Narrow Tube Research Articles

Secondary pollinators contribute to reproductive success of a pink-flowered sand verbena population.

Secondary pollinators contribute to reproductive success of a pink-flowered sand verbena population.

Evaluation of Ultrasonic Sensor for Precision Liquid Volume Measurement in Narrow Tubes and Pipes

The introduction of computer vision and machine learning into agricultural systems has produced significant new opportunities for high precision application of liquid products in both grain and livestock agriculture. These technologies, which enable liquid application in site-specific, non-broadcast applications, are driving new evaluations of nozzle technologies which apply a consistent dose of liquid product in a non-conventional manner compared to historic perceptions. This field of innovation is driving the need for improved high-capacity systems for evaluating nozzle performance in high-precision applications. Historically, patternator tables with volumetric measurements of total applied liquid have served as the standard for fluid nozzle evaluation. These volumetric measurements are based on measuring the displaced distance of liquid over a defined time to determine flow rate. However, current distance sensors present challenges for achieving small-volume measurements and enabling automation at a scale necessary to meet innovation demands of high-precision nozzle systems. A novel concept for high speed and automated measurement of a high precision patternator table was developed using an ultrasonic sensor and a carefully designed liquid retainment system to maximize measurement precision. The performance of this system was quantified by comparing calibrations and performance across different vessels for volume measurement (tubes and pipes) used in the application of a nozzle patternator. A total of three square tubes (15.9, 22.3, 31.0 mm widths) and three pipes (25.2, 27.0, 35.1 mm diameters) were evaluated, with the 27 mm pipe matching the ultrasonic sensor’s rating. All calibrations were successful, depicting linear characteristics with R2 > 0.99. The smallest pipe presented issues for the sensor to measure in post-calibration and was thus not evaluated further. The residual values from operational performance highlight that the 25.2 mm tube and the 27.0 mm pipe are highly accurate with no indication of bias or non-normality. The relative uncertainty ranges from 2.9 to 42% (350 mL to 25 mL) depending on the tube and pipe cross-sectional diameter or width with the sensor accuracy and uncertainty in the tube and pipe area being the largest factors. The results of this study indicate that the 25.2 mm tube and the 27.0 mm pipe could be excellent options for autonomous liquid volume measurement with the ultrasonic sensor. A key challenge identified in this study is that the assumptions in the sensor’s intrinsic calibration are violated with the tubes and pipes evaluated.

The impact of endoplasmic reticulum morphology on IRE1 protein clustering.

The Unfolded Protein Response (UPR) is a signaling network that responds to an increased load of unfolded proteins within the Endoplasmic Reticulum (ER), referred to as ER stress. ER stress activates the transmembrane signaling protein IRE1, which subsequently forms oligomers and clusters with signaling activity that modifies target gene expression to reestablish ER homeostasis. Experiments have shown that IRE1 clusters can have complex shapes that form along the ER tube structure, including wrapping around an ER tube, and suggest that IRE1 protein clusters tend to be found on narrower ER tubes. However, the influence of ER morphology on the dynamics of these IRE1 clusters remains largely unexplored. We quantitatively modeled the dynamics of IRE1 protein clusters on a tubular surface, using a kinetic Monte Carlo algorithm that treats the IRE1 proteins as particles undergoing stochastic diffusion. We show that cluster shape exhibits a phase transition from approximately round clusters to clusters that wrap around the ER tube as a cluster becomes sufficiently large or on sufficiently narrow tubes. These wrapped clusters, which easily form on narrow tubes, evaporate much slower compared to circular clusters of equal size that form on larger tubes. The threshold concentration between cluster growth and decay is also lower for wrapped clusters compared to circular clusters, exhibiting greater stability of wrapped clusters under varying cellular concentrations of IRE1. This modeled behavior aligns with experimental observations and suggests cluster wrapping around the ER tube is important to understanding IRE1 cluster dynamics and corresponding signaling. UPR malfunction is implicated in the development of many diseases including neurodegeneration and cancer. By furthering understanding of IRE1 protein clustering, we gain insight into how ER morphology controls the IRE1 behavior and impacts UPR signaling

