined as any condition that does not meet a performance criterion or a set of criteria. In contrast to the global factor of safety, the probability of failure respects both mechanics and statistics, is sensitive to data (thus opening one potential pathway to digital transformation), and it is meaningful for both system and component failures. Resilience engineering requires system level analysis. As such, geotechnical software can provide better decision support by computing the probability of failure/reliability index as one basic output in addition to stresses, strains, forces, and displacements. It is further shown that more critical non-classical failure mechanisms can emerge from spatially variable soils that can escape notice if the engineer were to restrict analysis to conventional homogeneous or layered soil profiles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Ionic liquid-based membrane contactor setup for CO2 capture was modeled.•Isothermal model predicted high temperature pre-combustion CO2 capture operation.•Comparative analysis was performed for ...different number of membrane fibers.•CO2 flux, mass transfer coefficients and separation efficiencies were investigated.•Transient state of CO2 absorption was studied against different operating parameters.
A pre-combustion carbon capture process at high temperatures in membrane contactor setup using ionic liquid 1-Butyl-3-methlyimidazolium tricyanomethanide (BmimTCM) as an absorbent was studied here by developing a comprehensive mathematical model. A detailed 2D mass transport model based on finite element analysis was presented for this purpose. The model considers molecular diffusion in both axially and radially. The effects of various operational parameters were studied for CO2 absorption flux. A comparative study was carried out among different membrane contactor modules having different number of fibers. The increase in number of fibers has significantly enhanced the CO2 absorption process. An increase of 31% in the CO2 separation efficiency was observed by increasing the number of fibers from 1 to 10. Furthermore, the transient state behavior of CO2 concentration during the absorption process until reaching a steady state was systematically studied for various operating temperatures and gas flow rates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nowadays, carbon-rich fuels are the principal energy supply utilized for powering human society, and it will be continued for the next few decades. Connecting with this, modern energy technologies ...are very essential to convert the available limited carbon-rich fuels and other green alternative energies into useful energy efficiently with an insignificant environmental impression. Amongst all kinds of power generation systems, SOFCs running with high temperatures are emerging as a frontrunner in chemical to electrical transformation efficiency, allows the engagement of all-embracing fuel varieties with negligible environmental impact. This study investigates the effect of ammonia usage in tubular SOFC performance. Firstly, the use of ammonia and hydrogen in the electrolyte-supported SOFC (ES-SOFC) has investigated. Then, the effect of using ammonia in anode-supported SOFC (AS-SOFC), ES-SOFC and cathode-supported SOFC (CS–SOFC) on performance has been examined by using COMSOL software. As a result of the study performed, it is found that the ammonia can be used in tubular SOFC's as a carbon-free fuel and CS-SOFC shows better performance compared with ES-SOFC and AS-SOFC. Besides, the findings of this study indicate that the use of ammonia as a fuel for SOFCs is comparable to the use of hydrogen.
•The effect of using different fuel has been investigated on the cell performance.•The increasing temperature increases the performance of SOFC for both fuels.•The CS-SOFC outperforms the ES-SOFC and AS-SOFC for ammonia fuel.•The position of the anode is playing a great roll in performance and polarization.
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•The influence of gas mixing and heating on gas-phase reactions.•Path 1: The adduct decomposes the amine DMInNH2 and oligomer particles.•Path 2: Reversible decomposition of the adduct to TMIn and NH3 ...is the dominant path.•The different gas-phase reactions path in three typical reactors.
This study investigates the controversies about the gas-phase reaction path in the InN MOVPE process. Numerical modeling of the reaction-transport processes in three typical reactors was conducted for main reaction paths. By comparisons of the molar concentrations of the major In-containing species, it was determined that the different approaches of the gas mixing and heating led to three distinct reaction paths. When the non-premixed gas precursors are heated very fast upon entering the reactor, the adduct/amide formation path predominates and the pyrolysis path is negligible (Path 1). When the precursors are mixed at room temperature and heated gradually, the adduct TMIn:NH3 dissociates back into TMIn, with the pyrolysis path dominating. However, the formation of amides DMInNH2 intensifies the generation of nanoparticles (Path 2). When mixing occurs at warm temperature and heated fast, both the pyrolysis and adduct paths co-exist, but their effects are different (path 3). In the CCS reactor the dominant reaction path will be Path 1, while in the vertical reactor with a greater height, Path 2 is predominant. In the pre-mixed horizontal reactor, Path 3 is dominant, the pyrolysis path forms a competition with the adduct path near the substrate, and the adduct path dominating at the top of the reactor.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•In-bed combustion optimization can largely reduce NOx emission of grate boiler.•A multi-section fuel bed model with thermally thick treatment is developed.•The combined influence of primary air ...distribution and grate velocity is studied.•Modeling results and real-furnace validation indicates a 53.58 % decrement of NOx.
