Short Tube Research Articles

Petrocodon mirus (Gesneriaceae), a new species from southwest Guangxi, China

Based on morphological observations, molecular phylogenetic analyses and literature consultations, a new species of Gesneriaceae, Petrocodon mirus, is described and illustrated here. This new species exhibits morphological similarity with P. pulchriflorus and P. hechiensis, but is easily distinguished from the latter two by its slightly leathery leaf blade, liner to ligulate‐oblong lip lobes, and shorter tube with constriction at middle. In addition, the new species differs from P. pulchriflorus by its reflexed adaxial lip lobes, and from P. hechiensis by its included stamen and pistil. However, the stigma of P. mirus is much similar to the chiritoid stigma diagnostic for ChiritaBuch.‐Ham. ex Don (now mostly included in Primulina); based on this observation a new hypothesis for the evolution of the chiritoid stigma is proposed.

A New Species of Anacanthorus (Dactylogyridae, Anacanthorinae) Parasitizing Gills of Hoplias aff. malabaricus (Bloch, 1794) (Characiformes, Erythrinidae) from the Caatinga Domain.

Anacanthorus silvoi n. sp. (Dactylogyridae, Anacanthorinae) is described from the gills of Hoplias aff. malabaricus (Bloch, 1794) from the Salgado River, Ceará state, Brazil. The monogeneans were affixed onto slides using Gray and Wess's medium for examination of their sclerotized structures. For analysis of internal organs, a single specimen was preserved in 5% formalin, stained with Gomori's trichrome, and mounted in Gray and Wess's medium. Anacanthorus silvoi n. sp. is characterized by having a short broad tube MCO with a medial constriction (i.e., MCO with distal region wider than the proximal region, and flexed lateral flap in the distal region in A. cururutuiensis and a MCO with a small projection in the form of a hook in the distal region in A. siphonocommus). The present study corroborates previous studies that the absence of an accessory piece is a characteristic shared by all Anacanthorus members parasites of Erythrinidae.

A Method for the Coefficient Superposition Buckling Bearing Capacity of Thin-Walled Members

Axial compression tests were conducted on short rhombic tubes of different cross-sectional shapes. The deformation modes of the rhombic short tubes were obtained. To induce a finite element model with deformation modes consistent with the actual working conditions, buckling modes are introduced into the model as the initial imperfections of the structure. However, the buckling modes resulting from finite element buckling analyses often do not meet the needs of actual crushing modes. A coefficient superposition method of solution is proposed to derive modal characteristics consistent with the actual deformation modes by linear superposition of the buckling modes. Through the study of three aspects of theory, test, and simulation, and the comparison and verification of this method with the simulation results of related literature, the results show that the indexes derived from this method are closer to the actual circumstances and are more expandable, which provides a reference for the project.

Genetic structure of interspecific hybridization between the long corolla tube species, Isodon longitubus, and its short corolla tube congener, I. inflexus

Genetic structure of interspecific hybridization between the long corolla tube species, Isodon longitubus, and its short corolla tube congener, I. inflexus

A unified confinement-based direct design approach for novel double-skin composite columns

Concrete-filled stiffened steel tubular short columns, with cold-formed stiffened steel tubes for the outer section, have been widely used in Asia in large commercial facilities and warehouses. This paper focuses on the response of concrete-filled double-skin stiffened steel tubular (CFDSST) short columns and concrete-filled dual stiffened steel tubular (CFDST) short columns, with either square or circular inner tubes. A detailed database of existing information is assembled and presented, as well as a thorough analysis of existing design expressions. Additional examination of the concrete confinement has been undertaken which highlight the differences in behaviour between CFDSST and CFDST cross-sections. The major aim in this work is to provide a unified design approach, which accounts for concrete confinement and accounts for the material and geometric properties of the section, and offers improved accuracy over the existing approaches given in the European, American, British and Chinese design codes. The newly proposed unified confinement-based direct design approach for axially-loaded CFDSST and CFDST short columns is discussed, including the consideration given to the lateral confining pressure provided by the steel tubes. This method is shown to provide more accurate depictions of the load resistances of CFDSST and CFDST short columns relative to the international specifications, with lower scatter and greater range of applicability. It has also been shown that the CFDSST sections with a stiffened outer steel tube provides greater confinement and additional strength compared with equivalent unstiffened circular tubes of high relative tube slenderness. Given the easier fabrication and installation of beam-to-square column joints compared with circular columns, this is likely to extend their range of application in the future.

