Shell Construction Research Articles

Smart construction of polyaniline shell on Fe2O3 as enabling high performance anode toward flexible lithium-ion battery

Smart construction of polyaniline shell on Fe2O3 as enabling high performance anode toward flexible lithium-ion battery

Self-supporting thin Shells in Italy. Space and Structure of the Industrial Buildings (1930-1970)

In the Twentieth Century, the industrial buildings featured a broad experimentation on the load-bearing structures suited to the production spaces. Among the structural elements explicitly designed for factories were reinforced concrete thin shells. In Italy, where reinforced concrete was the predominant construction technique for the entire century, the evolution of the thin shells for industrial buildings traced a significant story: starting from the introduction of foreign systems and patents in the 1920s, the design and construction of the thin shells gradually stacked to national productive and technological specificities. This paper presents a historical investigation of the application of thin shells in Italy between 1930 and 1970, remarking, thus, the local contribution of Italian contractors and designers in the evolution of both the design solutions and production process. Furthermore, the study presents a systematic historical and technical framework related to thin shells to support the actions of knowledge and safeguard the industrial building heritage.

MercuryII-mediated construction of DNA capsules for turn-on fluorescencedetection of melamine.

Researchers have shown significant interest in three-dimensional DNA building blocks due to their potential applications in biomedicine and biosensing. This study focuses on the synthesis of an HgII ion-stabilized DNA capsule with T-HgII-T pairs for the purpose of detecting melamine (MA). MA reacts with HgII to form a MA-HgII-MA complex, which causes HgII to leave the capsule shell, ultimately leading to capsule collapse and release of fluorescent cargo asoutput signal. Density functional theory (DFT) calculations and X-ray absorption spectroscopy (XAS) were used to demonstrate the ability of MA to extract HgII from the T-HgII-T adducts. The DNA capsules were characterized using TEM, SEM, DLS, zeta-potential, and melting curve analysis, which indicated the successful construction of the HgII-intercalated DNA shell. The MA-triggered destruction of the DNA capsules was visualized by confocal microscopy, and the dynamics of decapsulation were evaluated through fluorescent cargo release. The HgII-stabilized DNA capsules enable MA detection with a detection limit of 0.037 µM and are insensitive to potential interfering ions and amino acids. The tests conducted usingMA spiked milk solution resulted in recoveries ranging from 109 to 113% (0.1 µM) and 94.5 to 96% (0.5 µM). These results suggest that the system is promising for highly accurate and reproducible monitoring of MA adulteration.

Core-shell structured composite high-efficiency catalyst Co@Pd/TiO2 with a compressed-strain Pd shell for the direct synthesis of H2O2

Direct synthesis of H2O2 from H2 and O2 still faces the dilemma of low selectivity and productivity due to the O-O bond dissociation. To expedite the resolution of this issue, we introduce a core–shell structured catalyst Co@Pd/TiO2 with a compressed-strain Pd shell. The Co@Pd/TiO2 catalyst demonstrates a superior H2O2 productivity of 6.95 × 103 mmol·gPd-1·h−1 and H2O2 selectivity of 98.1 %, with enhancements of over 192 % and 139 %, respectively, when compared to Pd/TiO2. The construction of the compressed-strain Pd shell on the Co@Pd/TiO2 catalyst induces a winder width (wd) and a lower center (εd) of the Pd d-band, allowing the Co@Pd/TiO2 catalyst to achieve the following benefits for improving H2O2 selectivity and productivity: (1) Reducing the degree of electron back-donation to O2* (* denotes adsorbed state, the same below), thus inhibiting the cleavage of the O-O bond in O2*; (2) Showing a weaker Pd-O bond strength, which stabilizes the OOH* species and suppresses the breakage of the O-O bond therein; (3) Weakening the interaction between the catalyst and chemical substances, thereby restraining H2O2 degradation.

