Fluid-filled Tube Research Articles

Assessing the efficacy of flat-plate solar collectors using nanofluids in the climatic context of Kirkuk city, Iraq

Solar energy is a key renewable energy source. Research and development have focused on enhancing the heat transfer coefficient, heat gain, and practical efficiency of solar systems. The aim of this study is to evaluate the performance of a flat solar panel collector using a nanofluid under conditions in the city of Kirkuk/Iraq, 35° latitude and 45° longitude, in terms of practical calculation of thermal efficiency. The study included making two solar collectors, one traditional and the other improved using a nanofluid (CuO). The CuO/Water nanofluid was prepared with a volumetric concentration of 0.25 % by mechanical mixing and then ultrasonic mixing to homogenise the particles and eliminate the agglomerations that form inside the fluid. Practical testing was conducted for the two solar collectors, one using distilled water and the other using the nanofluid, during four months (January, February, March, and April) of the year 2023. The experiments revealed that the efficiency progressively improves from 9:00 a.m. to 1:00 p.m. This increase is attributed to solar radiation’s decreasing intensity post 12:00 p.m., while thermal storage and minimised thermal losses continue to contribute. After 2:00 p.m., the efficiency dwindles due to the declining solar radiation intensity. The practical efficiency of a 0.25 % nanofluid (CuO) attains its zenith at a mass flow rate of 0.015 ls−1. Higher mass flow rates enhance heat transfer within fluid-filled tubes. The collector efficiency at this flow rate ranges from 31.66 % in January to 44.44 % in April.

Local control of magnetic microbubble behavior by magnetic field and pulsed ultrasound

The localization of magnetic microbubbles (MMBs) to a target site has been shown to be essential to their efficacy in therapeutic applications such as targeted drug delivery and gene therapy. In this work, the MMBs’ dynamic equations of vibration, horizontal and vertical motion in a fluid-filled tube, subject to a magneto-acoustic complex field, are established by Lagrange method. The responses and capture efficiency under three ultrasonic pulses waveform in a magnetic field are numerically analyzed. The regulation effects of the external field are observed by experiments. The results show that the transport behavior is influenced by bubble size, original position, liquid flow rate, tube diameter, parameters of acoustic and magnetic field. For the same acoustic parameters, square wave pulse can make stronger vibrate compared with cosine wave and sawtooth wave, which pushes MMBs closer to the magnet. In addition, high frequency and large amplitude pulse are benefit to translation, and increasing the cycle number in a single pulse can also promote translation. In practical applications, variable parameters such as bubble speed and magnet length can be used to improve the capture efficiency. The observations of high-speed camera are consistent with the prediction of theoretical model, which indicates the model is mostly correct.

The modulations of higher order solitonic pressure and energy of fluid filled elastic tubes

In this article, we investigate the weak higher order nonlinear solitonic pressure waves in elastic, incompressible, nonviscous fluid-filled tubes. The higher order Korteweg–de Vries equation has been developed from the perturbed nonlinear equation. The dependence of higher-order solitonic pressure, higher order fluid velocity, and higher order solitonic energy on the nonlinear coefficient and the perturbation parameter has been established. The presented solutions will be more beneficial in the several disciplines of blood flow and many other related fields of applied science.

Multistable Metafluid based Energy Harvesting and Storage.

The thermodynamic properties of fluids play a crucial role in many engineering applications, particularly in the context of energy. Fluids with multistable thermodynamic properties may offer new paths for harvesting and storing energy via transitions between equilibria states. Such artificial multistable fluids can be created using the approach employed in metamaterials, which controls macro-properties through micro-structure composition. In this work, the dynamics of such "metafluids" is examined for a configuration of calorically-perfect compressible gas contained within multistable elastic capsules flowing in a fluid-filled tube. The velocity-, pressure-, and temperature-fields of multistable compressible metafluids is studied by both analytically and experimentally, focusing on transitions between different equilibria. The dynamics of a single capsule is first examine, which may move or change equilibrium state, due to fluidic forces. The interaction and motion of multiple capsules within a fluid-filled tube is then studied. It shows that such a system can be used to harvest energy from external temperature variations in either time or space. Thus, fluidic multistability allows specific quanta of energy to be captured and stored indefinitely as well as transported as a fluid, via tubes, at standard atmospheric conditions without the need for thermalisolation.

