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Accuracy and safety of tank guns are dependent a great degree on the condition of its gun bore. Many parameters affect accuracy and safety and have strong and complex interdependencies. While it is extremely difficult to monitor all these parameters during battle conditions, it is also essential to enhance the accuracy of the gun by measuring and compensating these parameters. Among all, bore wear and bore centreline are predominant factors. The surface characteristics of the bore also are indicative of potential accidents/deterioration, which should be monitored continuously. Hence, condition monitoring of tank gun bore characteristics in near real-time is an impending need with huge potential for enhancing the combat effectiveness of tank formations. This paper analyses various bore parameters affecting accuracy and safety and proposes a comprehensive condition monitoring method that uses vision camera, thermal camera and mechanical profiler. This integrated approach provides enhanced accuracy in measuring surface characteristics of tank bore that has been partially validated.

The present study experimentally investigated the flow kinematics and hydrodynamic pressures and forces on a simplified coastal building under tsunami bore impact. A rectangular structure sitting on a 1/10 sloping beach at four different headings, at 0°, 15°, 30° and 45°, was considered under bore impacts. The input wave condition was designed to generate a tsunami bore traveling at high speed on a sloping beach. The interaction between bore and structure (oriented at four different headings) was investigated using the nonintrusive bubble image velocimetry technique that enables the quantitative visualization of the full-field flow behavior. Simultaneous measurements of forces and pressures during the impacts were correlated with the measured flow velocities. As the tsunami bore is highly turbulent, ensemble averages from repeated tests were obtained for the investigation. To model the interaction, the validity of a dam break solution for a sloping bed as a suitable representation was examined, while the initial water depth was approximated using wave properties and calibrated with measured bore celerity. The study found that the profile of peak impact pressures is similar to a hydrostatic distribution for each heading, but one order of magnitude greater than the hydrostatic pressure. Similar linear distribution is also found in the correlation between peak impact pressure and angle of heading. By correlating the peak impact pressures with the impact velocity, the impact coefficient was estimated as 0.55. The measured pressures were further applied to model the surge force. By examining the peak surge forces against the heading angle, the lowest magnitude occurred when the structure was orientated at 30°.

Managing forests to preserve biodiversity requires a good knowledge not only of the factors driving its dynamics but also of the structural elements that actually support biodiversity. Tree-related microhabitats (e.g. cavities, cracks, conks of fungi) are tree-borne features that are reputed to support specific biodiversity for at least a part of species' life cycles. While several studies have analysed the drivers of microhabitats number and occurrence at the tree scale, they remain limited to a few tree species located in relatively narrow biogeographical ranges. We used a nationwide database of forest reserves where microhabitats were inventoried on more than 22,000 trees. We analysed the effect of tree diameter and living status (alive or dead) on microhabitat number and occurrence per tree, taking into account biogeoclimatic variables and tree genus. We confirmed that larger trees and dead trees bore more microhabitats than their smaller or living counterparts did; we extended these results to a wider range of tree genera and ecological conditions than those studied before. Contrary to our expectations, the total number of microhabitat types per tree barely varied with tree genus-though we did find slightly higher accumulation levels for broadleaves than for conifers-nor did it vary with elevation or soil pH, whatever the living status. We observed the same results for the occurrence of individual microhabitat types. However, accumulation levels with diameter and occurrence on dead trees were higher for microhabitats linked with wood decay processes (e.g. dead branches or woodpecker feeding holes) than for other, epixylic, microhabitats such as epiphytes (ivy, mosses and lichens). Promoting large living and dead trees of several tree species may be a relevant, and nearly universal, way to favour microhabitats and enhance the substrates needed to support specific biodiversity. In the future, a better understanding of microhabitat drivers and dynamics at the tree scale may help to better define their role as biodiversity indicators for large-scale monitoring.

We present observations of shoaling nonlinear internal bores off the coast of central California. The dataset includes 15 moorings deployed during September–October 2017 and cross-shore shipboard surveys. We describe the cross-shore structure and evolution of large-amplitude internal bores as they transit from 9 km (100-m depth) to 1 km offshore (10 m). We observe that two bores arrive each semidiurnal period, both propagating from the southwest; of the total, 72% are tracked to the 10-m isobath. The bore speeds are subtidally modulated, but there is additional bore-to-bore speed variability that is unexplained by the upstream stratification. We quantify temporal and cross-shore variability of the waveguide (the background conditions through which bores propagate) by calculating the linear longwave nonrotating phase speed c o and using the nonlinearity coefficient of the Korteweg–de Vries equation α as a metric for stratification. Bore fronts are generally steeper when α is positive and are more rarefied when α is negative, and we observe the bore’s leading edge to rarefy from a steep front when α is positive offshore and negative inshore. High-frequency α fluctuations, such as those nearshore driven by wind relaxations, contribute to bore-to-bore variability of the cross-shore evolution during similar subtidal waveguide conditions. We compare observed bore speeds with c o and the rotating group velocities c g , concluding that observed speeds are always faster than c g and are slower than c o at depths greater than 32 m and faster than c o at depths of less than 32 m. The bores maintain a steady speed while transiting into shallower water, contrary to linear estimates that predict bores to slow.

