Sliding and damming properties of granular debris with different geometric configurations and grain size distributions

Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of granular debris during the occurrence of granular debris is essential for precise assessment and effective mitigation of landslide hazards in mountainous terrains. This research aims to investigate the impact of GSD and geometric configurations on sliding and damming properties through laboratory experiments. The geometric configurations were categorized into three categories based on the spatial distribution of maximum volume: located at the front(Type Ⅰ), middle(Type Ⅱ), and rear(Type Ⅲ) of the granular debris. Our experimental findings highlight that the sliding and damming processes primarily depend on the interaction among the geometric configuration, grain size, and GSD in granular debris. Different sliding and damming mechanisms across various geometric configurations induce variability in motion parameters and deposition patterns. For Type Ⅰ configurations, the front debris functions as the critical and primary driving component, with energy dissipation primarily occurring through inter-grain interactions. In contrast, Type Ⅱ configurations feature the middle debris as the dominant driving component, experiencing hindrance from the front debris and propulsion from the rear, leading to complex alterations in sliding motion. Here, energy dissipation arises from a combination of inter-grain and grain-substrate interactions. Lastly, in Type Ⅲ configurations, both the middle and rear debris serve as the main driving components, with the rear sliding debris impeded by the front. In this case, energy dissipation predominantly results from grainsubstrate interaction. Moreover, we have quantitatively demonstrated that the inverse grading in damming deposits, where coarse grain moves upward and fine grain moves downward, is primarily caused by grain sorting due to collisions among the grains and between the grain and the base. The impact of grain on the horizontal channel further aids grain sorting and contributes to inverse grading. The proposed classification of three geometric configurations in our study enhances the understanding of damming properties from the view of mechanism, which provides valuable insights for related study about damming granular debris.

Engineering of geometrical configurations in dual-atom catalysts for electrocatalytic applications

Geometrical configurations play a crucial role in dual-atom catalysts(DACs)for electrocatalytic applications.Significant progress has been made to design DACs electrocatalysts with various geometri-cal configurations,but in-depth understanding the relationship between geometrical configurations and metal-metal interaction mechanisms for designing targeted DACs is still required.In this review,the recent progress in engineering of geometrical configurations of DACs is systematically summarized.Based on the polarity of geometrical configuration,DACs can be classified into two different types that are homonuclear and heteronuclear DACs.Furthermore,with regard to the geometrical configurations of the active sites,homonuclear DACs are identified into adjacent and bridged configurations,and heteronuclear DACs can be classified into adjacent,bridged,and separated configurations.Subsequently,metal-metal interactions in DACs with different geometrical configurations are introduced.Additionally,the applications of DACs in different electrocatalytic reactions are discussed,including the oxygen reduction reaction(ORR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and other catalysis.Finally,the future challenges and perspectives for advancements in DACs are high-lighted.This review aims to provide inspiration for the design of highly effcient DACs towards energy relatedapplications.

Optimizing geometric configuration of single Zn-N_(4) sites for boosting reciprocal transformation between aromatic alcohols and aldehydes

It is significant to optimize geometric configuration of metal catalytic sites and boost their catalytic activity.Herein,we synthesized isolated single Zn-N_(4)sites on N-doped carbon(Zn-CN)by pyrolyzing zeolite imidazole framework-8(ZIF-8)at different temperatures.For the reciprocal transformation between benzyl alcohol and benzaldehyde,the catalytic activities of Zn-CN catalysts exhibited a volcano-like trend as the pyrolysis temperatures increased.The optimal catalyst was Zn-CN-900,with outstanding catalytic activity exceeding commercial 20 wt.%Pd/C and 20 wt.%Pt/C,promising to substitute the noble metalbased catalysts.X-ray absorption near-edge structure(XANES)measurements and density functional theory(DFT)calculation revealed the gradual transformation from tetrahedral ZnN_(4)sites of ZIF-8 into planar ZnN_(4)sites above 700℃,with the maximum planar ZnN_(4)sites in Zn-CN-900.The stronger adsorption between reactants and planar ZnN_(4)sites facilitated the activation of reactants compared with tetrahedral ZnN_(4)sites.This work will provide valuable insight into rational design of efficient catalysts by optimizing geometric configuration of catalytic sites.