The adult shell matrix protein repertoire of the marine snail Crepidula is dominated by conserved genes that are also expressed in larvae

Mollusca is a morphologically diverse phylum, exhibiting an immense variety of calcium carbonate structures. Proteomic studies of adult shells often report high levels of rapidly-evolving, ‘novel’ shell matrix proteins (SMPs), which are hypothesized to drive shell diversification. However, relatively little is known about the phylogenetic distribution of SMPs, or about the function of individual SMPs in shell construction. To understand how SMPs contribute to shell diversification a thorough characterization of SMPs is required. Here, we build tools and a foundational understanding of SMPs in the marine gastropod species Crepidula fornicata and Crepidula atrasolea because they are genetically-enabled mollusc model organisms. First, we established a staging system of shell development in C. atrasolea for the first time. Next, we leveraged previous findings in C. fornicata combined with phylogenomic analyses of 95 metazoan species to determine the evolutionary lineage of its adult SMP repertoire. We found that 55% of C. fornicata’s SMPs belong to molluscan orthogroups, with 27% restricted to Gastropoda, and only 5% restricted at the species level. The low percentage of species-restricted SMPs underscores the importance of broad-taxon sampling and orthology inference approaches when determining homology of SMPs. From our transcriptome analysis, we found that the majority of C. fornicata SMPs that were found conserved in C. atrasolea were expressed in both larval and adult stages. We then selected a subset of SMPs of varying evolutionary ages for spatial-temporal analysis using in situ hybridization chain reaction (HCR) during larval shell development in C. atrasolea. Out of the 18 SMPs analyzed, 12 were detected in the larval shell field. These results suggest overlapping larval vs. adult SMP repertoires. Using multiplexed HCR, we observed five SMP expression patterns and three distinct cell populations within the shell field. These patterns support the idea that modular expression of SMPs could facilitate divergence of shell morphological characteristics. Collectively, these data establish an evolutionary and developmental framework in Crepidula that enables future comparisons of molluscan biomineralization to reveal mechanisms of shell diversification.

Analysis of the form, construction, and structural conception of Silberkuhl shells through construction history and advanced HBIM

In the 20th century, the development of industrial buildings featured a strong relationship between form, conception, needs of production processes, and advanced structural solutions. The knowledge, safeguard, and valorization of the industrial heritage structures, of the 20th century, requires a multidisciplinary approach, including construction history, structural analysis, and advanced 3D modeling. In particular, the study of shape-resistant structures in reinforced concrete – such as thin shells – needs to consider the deeply intertwined aspects of form, construction, and structural conception. The main aim of the present paper is to set a methodological workflow based on the combination of archival research, Historic/Heritage Building Information Modeling (HBIM), and numerical structural analysis to support the knowledge, safeguard, and valorization of the thin shells in reinforced concrete. The effectiveness of the proposed methodology, scalable for the analysis of historical shell structures in reinforced concrete, is tested on the noteworthy case study of the so-called Silberkuhl shells. According to their convenience in terms of structural efficiency and economy of construction, this system stood out worldwide for industrial roofing in the second half of the 20th century, exploiting the possibility of both industrial production and on-site precast, adapting to different economic and technological backgrounds.

Construction of Tb-rich shells via novel interdiffusion approach to tackle coercivity-remanence trade-off

The strategic introduction and efficient utilization of heavy rare earth elements within Nd-Fe-B-based permanent magnets are instrumental in achieving an optimal balance between remanence (Br) and high coercivity (Hcj). Herein, we propose a novel interdiffusion approach based on hydrogen decrepitation (HD) for the cost-effective and high-performance sintered Nd-Fe-B magnets. With the aim of generating continuous Tb-rich shells on the grain surface, which favors high Br and high Hcj, strip cast (SC) flakes homogeneously mixed with 0.9 wt% Tb were processed by the HD. It is shown that the formation of (Nd, Tb)-Fe-B by the interdiffusion of Nd-Fe-B and Tb during de-hydrogenation, as well as the interdiffusion of Nd-Fe-B and (Nd, Tb)-Fe-B during sintering and tempering, is the key to the construction of Tb-rich shells. As a result, a magnet (Mag-Tb&HD) with maximum magnetic energy product ((BH)max) of 52.21 MGOe was achieved, which is superior to magnet prepared form SC flakes containing 0.9 wt% Tb (Mag-Tb&SC, (BH)max=49.36 MGOe) and the magnet prepared by adding 0.9 wt% Tb to the jet milling (Mag-Tb&JM, (BH)max=50.41 MGOe).

