Tube Length Research Articles

Single channel sound source localization by using combinations of multiple tubes

A method for localizing the direction arrival of the sound source with a single channel is proposed with the configuration of system consists of a single channel acoustic sensor and multiple inlets with specific path length of tubes or pipes. The time delay of arrival at each inlet can be estimated from the autocorrelation function measured at the sensor and the positions of peak in autocorrelation function are changed according to the incidence angle. By using this concept, the basic configurations are considered and the related investigations are conducted as solutions to several problems that need to be solved. The proposed concept is validated experimentally in anechoic chamber and outdoor conditions. As a method to expand the range of observation angle, the configuration with difference length is investigated and it is confirmed that the unique solution for the whole direction can be obtained by a combination of tubes and inlets.

Arabidopsis pollen prolyl-hydroxylases P4H4/6 are relevant for correct hydroxylation and secretion of LRX11 in pollen tubes.

Major constituents of the plant cell walls are structural proteins that belong to the hydroxyproline-rich glycoprotein (HRGP) family. Leucine-rich repeat extensin (LRX) proteins contain a leucine-rich domain and a C-terminal domain with repetitive Ser-Pro3-5 motifs that are potentially to be O-glycosylated. It has been demonstrated that pollen-specific LRX8-LRX11 from Arabidopsis thaliana are necessary to maintain the integrity of the pollen tube cell wall during polarized growth. In HRGPs, including classical extensins (EXTs), and probably in LRXs, proline residues are converted to hydroxyproline by prolyl-4-hydroxylases (P4Hs), thus defining novel O-glycosylation sites. In this context, we aimed to determine whether hydroxylation and subsequent O-glycosylation of Arabidopsis pollen LRXs are necessary for their proper function and cell wall localization in pollen tubes. We hypothesized that pollen-expressed P4H4 and P4H6 catalyze the hydroxylation of the proline units present in Ser-Pro3-5 motifs of LRX8-LRX11. Here, we show that the p4h4-1 p4h6-1 double mutant exhibits a reduction in pollen germination rates and a slight reduction in pollen tube length. Pollen germination is also inhibited by P4H inhibitors, suggesting that prolyl hydroxylation is required for pollen tube development. Plants expressing pLRX11::LRX11-GFP in the p4h4-1 p4h6-1 background show partial re-localization of LRX11-green fluorescent protein (GFP) from the pollen tube tip apoplast to the cytoplasm. Finally, immunoprecipitation-tandem mass spectrometry analysis revealed a decrease in oxidized prolines (hydroxyprolines) in LRX11-GFP in the p4h4-1 p4h6-1 background compared with lrx11 plants expressing pLRX11::LRX11-GFP. Taken together, these results suggest that P4H4 and P4H6 are required for pollen germination and for proper hydroxylation of LRX11 necessary for its localization in the cell wall of pollen tubes.

In-situ synthesis of BN/Al18B4O33 heterogeneous core-shell nanowires with different BN shell thicknesses and the microstructure evolution mechanism

A simple method was developed for the controllable synthesis of novel BN-coated aluminum borate (Al18B4O33) heterogeneous core-shell nanowires using Al4B2O9 nanowhiskers as rigid templates. This method allows the fabrication of Al18B4O33 nanowires with BN coatings of different thicknesses. The phases, microstructures, and chemical compositions of the samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and other characterization techniques. The heterogeneous core-shell nanowires of BN/Al18B4O33 had diameters and tube lengths of 35–60 nm and 400–600 nm, respectively, and the thickness of the BN cladding shell was between 2 and 7 nm. The concentration of B* volatilized on the whisker surface could be controlled by varying the ammonia flow rate, which in turn regulated the thickness of the BN cladding layer. The thickness of the BN cladding changed more significantly when the ammonia flow rate was varied at the Al4B2O9 nanowhisker's decomposition temperature. The experimental results show that the BN on the BN/Al18B4O33 heterogeneous core-shell structured nanowires conforms to the vapor–solid (VS) growth mechanism.