Behavior of CFRP-strengthened short spiral welded tubes under axial load

Spiral welded tubes (SWTs) are formed by rolling steel plates at a certain angle and welding the resulting abutting edges. They are extensively utilized because of their large diameter ranges, high production efficiency, and low production cost. Thin-walled spiral welded tubes with large diameter-to-thickness ratios are susceptible to local buckling under compressive load, and their performance can be affected by corrosive environments. Therefore, this paper proposed the use of carbon fiber-reinforced polymer (CFRP) to strengthen tubes by external bonding. There are limited studies on the axial compression behavior of CFRP strengthened spiral welded tubes, particularly studies that consider the initial imperfections and residual stresses in spiral welded tubes. To bridge this gap, this paper first investigated the distributions of initial imperfections and residual stresses in spiral welded tubes, finding that both are significantly influenced by distinct forming and welding manufacturing processes. Subsequently, axial compression tests were carried out on four unstrengthened specimens and twelve CFRP-reinforced specimens to investigate the compressive behavior by considering the diameter-to-thickness ratio, the length of the steel tubes, and CFRP layer orientation. The experimental results indicate that CFRP strengthening delays local buckling, and significantly enhances the yield load, ultimate load, and initial stiffness of spiral welded tubes, achieving a maximum increase of the yield load up to 69.11 % and the ultimate load up to 61.99 %, while its impact on the ductility index remains uncertain and is influenced by variables such as the diameter-to-thickness ratio of the tubes and the CFRP layer orientation. Finally, a comparison of the ultimate loads of the specimens by tests and design codes was conducted.

Shorter Drainage Tube to the Pancreatic Stump Reduces Pancreatic Fistula After Distal Pancreatectomy.

We investigated the relationship between the length of a prophylactic closed-suction drainage tube and clinically relevant postoperative pancreatic fistula (CR-POPF) in distal pancreatectomy (DP). The clinical data of 76 patients who underwent DP using a reinforced stapler for the division of the pancreas at Ehime University Hospital between December 2017 and May 2023 were retrospectively analyzed. Laparoscopic DP was performed in 41 patients (53.9%). Closed-suction drainage was performed using a 19Fr ExuFlow Round Drain with a vacuum bulb. The drainage tube length was defined as the distance between the peripancreatic stump site and the abdominal wall insertion site using abdominal radiography. CR-POPF was observed in 12 patients (15.8%). Univariate analyses demonstrated that male sex (P=0.020), American Society of Anesthesiologists Physical Status (P=0.017), current smoking (P=0.005), and drainage tube length (P<0.001) were significantly associated with CR-POPF. The optimal cut-off value of drainage tube length for CR-POPF was 220mm (area under the receiver operating characteristic curve=0.80). In multivariate analyses, drainage tube length (≥220mm) was the sole independent predictor for CR-POPF (odds ratio, 6.59; P=0.023). According to computed tomography performed ∼1 week after surgery, the median volume of peripancreatic fluid collection was significantly higher in the long drainage tube group than in the short drainage tube group (P<0.001). A drainage tube inserted at a shorter distance to the pancreatic stump may reduce the incidence of CR-POPF after DP.

Performance testing of a novel short axis photomultiplier tube for the HUNT project

Photomultiplier tubes (PMTs) with large-area cathodes are increasingly being used in cosmic-ray experiments to enhance detection efficiency. The optical modules (OMs) of the High-Energy Underwater Neutrino Telescope (HUNT) have employed a brand new N6205 20-inch microchannel plate photomultiplier tube (MCP-PMT) developed by the North Night Vision Science & Technology (Nanjing) Research Institute Co. Ltd. (NNVT). In order to make the 20-inch PMT fit into the 23-inch diameter pressure-resistant glass sphere, NNVT improved the internal structure of PMT and shortened the height of PMT by more than 10 cm. The first batch of these PMTs has been delivered for preliminary research work. This paper describes a specific PMT testing platform built for the first batch of 15 MCP-PMTs, and some performance parameters of PMT, such as peak-to-valley ratio, TTS and nonliniearity, are measured. The measurement results show that the new PMT still has good performance and can meet the requirements of HUNT project.