INFLUENCE OF GEOMETRICAL CONFIGURATION OFSUPERCONDUCTING MATERIAL ON GROWTH OF Nb_3 Sn

Boundary conditions constructed by two typical geometrical configurations related to the manufacturing methods of bronze process and tin-rich Nb tube method have been considered in a diffusion model in which the diffusion of Sn in CuSn matrix plays a major role is as- sumed.The dependence of thickness of Nb_3Sn layer on reaction time has been derived.It is shown that the growth rate of Nb_3Sn relates to the configuration of the superconductor,the geometrical parameters of Nb filaments and CuSn matrix.The theory is qualitatively con- sistent with the experimental results.

Optimal geometrical configuration and oxidation state of cobalt cations in spinel oxides to promote the performance of Li-O_(2) battery

Co_(3)O_(4) is considered as one of promising cathode catalysts for lithium oxygen(Li-O_(2))batteries,which contains both tetrahedral Co^(2+)sites(Co^(2+)Td)and octahedral Co^(3+)sites(Co^(3+)Oh).It is important to reveal the effect of optimal geometric configuration and oxidation state of cobalt ion in Co_(3)O_(4) to improve the performance of Li-O_(2) batteries.Herein,through regulating the synthesis process,Co^(2+)and Co^(3+)sites in Co_(3)O_(4) were replaced with Zn and Al atoms to form materials with a unique Co site.The Li-O_(2) batteries based on ZnCo_(2)O_(4) showed longer cycle life than that of CoAl_(2)O_(4),suggesting that in Co_(3)O_(4),the Co^(3+)Oh site is a relatively better geometric configuration than Co^(2+)Td site for Li-O_(2) batteries.Theoretical calculations revealed that Co^(3+)Oh sites provide higher catalysis activity,regulating the adsorption energy of the intermediate LiO_(2) and accelerating the kinetics of the reaction in batteries,which further leads to the change of the morphology of the discharge product and ultimately improves the electrochemical performance of the batteries.

Density functional investigations for geometric and electronic properties of In_4M and In_(12)M (M=C,Si,In) clusters

First-principle calculations are performed to study geometric and electronic properties of both neutral and anionic In4M and In12M （M = C, Si, In） clusters. In4C and In4Si are found to be tetrahedral molecules. The icosahedral structure is found to be unfavourable for In12M. The most stable structure for In12C is a distorted buckled biplanar structure while for In12Si it is of an In-cage with the Si located in the centre. Charge effect on the structure of In12M is discussed. In4C has a significantly large binding energy and an energy gap between the highest-occupied molecularorbital level and the lowest unoccupied molecular-orbital level, a low electron affinity, and a high ionization potential, which are the characters of a magic cluster, enriching the family of doped-group-IIIA metal clusters for cluster-assembled materials.

Construction of pH-universal hydrogen evolution freeway in MoO_(3)-MoNi_(4)@Cu core-shell nanowires via synergetic electronic and geometric effect

Both the adsorption/dissociation of water molecules and hydrogen intermediate(H*)are the major limitations to hydrogen evolution reaction(HER).Herein,the modulation of electronic structure and geometric configuration are combined to design onedimensional electrocatalyst with outstanding HER activity in a wide pH range.The catalyst was composed of molybdenum trioxide doped molybdenum nickel alloy supported by copper nanowires(MoO_(3)-MoNi_(4)@Cu NWs).As revealed by the experimental characterizations and theoretical calculations,Cu NWs act as the electron donator to MoNi4,resulting in up shift of the d-band center in MoNi4,thus expediting H_(2)O adsorption and dissociation.Moreover,the introduction of amorphous MoO_(3) sets up a unique geometric configuration on MoNi4 for the accelerated H*transfer via hydrogen-bond and hydrogen spillover.This work provides a synergetic route for constructing HER freeway and promotes further investigations on more versatile electrocatalysis involving H_(2)O or H*.

Structure and stability of neutral and cationic AlnO clusters

In this paper various structural possibilities for AlnO neutral and cationic isomers were investigated by using the B3LYP/6-311G（3df） method. Calculations of this paper predicted the existence of a number of previously unknown isomers. The stabilities of the AlnO （n = 2 - 7） clusters with even n are greater than those with odd n, however the stabilities Of cationic ions have the opposite odd-even alternation. The mass spectra observations of Al17O^＋ and Al19O^＋ ions support our theoretical predictions on their stabilities.

Computational Evidence for the Smallest Boron Nanotube

The structure of boron nanotubes （BNTs） was found not to be limited to hexagonal pyramidal structures. Based on density functional theory calculations we provided evidence for the smallest boron nanotube, a geometrical analog of the corresponding carbon nanotube. As shown by our calculations, the smallest BNT possesses highly structural, dynamical, and thermal stability, which should be interest for attempts at its synthesis.