Specific features of focused electron beam transport through a narrow metal tube at negative potential in the forevacuum pressure range

We describe our investigations on the transport of a focused electron beam through a long and narrow metal tube, held at negative potential with respect to the vacuum chamber walls, in the elevated forevacuum pressure range. We have explored the effect of electron beam parameters and tube potential on beam transport. It is shown that the strength of this effect is connected to the initiation of a non-self-sustained glow discharge within the tube, as well as to the beam magnetic focusing parameters. We also show that increase in the fraction of electrons transported through the tube is conducive to uniformity of the distributions of the non-self-sustained discharge current and the discharge plasma density along the tube length.

Tube geometry controls protein cluster conformation and stability on the endoplasmic reticulum surface.

The endoplasmic reticulum (ER), a cellular organelle that forms a cell-spanning network of tubes and sheets, is an important location of protein synthesis and folding. When the ER experiences sustained unfolded protein stress, IRE1 proteins embedded in the ER membrane activate and assemble into clusters as part of the unfolded protein response (UPR). We use kinetic Monte Carlo simulations to explore IRE1 clustering dynamics on the surface of ER tubes. While initially growing clusters are approximately round, once a cluster is sufficiently large a shorter interface length can be achieved by 'wrapping' around the ER tube. A wrapped cluster can grow without further interface length increases. Relative to wide tubes, narrower tubes enable cluster wrapping at smaller cluster sizes. Our simulations show that wrapped clusters on narrower tubes grow more rapidly, evaporate more slowly, and require a lower protein concentration to grow compared to equal-area round clusters on wider tubes. These results suggest that cluster wrapping, facilitated by narrower tubes, could be an important factor in the growth and stability of IRE1 clusters and thus impact the persistence of the UPR, connecting geometry to signaling behavior. This work is consistent with recent experimental observations of IRE1 clusters wrapped around narrow tubes in the ER network.

Transient dynamics of pressure-driven encroachment in narrow conduits with rate-dependent body force

We analytically explore the flow of a Newtonian liquid forced to encroach a narrow tube of uniform cross section, by an unsteady pressure gradient, assisted by an encroachment-rate dependent external force. This novel problem is thought to have interesting implications. For instance in medicine where narrow tubes like syringes and needles are typically used to administer medication and in the printing industry. Using an unsteady eigenfunction expansion, the velocity distribution is accurately defined to yield unsteady profiles, contrasting with the classical Poiseuille parabola. We subsequently used our unsteady spectral decomposition to properly capture the kinematics and dynamics hidden in the models. By a detailed comparison between rectangular and circular channels, we show that such model ducts yield interesting similarities that can inform the choices of channels. Moreover, we obtain short and long-time dynamic behaviors, captured using a robust perturbation scheme that elegantly highlights the early and long-time characteristics. In the end, we present plots for encroachment depth and rate and the early and long-term asymptotic approximations and appropriately their graphical trends.

Gastric perforation after endoscopic sleeve gastroplasty: a case report of a rare but dangerous complication.

Background: Alternative and less invasive methods for laparoscopic sleeve gastrectomy include endoscopic sleeve gastroplasty (ESG), where the stomach is transformed into a narrow tube by using an endoscopic suturing device. Despite satisfying weight loss results, severe adverse events, including gastric perforation, have occurred. Case Presentation: This case report describes a 38-year-old woman with acute abdominal pain four days after ESG. An emergency laparoscopic exploration revealed a stomach perforation fixed to the anterior abdominal wall by a suture anchor of the gastroplasty. Conclusion: A full-thickness perforation harming neighboring organs and structures is a possible complication after ESG. Therefore, this procedure should only be performed if morbidity can be monitored during the procedure to avoid situations where dangerous complications remain unrecognized for too long.

