Aqueous Zn-ion batteries present low-cost, safe, and high-energy battery technology but suffer from the lack of suitable cathode materials because of the sluggish intercalation kinetics associated ...with the large size of hydrated zinc ions. Herein we report an effective and general strategy to transform inactive intercalation hosts into efficient Zn
storage materials through intercalation energy tuning. Using MoS
as a model system, we show both experimentally and theoretically that even hosts with an originally poor Zn
diffusivity can allow fast Zn
diffusion. Through simple interlayer spacing and hydrophilicity engineering that can be experimentally achieved by oxygen incorporation, the Zn
diffusivity is boosted by 3 orders of magnitude, effectively enabling the otherwise barely active MoS
to achieve a high capacity of 232 mAh g
, which is 10 times that of its pristine form. The strategy developed in our work can be generally applied for enhancing the ion storage capacity of metal chalcogenides and other layered materials, making them promising cathodes for challenging multivalent ion batteries.
•Memory-for-when judgments indicate when in a list an item first appeared and measure a kind of explicit temporal context memory.•Correct memory-for-when during study of items’ second occurrence ...predicted items’ final free recall on a later test.•Memory-for-when advantage was mainly driven by superior memory-for-when for items in the primacy region; other items showed no such benefit.•Explicit temporal context information probably doesn’t cause the benefits of spaced repetition (though implicit context information or distinctiveness might)
A number of temporal context-based theories of the spacing effect assume that temporal context is retrieved during repetitions, allowing better memory on a later test. Since associations in memory are often bidirectional, if we can use temporal context to recall an item, perhaps we can also use the item to explicitly recall its temporal context. If so, explicit memory-for-when during study would be a good predictor of later recall for repeated items. Experiment 1 appeared to be consistent with our predictions; items with memory-for-when during List 2 showed superior recall accuracy on a final free recall test. However, the effect was primarily driven by better memory-for-when in the primacy region. Experiment 2 used an incidental learning procedure during List 1 to reduce this confound since the primacy region is greatly attenuated in incidental learning. While the benefits of having memory-for-when persisted in Experiment 2, they were again attributable solely to the first few items on the list. The results suggest that explicit temporal context information is unlikely to underlie the benefits of spaced repetition. Either temporal context information is strengthened implicitly, our measures of context failed to capture the type of context used in spacing, or other mechanisms entirely produce the benefits of repetition.
Testing for uniformity for any given data set on the circle is an important first step before any further inference. One important class of tests are those based on spacings, which assume that the ...data are measured on a continuous scale. In practice however, the observed data may come grouped, or the recorded observations may be rounded values. Ignoring this fact can result in incorrect Type I error probabilities and inference, especially if the degree of rounding is severe or if the sample size is large. In this article, we propose a simple modification to such rounded data, which then allows us to continue to use the Rao’s spacing test and its exact critical values, without affecting the probability of Type I error. We provide theoretical justification for the suggested modification, as well as simulation studies that demonstrate its strong and robust performance.
•The preparation protocols for MXene-based NF membranes are presented.•The innovations in channels regulation and surface functionalization are discussed.•Customized modification strategies heighten ...the performances of MXene-based NF membranes.•The technological challenges and future directions are elaborated.
MXene-based membranes have gained widespread attention in the field of water purification because of their excellent separation performance. However, three major obstacles are encountered in the performance improvement of MXene-based membranes including membrane fouling, trade-off effect and stability. The modification of MXene materials has become the most straightforward and effective solution to this problem. To date, the modification strategies for MXene-based membranes to enhance nanofiltration performance have not been systematically reviewed. In this review, this knowledge gap is addressed by systematically elucidating the efforts and innovations in the modification of MXene-based membranes. The distinctive preparation techniques for MXene nanosheets and membranes are briefly described. Various modification strategies for MXene materials, including the reconstruction of the interlayer nanochannels between MXene nanosheets and optimization of the MXene surface functional groups/charges, are comprehensively discussed. Moreover, future technological challenges, such as reproducibility, scale-up potential, and sustainability of MXene-based membranes are discussed in detail. These challenges are expected to serve as a source of motivation for future researchers to continue enhancing the characteristics of MXene materials to expedite the use of MXene membranes in practical industrial applications. This review provides novel insights into the design of advanced MXene-based membranes for water-separation applications.
•2600 computationally intensive simulations for geothermal doublet systems conducted.•Discharge, well/doublet spacing, poro-perm correlation lengths and variance varied.•A doublet spacing equal to ...well spacing produced consistently best performance.•Anisotropic heterogeneity led to shorter/longer lifetime for short/long spacing.•Sufficient lifetime for shorter well spacing than the ones conventionally designed.