Evaluation of oryzalin-induced putative polyploids of <i>Jasminum sambac</i> cv. Ramanathapuram Gundumalli

The aim of the research was to create genetic variations in Jasminum sambac using oryzalin as a polyploidizing agent. Rooted stem cuttings of J. sambac were treated with oryzalin (0.005, 0.01 and 0.05%) and their vegetative and flowering parameters were recorded on 150 days after treatment. The study revealed that the higher concentration of oryzalin (0.05%) caused reduction in plant height, internodal length, number of flowering cymes per plant and number of flower buds per cyme. However, the same treatment significantly enhanced certain vegetative parameters viz., number of secondary branches, stem girth, number of leaves and leaf area, and flowering parameters namely flower bud length, corolla tube length, flower bud girth, diameter of open flower and hundred flower bud weight. High GCV was recorded in major yield attributing traits, i.e. number of flowering cymes per plant and hundred flower bud weight. High heritability and genetic advance registered for the traits viz., plant height, number of secondary branches, internodal length, number of flowering cymes, flower bud girth and hundred flower bud weight per plant indicates least influence by environment and selection such characters may be useful.

Evaluation of oryzalin-induced putative polyploids of <i>Jasminum sambac</i> cv. Ramanathapuram Gundumalli

The aim of the research was to create genetic variations in Jasminum sambac using oryzalin as a polyploidizing agent. Rooted stem cuttings of J. sambac were treated with oryzalin (0.005, 0.01 and 0.05%) and their vegetative and flowering parameters were recorded on 150 days after treatment. The study revealed that the higher concentration of oryzalin (0.05%) caused reduction in plant height, internodal length, number of flowering cymes per plant and number of flower buds per cyme. However, the same treatment significantly enhanced certain vegetative parameters viz., number of secondary branches, stem girth, number of leaves and leaf area, and flowering parameters namely flower bud length, corolla tube length, flower bud girth, diameter of open flower and hundred flower bud weight. High GCV was recorded in major yield attributing traits, i.e. number of flowering cymes per plant and hundred flower bud weight. High heritability and genetic advance registered for the traits viz., plant height, number of secondary branches, internodal length, number of flowering cymes, flower bud girth and hundred flower bud weight per plant indicates least influence by environment and selection such characters may be useful.

Power-to-X system utilizing an advanced solar system integrated with a thermally regenerative electrochemical cycle

This article discusses power-to-X technology by proposing an advanced system to generate green electricity and hydrogen. The proposed system is powered by an advanced concentrated parabolic photovoltaic thermal (CPV/T) hybrid system. A proton exchange membrane (PEM) water electrolyzer system is used for the hydrogen production process, with a multistage compression system to increase hydrogen pressure and regulate hydrogen temperature. Additionally, a heat recovery system is employed through the thermally regenerative electrochemical cycle (TREC). A parametric analysis was performed based on thermal resistance to investigate the effect of solar radiation, Reynolds number, lengths of both the receiver side and tube and ambient temperature. A mathematical model was developed and validated to investigate the integrated system performance. CPV/T achieved a maximum system efficiency of 85.4% at 1000 W/m2 and a side length of 0.2 m, with electrical and thermal contributions of 21.1% and 64.3%, respectively. With a tube length of 20 m, the maximum hydrogen flow rate reached 280 kg/h, requiring 2.5 TJ/h for production under a pressure of 750 bar. The TREC system showed a maximum electrical production contribution of about 25.4% at a Reynolds number equal to 3000 compared to the contribution of CPV/T cells.

Effect of tube bend angle on liquid propulsion system priming event pressures

Experimental work was performed to measure the priming event pressure transient levels in unrestricted liquid propulsion system tubing. An existing water hammer experimental setup was utilized, where system tubing diameter, length, and bend angle were examined. Experiments were performed under both atmospheric and low-pressure pre-test element conditions to understand any impact of tube bend angle on the mitigation of priming event pressure transients inside the liquid system. Experimental results showed pressure levels were influenced by a combination of tube diameter, length, and pre-test pressures; however, tube bend angle had minimal to no discernible change on the average peak pressure levels or rise times to peak pressure for all conditions examined.

