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Stable density stratification in a large enclosure could significantly hamper the effectiveness of natural convection cooling in pool-type liquid metal or gas-cooled advanced reactors. In addition, accurate prediction of stratified front behavior remains to be a challenging task for turbulence modeling. With the rapid growth of high-performance-computing capabilities in recent years, conducting high-fidelity simulations for a large-timescale transient has become more affordable and hence a valuable data source to support turbulence modeling as well as to gain further physical insights. In this work, direct numerical simulation is performed at experiment-consistent conditions to simulate the density stratification transient High-Resolution Jet (HiRJET) facility. Specifically, we focus on the case where an injected aqueous sugar solution has 1.5% density higher than that in the enclosure. In the early stage of the transient, the impingement of the denser jet to the bottom surface of the enclosure promoted turbulent mixing locally. This rendered the establishment of the mixture layer, formation and swift upward propagation of the stratified front, and elevation with (locally) the highest vertical concentration gradient. As the front rose, the diminishing turbulent mass flux slowed down the propagation, and a larger vertical concentration gradient was established. In this stage, both the velocity and the concentration scalar showed large-timescale fluctuation behavior around the stratified front. For the concentration time signal, the characteristic frequency in the power spectral density was found to agree well with the Brunt-Väisällä frequency. The preliminary validation endeavor showed that the stratified front location and the corresponding concentration gradient magnitude in the simulation agreed well with the experiment data. Further validation will mainly revolve around benchmarking against high-resolution density measurement and high-order flow statistics. [ABSTRACT FROM AUTHOR]

The article focuses on improving the first-stage retrieval of Point-of-interest (POI) search by pre-training models. Topics include limitations of existing first-stage POI retrieval models, the proposed Geo-Enhanced Dense Retrieval framework, and the use of pre-trained language models to better model semantic match and geographical context information.

Measuring the flow rate in High-Temperature Gas-cooled Reactors is a challenge for traditional flowmeters due to the high flow rate (10 to 15 m/s at nominal operating conditions), high operating temperatures (>700°C), and high neutron flux and gamma fields in the reactor core. This paper discusses developing a novel flowmeter that can work under these extreme conditions. Oak Ridge National Laboratory first proposed using acoustics to measure the flow in the reactor, more specifically, using a Kelvin-Helmholtz resonator to correlate the gas flow rate with vibration frequency. With the primary goal of developing an acoustic measurement technique, we propose an acoustic corrugated pipe as a candidate for the development of a novel gas flowmeter. Experimental investigations on corrugated pipes have confirmed the dependence of the whistling frequency on the gas flow rate. Also, a tube-in-tube configuration is proposed for the flowmeter prototype, which can help mitigate resonance between the system and the flowmeter. Experimental investigation using the prototype has shown good independence from the piping system. Furthermore, Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations have been performed and validated with a satisfactory agreement, providing confidence that URANS models can adequately predict the characteristic curve (flow rate versus frequency) of the corrugated pipe and can therefore be used to optimize the flowmeter designs cost-effectively. [ABSTRACT FROM AUTHOR]

Dendrites can severely impair zinc battery performance. An in‐depth understanding of the dynamic morphology evolution of dendrites with operando approaches is pivotal when addressing these issues. However, in previous studies, the corresponding electrochemical signals are usually ensemble and averaged. It is very challenging to obtain detailed information about the key morphology–performance relationship. Herein, correlated high‐resolution operando optical and electrochemical studies of single dendrites on Pt reflective nanopore electrodes are reported. The zinc deposition and dissolution can be directly imaged by a high NA optical microscope, while corresponding galvanic charging and discharging curves are obtained. The correlated information of morphology changes and dynamic overpotential fluctuations under different circumstances unveils the competition between active growth vs. passivation. The isolated zinc formation at the single dendrite level is also evaluated. The methodology can be further extended to elucidate the direct relationship between dendrite evolution and electrochemical responses in various battery systems. [ABSTRACT FROM AUTHOR]

The article focuses on improving the efficiency of late-interaction multi-vector models like ColBERT and COIL, which achieve state-of-the-art retrieval effectiveness but suffer from high storage overhead. It mentions through systematic analysis, the study proposes document pruning methods to reduce storage requirements and compares the effectiveness of different pruning techniques, along with leveraging query pruning methods to decrease retrieval latency.