The low-enthalpy geothermal systems are commonly deployed in sedimentary geological settings that feature significant levels of deposition-induced heterogeneity. In this paper, realistic levels of heterogeneity in the form of varying porosity variance and spatial correlation lengths are considered for a 3D geothermal system. Using 2600 computationally intensive numerical simulations of two doublets placed in a checkboard pattern, the influence of well and doublet spacings on performance metrics of low-enthalpy geothermal systems are investigated. The simulations strongly support that in varyingly heterogeneous systems, the lifetimes of operation are shorter, and depending on isotropicity or anisotropicity of correlated heterogeneity, the lifetimes vary. Most notably the anisotropically correlated heterogeneity can lead to either positive impact (by diverting the cold water plume) or negative impact (by facilitating an early breakthrough of cold water plume) on the lifetime of the operation compared to isotropically correlated heterogeneity. We also calculate the boundary of the region around the wells designated as the “license area” (where the cold water front reaches to or where a threshold temperature drop of 1 °C occurs). By doing so, it is found that the operator can assume larger extents (of up to 50%) for the license areas of the aquifer than the ones conventionally assumed. To minimize the impact of heterogeneity on operation, the best practice was found to place the doublets in the same spacings as of the wells. Moreover, it is found that the well distance can be significantly shorter than what is commonly realised for heterogeneous geothermal aquifers.
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•The effect of interlayer spacing on the catalytic performance of MoS2 is confirmed.•The dependence of interlayer spacing and MoS2 catalytic performance was established for the first ...time.•The catalytic performance of MoS2 can be regulated in an orderly manner by adjusting the interlayer spacing.•The variation of interlayer spacing will improve the electron transfer ability of MoS2 catalytic sites.•More than 20% interlayer spacing expansion greatly improves the catalytic performance of MoS.
The effect of interlayer spacing on the catalytic properties of MoS2 is systematically investigated by the ab-initio calculation. The results show that the expansion of interlayer spacing is beneficial to the catalytic hydrogen evolution when the hydrogen coverage on MoS2 is 25% and 50%. In particular, at 25% hydrogen coverage, the controllable tuning of the catalytic properties of MoS2 can be achieved by orderly tuning the interlayer spacing. When hydrogen coverage is up to 75% and 100%, the negative effect of interlayer spacing on the catalytic hydrogen evolution of MoS2 is negligible. Importantly, the 20% interlayer expansion is a critical state. If the interlayer expansion exceeds 20%, the catalytic properties of MoS2 will be greatly improved, which provides an idea to control the catalytic properties of MoS2 through tuning the interlayer spacing. Finally, the enhanced effect of interlayer expansion on the catalytic properties of MoS2 stems from the fact that the expansion of the interlayer spacing causes the occupancy density of the partially occupied antibonding orbitals near the Fermi level of Mo atoms to increase and move toward the high-energy region, which enhances the electron transfer of Mo.
The illusory truth effect refers to the fact that repetition increases perceptions of truth. In these experiments, we examined whether the magnitude of the illusory truth effect varies based upon ...repetition spacing. In Experiment 1, participants read facts that repeated twice, with a lag of 0, 1, 2, 4, 8, 16, or 32 intervening facts. Participants later rated the truthfulness of these facts in addition to new facts. Here, we observed a spacing effect: Truth ratings were higher when repetitions were spaced (i.e., lags of 1 through 32) rather than massed (i.e., lag of 0). We also observed a lag effect that followed a quadratic pattern: Truth ratings increased up to a lag of 16, after which they decreased. In Experiment 2 we tested whether the spacing effect in truth ratings depends upon the number of repetitions. In Experiment 2a we used a small number of repetitions (2, 3, or 4) and short lag lengths (0, 1, or 2). In Experiment 2b, we increased the number of repetitions (2 or 10) and the lag lengths (0 or 10). In Experiment 2a there was an illusory truth effect, but its magnitude did not depend upon lag length or repetition number. However, in Experiment 2b the magnitude of the illusory truth effect increased as lag length and repetition number increased, but there was no interaction between these two factors. Together, these findings show that repetition is most likely to increase perceived truth when repetitions are spaced with a moderate number of intervening items.
Pumpkins ( Cucurbita sp.) grown in North Carolina are a nascent specialty crop that has only risen to a national production level in the past 10 years. There are only general cultural management ...guidelines for this region, resulting in variation in plant density and inefficient production. Production field studies of the cultivar Kratos were conducted to investigate the impact of plant density and row width on marketable yield and individual fruit size for large carving pumpkins. Plant densities of 2691, 3588, 5382, and 10,764 plants per hectare with row widths of 1.5 and 3.0 m were grown in 2020 and 2021 in North Carolina. Data regarding fruit size, fruit size variance, and yield per area were collected. Fruit size in terms of weight, length, and diameter increased as plant density decreased. There was no difference in fruit size variation between plant densities and row widths. The fruit number per hectare and fruit weight per hectare increased as plant density increased, with the highest production at 10,764 plants per hectare. For years combined, reducing the row width from 3.0 to 1.5 m increased the fruit weight and diameter, but not the length. Additionally, the 1.5-m row width produced more fruit weight per hectare than the 3.0-m row width for both years. Growers can optimize fruit weight per area and fruit number per area by using a density of 10,764 plants per hectare. Overall, using a row width distance that is more equidistant to the in-row spacing promotes higher fruit yield and larger fruit size.
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