Determination of Temperature Stresses during Construction of the Monolithic Thick-Walled Cylindrical Shells

Determination of Temperature Stresses during Construction of the Monolithic Thick-Walled Cylindrical Shells

Enhanced low-temperature activity of Mn-based catalysts for NH3 selective catalytic reduction of NO through Ce-modulated redox and TiO2 shell construction

Manganese-based catalysts presented great challenges for the wide operating window in the selective catalytic reduction of NOx with NH3 (NH3-SCR). Aiming at enhancement of the SCR performance, a series of MnCeOx (MnyCe1) and Mn1Ce1@TiO2 catalysts were prepared. Impressively, the Mn1Ce1 catalyst exhibited excellent low-temperature activity, achieving over 80 % conversion of NO within the temperature range of 85–350 °C, but the N2 selectivity decreased with the increasing temperature. Upon coating a TiO2 shell, the temperature window with N2 selectivity exceeding 80 % was significantly widened to 85–350 °C since the weak redox ability limited the NH3 oxidation to undesired N2O. High surface area, together with abundant acid sites and chemical adsorbed oxygen that formed via the interaction between Mn4+/Mn3+, Ce4+/Ce3+ and Ti4+/Ti3+, contributed to the superior catalytic performance of Mn1Ce1@TiO2. In addition, through in situ DRIFTS analysis, both Eley-Rideal and Langmuir-Hinshelwood reaction routes were observed. This work would provide an efficient and low-cost strategy for preparing Mn-based catalysts with excellent low-temperature activity for NOx removal.

Complete tree-level dictionary between simplified BSM models and SMEFT d≤7 operators

Finding all possible UV resonances of effective operators is an important task in the bottom-up approach of effective field theory. We present all the tree-level UV resonances for the dimension-5, -6, and -7 operators in the Standard Model effective field theory (SMEFT) and then obtain the correspondence between the UV resonances and the effective operators from the relations among their Wilson coefficients, through the functional matching and operator reduction procedure. This provides a cross-dimension UV/IR dictionary for the SMEFT at tree level, and the methods used here, especially the on shell construction of general UV Lagrangian and the systematic reduction of operators, are extendable for UV resonances of d≥8 operators in SMEFT and other effective field theories. Published by the American Physical Society 2024

Hierarchically porous MOF@COF structures with ultrafast gas diffusion rate for C2H6/C2H4 separation

For ethylene purification, C2H6-selective metal–organic frameworks (MOFs) show great potential to directly produce polymer-grade C2H4 from C2H6/C2H4 mixtures. Most C2H6-traping MOFs are ultra-microporous structures so as to strengthen multiple supramolecular interactions with C2H6. However, the narrowed pore channels of C2H6-traping MOFs cause large guest diffusion barriers, greatly hampering their practical applications. Herein, we present a feasible strategy by precisely constructing hierarchically porous MOF@COF core–shell structures to address this issue. Additional mesoporous diffusion channels were incorporated between MOF crystals through the construction of the COF shell, thereby enhancing the gas adsorption kinetics. Notably, designing a core–shell MOF@COF structure with an optimal coating amount of mesoporous COF shell will further improve the gas diffusion rate. Breakthrough experiments reveal that the tailored MOF@COF composites can effectively achieve C2H6/C2H4 separation and maintain its separation performance over five continuous measurement cycles. This investigation opens up a new avenue to solve the diffusion/transfer issues and provides more opportunities and potentials for MOF@COF composites in practical separation applications.