Middle ear morphology and mastoid pneumatization: a computed tomography study.

Mastoid pneumatization is subject to numerous influencing factors including race, sex, and surrounding structures of the middle ear. This study aims to determine the mastoid air cell system (MACS) volume and its relationship with middle ear structures, and the influence of sex. A cross-sectional study was performed analyzing computed tomography (CT) scans in which MACS volume and the Estachian tube length (ETL) were visible. MACS volume, ETL, and width and height of the aditus ad antrum were obtained. A total of 100 CT were included with a mean age of 38.5 ± 15.3 years, of which 56 were women and 44 were men. The mean right and left MACS volume were 5.43 ± 3.15 cm³ and 5.54 ± 3.43 cm3 respectively , with a ETL of 24.55 ± 3.07 mm in right side and 24.24 ± 2.60 mm on left side. A aditus ad antrum width of 2.98 ± 0.65 in right and 2.98 ± 0.58 on the left and height of 4.51 ± 1.05 and 4.32 ± 0.85, on right and left side respectively. There were statistical differences between sexes in left ETL, and in MACS volume bilaterally. A low positive correlation between aditus ad antrum height and MACS volume was identified. Mastoid pneumatization was bigger in men than women. There was a low positive correlation between mastoid volume and ETL on both sides, and a significant correlation between right mastoid volume and aditus ad antrum height. This could lead us to believe that the length of ETL does not affect the pneumatization of MACS.

The influence of mold design and process parameters on dimensional shrinkage of perfluoroalkoxy alkane injection molding parts

AbstractIn mass production, injection molding plays a vital role in manufacturing various parts with complex settings. As perfluoroalkoxy alkane (PFA) injection‐molded products are widely used in immersion system, dimensional quality needs more attention. However, there is limited research on the dimension defects of PFA injection‐molded products. This study focused on the influence of mold design and process parameters on PFA part shrinkage, using mold flow simulation and orthogonal testing separately. Several gate locations and sizes were simulated to minimize shrinkage in mold design. Displacements varied with gate locations, and shrinkage decreased with larger gate sizes. The Taguchi method analyzed process parameters' impact on shrinkage. The results indicated that the injection rate had the most significant effect on the shrinkage of tube length, while melt temperature, holding pressure, and screw speed affected the shrinkage of tubes' outside diameter. Different flow directions exhibited variance in shrinkage. Using max–min normalization, the two shrinkage values reached 0.00972, whereas the smallest value obtained in the orthogonal experiment was 0.1545 in run 3. Thus, optimizing mold design and process parameters were two effective methods to reduce shrinkage. This study reduced shrinkage and improved the quality of PFA injection molding parts for semiconductor systems.

Temperature dependence of pollen germination and tube growth in conifers relates to their distribution along an elevational gradient in Washington State, USA.

Pollen germination and tube growth are essential processes for successful fertilization. They are among the most temperature-vulnerable stages and subsequently affect seed production and determine population persistence and species distribution under climate change. Our study aims to investigate intra- and inter-specific variations in the temperature dependence of pollen germination and tube length growth and to explore how these variations differ for pollen from elevational gradients. We focused on three conifer species, Pinus contorta, Picea engelmannii, and Pinus ponderosa, with pollen collected from 350 to 2200m elevation in Washington State, USA. We conducted pollen viability tests at temperatures from 5 to 40°C in 5°C intervals. After testing for four days, we took images of these samples under a microscope to monitor pollen germination percentage (GP) and tube length (TL). We applied the Gamma function to describe the temperature dependence of GP and TL and estimated key parameters, including the optimal temperature for GP (Topt_GP) and TL (Topt_TL). Results showed that pollen from three species and different elevations within a species have different GP, TL, Topt_GP, and Topt_TL. The population with a higher Topt_GP would also have a higher Topt_TL, while Topt_TL was generally higher than Topt_GP, i.e., a positive but not one-to-one relationship. However, only Pinus contorta showed that populations from higher elevations have lower Topt_GP and Topt_TL and vice versa. The variability in GP increased at extreme temperatures, whereas the variability in TL was greatest near Topt_TL. Our study demonstrates the temperature dependences of three conifers across a wide range of temperatures. Pollen germination and tube growth are highly sensitive to temperature conditions and vary among species and elevations, affecting their reproduction success during warming. Our findings can provide valuable insights to advance our understanding of how conifer pollen responds to rising temperatures.