The dynamic response of a pressure transducer for measurements in water

Dynamic pressure measurements are indispensable in the field of fluid mechanics. Attaching tubing as a transmission line to the pressure transducer is often unavoidable but significantly reduces the usable bandwidth of the measurement system. Complex fluid-wall interactions and potential outgassing of air are present within systems with water-filled tubes. Comprehensive studies aiding researchers in selecting suitable transmission line parameters (i.e., material, length, and diameter) are not available. A simple calibration apparatus is designed for the frequency response characterization of multiple pressure transducers simultaneously applying a pressure step. The setup is thoroughly characterized and a detailed description is provided to optimize the bandwidth. A piezoresistive pressure transducer attached to water-filled tubes, as commonly used in hydrodynamic experiments, is characterized in the low-frequency range (i.e., f≤300\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f \\le {300}$$\\end{document} Hz). Tube-related effects, such as length, diameter, and material are investigated. The impact of entrapped air within the tubing is analyzed. The feasibility of substituting water with silicone oil to fill the tubes is explored. To optimize the usable bandwidth of the pressure measurement system for dynamic applications, it is essential to maintain short tubing that is as rigid as possible and free from entrapped air. Pressure wave propagation speed is reduced by two orders of magnitude in elastic transmission lines made of silicone. Pressure corrections through dynamic calibration are challenging due to the system’s sensitivity to various parameters affecting the dynamic response.

Cytological and ultrastructural investigation of pathogen infection pathway and host responses in asparagus stem infected by Phomopsis asparagi

Asparagus stem blight, a highly destructive disease in global asparagus cultivation, is caused by the fungus Phomopsis asparagi. However, the underlying mechanisms of the infectious process and pathogenesis of P. asparagi remain poorly understood. This study aims to elucidate the infection event of P. asparagi at the cytological and ultrastructural levels in asparagus stem through a microscopic observation. The host responses were also examined by microscopic observation and fluorescent probe. It revealed that P. asparagi germinated at either the tip or the middle of the conidia to produce short germ tubes on the surfaces of the asparagus stem at 20 h post-inoculation (hpi). The germ tubes penetrated the host cell wall with appressorium-like structures or narrow pegs at 1 day post-inoculation (dpi). At 3 − 5 dpi, a large number of P. asparagi hyphae colonized the epidermal cells. The hyphae were found to grow both intracellularly and intercellularly. The movement of hyphae between cells was facilitated by constricted invasive hyphae pegs. The hyphae exhibited bidirectional intracellular growth, extending and branching along the inner side of the cell wall within the stem cortex and towards the central cylinder. The fungal colonization resulted in cellular damage in plants, which is characterized by plasmolysis, rupture of the cell wall, and disruption of the cytoplasm. At 11 dpi, the fungi penetrated the parenchyma cells, and the fungal pycnidia were formed. At 13 dpi, the fungi penetrated the stem center parenchyma cell, where the conidia were released. In addition, the host defense response was investigated, which revealed a notably reduced germination rate of conidium, the formation of callose analogs, and the reactive oxygen burst. These findings provide unexpected perspectives on the infection process and host response in P. asparagi-plant interaction.

Effect of aspect ratio and axial tensile load on the inflation of cylindrical tubes

We explore the snap-through instability in hyper-elastic cylindrical tubes during inflation, specifically investigating the influences of geometry and imposed axial tensile loads on both the bulging shape profiles and the initiation pressure of the bulge. We perform bulging experiments on latex rubber tubes with different parameters such as the length-to-diameter aspect ratio and axial tension. To complement these experiments, finite element simulations across various geometries and a theoretical analysis of an infinite-length tube are conducted. Our simulations reveal a critical aspect ratio that divides the bulging into two possibilities: short tubes exhibit whole bulging, while longer tubes show localized bulging. Both experimental and simulation findings indicate that as the aspect ratio and axial tensile load increase, the initiation pressure diminishes and then converges. Notably, when the axial tensile load surpasses the shear modulus, it obstructs snap-through in shorter tubes and neutralizes the influence of the aspect ratio on the initiation pressure. The outcomes of this research offer valuable perspectives on modulating the bulging mode and initiation pressure in tubular structures within soft devices, including soft pneumatic actuators and energy harvesters.

Film cooling performances of short fan-shaped-holes under oscillating freestream

Freestream oscillation presents a significant challenge in optimized design of short fan-shaped-hole, a good choice for more promising double-wall cooled blades. An experimental investigation was conducted to understand detailed effects of key geometrical parameters of the fan-shaped hole, freestream oscillating frequency and cooling air-to-mainstream blowing ratio on the unstable film cooling performances. The selected geometrical parameters included the length-to-diameter ratio, the lateral diffusion angle, and the length ratio of cylindrical section-to-diffusion section. Time-resolved planar quantitative light sheet technique was employed to visualize the temporal variations of jet trajectory and transported scalar concentrations. The experimental results indicated that freestream oscillation causes variations in jet mechanisms, changing the trend in film cooling with blowing ratio and reversing the universally-acknowledged harmful influence of non-fully development of cooling air in short tube. The optimized short-hole can achieve an increment up to 40% in film effectiveness under oscillating freestream, in comparison with the long-hole-jet. The primary principle of the optimized design of short shaped-hole is properly enlarging the lateral expansion angle, aiming at the higher steady film effectiveness while the lower unsteadiness due to the transient fluctuations. Further enlarging the length ratio can improve the stability of film cooling in an oscillating cycle.