Visualizing endoscopy-generated aerosols with laser light scattering (with videos)

Background and AimsUpper GI endoscopy is speculated to be an aerosol-generating procedure (AGP). Robust evidence exists for aerosol transmission of severe acute respiratory syndrome coronavirus 2. The quality of data available confirming aerosol generation during GI endoscopy is limited. We aimed to objectively demonstrate that GI endoscopy is an AGP and illustrate the mechanism by which the greatest risk for aerosolization of droplets during endoscopy may occur.MethodsAerosolized droplets generated during insertion and withdrawal of an endoscope and with passage of various tools through the endoscopic working channel using 2 experimental apparatuses modeling an upper GI tract (ie, a fluid-filled tube and a lamb esophagus) were qualitatively assessed by laser light scattering.ResultsInsertion and withdrawal of the upper endoscope into the upper GI tract models generated numerous aerosolized particles. A large number of brightly scattering particles were observed at the site of insertion and withdrawal of the endoscope. Passage of a cytology brush, biopsy forceps, and hemostatic clip through the working endoscope channel also generated aerosolized particles but in fewer numbers. There was no significant variation in quantity or brightness of droplets generated on testing different biopsy valve cap models or when suctioning fluid with an open versus closed biopsy valve cap. These results were reproducible over several trials.ConclusionsWe illustrate in an objective manner that upper GI endoscopy is an AGP. These findings may have implications for transmission of infectious airborne pathogens outside of severe acute respiratory syndrome coronavirus 2 and can help to inform guidance on appropriate personal protective equipment use and other measures for transmission risk mitigation during GI endoscopy.

The acoustic radiation force on a multi-layered polymer capsule placed in a fluid-filled tube

Acoustic manipulation has a series of application in biomedicine, colloidal assembly, and chemistry. A three-layered polymer capsule is generally used structure in manipulation system because it has better protection to the core filled drug or compounds and possesses higher flexibility. In this paper, a theoretical model of acoustic radiation force acting on a three-layered drug capsule in a vessel is established. The acoustic radiation force on a capsule, which comprises of a drug core, a poly(lactide-co-glycolide) mid shell and a chitosan outer shell in the cylindrical tube filled with ideal fluid, is calculated using acoustic wave theory. The influences of the tube, the surrounding fluid and the geometric size of chitosan, poly(lactide-co-glycolide) shell and drug core on acoustic radiation force are investigated. The numerical simulations based on finite element method are introduced to compute the acoustic radiation force and compared with the analytical results. Moreover, the comparison among the capsule in impedance tube, in rigid tube and in unbounded space is obtained simulating specific environment. Simulation results show that the influences of the rigid tube on the acoustic radiation force of the capsule can be ignored when the capsule is much smaller than the radius of the tube. With the increase of the capsule radius, the acoustic radiation force of the capsule changes demonstrably with the frequency and the tube radius because of the influence of the reflective wave resulted from the inner surface of the tube. The properties of the surrounding fluid affect the position of the resonant peaks. Outer radius and mid layer radius have more effects on the acoustic radiation force, but the drug core radius almost exerts no effect on it. The study illustrates that the capsule can be manipulated by acoustic wave with the suitable selection for the outer or mid shell radii, and the selection of drug core radius is of more freedom in this process.

Magnetic Soft Robot With the Triangular Head–Tail Morphology Inspired By Lateral Undulation