Clogging of the delivery tube during preparation of copper powder by vacuum atomisation: coupling analysis of flow resistance and heat transfer

ABSTRACT During the production of micro-fine powders using gas atomization technology, the problem of clogging of the delivery tube is often encountered. Flow resistance inside the delivery tube and heat transfer of the delivery tube is one of the critical factors causing the clogging of the delivery tube. In this paper, the volume of the fluid model (VOF) coupled with the discrete phase model (DPM) were used to simulate the delivery tube-clogging process of the delivery tube involved in atomizing copper powder. The results indicate that, with the increase in the length of the delivery tube, the flow resistance increased; Shortening the length of the tube reduces the flow resistance and increases the superheat of the melt, the atomization process is uninterrupted. The atomized powder was qualitatively determined by standard deviation to determine the number of satellite balls. This research has guiding value in understanding the continuity of the atomization process.

Experimental and simulation analysis of the performance of premixed vertical ejectors

Infrared gas stoves have advantages such as rapid combustion speed and high thermal efficiency. The ejector, a pivotal component of the infrared gas stove, plays a crucial role in influencing the mixing ratio of gas and air. The vertical ejector is modeled and the simulation method is validated through experiments. The impact of structural parameters on the vertical ejector performance is investigated in this paper, like the contraction tube length, inlet diameter, and mixing tube length. The simulation results indicate that with the change in the contraction tube length, the excess air coefficient peaks at approximately 1.16. An increase in mixing tube length leads to a decreasing trend in the excess air coefficient. For ejectors with throat diameters of 9.8 mm, 11.2 mm, and 12.6 mm, their excess air coefficient reaches peak values at diffusion angles of 3.5°, 4.7°, and 5.0°, respectively. Furthermore, Response Surface Methodology is utilized to study the comprehensive influence of structural parameters on ejector performance and obtain the optimal structure. The excess air coefficient is 1.13 with the optimal geometric structure.

A new species of Phlogacanthus (Acanthaceae) from India

Phlogacanthus sudhansusekharii, a new species is described here from the state of Arunachal Pradesh, India. This newly described species is closely allied to Phlogacanthus guttatus (Wall.) Nees, but can be differentiated by its strikingly different yellowish-cream colored corolla with yellow patches and brown maculation, ratio of calyx lobes and tube length being ~1:1 and deltoid staminodes (vs. greenish-cream to white corolla with red-maroon maculation, ratio of calyx lobes and tube length ~2:1 and subulate-ensiform staminodes in the latter).

Feasibility of using superelastic shape memory alloy in plastic hinge regions of steel bridge columns for seismic applications

AbstractThis paper contributes to the further development of seismic resilient infrastructure by introducing a novel prototype bridge which integrates tubular steel piers with superelastic shape memory alloy (SMA). The proposed bridge pier is composed of a circular steel tube which is bonded to a superelastic SMA tube in regions of high stress. The pier is distinguished by its ability to minimize residual drifts following inelastic deformations induced by cyclic loading. Three‐dimensional continuum finite element (FE) models are utilized to examine its lateral behavior. Experimental data is used to demonstrate the effectiveness of the continuum FE procedure in replicating the cyclic response and capturing both global and localized behaviors. A novel composite material model is proposed to represent the degradation of strength and accumulation of irreversible strains in the cyclic response of superelastic SMAs. An iterative procedure for the calibration of this material is presented. Investigations, employing the calibrated FE procedure, focus on the quasi‐static cyclic response of steel piers with superelastic SMA in the plastic hinge zone, aiming to identify the optimal length of the SMA tube for achieving a self‐centering response with reduced residual deformation. The study is then further expanded to examine the seismic response of a bridge structure incorporating such piers. Development of the FE model for the prototype bridge includes the modelling of the piers using continuum elements, while the superstructure, bearing units, abutment walls, and backfill material are modelled using discrete elements. Nonlinear time history analyses are undertaken to investigate the effects of column wall thickness and materials used in the plastic hinge zones of the piers. Dynamic FE study results indicate that bridges employing such piers are capable of returning to their original position, provided the SMA tube is of adequate length.