FLOW BOILING HEAT TRANSFER AND HEAT CONDUCTION ANALYSIS OF HIGH-POWER ELECTRONIC DEVICES

A flow boiling experiment in a narrow channel was conducted using subcooled water. Moreover, the experimentally measured heat flux of the channel was applied for the heat conduction analysis of insulated gate bipolar transistors (IGBTs). The relationship between the heat flux and the temperature difference was investigated experimentally, ranging from nonboiling to boiling in the narrow tube. The boiling heat transfer in the fully nucleate boiling region was validated by comparing with the Rohsenow correlation. Moreover, the measured critical heat flux (CHF) agreed with the Hall and Mudawar correlation within ± 15%. The heat conduction analysis of an IGBT module with a heatsink was solved using the measured heat flux in the narrow channel as a boundary condition, applied from the nonboiling region to the film boiling region. The thermal resistance of the material was obtained when the heatsink with narrow channels was modeled. The numerical result indicated that the thermal resistance of the material was influenced by the heat transfer process of the cooling channel.

Why the Funnel in Neurosurgery?

According to Cambridge Dictionary, Funnel is an object that has a wide round opening at the top, sloping sides, and a narrow tube at the bottom, used for pouring liquids or powders into containers with narrow necks.From an semplified anatomic point of view, the skull base along with its offshoot, the spine, replicate a bone funnel as a vessel sustaining the brain, the cerebellum and the spinal cord along with cranial and radicular nerves. Non doubt at all that the knowledge of the embryology, anatomy, physiology, pathophysiology and the more effective surgical pathways to engage and remove surgical diseases is of paramount importance in the surgical cultural heritage to be strongly encouraged and supported in young neurosurgeons.So to the steps that seem to emerge from this Issue of Acta Neurochirurgica suppl are exploratory, strategic, tactical and finally operational. From the skull base to the sacrum we meet a macrosystem of anatomic and functional complex network with a common embryological hystory as well as contiguity. Different skills are necessary to face with a 360° universe of functions and diseases to deal with. Intelligence and culture as knowledge of both anatomy and pathology help to elaborate the STRATEGY while technical and manual supports are part of the TACTIC armamentarium which is proactive and determinant to the final OPERATIONAL step.

Suspended in sound: New constraints on isotopic fractionation of falling hydrometeors using acoustically levitated water droplets

AbstractThe isotopic composition of precipitation (δ18O, δ2H, and δ17O) is affected by evaporation and exchange as hydrometeors descend. These processes can significantly alter the isotopic ratio of precipitation relative to its initial condensation state in the cloud yet are exceedingly difficult to study in situ. The most widely utilized model for droplet‐atmosphere exchange was derived from controlled experiments where droplets were suspended by forced air in a narrow glass tube‐ a design that manipulated the structure of the boundary layer around the droplet. Here, we provide a novel experimental test of atmosphere‐hydrometeor isotopic exchange using the mechanism of acoustic levitation, where sound waves are projected vertically to levitate droplets in free‐flowing ambient air. We present results from a series of droplet levitation experiments where the droplets' surface temperatures were measured by a thermal camera and the background atmospheric isotope concentration was measured via cavity‐ringdown spectroscopy, providing a high degree of constraint on the fractionation conditions. We show that isotope enrichment of the suspended droplets met first order expectations based on existing models. However, to account for the slope of δ18O versus δ2H (i.e., the meteoric water line) and deuterium excess of the droplets as they evolved, we had to modify the existing model for droplet‐atmosphere exchange to account for the fact that some portion of the evaporative flux from the droplet remained present in the boundary layer around the droplet leading to an evolving feedback between droplet and the atmosphere‐that is, a quasi closed‐system effect. The isotopic enrichment of the boundary layer surrounding the droplet as a consequence of the closed‐system dynamics, drives more rapid δ18O isotope enrichment relative to δ2H of the droplet compared to what is predicted using an open system model. Although these were controlled experiments, they illustrate important dynamics regarding the isotopic signature of feedbacks between droplet evaporation and atmospheric humidity.