In this article, extend the uses of a deformable structure of magnetic elastomer to develop a bio-inspired locomotion system for millimeter-scaled robots. As proposed in other researches, this material allows a possibility of the motor-less mechanism powered by magnetic field. The actuating mechanism of the robot mainly relies on the body deformation due to magnetic alignment. On the other hand, herein, the magnetic soft robot with the triangular head-tail morphology and sine-based magnetization utilizes a high degree of freedom provided by magnetic compliance for mobility in a form of lateral undulation. Under the oscillating magnetic field, dynamic torque primarily acts to the head, the tail passively waves, and the whole body propagates a series of lateral body-waves for self-propulsion in fluid, instead of pushing out surrounding fluid to make a swimming gait. We achieve the independent control of the laterally undulating robot in force-free swimming, and demonstrate its tunable body deformation to swim in various diameters of the fluid-filled tubes. A by-product of the undulation can transfer a force rate to swim through the fabric-media. By the increase of the actuating frequency, the undulating robot propels faster to retain a stable swimming in the flow. The versatilities of the robot with the proposed mechanism can be applied to serve the diverse purposes as a reliable and effective locomotion system with a minimal control. Particularly in biomedical applications, miniature soft robots with a potential mechanism for self-propulsion can contribute the great results to pursue minimally invasive treatments.

Design of 2D Sparse Array Transducers for Anomaly Detection in Medical Phantoms.

Aperiodic sparse 2D ultrasonic array configurations, including random array, log spiral array, and sunflower array, have been considered for their potential as conformable transducers able to image within a focal range of 30–80 mm, at an operating frequency of 2 MHz. Optimisation of the imaging performance of potential array patterns has been undertaken based on their simulated far field directivity functions. Two evaluation criteria, peak sidelobe level (PSL) and integrated sidelobe ratio (ISLR), are used to access the performance of each array configuration. Subsequently, a log spiral array pattern with −19.33 dB PSL and 2.71 dB ISLR has been selected as the overall optimal design. Two prototype transducers with the selected log spiral array pattern have been fabricated and characterised, one using a fibre composite element composite array transducer (CECAT) structure, the other using a conventional 1–3 composite (C1–3) structure. The CECAT device demonstrates improved coupling coefficient (0.64 to 0.59), reduced mechanical cross-talk between neighbouring array elements (by 10 dB) and improved operational bandwidth (by 16.5%), while the C1–3 device performs better in terms of sensitivity (~50%). Image processing algorithms, such as Hough transform and morphological opening, have been implemented to automatically detect and dimension particles located within a fluid-filled tube structure, in a variety of experimental scenarios, including bespoke phantoms using tissue mimicking material. Experiments using the fabricated CECAT log spiral 2D array transducer demonstrated that this algorithmic approach was able to detect the walls of the tube structure and stationary anomalies within the tube with a precision of ~0.1 mm.

Characterization and dynamical stability of fully nonlinear strain solitary waves in a fluid-filled hyperelastic membrane tube

We first characterize strain solitary waves propagating in a fluid-filled membrane tube when the fluid is stationary prior to wave propagation and the tube is also subjected to a finite stretch. We consider the parameter regime where all traveling waves admitted by the linearized governing equations have nonzero speed. Solitary waves are viewed as waves of finite amplitude that bifurcate from the quiescent state of the system with the wave speed playing the role of the bifurcation parameter. Evolution of the bifurcation diagram with respect to the pre-stretch is clarified. We then study the stability of solitary waves for a representative case that is likely of most interest in applications, the case in which solitary waves exist with speed c lying in the interval [0, c_1) where c_1 is the bifurcation value of c, and the wave amplitude is a decreasing function of speed. It is shown that there exists an intermediate value c_0 in the above interval such that solitary waves are spectrally stable if their speed is greater than c_0 and unstable otherwise.

Equations Describing Waves in Tubes with Elastic Walls and Numerical Methods with Low Scheme Dissipation

Equations for a tube with elastic waves (tube with controlled pressure, fluid-filled tube, and gas-filled tube) are considered. A full membrane model and the nonlinear theory of hyperelastic materials are used for describing the tube walls. The Riemann problem is solved, and its solutions confirm the theory of reversible discontinuity structures. Dispersion of short waves for such equations vanishes; for this reason, dissipative discontinuity structures can be included. The equations under examination are complicated due to which general numerical methods are developed. Application of the centered three-layer cross-type scheme and schemes based on the approximation of time derivatives using the Runge–Kutta method of various orders is considered. A technology for correcting schemes based on the Runge–Kutta method by adding dissipative terms is developed. In the scalar case, the third- and fourth-order methods do not require correction. The possibility of using terms with high-order derivatives for computing solutions that simultaneously include dissipative and nondissipative discontinuities is analyzed.