Selective mural cell recruitment of pericytes to networks of assembling endothelial cell-lined tubes.

Mural cells are critically important for the development, maturation, and maintenance of the blood vasculature. Pericytes are predominantly observed in capillaries and venules, while vascular smooth muscle cells (VSMCs) are found in arterioles, arteries, and veins. In this study, we have investigated functional differences between human pericytes and human coronary artery smooth muscle cells (CASMCs) as a model VSMC type. We compared the ability of these two mural cells to invade three-dimensional (3D) collagen matrices, recruit to developing human endothelial cell (EC)-lined tubes in 3D matrices and induce vascular basement membrane matrix assembly around these tubes. Here, we show that pericytes selectively invade, recruit, and induce basement membrane deposition on EC tubes under defined conditions, while CASMCs fail to respond equivalently. Pericytes dramatically invade 3D collagen matrices in response to the EC-derived factors, platelet-derived growth factor (PDGF)-BB, PDGF-DD, and endothelin-1, while minimal invasion occurs with CASMCs. Furthermore, pericytes recruit to EC tube networks, and induce basement membrane deposition around assembling EC tubes (narrow and elongated tubes) when these cells are co-cultured. In contrast, CASMCs are markedly less able to perform these functions showing minimal recruitment, little to no basement membrane deposition, with wider and shorter tubes. Our new findings suggest that pericytes demonstrate much greater functional ability to invade 3D matrix environments, recruit to EC-lined tubes and induce vascular basement membrane matrix deposition in response to and in conjunction with ECs.

Neurorehabilitation in a Pediatric Stroke Patient Supported on a CentriMag.

Patients supported on ventricular assist devices (VADs) benefit from rehabilitation while awaiting heart transplantation to recover from surgery, prevent deconditioning, and, in most cases, optimize transplant candidacy. With bleeding and neurological dysfunction as the most common VAD complications, the importance of rehabilitation dramatically increases when a patient on a VAD also suffers from a neurological injury. The rehabilitation needs for cardiac conditioning and neurological reeducation are not the same. Patients with severe neurological deficits require intense rehabilitation that often includes base-of-support challenges, usage of bolsters and balls, partial weight-bearing treadmill training, and assumption of various body positions in prone, kneeling, or quadruped for neuromotor reeducation. However, some devices are more conducive to rehabilitation than others. For children supported by the CentriMag in particular, rehabilitation is challenged by short cannula tubing, an external motor, a large interface, and an intensive care unit (ICU) admission. We report a safe and successful physical therapy course of a pediatric stroke patient with a diagnosis of Ebstein's anomaly supported by a CentriMag right VAD (RVAD) while awaiting heart transplant in the ICU.

Food resource partitioning between males and females of Volcano Sunbird (Cinnyris preussi) on Mount Cameroon

Competition for nectar is expected to result in feeding niche differentiation. Here, we targeted the sexually size-dimorphic Volcano Sunbird (Cinnyris preussi) on Mount Cameroon. We investigated whether males and females feed on different plant species, whether females with shorter bills than males prefer shorter flowers, and whether larger dominant males visit more energetic flowers that produce higher amounts of nectar sugars. We also asked whether feeding niches were spatially separated along the elevation gradient and whether this separation varied between the two contrasting seasons. We collected data on the frequency of visits to individual plant species and analyzed the male-to-female ratios in the mist-netted dataset. In addition, we estimated production of nectar sugar in individual habitats and seasons. Despite the large dataset collected, encompassing 6476 bird–plant interactions, our findings did not provide evidence of differences in the spectra of the visited plant species. In addition, females did not visit flowers with shorter tubes, nor did males visit flowers that produced higher amounts of sugars. However, we observed a sex-specific dispersion of sunbirds during the wet season. During the dry breeding season, both males and females feed mainly in nectar-rich montane and submontane forests. In the wet season, the production of nectar sugar in these habitats decreased dramatically, and females largely disappeared. In contrast, female activity increased in the lowest and highest parts of the altitudinal range. Our findings on elevational movements are important in the current context, in which species face potential threats from habitat destruction and climate change.