Akış Kontrollü Ventilasyon Modu ve Dar Lümenli Tüp Kullanarak Kesintisiz Ventilasyon Yöntemiyle Trakeostomi Açılması: Yeni Bir Yaklaşım

Akış Kontrollü Ventilasyon Modu ve Dar Lümenli Tüp Kullanarak Kesintisiz Ventilasyon Yöntemiyle Trakeostomi Açılması: Yeni Bir Yaklaşım

Effects of the housing system and environmental enrichment on social dominance in laboratory male rats

In laboratory rats, dominance manifests as agonistic behaviour that damages social bonds between individuals. In this study, the effect of the housing system and environmental enrichment on the social dominance in male Wistar rats was assessed in the social dominance tube test. Rats were housed in different housing systems (individual vs. social housing, with or without enrichment) from weaning and tested at the age of 7 weeks. In each test, two rats from different housing systems were released into opposite ends of a narrow tube and the rat that forced its opponent out of the tube was declared the winner (the more dominant animal). In this way, all possible combinations of housing systems were tested and number of wins were recorded and percentage of the total number of matches was calculated. The results show that environmental enrichment suppresses (P < 0.001) dominant behaviour in individually housed rats while no such effect was seen in socially housed male rats (P = 0.532). However, social housing combined with enrichment was more effective in reduction of dominant behaviour compared to only providing enrichment for individually housed rats. Reduction of variability in the manifestations of dominant behaviour is important in animals used for experimental purposes from the perspective of greater homogeneity of animals, which ensures obtaining valid research results and at the same time better living conditions for laboratory animals.

Effect of Acoustic fMRI-Scanner Noise on the Human Resting State

Our knowledge about the human resting state is predominantly based on either electroencephalographic (EEG) or functional magnetic resonance imaging (fMRI) methods. While EEG recordings can be performed in seated posture in quiet conditions, the fMRI environment presents a substantial contrast with supine and restricted posture in a narrow tube that is filled with acoustic scanner noise (ASN) at a chainsaw-like volume level. However, the influence of these diverging conditions on resting-state brain activation is neither well studied nor broadly discussed. In order to promote data as a source of sharper hypotheses for future studies, we investigated alterations in EEG-frequency-band power (delta, theta, alpha, beta, gamma) and spatial power distribution as well as cortical vigilance measures in different postures and ASN surroundings over the course of time. Participants (N = 18) underwent three consecutive resting-state EEG recordings with a fixed posture and ASN setting sequence; seated, supine, and supine with ASN (supnoise) using an MRI simulator. The results showed that compared to seated, supnoise, the last instance within the posture sequence, was characterized by lower power and altered spatial power distribution in all assessed frequency bands. This might also have been an effect of time alone. In delta, theta, alpha, and beta, the power of supnoise was also reduced compared to supine, as well as the corresponding distribution maps. The vigilance analysis revealed that in supine and supnoise, the highest and lowest vigilance stages were more dominant compared to the seated and earliest posture condition within the sequence. Hence, our results demonstrate that the differences in recording settings and progress of time are related to changes in cortical arousal and vigilance regulation, findings that should be taken into account more profoundly for hypothesis generation as well as analytic strategies in future resting-state studies.