Impulsive Motion in a Cylindrical Fluid-Filled Tube Terminated by a Converging Section

The syringe in a subcutaneous auto-injector may be subjected to internal pressure transients due to the normal operation of the injection mechanism. These transients are similar to transients in fluid-filled pipelines observed during water hammer events. In this paper, the effect of an air gap in the syringe and a converging section is studied experimentally and numerically in a model system which consists of a fluid-filled metal tube that is impulsively loaded with a projectile to simulate the action of the auto-injector mechanism operation. The air between the buffer and the water results in a complex interaction between the projectile and the buffer. Also, there are tension waves inside the tube due to the presence of a free surface and the motion of the buffer, and this causes distributed cavitation which, in turn, gives rise to steepening of the pressure waves. The converging section can amplify the pressure waves if the wave front is sharp, and it can enhance the collapse of bubbles. Pressures as high as 50 MPa have been measured at the apex of the cone with impact velocities of 5.5 m/s.

Suction forces generated by passive bile bag drainage on a model of post-subdural hematoma evacuation.

Passive drainage systems are commonly used after subdural hematoma evacuation but there is a dearth of published data regarding the suction forces created. We set out to quantify the suction forces generated by a passive drainage system. We created a model of passive drainage after subdural hematoma evacuation. We measured the maximum suction force generated with a bile bag drain for both empty drain tubing and fluid-filled drain tube causing a siphoning effect. We took measurements at varying heights of the bile bag to analyze if bile bag height changed suction forces generated. An empty bile bag with no fluid in the drainage tube connected to a rigid, fluid-filled model creates minimal suction force of 0.9mmHg (95% CI 0.64-1.16mmHg). When fluid fills the drain tubing, a siphoning effect is created and can generate suction forces ranging from 18.7 to 30.6mmHg depending on the relative position of the bile bag and filled amount of the bile bag. The suction forces generated are statistically different if the bile bag is 50cm below, level with or 50cm above the experimental model. Passive bile bag drainage does not generate significant suction on a fluid-filled rigid model if the drain tubing is empty. If fluid fills the drain tubing then siphoning occurs and can increase the suction force of a passive bile bag drainage system to levels comparable to partially filled Jackson-Pratt bulb drainage.

"Moneyball" Comes to Replantation: How We Assess Our Work: Commentary on an article by Hongyi Zhu, MD, et al.: "Patency Test of Vascular Anastomosis with Assistance of High-Speed Video Recording in Digit Replantation".

Commentary In the 50-plus years of replantation surgery, the “strip test” has been the universal, manual observational test of vessel patency. All other downstream evaluations with pulse oximetry, ultrasonic flow metering, laser Doppler scanning, and/or capillary refill testing are preceded by, and predicated on, a successful strip test of the vessel. A successful test denotes appropriate directional flow through the repair. Patency of the repair is the near-term outcome sought by the surgeon who creates a microvascular anastomosis with the operating microscope. Modern dual-head, binocular operating microscopes are equipped with electronic controls for 2-axis motion, focus, light intensity, and video monitoring with high-definition video cameras that can grab single freeze-frames of images. Experienced surgeons can look at a microsurgical anastomosis of either vein or artery and evaluate the quality and dimension of the repair. Once happy with the coaptation of vessel walls, the spacing of the sutures, and the parallel nature of the lumens both upstream and downstream, they are then ready for the next functional test. The strip test is that functional test and requires an experienced eye to judge the speed and volume of blood with which the deflated vessel fills. The surgeon’s overall perception or gestalt of the repair can be tempered or even impaired by unseen biases that shape the surgical experience. The number of times the repair was revised, the hour of the night, the third digit being replanted rather than the first, or the level of expertise of the assistant or the surgical technician can alter the overall judgment of the quality of the test. In the 2003 book Moneyball: The Art of Winning an Unfair Game, Michael Lewis described new analytical methods used in baseball to quantify what experienced scouts, coaches, and pundits were subjectively observing1. Zhu and colleagues have applied a similar quantifiable approach to the strip test to predict outcome. They used an off-the-shelf, consumer-grade, high-speed digital camera with close-up lenses to concurrently capture their observations. In real time, they applied a numeric value to what was previously the subjective judgment of the surgeon in declaring a vessel suitable for adequate flow to keep the replant viable. The strip test is not without its risk. The applied pressure can damage the intima of the vessel and should be kept to a minimum. The authors’ method of evaluation took me <1 hour to prepare following their text. I used the same camera, which I already possessed and was familiar with. I tested the method using a microscope and a fluid-filled tube. They developed the idea and set out to use it in a busy clinical practice of replantation. They created a model that gave some prediction as to whether or not they and their patient would enjoy a good result. Once a certain threshold during collection in the repaired vessels had been reached in the strip test, they could stop repairing and move to the next phase of the surgery. With replants there is much to accomplish. Being sure of the quality of the strip test is time well spent. Microscopic robotics have yet to be proven of value in the mainstream of replantation procedures. However, we now have a reliable microscopic, visual assessment tool to measure our work in a consistent fashion. Better patient outcomes will hopefully prevail, as the universally applied strip test has a quantifiable and visually measurable result in digit replantation. This evaluation paves the way for a more standard comparison of surgeons and their repairs. Late at night and far into the case, it is a reasonable end point to achieve. Electronically assisted microsurgery is starting with a high-speed digital video assessment of surgical repair.