Coordinated response of endemic gastropods to Late Glacial and Holocene climate-driven paleohydrological changes in a small thermal pond of Central Europe

The thermal spring-fed Lake Pețea located in NW Romania southeast of the city of Oradea harbors a unique endemic warm water biota. It is the only location in Europe where thermal water endemic melanopsid Microcolpia parreyssii (Philippi, 1847) lived along with the highly endangered warm-water relict neritid Theodoxus prevostianus. Lake Petea’s evolution was mainly controlled by major climate-driven hydrological changes also seen in regional records. The hydrological changes were mainly controlled by varying input of thermal water due to recurring increased/decreased recharge of the underground karst water system. The driving factor was warming connected to the interstadial GI 1 increasing recharge by melting of regional ice sheets in the Late Glacial. Conversely, during the Younger Dryas (H0) and the Holocene increasing/decreasing moisture availability was in control. Low stands created multiple bottlenecks reducing genetic variability seen in the appearance of extreme morphologies during next rapid climate melioration. The studied gastropods responded mostly similarly to changes controlling the availability of elements in shell construction and habitat reduction leading to changes in shape, density, size. Periods of lower lake levels and reduced warm water input are characterized by the emergence of elongated tightly coiled shells while globular, compressed loosely coiled shells develop at times of warmer water provision and increased Mg availability. In size there is a contrasting trend. Namely globose Th. prevostianus shells are larger than the elongated ones. Conversely globose, compressed Microcolpia are generally smaller than their elongated spindle-shaped counterparts. In this sense the development of dwarf morphotypes in warmer water habitats is characteristic of Lake Pețea melanopsids. This type of dwarfism i.e. the reduction of shell size is lacking though in Lake Pețea neritids. Our findings also confirm the presence of various ecophenotypes of Microcolpia in the pond degrading our endemic species Mi. parreyssii to a variety of Mi. daudebartii.

Structure and assembly of the α-carboxysome in the marine cyanobacterium Prochlorococcus.

Carboxysomes are bacterial microcompartments that encapsulate the enzymes RuBisCO and carbonic anhydrase in a proteinaceous shell to enhance the efficiency of photosynthetic carbon fixation. The self-assembly principles of the intact carboxysome remain elusive. Here we purified α-carboxysomes from Prochlorococcus and examined their intact structures using single-particle cryo-electron microscopy to solve the basic principles of their shell construction and internal RuBisCO organization. The 4.2 Å icosahedral-like shell structure reveals 24 CsoS1 hexamers on each facet and one CsoS4A pentamer at each vertex. RuBisCOs are organized into three concentric layers within the shell, consisting of 72, 32 and up to 4 RuBisCOs at the outer, middle and inner layers, respectively. We uniquely show how full-length and shorter forms of the scaffolding protein CsoS2 bind to the inner surface of the shell via repetitive motifs in the middle and C-terminal regions. Combined with previous reports, we propose a concomitant 'outside-in' assembly principle of α-carboxysomes: the inner surface of the self-assembled shell is reinforced by the middle and C-terminal motifs of the scaffolding protein, while the free N-terminal motifs cluster to recruit RuBisCO in concentric, three-layered spherical arrangements. These new insights into the coordinated assembly of α-carboxysomes may guide the rational design and repurposing of carboxysome structures for improving plant photosynthetic efficiency.