Peristaltic transport characteristics of a second-grade dusty fluid flown with heat transfer through a tube revisited

This paper provides a rudimentary insight into the influence of heat transfer on the transport characteristics of a second-grade dusty fluid flown in a flexible tube with walls subjected to the peristaltic motion. Both dust particles and fluid movements were modeled using the coupled differential equations. The effects of different types of parameters such as Reynolds number, Prandtl number, Grashof number, wave number, wave amplitude ratio, second grade parameter as well as nature of the heat source and sink are studies on the dust particles velocity, fluid velocity, temperature, pressure profiles of the fluid and streamline patterns of the fluid. The derived equations were solved analytically via the standard perturbation method to determine the fluid temperature, streamline pattern and velocity of the dust particles as well as fluid. The values in the increase of pressure and frictional forces were calculated numerically using DSolve of the Mathematica 11 software (https://www.wolfram.com/mathematica/new-in-11/). In addition, the trapping mechanisms were ascertained by computing the streamlines and various physical parameters. The obtained results were validated with the state-of-the-art literature reports. It was claimed that our systematic approach may constitute a basis for accurately examining the impact of heat transfer on the peristaltic transport of a complex fluid through narrow tubes, useful for diverse medical applications such as the gastric fluid flow through the small intestine during endoscopy. Numerical results are computed and discussed numerically and presented through graphs. The impacts of pertinent parameters on the aforementioned quantities are examined by plotting graphs on the basis of computational results. The results indicate that the effect of parameters is very pronounced. A suitable comparison has been made with the prior results in the literature as a limiting case of the considered problem.

Numerical prediction of cavitation damage based on shock-induced single bubble collapse near solid surfaces

The prediction of cavitation damage through bubble collapse impact loads (BCIL) is essential, because it opens the opportunity to develop a phenomenological model that can be useful to improve the design process of hydraulic machinery components. Owing to the fast process and small-scale phenomena, direct measurement of the BCIL is greatly challenging if conducted through experimental methods. This study aims to reveal the underlying deformation process of solid materials under a single BCIL using a coupled multi-material hydrocode solver. Three different material constitutive models – purely elastic, elasto-plastic, and strain-hardening – were investigated through various types of metals and polymers. A detached single air bubble was placed near the solid surface inside a long and narrow tube. A planar shockwave was introduced to induce the bubble to collapse, resulting in BCIL that is high enough to cause plastic deformation on the solid surfaces. Measured BCILs from solid material cases show good agreement with the cavitation erosion test result of A1050, SS400, Epoxy resin, PP, and HDPE. These findings indicate that, in the case of metals, the deformation process can be inferred to acoustic impedance since impact energy evaluation shows no significant change when material plasticity is introduced. However, in the case of polymers, the deformation process is greatly influenced by yielding.

The comparison of two microextraction methods for the determination of safranal from Iranian saffron

In this study, safranal as the main component of the pleasant aroma of saffron was extracted and analyzed by two liquid-phase microextraction based methods, namely ultrasound-assisted emulsification microextraction and solidified floating organic drop microextraction. These methods are fast, simple, low-cost, environmentally friendly and efficient procedures that have been developed for the determination of safranal from aqueous samples. Extracted safranal was determined by high pressure liquid chromatography and the performance of the above mentioned methods was compared accurately. A narrow neck glass tube was used for the simple and rapid collection of the low-density organic phase from the sample surface after its centrifugation. A dynamic range over 0.1 to 5 μg mL−1 of safranal and limit of detection of 20 ng mL−1 were obtained for ultrasound-assisted emulsification microextraction. In addition, the dynamic range for solidified floating organic drop microextraction was between 0.02 to 5 μg mL−1 as well as a limit of detection of 3 ng mL−1 was obtained. Furthermore, the enrichment factor and recovery percent were 38 and 101±4.6% in ultrasound-assisted emulsification microextraction besides 252 and 25.2 ± 5.8% in solidified floating organic drop microextraction. The applicability of the proposed methods was evaluated by the extraction and determination of safranal from different Iranian saffron samples and finally, the results were validated by the ISO 3632 procedure.