Stability of solitary waves in membrane tubes: A weakly nonlinear analysis

We study the problem of the stability of solitary waves propagating in fluid-filled membrane tubes. We consider only waves whose speeds are close to speeds satisfying a linear dispersion relation (it is well known that there can be four families of solitary waves with such speeds), i.e., the waves with small (but finite) amplitudes branching from the rest state of the system. In other words, we use a weakly nonlinear description of solitary waves and show that if the solitary wave speed is bounded from zero, then the solitary wave itself is orbitally stable independently of whether the fluid is in the rest state at the initial time.

Wave generation and source energy distribution in cylindrical fluid-filled waveguide structures

The paper deals with an analytically based computer simulation of wave fields generated by a monopole source in a multilayered fluid-filled tube waveguide in an elastic or porous-elastic space. The mathematical problems considered relate to various practical applications ranging from a micro scale for fibers and nano-tubes to a macro scale for seismo-acoustics and well production. To be specific, the presentation is given for borehole waveguides, aiming at estimating the efficiency of an in-hole source for various surrounding media. The time-harmonic and transient solutions are obtained in terms of inverse Fourier integrals. The tube, body, and leaky waves propagating from the source to infinity are derived from those path integrals as an asymptotic contribution of the residues, stationary points, and approaching complex poles and stationary points. On this basis, the wave energy radiation from the source, which is dependent on the geometry and material properties of a cased fluid-filled borehole and formation, is numerically studied. The analysis is focused on the peculiarities of the source power distribution among the generated waves as well as between the radial and axial directions of wave propagation. A qualitative difference in source energy radiation modes for hard and soft environments and the role of leaky waves in the power transport into a soft formation are discussed. The emergence of additional tube waves due to a fluid saturation of porous interlayers is revealed.

Dynamics of Wave Propagation Across Solid–Fluid Movable Interface in Fluid–Structure Interaction

A theoretical model for wave propagation across solid–fluid interfaces with fluid–structure interaction (FSI) was explored by conducting experiments. Although many studies have been conducted on solid–solid and fluid–fluid interfaces, the mechanism of wave propagation across solid–fluid interfaces has not been well examined. Consequently, our aim is to clarify the mechanism of wave propagation across a solid–fluid interface with the movement of the interface and develop a theoretical model to explain this phenomenon. In the experiments conducted, a free-falling steel projectile was used to impact a solid buffer placed immediately above the surface of water within a polycarbonate (PC) tube. Two different buffers (aluminum and polycarbonate) were used to examine the relation between wave propagation across the interface of the buffer and water and the interface movement. With the experimental results, we confirmed that the peak value of the interface pressure can be predicted via acoustic theory based on the assumption that projectile and buffer behave as an elastic body with local deformation by wave propagation. On the other hand, it was revealed that the average profile of the interface pressure can be predicted with the momentum conservation between the projectile and the buffer assumed to be rigid and momentum increase of fluid. The momentum transmitted to the fluid gradually increases as the wave propagates and causes a gradual decrease in the interface pressure. The amount of momentum was estimated via the wave speed in the fluid-filled tube by taking into account the coupling of the fluid and the tube.