This study focuses on reducing NOx emissions in large-scale municipal solid waste (MSW) grate furnaces through in-bed combustion control. A multi-section fuel bed model with thermally thick treatment is developed to accommodate the configurations of large-scale MSW grate furnaces. The model incorporates detailed sub-grid models to simulate the intraparticle gradient, and the stochastic mixing is accounted to deal with the multi-section fuel beds with vertical drop-offs. The influences of primary air distribution and average grate velocity on combustion status and NOx emissions are investigated numerically and validated in a 600 t/d MSW grate boiler. The results indicate that combining a relatively low primary air ratio with a thickened fuel bed ensures both reduced NOx emissions and high burnout efficiency. By reducing the excess air ratio of primary air from 1.2 to 0.9 and distributing it through a rear-enhanced air mode, the overall NOx emission decreased from 398.50 mg/Nm3 to 215.05 mg/Nm3, although at the expense of an increased unburned carbon content from 1.995 wt% to 3.063 wt%. Further lowering the grate velocity to thicken the fuel bed allowed for leveraging the heterogeneous reduction effect of the char layer, reducing the NOx emissions to 184.95 mg/Nm3. Additionally, the unburned carbon content was also remarkably reduced to 1.560 wt%. The proposed strategies of delaying the primary air supply and thickening the fuel bed offer a cost-effective alternative to post-combustion measures, with which the MSW grate boilers can achieve lower NOx emissions while maintaining efficient and stable combustion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The fabrication of 3-D parts from CAD models by additive manufacturing (AM) is a disruptive technology that is transforming the metal manufacturing industry. The correlation between solidification ...microstructure and mechanical properties has been well understood in the casting and welding processes over the years. This paper focuses on extending these principles to additive manufacturing to understand the transient phenomena of repeated melting and solidification during electron beam powder melting process to achieve site-specific microstructure control within a fabricated component. In this paper, we have developed a novel melt scan strategy for electron beam melting of nickel-base superalloy (Inconel 718) and also analyzed 3-D heat transfer conditions using a parallel numerical solidification code (Truchas) developed at Los Alamos National Laboratory. The spatial and temporal variations of temperature gradient (G) and growth velocity (R) at the liquid-solid interface of the melt pool were calculated as a function of electron beam parameters. By manipulating the relative number of voxels that lie in the columnar or equiaxed region, the crystallographic texture of the components can be controlled to an extent. The analysis of the parameters provided optimum processing conditions that will result in columnar to equiaxed transition (CET) during the solidification. The results from the numerical simulations were validated by experimental processing and characterization thereby proving the potential of additive manufacturing process to achieve site-specific crystallographic texture control within a fabricated component.
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Accurate assessment and prediction of airflow dynamics and particle deposition in the human respiratory tract are essential for human health, involving inhaled drugs for treating various diseases and ...toxic particles that can cause illnesses. This intricate process involves complex multiphase flow with distinct respiratory characteristics. Computational fluid dynamics (CFD) acts as a bridge, overcoming the limitations of in vivo and in vitro experiments and providing a means to fully comprehend and reveal the fundamental mechanisms of respiratory flow and particle behavior on a microscopic scale. This paper provides a comprehensive overview and concise summary of recent advancements in the numerical simulation of airflow and particle deposition in the human respiratory tract. Particularly, it summarizes the transition of respiratory tract models from segmented models to emerging physiological characteristic models and whole-lung airway models, and the latest developments on the effects of key factors such as geometric variations, respiratory patterns, and particle physical/chemical properties on respiratory flow and particle deposition. A notable focus of this review is on emerging physiological characteristics models and their associated complex airflow and particle dynamics inside it. The paper concludes with recommendations for future research to further advance the development of this field.
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•Review on geometry, numerical method, and characteristics of respiratory multi-flows.•Geometrical models from segmented models to physiological characteristic models.•Impact of emerging models on respiratory airflow dynamics and particle deposition.
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•A new numerical model has been developed with integrating petrological models.•Single plume event can produce both mafic rocks and felsic to intermediate rocks.•Mantle plumes are feasible mechanism ...for continental crust growth in the early Earth.
The origin of Earth’s felsic continental crust remains a mystery. The generation of felsic continental crust requires a two-stage partial melting from original mantle sources. There are two hypotheses for the continental crust generation in the early Earth. One is the subduction-related magmatism, e.g., island arcs, which produces intermediate to felsic magma that constitutes the early buoyant continental crust. The other is the magmatism induced by the mantle plume that creates thick basaltic crust and finally the continental crust. However, there is controversy about the origin of plate tectonics, which is an obstacle for simply applying the subduction-induced model in the early Earth. On the other hand, the efficiency of mantle plume-induced continental crust growth remains unknown. In this study, we develop a new numerical model, integrating the petrological-thermo-mechanical model with melt migration and crystallization, to evaluate the efficiency of continental crust production by mantle plumes in Earth’s history. Our results indicate that mantle plumes are considerably more effective for continental crust generation in the hot early Earth than that in the present Earth. The contribution of plume-induced continental crust growth may be greatly promoted by the possible high frequency of mantle plume generation in the early Earth than the present.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Composite pressure vessels are highly promising components of solid rocket motor casing, yet it has long been plagued by burst risk of dome section. Although current advances via the addition of ...composite layers can enhance dome strength, the weight redundancy still restricts the lightweight implementation. To this end, this paper presents an innovative contour-driven collaborative design for dome section, which helps suppress burst risk and avoid redundant weight due to composite layer thickening. Numerical burst assessment reveals that the pole size engenders a failure competition between pole and equator, indicating that rational utilization of this competition paves a feasible way for dome reinforcement. Besides, the burst risk is further suppressed by collaborative design between polar opening radius, polar boss size, and aspect ratio of ellipsoidal dome. Notably, it is concluded that greater polar boss size effectively reduces the stress concentration near pole, and rational manipulation of dome aspect ratio ensures compatible deformation near equator. More interestingly, we offer a collaborative design methodology to reinforce dome with various polar opening radii without thickening composite layers. This unique contour-driven collaborative design opens new avenues for simultaneous implementation of burst risk suppression and lightweight construction of composite pressure vessels.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In article number 2100157, Ramirez and coworkers propose an original computational approach to differentiate the various serotypes of dengue in the presence of other flaviviruses, after a detection ...process using localized surface plasmon resonance (LSPR)‐based biosensors, with high sensitivity, selectivity, and precision. This study demonstrates genetic similarity between DENV3/DENV2, and DENV4/DENV1, implementing recurrence maps, largest Lyapunov exponent, among others, on the measured resonance curve.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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