Depression is a devastating mood disorder that causes profound disability worldwide. Despite the increasing number of antidepressant medications available, the treatment options for depression are limited. Therefore, understanding the etiology and pathophysiology of depression, and exploiting potential novel agents to treat and prevent this disorder are imperative. Endoplasmic reticulum (ER) stress activates the unfolded protein response and mediates the pathogenesis of psychiatric diseases, including depression. Emerging evidence in human and animal models suggests an intriguing link between ER stress and depression. The ER serves as an important subcellular organelle for the synthesis, folding, modification, and transport of proteins, a process that is highly developed in neuronal cells. Perturbations of ER homeostasis lead to ER stress, and ER stress helps to restore the normal ER function by restoring the protein-folding capacity of the ER. This biological defense mechanism is imperative to prevent the disease. However, excessive or persistent ER stress eventually causes cell death. If the damage occurs in the hippocampus, the amygdala and striatum and other areas of the neurons will be involved in the development of depression. In this review article, we explore how ER stress might have an important role in the pathophysiology of depression and how different drugs affect depression through ER stress. [ABSTRACT FROM AUTHOR]

In the present work, two large eddy simulations (LESs) of single isothermal jets discharging into large enclosure facilities are proposed. The geometries and tested flow conditions correspond to scaled experiments of the upper plenum of high-temperature gas-cooled reactors. More specifically, two reference experiments were conducted at Texas A&M University and Michigan University. The objective of the present work is to validate these simulations with their corresponding reference experiments. The proposed LES models are performed with NekRS, a spectral element code with graphics processing unit capabilities developed at Argonne National Laboratory. These simulations were performed on the Summit supercomputer at Oak Ridge National Laboratory. For validation purposes, first- and second-order statistics from the computational fluid dynamics (CFD) calculation are compared with measurements obtained from the experiments. The models proved to be accurate, as these results are in good agreement. Additionally, flow visualization is provided showing that these models are able to retrieve similar effects to what are described in the literature for this type of flow configuration. Finally, the proposed models are part of a broader effort under the current Integrated Research Project of Nuclear Energy Advanced Modeling and Simulation 1.1, whose main objective is to deliver fast-running models to accurately predict complex physical phenomena, including for instance, turbulent mixing and thermal stratification. In this regard, the CFD models proposed here will be used to generate a high-fidelity data set to be applied in conjunction with data-driven methods to improve turbulence modeling closures. [ABSTRACT FROM AUTHOR]

User interactions in Web search, in particular, clicks, provide valuable hints on document relevance; but the signals are very noisy. In order to better understand user click behaviors and to infer the implied relevance, various click models have been proposed, each relying on some hypotheses and involving different hidden events (e.g. examination). In almost all the existing click models, it is assumed that clicks are the only observable evidence and the examinations of documents are deduced from it. However, with an increasing number of embedded heterogeneous components (e.g. verticals) on Search Engine Result Pages, click information is not sufficient to draw a complete picture of process of user examination, especially in federated search scenario. In practice, we can also collect mouse movement information, which has proven to have a strong correlation with examination. In this paper, we propose to incorporate mouse movement information into existing click models to enhance the estimation of examination. The enhanced click models are shown to have a better ability to predict both user clicks and document relevance, than the original models. The collection of mouse movement information has been implemented in a commercial search engine, showing the feasibility of the approach in practice. [ABSTRACT FROM AUTHOR]