Исследование моделей, описывающих распространение волн в трубе с упругими стенками при наличии заполнения ее жидкостью и газом

Исследование моделей, описывающих распространение волн в трубе с упругими стенками при наличии заполнения ее жидкостью и газом

Application of the theory of reversible discontinuities to the investigation of equations describing waves in tubes with elastic walls

Abstract Equations which describe the propagation of waves in tubes with elastic walls are investigated, methods for calculating them are developed, and solutions containing reversible discontinuity structures are analysed in the case of a fluid-filled tube. The model of a tube with elastic walls constructed on the basis of the complete model of a membrane and the non-linear theory of elasticity is generalized. The viscosity and compressibility of the material, the possibility of filling the tube with a gas, and the flexural rigidity of the tube walls are taken into account. The problem of the decay of an arbitrary discontinuity is solved numerically in the case of a fluid-filled tube. The results obtained correspond to the previously developed theory of reversible discontinuities. Simplified hyperbolic equations of long waves, as well as equations for small-amplitude waves which do not take into account longitudinal elastic waves and are similar to the Boussinesq equations, are derived for cases when a tube is filled with a liquid and a gas. The possibility of overturning of the waves is analysed. A procedure for correcting the numerical schemes by adding terms with high-order derivatives to the equations is developed, and the order of approximation of the numerical scheme remains unchanged, enabling the performance of calculations with low schematic dissipation.

Endovascular placement of an extraluminal arterial bypass graft – in vitro feasibility study

Purpose: A novel approach for arterial bypass grafting using exclusively endovascular techniques was established in-vitro in a phantom model.Material and methods: The experimental setting consisted of a gel-wax phantom with two embedded parallel fluid-filled silicon tubes simulating the superficial femoral vessels. Through an 8-French sheath, a re-entry catheter (OUTBACK®, Cordis) was placed in the simulated artery and used to puncture the vascular wall. Then a 0.014-inch guide wire was advanced into the extravascular space. With the curved needle of the re-entry catheter, the guide wire was steered on a course parallel to the vessel wall in the extravascular space for 5-10 cm. At the desired reentry site, the re-entry catheter was used to puncture the vascular wall again in order to regain access to the endovascular space. Once the tip of the guide wire had safely been placed in the vascular lumen, a self-expandable stent graft (VIABAHN® GORE®) was deployed to complete the extraluminal bypass.Results: Endovascular placement of an extraluminal bypass was successfully achieved in 20 attempts. The mean duration of the procedure amounted to 14:58 (minutes: seconds) (SD ± 3:56).Conclusions: This in-vitro study suggests that endovascular placement of an extraluminal arterial bypass graft is technically feasible.

A Study of Acoustic Wave Resonance in Water-Filled Tubes With Different Wall Thicknesses and Materials

Acoustic resonance of a fluid-filled tube with closed and open outlet ends for zero and turbulent mean flows is investigated both experimentally and numerically for different wall materials and thicknesses. The main goal is to create a data bank of acoustic wave resonance in fluid-filled tubes at a frequency range of 20–500 Hz to validate and verify numerical prediction models used by the nuclear industry and to determine if there is a better method with existing technology. The experimental results show that there is a strong effect of turbulent flow, wall material, and wall thickness on resonant amplitudes at frequencies above ∼250 Hz. A numerical investigation is performed solving the linear wave equation with constant and frequency-dependent damping terms and a computational fluid dynamic (CFD) code. Comparing the one-dimensional (1D) and CFD results shows that CFD solution yields better predictions of both resonant frequency and amplitude than the 1D solution without the need for simplified added damping methods, which are required by the 1D methodology. This finding is valid especially for frequencies higher than ∼300 Hz.