Mitigation of UV-B Radiation Stress in Tobacco Pollen by Expression of the Tardigrade Damage Suppressor Protein (Dsup).

Pollen, the male gametophyte of seed plants, is extremely sensitive to UV light, which may prevent fertilization. As a result, strategies to improve plant resistance to solar ultraviolet (UV) radiation are required. The tardigrade damage suppressor protein (Dsup) is a putative DNA-binding protein that enables tardigrades to tolerate harsh environmental conditions, including UV radiation, and was therefore considered as a candidate for reducing the effects of UV exposure on pollen. Tobacco pollen was genetically engineered to express Dsup and then exposed to UV-B radiation to determine the effectiveness of the protein in increasing pollen resistance. To establish the preventive role of Dsup against UV-B stress, we carried out extensive investigations into pollen viability, germination rate, pollen tube length, male germ unit position, callose plug development, marker protein content, and antioxidant capacity. The results indicated that UV-B stress has a significant negative impact on both pollen grain and pollen tube growth. However, Dsup expression increased the antioxidant levels and reversed some of the UV-B-induced changes to pollen, restoring the proper distance between the tip and the last callose plug formed, as well as pollen tube length, tubulin, and HSP70 levels. Therefore, the expression of heterologous Dsup in pollen may provide the plant male gametophyte with enhanced responses to UV-B stress and protection against harmful environmental radiation.

Sanxiapeptin is an ideal preservative with a dual effect of controlling green mold and inducing systemic defense in postharvest citrus

Green mold is a common postharvest disease infected by Penicillium digitatum that causes citrus fruit decay, and severely affects fruit storage quality. This work aimed to investigate the antifungal activity of Sanxiapeptin against P. digitatum, and elucidate the possible mechanisms involved. Sanxiapeptin was capable of inhibiting spore germination, germ tube length and mycelial growth. The SYTOX green staining assay revealed that Sanxiapeptin targeted the fungal membrane, and changed the membrane permeability, leading to the leakage of cell constituents. Meanwhile, Sanxiapeptin could influence the cell wall permeability and integrity by increasing the activities of chitinase and glucanase, resulting in abnormal chitin consumption and the decrease of glucan. Intriguingly, Sanxiapeptin could effectively control postharvest decay in citrus fruits, and activate the host resistance responses by regulating the phenylpropanoid pathway. In conclusion, Sanxiapeptin exhibits multiphasic antifungal mechanisms of action to control green mold in citrus fruits, shows great potential as novel food preservatives.

Influence of length of resonance tubes on multi-stage looped thermoacoustic electric generator

Resonance tubes are often used to connect multi-stage looped thermoacoustic heat engine and linear alternators to form a multi-stage looped thermoacoustic electric generator. In this paper, we experimentally investigate the performance of a multi-stage looped thermoacoustic electric generator with two sets of resonance tubes of different lengths. With the increase of the length of resonance tubes from 1.5 m to 2 m, the system frequency decreases from 70 Hz to 62 Hz. The maximum output acoustic power increases from 6.97 kW to 8.16 kW, and the maximum output electric power increases from 5.09 kW to 6.24 kW. Meanwhile, the maximum thermoacoustic efficiency increases from 23.08 % to 23.94 %, the maximum acoustic-to-electric efficiency increases from 78.03 % to 82.06 % and the maximum thermal-to-electric efficiency increases from 17.79 % to 19.64 %. Numerical simulation is also conducted based on a 3-step coupling method and validates the experimental results. This study demonstrates that adjusting the length of resonance tubes in a multi-stage looped thermoacoustic electric generator is an effective way to tune the frequency as well as to improve the coupling between the multi-stage looped thermoacoustic heat engine and linear alternators.