• Triazine-containing COF and MOFs covalently configured three type-II heterostructures. • The charge-transfer efficiency was highly accelerated due to the integration between COF and MOF. • In-MOF@TP-TA furnished the optimal photocatalytic CO 2 RR efficiency amid the samples. Photocatalytic CO 2 reduction into high value-added chemicals is of considerable prospect for tackling quandaries in energy scarcity. One potent strategy to raise up its conversion efficacy is engineering heterostructure by virtue of tunable substituent in organic structure to facilitate the charge delivery within the photocatalyst. Herein, three metal organic frameworks (MOFs) built by the same ligand but different metal ions, are in - situ grown onto a triazine-containing covalent framework (COF), TP-TA, resulting in three hetero-frameworks, namely, In-MOF@TP-TA, Zr-MOF@TP-TA and Fe-MOF@TP-TA (In-MOF, Zr-MOF and Fe-MOF are abbreviations for NH 2 -MIL-68(In), NH 2 -UiO-66(Zr) and NH 2 -MIL-101(Fe) MOFs, respectively). Owning to the configured type-II heterojunctions that apparently suppress the charge recombination, the light-driven CO 2 reduction reaction (CO 2 RR) manipulated by the three hybrids behave higher catalytic performance by contrast to the pristine MOFs or COF. Amid the three heterostructure, In-MOF@TP-TA provides the optimal catalytic activity, giving the CO and CH 4 production rate as 25 and 11.67 μmol·g−1·h−1, respectively. In addition, their photocatalytic activities follow the order as In-MOF@TP-TA > Zr-MOF@TP-TA > Fe-MOF@TP-TA, consisting with the CB potentials of the MOF components (from negative to positive) and in turn certifying the charge flowing orientation within the type-II heterostructure. Our work broadens the rational design for the covalently integrated heterostructures as well as their melioration in photocatalytic CO 2 RR. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enzyme-response hydrogel-controlled release of cationic dyes was used in PEC assays for the first time. • BiOBr sensitized by crystal violet produced greatly improved cathodic photocurrent signals. • The prepared sensors are simple and environmentally friendly. • The developed sensor realized highly sensitive detection of hyaluronidase activity. Targeted response-based controlled release strategy exhibits high specificity and sensitivity in many biomedical applications. In this paper, we report a novel and simple "signal-on" photoelectrochemical (PEC) assay strategy, which regulates the release of cationic dyes through the utilization of target-specific enzymolysis hydrogel. The cationic dye crystal violet (CV) embedded in the hyaluronic acid (HA) hydrogel was released in the presence of hyaluronidase (HAase) and increased the cathodic photocurrent of BiOBr nanoflowers. The cathodic photocurrent response is linear with the logarithm of HAase activity in the range of 0.10–120 U/mL, with an ultralow detection limit of 0.034 U/mL detected. Our work provides a simple and efficient strategy to detect HAase activity by monitoring the enzyme response of hydrogel-controlled release photosensitizer, which is expected to be able to provide an efficient strategy for early clinical diagnosis of some other diseases and meet the ever-increasing needs in pharmaceutical and medical fields. [ABSTRACT FROM AUTHOR]

To reduce the flow dead zone in spouted beds (SBs), a novel multi-jet–axial swirl blade spouted bed (MJ-ASB SB) is proposed. Experimental verification and simulation analyses of the MJ-ASB SB, a conventional SB (CSB), and an integral multi-jet spout-fluidized bed (IMJSFB) were carried out. The simulation results showed that the combined structure resulted in more powerful turbulence, better radial mixing of particles in the spouting and annulus regions, and improved the flow−field uniformity. The intensification factor of the MJ-ASB SB was more than 20%, which was better than that of the IMJSFB, and the enhancement factors of the gas and particle velocities were four and five times those of the IMJSFB, respectively. Optimal structural parameters were obtained by analyzing the different structural parameters of the novel internal devices, and it was found that particle fluidization in the MJ-ASB SB was best when the height ratio ξ was 3, the width ratio was 1.3 and the rotation was clockwise. • A novel spouted bed is proposed by adding multi-jets and the axial swirl blade. • The enhancement factor I of MJ-ASB SB is 5 times that of IMJSFB. • The optimal structural parameters of the axial swirl blade are determined. • The combined internals can significantly improve the particle mixing in the annulus area. [ABSTRACT FROM AUTHOR]

A diketopyrrolopyrrole–based probe DPP-PyR was able to recognize Fe 3+ and Au 3+ with fluorescent turn–on response via different emission modes with relatively low detection limit. Moreover, DPP-PyR exhibited preferential second mode of selectivity for Au 3+ as it ratiometrically displaced Fe 3+ from the [ DPP-PyR +Fe 3+ ] complex. Furthermore, the imaging experiments indicated that this probe was cell–permeable and could be used to detect Fe 3+ and Au 3+ ions within living cell. To the best of our knowledge, it was the first probe for detection Fe 3+ and Au 3+ at the same time ever reported. [ABSTRACT FROM AUTHOR]