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The wear of small-caliber barrels is one of the key factors affecting barrel life. Based on the Archard wear model, a high-temperature pin plate wear experiment was carried out, and wear models of chrome-plated layers and gun barrel materials were established. In addition, a finite element model of the interaction between the bullet and the barrel was established. The movement of the projectile along the barrel was simulated and analyzed, and the force distribution of the spatial geometry structure of the rifling was mastered through simulation. The wear law of the gun barrel along the axial direction was obtained based on the wear model of the chrome-plated layer and gun barrel material. A position 100 mm away from the barrel breech wears very fast; this position is where the cone of the bullet is engraved in the barrel. At the position 150–350 mm away from the barrel breech, the barrel bore wears even faster. The barrel chrome layer is mainly affected by the gunpowder impact and projectile engraving, which is consistent with the actual failure of the coating. When the distance to the barrel breech is 350 m, the wear becomes stable. Through an analysis of the diameter of the barrel, it was found that, when the diameter of the barrel exceeded 12.85 mm, the barrel reached the end of its life.

The wear of artillery barrels directly impacts the accuracy and firepower of weapon systems, and precise detection of barrel wear is paramount for enhancing military capabilities. This study proposes a sound-based method for detecting artillery barrel wear, aimed at addressing the challenges of invasiveness and inefficiency in traditional methods, as well as the high cost and resource demands of modern approaches. We introduce AcouDAR, an end-to-end adaptive framework designed to elevate information extraction capabilities through the integration of time convolutional networks (TCN) and bidirectional gated recurrent units (Bi-GRU). Additionally, a domain adaptation module comprising domain alignment and domain relevance elimination modules is incorporated to mitigate the model’s reliance on specific historical sound data of artillery barrels and to bolster its adaptability in real-world scenarios. Extensive experimentation validates the superior performance of the AcouDAR model in detecting artillery barrel wear.

Small beta barrel proteins are attractive targets for computational design because of their considerable functional diversity despite their very small size (<70 amino acids). However, there are considerable challenges to designing such structures, and there has been little success thus far. Because of the small size, the hydrophobic core stabilizing the fold is necessarily very small, and the conformational strain of barrel closure can oppose folding; also intermolecular aggregation through free beta strand edges can compete with proper monomer folding. Here, we explore the de novo design of small beta barrel topologies using both Rosetta energy–based methods and deep learning approaches to design four small beta barrel folds: Src homology 3 (SH3) and oligonucleotide/ oligosaccharide-binding (OB) topologies found in nature and five and six up-and-down-stranded barrels rarely if ever seen in nature. Both approaches yielded successful designs with high thermal stability and experimentally determined structures with less than 2.4 Å rmsd from the designed models. Using deep learning for backbone generation and Rosetta for sequence design yielded higher design success rates and increased structural diversity than Rosetta alone. The ability to design a large and structurally diverse set of small beta barrel proteins greatly increases the protein shape space available for designing binders to protein targets of interest.

Background and Aims Ellagitannins released from wood to wine during barrel ageing can affect wine colour and astringency. This work aimed to examine the influence that oak wood type (French or American) and age (first‐fill or second‐fill) of barrels has on the concentration of individual ellagitannins and their evolution during winemaking and ageing. Methods and Results The ellagitannin composition of red wines during ageing was determined by HPLC‐MS/MS‐multiple reaction monitoring. Differences in the extractability and stability of the individual ellagitannins were observed. Moreover, the ellagitannin composition of wines was determined by the type of barrel. Wines aged in new French oak barrels showed a concentration of ellagitannin about twofold higher than that aged in American or in second‐fill French ones. The vescalagin/castalagin ratio was higher in wines aged in French oak barrels than that in wines aged in American barrels. Wine samples were grouped by discriminant analysis into three groups depending on the type of barrel employed during ageing. Conclusions The ellagitannin profile of aged red wines is strongly influenced by the type of oak barrel employed. Wines aged in new French oak barrels can be differentiated from those aged in second‐fill French or in new American oak barrels by the ellagitannin concentration, whereas the vescalagin/castalagin ratio may assist in tracing the oak type (French or American) of the barrels. Significance of the Study The ellagitannin concentration along with the vescalagin/castalagin ratio in red wines aged in oak barrels can be employed for tracing the oak type of the barrels.

The main goal of the ageing process of tequila is to improve its organoleptic properties. This process is mainly performed in white oak barrels from trees of the Quercus species, whose wood confers a wide variety of aromas, flavors, and colors to the beverage, providing the desirable organoleptic character to this beverage. In this work, the effects of tequila maturation in recycled and regenerated oak barrels were evaluated by determining minor volatile compounds (VOCs) obtained by microdistillation of the liquid–liquid extraction of tequila samples. GC–MS analysis shows that in silver, aged, and extra-aged tequila types, ~62 VOCs were identified. The principal component analysis of VOC content for each type of tequila showed that they could be classified as four patterns (α, β, γ, and δ groups), proposed to establish their VOC content associated with the maturation process in recycled and regenerated oak barrels from Quercus alba . The α group, constituted by 21 VOCs, did not show significant differences in the concentration of compounds between the silver, aged, and extra-aged types of tequila, β group, constituted by 16 VOCs, which decreased or went missing by maturation process of silver tequila, the γ and δ groups, constituted by 15 and 10 VOCs, correlate with aged and extra-aged tequila, respectively. Findings indicate that the γ and δ groups are associated with the maturation process of tequila, suggesting that recycled and regenerated oak barrels of Q. alba is a procedure suitable for ageing of tequila, providing important VOC content to the beverage.