Catalytic ozonation with carbon-coated copper-based core-shell catalysts (C/Cu-Al2O3) for the treatment of high-salt petrochemical wastewater

High-salt petrochemical wastewater requires advanced treatment for water reuse due to its high salinity and the presence of refractory organic compounds. Heterogeneous catalytic ozonation is an effective advanced treatment method, with the key to its success lying in the preparation of catalysts. A novel carbon-coated copper-based core-shell catalyst (C/Cu-Al2O3) was successfully prepared. In this work, Al2O3 was used as a carrier and copper as an active component to construct a catalyst with levodopa (L-DOPA) shell and embedded copper sites through the self-polymerization of L-DOPA. The active groups in L-DOPA molecules such as amine and carboxyl groups can be introduced into catalyst and L-DOPA also served as carbon source to reduce Cu(II) to more reactive Cu(I) and Cu(0). Under optimal conditions, its chemical oxygen demand (COD) removal rate for high-salt petrochemical wastewater reached 62.5%. After 20 cycles, its COD removal rate was maintained at above 53%. Electron paramagnetic resonance (EPR) investigations, quenching tests, and degradation experiments of oxalic acid revealed that the generation of embedded copper sites (Cu-O, Cu-N) and the construction of the carbon shell provided the catalyst with rich surface hydroxyl groups and Lewis acid sites, which promoted the decomposition of ozone into hydroxyl radicals (•OH), superoxide radicals (•O2-), and singlet oxygen (1O2) and achieved efficient degradation of organic compounds.

Model construction and energy harvesting investigation of shell shaped multi-section compound parabolic concentrator with solar vacuum tube

The solar non-imaging concentrator has the characteristics of no tracking device, stable system structure, and collected beam radiation and diffuse radiation. In particular, the Multi-section Compound Parabolic Concentrator(M-CPC) also has the advantages of a high utilization rate of reflector, long working time, and low manufacturing cost. In present research, a Novel Multi-section Compound Parabolic Concentrator (NM-CPC) is constructed based on the edge ray principle and Monte Carlo ray tracing (MCRT) method for the Shell Shaped Compound Parabolic Concentrator (SS-CPC) horizontally placed. The reliability of the model is verified by visual laser experiments, and its optical performance is analyzed considering the influence of the outer tube glass of the vacuum tube on the ray propagation. Compared to SS-CPC of the same specification, NM-CPC can eliminate the rays that escaped from the vacuum tube interlayer effectively. The heat-absorbing surface has a more uniform energy flux distribution and lower peak of energy flux. In spring and autumn, it has better solar radiant energy harvesting, which is 206 MJ and 297 MJ respectively. In terms of economic performance, the cost of the reflector is saved by 75.5%. All results show that NM-CPC has good application potential and economic performance.

Precast-Monolithic Reinforced Concrete Large-Span Shells of Unique Buildings from Enlarged Elements

The stress-strain state of precast monolithic reinforced concrete shells from enlarged elements taking into account the installation conditions. The results of experimental-theoretical studies of precast monolithic reinforced concrete shells of complex geometry assembled from enlarged elements are given. The studies were carried out on full-scale composite shells 48x48 m and diameter 96m, its enlarged elements 3x18m and 3x24m as well as on the shell model on a scale of 1:10 and 1: 4. The stress-strain state of shells of a similar type was studied with different mounting and splitting designs. Recommendations are given on rational methods for the construction of shells from enlarged elements for public buildings.

Physical and mechanical modeling of shaping pneumatic formwork by bicubic splines

The article deals with the hierarchical design structure, consisting of four stages of the stress state of pneumatic shells. The main tasks of designing and constructing pneumatic formworks during the construction of thin-walled architectural shells are considered. The introduction of pneumatic formwork into architectural and construction practice has a significant impact on the ability of the architect, builder and designer in the search for new and more advanced forms, as well as the builder in translating the creative ideas of the architect into steel and modern concrete. Thanks to the flexibility and elasticity of the material, it allows the construction of curvilinear spatial shells of a new elastic quality level. The proposed geometric model makes it possible to obtain a variety of software as well as the formation of a discrete-point frame of a finite shape by bicubic splines, which provides a predetermined accuracy for solving subsequent software design and construction problems.