Background: Pleural infection represents a significant clinical challenge worldwide. Although prompt drainage of pleural fluid is thought to play a key role in pleural infection management, the optimal size of intrapleural catheter has yet to be defined. Objectives: The aim of this systematic review and meta-analysis was to summarize data on efficacy and complications of small-bore drain (SBD), defined as ≤14F, in comparison to large-bore drain (LBD) in patients with pleural infection. Method: We searched MEDLINE and Embase for all studies reporting outcomes of interest published up to October 2021. Two authors reviewed selected full text to identify studies according to predefined eligibility criteria. Summary estimates were derived using the random-effects model. Results: Twelve original studies were included for qualitative analysis and 7 of these for quantitative analysis. The surgical referral rate of SBD and LBD were, respectively, 0.16 (95% confidence interval [CI], 0.12–0.21) and 0.20 (95% CI, 0.10–0.32), the pooled mortality were 0.12 (95% CI, 0.05–0.21) and 0.20 (95% CI, 0.10–0.32), and the length of hospital stay was 24 days in both groups. Data on complications suggest similar proportions of tube dislodgement. Intensity of pain was evaluated in one study only, reporting higher scores for LBD. Conclusions: This systematic review and meta-analysis provide the first synthesis of data on performance of SBD and LBD in management of pleural infection, and, overall, clinical outcomes and complications did not substantially differ, although the limited number of studies and the absence of dedicated randomized trials does limit the reliability of results.

Tidal bores inject large amounts of energy to the estuaries, and the variation of tidal bore is related to its energy distribution. In this study, the temporal and spatial changes of the tidal bore energy are investigated to demonstrate the propagation characteristics of tidal bores in the Qiantang River Estuary. Based on high frequency field data, the characteristics of the potential energy and the kinetic energy per unit area during the passage of tidal bores at Yanguan station is demonstrated. Numerical model employing shallow water equations is established to investigate the tidal bore energy along the estuary. Tidal level, tidal current and tidal bore during spring tides in September, 2019 are verified, and the tidal bore energy and its distribution characteristics along the sections from Ganpu to Wenjiayan are illustrated. The tidal bore energy is significantly decreased in the Daquekou reach but decreased relatively small in the reach from Qige to Wenjiayan. There is the maximum energy loss in the Jianshan reach. The tidal bore energy declines to 15% at Wenjiayan during the passage of the energetic breaking tidal bores, indicating tidal bore disappearance in the upstream reach.

Restoration of tropical forest depended in large part on seed dispersal by fruit-eating animals that transported seeds into planted forest patches. We tested effectiveness of dispersal agents as revealed by established recruits of tree and shrub species that bore seeds dispersed by birds, bats, or both. We documented restoration of dispersal processes over the first 76 months of experimental restoration in southern Mexico. Mixed-model repeated-measures randomized-block ANOVAs of seedlings recruited into experimental controls and mixed-species plantings from late-secondary and mature forest indicated that bats and birds played different roles in the first years of a restoration process. Bats dispersed pioneer tree and shrub species to slowly regenerating grassy areas, while birds mediated recruitment of later-successional species into planted stands of trees and to a lesser extent into controls. Of species of pioneer trees and shrubs established in plots, seven were primarily dispersed by birds, three by bats and four by both birds and bats. Of later-successional species recruited past the seedling stage, 13 were of species primarily dispersed by birds, and six were of species dispersed by both birds and bats. No later-successional species primarily dispersed by bats established in control or planted plots. Establishment of recruited seedlings was ten-fold higher under cover of planted trees than in grassy controls. Even pre-reproductive trees drew fruit-eating birds and the seeds that they carried from nearby forest, and provided conditions for establishment of shade-tolerant tree species. Overall, after 76 months of cattle exclusion, 94% of the recruited shrubs and trees in experimental plots were of species that we did not plant.

•Bleeding and vascular access complications are associated with increased patient morbidity and mortality.•Procedural and device-related factors may optimize large-bore vascular access, management, removal, and closure.•Randomized controlled trials evaluating mechanical circulatory support device safety and efficacy in cardiogenic shock and high-risk percutaneous coronary intervention are needed.The number of large-bore femoral arterial procedures has increased significantly over the past decade, in part, because of the increasing use of mechanical circulatory support for cardiogenic shock and high-risk, complex, percutaneous coronary interventions. Access-related bleeding and vascular complications remain frequent and are associated with morbidity and mortality. The risk for bleeding and vascular complications increases with larger devices and delivery sheath sizes. Contemporary vascular access and closure techniques and indwelling device management strategies, when used in a systematic and standardized approach, may reduce these complications. In this article, we discussed the optimal planning, preparation, and procedural techniques for large-bore femoral vascular access, indwelling device management, safe device removal and percutaneous arteriotomy closure, complication prevention and management, and future clinical and research directions. In conclusion, this review represents a collaborative step-by-step approach of the investigators’ recommended contemporary practices, including practical “tips and tricks” for operators using percutaneous mechanical circulatory support devices. State-of-the-art large-bore vascular access for percutaneous mechanical circulatory support: planning and preparation, vascular access and closure, device insertion and removal, and future outlook.

Sediment transport is a geophysical phenomenon characterized by the displacement of sediment particles in both the horizontal and vertical directions due to various forces. Most of the sediment transport equations currently used include only parameters related to the horizontal direction. This study measured both instantaneous longitudinal and vertical parameters, i.e., velocities and forces, and found that the magnitude and direction of the vertical force play an important role in sediment incipient motion. An innovative experimental system was developed to investigate the effect of vertical force on incipient motion in rapidly varying flows. A quadrant analysis of the instantaneous measured forces on the critical shear stress was performed. The research revealed that upward positive vertical forces enhance particle mobility, whereas downward negative vertical forces increase particle stability. Novel equations have been developed to represent the influence of vertical forces on sediment transport. A comprehensive critical Shields stress for sediment transport was proposed, extending the Classic Shields diagram to encompass the incipient motion in highly unsteady flows.

To conserve global biodiversity, countries must forge equitable alliances that support sustainability in traditional pastoral lands, fisheries-management areas, Indigenous territories and more. To conserve global biodiversity, countries must forge equitable alliances that support sustainability in traditional pastoral lands, fisheries-management areas, Indigenous territories and more.