Torsion and Combined Torsion-Axial Load Behaviour of Concrete Filled Steel Tube Columns with and without ECC/CFRP Wrap

ABSTRACT Concrete-filled tube columns may experience coupled torsion and axial compression under seismic and wind loading. Fifteen square, rectangular, and circular concrete filled steel/aluminium tube (CFST/CFAT) are tested under pure torsion to understand the behaviour and develop/validate finite element (FE) models. Parametric studies under pure torsion are conducted using FE models to study the effect of geometric (tube cross-section, length, and thickness) and tube/concrete material parameters on torsional strength, stiffness, and tube-concrete composite interaction. FE models are used to study strength, stiffness, and failure modes of CFST columns under combined torsion and axial compression load at various preload levels of axial and torsion. Coupled torsional preloading and subsequent axial load reduce the axial load capacity significantly, while coupled axial preloading and subsequent torsional loading have shown no significant influence on the torsional strength of CFST columns. Implementation of FE models developed for CFST columns with engineered cementitious composite (ECC) and carbon fibre reinforced polymer (CFRP) wraps showed significant enhancement of axial strength and stiffness compared to control (without wrap) even under high torsional preload level. The energy absorption capacity and ductility of the CFRP wrapped CFST column are about 1.38 and 1.1 times higher than its counterpart with ECC wrap of same axial load capacity. Overall, the results suggest that use of both CFRP and ECC wrap is an effective approach to enhance the torsional behaviour and ductility of CFST columns under combined torsion and axial loading conditions. However, high crack resistance and better post-peak ductility of ECC wrapped CFST compared to sudden CFRP rupture failure in CFRP-wrapped counterpart should be taken into consideration for seismic applications.

Echinoagave nievesiorum (Agavaceae, Asparagales): A new species from the Sierra Madre Occidental, Jalisco, Mexico

Echinoagave nievesiorum (Agavaceae, Asparagales), a new species endemic to the Sierra Wixárika (Huichola), part of the Sierra Madre Occidental, Jalisco, Mexico, is described. This species shares morphological characteristics with Echinoagave rzedowskiana but it differs from the latter by having narrower and striate leaves; leaf sheaths shorter, triangular and wider at the base; narrower ovary width; shorter tube length; tepal lobes at anthesis converging and tightening the filaments; larger filament length to flower length ratio; fruiting spikes thicker and denser with the peduncle covered by the capsules and the bracts usually deciduous; capsules broadly ellipsoid with dorsally blackish valves. A distribution map with biogeographic provinces is provided to place the species in an ecological and evolutionary context.

An experimental investigation on the effects of the vortex tube material, swirl generator material and the tube length to diameter ratio on vortex tube performance

The current research investigates the effects of the swirl generator material, the tube length to diameter (L/D) ratio, and the vortex tube housing material on its performance. Two vortex tube were designed and constructed using either stainless or brass. In addition to testing different materials for the housing, 5 different materials were examined as potential options for the swirl generator, including stainless steel, brass, polyamide, acrylic and wood. All were having nozzle number of 6. The study encompassed three main areas: examining the impact of various L/D ratios on an entirely stainless vortex tube (ESVT) and an entirely brass vortex tube (EBVT), exploring various swirl generator materials at an optimal L/D ratio for the stainless vortex tube and the brass vortex tube, and investigating the influence of an optimal swirl generator material with varying L/D ratios for the stainless and brass vortex tubes. Operating conditions were controlled for all tests, the natural refrigerant, compressed air was used, the inlet pressure was set to 3.0 bar and the cold mass fraction was varied from 0.40 to 0.90. The results revealed that the performance of the ESVT was greater than the EBVT. The best combination was the polyamide swirl generator and brass vortex tube with an L/D ratio of 19.0. This resulted in the maximum isentropic efficiency of 0.27 at a cold mass fraction of about 0.47.