Unified dynamics of hydrogen–oxygen–diluent detonations in narrow confinements

The present work addresses the interesting question that whether universal relationships can be obtained for characterizing the dynamics of hydrogen–oxygen–diluent detonations in narrow channels and as well in small circular tubes. Theoretically, we first demonstrate the success of adopting the effective induction zone length, which accounts for the leading shock velocity deficits resulting from wall losses, in unifying the quasi-one-dimensional (quasi-1D) detonation dynamics, predicted by the first principles models. These theoretically unified quasi-steady dynamics, irrespective of the geometry dimensions as well as the mixture compositions, are found to be in very good agreement with the large scores of already published detonation experiments in narrow confinements. Moreover, the experimentally unified dynamics of detonations at the macro-scale excellently follow the geometrically expected scaling of 2:1 between the 3D circular tube diameter and the 2D thin channel width results. Such excellent agreement of scaling between theory and experiments not only confirms the negligible role of small-scale cellular structures in the macro-scale propagation mechanism of weakly unstable detonations, but also permits the successful establishment of the universal correlation for characterizing the dynamics of hydrogen detonations in narrow channels and tubes.

TOPOLOGICAL STUDY OF TORSIONAL SPINE MAGNETIC RECONNECTION AT NULL POINT

The spine is an isolated field line which approaches the null (or recedes from it), so called torsional spine reconnection occurs when field lines in the vicinity of the fan rotate, with current becoming concentrated along the spine so that nearby field lines undergo rotational slippage. In of these region, the spine and fan are perpendicular and there is no flux transfer across spine or fan. The geometry of the current layers within which torsional spine reconnection occur is strongly dependent on the symmetry of the magnetic field. Torsional spine reconnection occurs in a narrow tube around the spine, with elliptical crosssection when the fan eigenvalues are different. The eccentricity of the ellipse increases as the degree of asymmetry increases, with the short axis of the ellipse being along the strong field direction. The spatiotemporal peak current, and the peak reconnection rate attained, are found not to depend strongly on the degree of asymmetry.

Seismic behaviour of diaphragm-through bolted-welded joints between CFST column to steel beam

A new generation of through-diaphragm bolted-welded joints between narrow cross-section concrete filled steel tube column to H-beam were developed in this paper. In such joints, the welded connection is adopted in the upper flange of the beam, and the bolted connection is still used in bottom flange and web of the beam. The new structures of through-diaphragm bolted-welded joints were mainly used to solve the problems of reserved installation gaps and smaller joint stiffness of through-diaphragm bolted joints proposed by authors previously. To investigate the seismic behaviour of through-diaphragm bolted-welded joints, this paper presents the details of four new experiments. For comparison, both monotonic and hysteretic loading cases were considered in the experiments. The test results show that through-diaphragm bolted-welded joints have larger stiffness, which can be categorized as rigid joints, and they also have good ductility, satisfactory bearing capacity, stable and effective hysteretic behaviour and desirable energy dissipation capacity.

Focused electron beam transport through a long narrow metal tube at elevated pressures in the forevacuum range

We present here our investigations of the features of focused electron beam transport in free space at elevated pressures of a few pascals. We have explored the effect of the beam accelerating voltage, operating gas pressure, and magnetic focusing upon the trajectory of beam electrons in the crossover region, in particular on the beam convergence and divergence angles. It is shown that for the forevacuum pressure range of 2–5 Pa explored, a distinctive feature of the propagation of a focused electron beam with a current of up to 20 mA at an accelerating voltage of 10–20 kV is the difference in the angles of convergence (before the focus) and divergence (after the focus). Whereas at a low pressure of 2 Pa the divergence angle is smaller than the convergence angle, as the pressure increases the divergence angle increases and for pressures greater than 5 Pa the divergence angle is greater than the convergence angle. The results obtained were used in experiments on electron beam transport through a long narrow metal tube with a diameter of 5.8–9.2 mm and length of 10–30 cm. We show that for a 30 cm long tube of 7.5 mm diameter, the focused beam transmission can exceed 70%.