A combined engineering of hollow and core-shell structures for C@MoS2 microcapsules toward high-efficiency electromagnetic absorption

Rational design of profitable structure is widely considered as an effective strategy for electromagnetic wave absorbing materials (EWAMs) to improve their performance. Herein, we conduct a combined engineering of hollow and core-shell structures, in which surface shell is formed by a number of MoS2 nanosheets crossing each other and internal core is hollow carbon microcapsule (HC). HC has strong dielectric loss ability, and its hollow structure facilitates the multiple reflection of incident EM wave. The construction of MoS2 shells not only improves impedance matching but also introduces heterogeneous interfaces that result in interfacial polarization loss. It is found that the synergistic effect of intrinsic loss mechanisms and structural advantages endow C@MoS2 composites (HCM-x) with excellent EM wave absorption performance, and especially for HCM-2, whose minimum reflection loss (RL) intensity and effective absorption bandwidth (EAB) are −63.8 dB and 6.0 GHz, respectively. It is believed that this work is valuable for the enhancement of performance for EWAMs through the upgrade of microstructure and regulation of chemical composition.

Yolk–shell Ni–Co bimetallic nitride/oxide heterostructures as high‐performance electrode of all‐solid‐state supercapacitor

Hierarchical core–shell structure is benefit for the fast diffusion and bulk storage of electron/ion while metal nitrides (MN) exhibit metal‐like behavior with excellent conductivity. Herein, nickel cobalt glycerate solid spheres (NiCo‐G) and nickel cobalt glycerate yolk–shell structure (NiCo‐GYS) were successfully synthesized via solvothermal reactions, accompanied by annealing using urea as a cheap and convenient nitrogen source to obtain metal nitride/bimetallic oxide core–shell heterostructure (NiCoNO). Excellent specific capacitance of 1878 F g−1 at 1 A g−1 is displayed by the prepared NiCoNO. Amazingly, the distinct core–shell construction guarantees high stability during the charge/discharge operation. NiCoNO maintains an 83.9% specific capacitance after 5000 cycles at 10 A g−1. Furthermore, the all‐solid‐state hybrid supercapacitor was assembled using NiCoNO cathode and active carbon (AC) anode components. The device has an excellent capacitive retention rate of 81.1% after 5000 cycles at 10 A g−1 and a good energy density of 64.2 Wh kg−1 at a power density of 900 Wh kg−1. A light‐emitting diode (LED) bulb can be lighted for 3 min, indicating the promising practical application prospect of the supercapacitor.

ХАРАКТЕР РАСПРЕДЕЛЕНИЯ МАКРО- И МИКРОЭЛЕМЕНТОВ В ОРГАНИЧЕСКИХ ОСТАТКАХ ИЗ МЕЗОЗОЙСКИХ ОТЛОЖЕНИЙ ЗАПАДНОЙ И СРЕДНЕЙ СИБИРИ

Features of biomineralization, fossilization and distribution of chemical elements were revealed in remains of various groups of organisms, and relationship with conditions of accumulation and post-sedimentation transformations of deposits of the Middle–Upper Jurassic and Lower Cretaceous of Siberia was determined. Plates of coccolithophorids, skeletons of radiolaria and acantharia, fragments of hetetoidea frameworks, relics of red algaes, diatoms and/or cyanobacteria were studied among the remains of organisms. The composition of coccoliths from various types of rocks includes essential (calcite, ankerite, siderite) and complementary (silica and hydroxyapatite) components. It is assumed that coccolithophorids could use Fe, Mg and Mn in the form of organomineral compounds in the construction of shells, the remnants of which, after accumulation, formed deposits of the appropriate composition. The absence of pyritized coccolithophorid relics was noted in the studied sections, while the siliceous remains of radiolaria buried with them are often fossilized with FeS2. It is considered that secondary mineralization was preceded by partial or complete bacterial dissolution of siliceous skeletal fragments and some terrigenous grains.S ubsequent pyritization developed due to the vital activity of sulfate reducing bacteria. As a result, there was a transformation of the intracellular content of radiolaria and membrane complexes separating it from the elements of the mineral skeleton. The possibility of preserving acantharia relics in a fossil state was proved.