Rifling depth is a very important parameter of howitzer barrel design, which has great influence on howitzer firing performance and security. At present, there are two types of barrel rifling depth design, which are 1.27mm depth rifling and 2.3mm depth rifling. This paper studies the extrusion stress between top surface of rifling land and bearing band of projectile and the rifling depth of projectile. This paper studies the extrusion stress between top surface of rifling land and bearing band of projectile and rotating driving side force when deep rifling howitzer and shallow rifling howitzer are used. This paper studies the extrusion stress between top surface of rifling land and bearing band of projectile and rotating driving side force when deep rifling howitzer and shallow rifling howitzer fires unguided projectiles and guided projectiles. It can be found by comparison that shallow rifling howitzer does better. It can be found by comparison that shallow rifling howitzer does better that deep rifling howitzer in barrel life and guided projectile firing security. Research of this paper will produce an important meaning to our nation’s next generation howitzer.

Gram-negative bacteria contain a double membrane which serves for both protection and for providing nutrients for viability. The outermost of these membranes is called the outer membrane (OM), and it contains a host of fully integrated membrane proteins which serve essential functions for the cell, including nutrient uptake, cell adhesion, cell signalling and waste export. For pathogenic strains, many of these outer membrane proteins (OMPs) also serve as virulence factors for nutrient scavenging and evasion of host defence mechanisms. OMPs are unique membrane proteins in that they have a β-barrel fold and can range in size from 8 to 26 strands, yet can still serve many different functions for the cell. Despite their essential roles in cell survival and virulence, the exact mechanism for the biogenesis of these OMPs into the OM has remained largely unknown. However, the past decade has witnessed significant progress towards unravelling the pathways and mechanisms necessary for moulding a nascent polypeptide into a functional OMP within the OM. Here, we will review some of these recent discoveries that have advanced our understanding of the biogenesis of OMPs in Gram-negative bacteria, starting with synthesis in the cytoplasm to folding and insertion into the OM.

The design of protein sequences that fold into prescribed de novo structures is challenging. General solutions to this problem require geometric descriptions of protein folds and methods to fit sequences to these. The α-helical coiled coils present a promising class of protein for this and offer considerable scope for exploring hitherto unseen structures. For α-helical barrels, which have more than four helices and accessible central channels, many of the possible structures remain unobserved. Here, we combine geometrical considerations, knowledge-based scoring, and atomistic modeling to facilitate the design of new channel-containing α-helical barrels. X-ray crystal structures of the resulting designs match predicted in silico models. Furthermore, the observed channels are chemically defined and have diameters related to oligomer state, which present routes to design protein function.

The analytical and sensory analysis of wines aged in barrels of French and American oak with three different levels of toasting was performed to determine the relationship between the volatile substances released by oak wood and sensory appreciation by a trained panel. For that purpose, a discolored white wine of Macabeo and a red wine of Cabernet Sauvignon from 2012 vintage were aged for 12 months in new barrels. Similar wines from the following vintage were aged in the same barrels for knowing how the use of the barrels affects their capacity to release volatile substances and its organoleptic impact. A significant correlation was found between the appreciation of coconut and smoked/toasted notes by the panel and the theoretical sensory impact of β-methyl-γ-octalactone and volatile phenols, respectively, in two different wines aged in new oak barrels. Vanillin correlated significantly in only one of the wines tasted. The panelists generally preferred wines aged in medium-toasted new barrels for both oak species. In a triangle test, tasters could distinguish between wines aged in new American and French oak barrels when the toasting level was light or medium but not when it was heavy. They were also able to distinguish between wines aged in new and 1-year-used barrels. It can be concluded that the botanical origin of the oak, the toasting level of the staves and the number of times that the barrels have been used previously have a real impact on the volatile composition of the wine and in its sensory impact.

Outer-membrane beta barrels (OMBBs) are found in the outer membrane of gram-negative bacteria and eukaryotic organelles. OMBBs fold as antiparallel β-sheets that close onto themselves, forming pores that traverse the membrane. Currently known structures include only one barrel, of 8 to 36 strands, per chain. The lack of multi-OMBB chains is surprising, as most OMBBs form oligomers, and some function only in this state. Using a combination of sensitive sequence comparison methods and coevolutionary analysis tools, we identify many proteins combining multiple beta barrels within a single chain; combinations that include eight-stranded barrels prevail. These multibarrels seem to be the result of independent, lineage-specific fusion and amplification events. The absence of multibarrels that are universally conserved in bacteria with an outer membrane, coupled with their frequent de novo genesis, suggests that their functions are not essential but rather beneficial in specific environments. Adjacent barrels of complementary function within the same chain may allow for functions beyond those of the individual barrels.