Photoacoustic method for measuring the elasticity of polydimethylsiloxane at various mixing ratios

Measuring elasticity without physical contact is challenging, as current methods often require deconstruction of the test sample. This study addresses this challenge by proposing and testing a photoacoustic effect-based method for measuring the elasticity of polydimethylsiloxane (PDMS) at various mixing ratios, which may be applied on the wide range of applications such as biomedical and optical fields. A dual-light laser source of the photoacoustic (PA) system is designed, employing cross-correlation signal processing techniques. The platform systems and a mathematical model for performing PDMS elasticity measurements are constructed. During elasticity detection, photoacoustic signal features, influenced by hardness and shapes, are analyzed using cross-correlation calculations and phase difference detection. Results from phantom tests demonstrate the potential of predicting Young's modulus using the cross-correlation method, aligning with the American Society for Testing and Materials (ASTM) standard samples. However, accuracy may be affected by mixed materials and short tubes. Normalization or calibration of signals is suggested for aligning with Young's coefficient.

Discussion of the paper “M. Askari-sedeh and M. Baghani, On the extension-torsion of short hyperelastic tubes of axially functionally-graded materials” [Eng Struct 301 (2024) 117344]

Discussion of the paper “M. Askari-sedeh and M. Baghani, On the extension-torsion of short hyperelastic tubes of axially functionally-graded materials” [Eng Struct 301 (2024) 117344]

Design of reactive particle fluidized bed heat exchangers for gas–solid thermochemical energy storage

Concentrated solar power (CSP) systems integrated with a supercritical carbon dioxide (sCO2) Brayton power cycle are regarded as the primary future direction for CSP technologies. Calcium-based particles can be a suitable storage medium to achieve high temperatures exceeding 750 ℃. However, there have been few studies on reactive particle/sCO2 heat exchangers (HXs) to drive high-performance power cycles with high energy storage efficiencies. In this paper, the mechanisms by which chemically reactive particles release energy in a fluidized bed (FB) heat exchanger has been investigated to evaluate the performance of thermochemical storage systems. A 1-MWt thermal duty fluidized bed heat exchanger with sCO2 as the working fluid operating at 988 K was designed in different configurations, featuring single stage and multistage counter-flow HXs. A detailed shell and tube model combining the chemical reaction kinetics and the heat transfer between the fluidized particle and sCO2 FB HX design was developed. A comparison of sensible and chemical heat materials shows that thermochemical energy storage is advantageous due to the relatively short tube length and slow particle mass flow rate. The tube length and particle mass flow rate are reduced by 3.5 and 11.5 times, respectively. The average chemical conversion is 97.30 % for a one-stage heat exchanger, which is lower than the 99.95 % conversion achieved by the two-stage heat exchanger. Additionally, a sensitivity analysis was carried out to understand the impacts of key operating parameters on the process performance. These findings provide insights into the operational stability and efficiency of the system, contributing to the development of advanced heat exchangers for thermochemical energy storage applications.

Asymmetrical disassortative pollination mediated by long-/short-tongued pollinators in a distylous Limonium myrianthum (Plumbaginaceae) with a short corolla tubular small flower.

In heterostylous plants, short-tongued pollinators are often ineffective/inefficient owing to the limitations imposed by a long corolla tube. However, it is unclear how disassortative pollen transfer is achieved in small flowers. We investigated the pollination pattern and floral morph variation by analyzing heterostylous syndrome, pollinator groups, and pollen deposition after a single visitation in two Limonium myrianthum populations with short-corolla-tubular small flowers. The predominant pollinators in the Hutubi population were pollen-seeking short-tongued syrphids, which can only transfer pollen between high-level sexual organs. In the Xishan population, nectar-seeking short-tongued insects were efficient pollinators with symmetrical disassortative pollen transfer between high- and low-level sexual organs, whereas long-tongued pollinators had a low efficiency between high-level sexual organs due to the low contact probability with the stigma of long-styled flowers (L-morph), which no longer offered the same advantage observed in tubular flowers. Asymmetrical disassortative pollination may cause the female fitness of short-styled (S-morph) individuals in the Hutubi and L-morph individuals in the Xishan population to suffer greater selection pressure and exhibit a higher degree of floral morph variation. Limonium myrianthum exhibits an unusual pollination pattern in which the small flowers with short corolla tubes make it possible for short-tongued insects to become effective pollinators. However, factors such as the position of stigma-anther within the flower, pollinator species and their preference further caused asymmetrical disassortative pollen transfer. Therefore, more factors should be considered when evaluating the effectiveness of short- and long-tongued insects in pollination service.

Investigation of the Flow-Induced Noise and Optimization Design of a Short Tube Throttle Valve

Investigation of the Flow-Induced Noise and Optimization Design of a Short Tube Throttle Valve