Geometries, stabilities, and electronic properties of Be-doped gold clusters: a density functional theory study

We have systematically investigated the geometrical structures, relative stabilities and electronic properties of small bimetallic AunBe （n = 1, 2, . .. 8） clusters using a density functional method at BP86 level. The optimized geometries reveal that the impurity beryllium atom dramatically affects the structures of the Aun clusters. The averaged binding energies, fragmentation energies, second-order difference of energies, the highest occupied-lowest unoccupied molecular orbital energy gaps and chemical hardness are investigated, All of them exhibit a pronounced odd-even alternation, manifesting that the clusters with even number of gold atoms possess relatively higher stabilities. Especially, the linear Au2Be cluster is magic cluster with the most stable chemical stability. According to the natural population analysis, it is found that charge-transferring direction between Au atom and Be atom changes at the size of n = 4.

Giorgio Vasari’s Celestial Utopia of Whimsy and Joy:Constellations,Zodiac Signs,and Grotesques

This study elaborates on the decoration of the ceiling in the refectory of the former Monteoliveto monastery in Naples,today part of the church of Sant’Anna dei Lombardi.It consists of three parts:an explanation of the ceiling design with its geometrical configurations of circles,octagons,hexagons,ovals,and squares;an iconographical analysis solely focusing on the ceiling decoration,which consists of grotesques,constellations,and zodiac signs;and a discussion of some of the literary and visual sources employed in the decoration.The Florentine Mannerist painter Giorgio Vasari,aided by several assistants,renovated and painted the ceilings between 1544 and 1545.Don Giammateo d’Anversa,the Abbot General of the Monteolivetan Order in Naples,composed the iconographical program with the assistance of insightful suggestions from the Florentine Monteolivetan prior Don Miniato Pitti,who was Vasari’s patron and friend as well.This oversight inspired Vasari to paint a celestial utopia of hilarity and whimsicality on the Neapolitan ceiling,thus leavening the other imagery,which combined both religious and secular representations of moral virtues and divine laws.

Review of Fiber-Optic Localized Surface Plasmon Resonance Sensors:Geometries,Fabrication Technologies,and Bio-Applications

Localized surface plasmon resonance(LSPR)biosensors,which enable nanoscale confinement and manipulation of light,offer the enhanced sensitivity and electromagnetic energy localization.The integration of LSPR with the fiber-optic technology has led to the development of compact and versatile sensors for miniaturization and remote sensing.This comprehensive review explores various sensor configurations,fiber types,and geometric shapes,highlighting their benefits in terms of sensitivity,integration,and performance improvement.Fabrication techniques such as focused non-chemical bonding strategies and self-assembly of nanoparticles are discussed,providing control over nanostructure morphology and enhancing sensor performance.Bio-applications of fiber-optic LSPR(FOLSPR)sensors are detailed,specifically in biomolecular interactions and analysis of proteins,pathogens and cells,nucleic acids(DNA and RNA),and other small molecules(organic compounds and heavy metal ions).Surface modification and detection schemes are emphasized for their potential for label-free and real-time biosensing.The challenges and prospects of FOLSPR sensors are addressed,including the developments in sensitivity,fabrication techniques,and measurement reliability.Integration with emerging technologies such as nanomaterials is highlighted as a promising direction for future research.Overall,this review provides insights into the advancements and potential applications of FOLSPR sensors,paving the way for sensitive and versatile optical biosensing platforms in various fields.

Approximation Algorithms for 3D Orthogonal Knapsack

We study non-overlapping axis-parallel packings of 3D boxes with profits into a dedicated bigger box where rotation is either forbidden or permitted, and we wish to maximize the total profit. Since this optimization problem is NP-hard, we focus on approximation algorithms. We obtain fast and simple algorithms for the non-rotational scenario with approximation ratios 9 ＋ ε and 8 ＋ ε, as well as an algorithm with approximation ratio 7 ＋ ε that uses more sophisticated techniques; these are the smallest approximation ratios known for this problem. Furthermore, we show how the used techniques can be adapted to the case where rotation by 90° either around the z-axis or around all axes is permitted, where we obtain algorithms with approximation ratios 6 ＋ ε and 5 ＋ ε, respectively. Finally our methods yield a 3D generalization of a packability criterion and a strip packing algorithm with absolute approximation ratio 29/4, improving the previously best known result of 45/4.