Tube Angle Research Articles

Collective properties of Petitella georgiae in tube environments

The movement of biological swarms is widespread in nature, and collective behavior enhances a swarm’s adaptability to its environment. However, most research focuses on free swarm movement, overlooking the impact of environmental constraints such as tubes. This study examines the swimming behavior of Petitella georgiae through a tube. Observations of position, speed, and direction reveal that each fish is influenced by the swarm’s distribution in its field of view. The speed ratio between the middle region and edge region positively correlates with tube angles, and higher speeds are associated with higher densities within specific angle ranges.

A Review on Heat Transfer Enhancement in a Heat Exchanger

Compact heat exchanger is commonly used in car radiators which is normally small with low flowrate. To produce a large surface area, thin plates or corrugated fins are attached closely separating the two fluids. Compact heat exchanger is normally used in applications where weight and volume are the significant factors for the enhancement of heat transfer. This paper reviews the research related to the characteristics, advantages and findings on various type of compact heat exchanger. It is found that the geometric parameters such as fin shape, tube shape, fin pitch, tube pitch, tube arrangement, tube angle and vortex generators affect the heat transfer performance in general. The air inlet angle of 45° and common flow upstream gives the optimum heat enhancement in most studies while the most suitable air flow is between 1.8 – 3.8 m/s.

Study on Crashworthiness of Shrink Tube Anti-Creep Device

Based on the requirements of the narrow installation space of a train end, compact energy-absorbing travel, and huge energy suck, a shrink tube anti-creep device was designed. The crashworthiness of different structures was studied by means of a material test, a trolley test, and numerical simulation. For every 1 mm increase in tube wall thickness, 1 mm increase in the axial length of the friction cone, and 0.01 increase in the friction coefficient, the mean crushing force (MCF) increased by 45.1 kN, 13.5 kN, and 30.5 kN, respectively. When the cone angle of the shrink tube increased from α = 5° to α = 25°, the increase in the MCF with different thicknesses was about 600%. The MCF was most affected by the cone angle, followed by the wall thickness, the friction coefficient, and the axial length of the friction cone. The change in the contact length of the friction cone of the shrink tube under different structural parameters was compared. The contact length decreased with the increase in tube wall thickness and increased with the increase in angle. The variation rule of MCF was obtained to provide a reference for the development of genealogical products.

Numerical study of the influence of structural parameters on the performance of annular ejector

Abstract Compared with the central ejector, the annular ejector is widely used in refrigeration, coal mining and chemical industry because the working fluid enters the suction chamber through the annular nozzle, the contact area with the ejection fluid increases, and the ejection fluid does not need to change the flow direction. In order to solve the problem of low performance of annular gas ejector, this paper designs an annular gas ejector with reference to the relevant model, and the axial length and suction angle of the mixing tube of the annular gas ejector are mainly studied. The results show that there is an optimal value for the length of the ring gas ejector mixing tube, and the length of the mixing tube is too long or too short is not conducive to the gas extraction of the ring gas ejector. Under the same annular gap, with the increase of the jet angle, the amount of gas consumed in the primary stream does not change much, and the gas to be pumped decreases, resulting in the performance of the annular gas ejector being reduced, which is not conducive to the suction of the ejector.

Australian radiographers’ digital era practice in selecting the image receptor angle for female body habitus for the mediolateral oblique view of the breast

IntroductionCorrect alignment of the image receptor (IR) in mammography for the mediolateral oblique (MLO) view of the breast is fundamental to enable the maximum inclusion of breast tissue. This study aims to assess Australian radiographers' knowledge and digital era practice in selecting the IR angle for female body habitus in the MLO view of the breast. MethodsAn online survey was distributed to all members of the Australian Society of Medical Imaging and Radiation Therapy (ASMIRT) through their electronic newsletter and via direct email to radiographers holding the Certificate of Mammographic Practice (CMP). Descriptive analysis was undertaken, and a Pearson's chi-squared test of independence was used to compare associations between academic qualification and IR selection data. A value of p < 0.05 was deemed statistically significant. ResultsA total of 107 valid surveys were returned; 67.3 % reported using the posterior lateral margin to select the IR angle. For linear body habitus, 44.9 % reported using 50°; for all other body habitus, participants most commonly used 45° (59.1 %); 85.1 % used a range of angles between 40 and 55°; 16.8 % recognised the link between correct IR angle selection and breast tissue inclusion. ConclusionThe range of angles used in practice has reduced in the digital era; the frequency of the use of 45° across all body habitus may reflect tube angle movement automation. Few radiographers recognised the important link between correct selection of IR angle and breast tissue inclusion on the image. Implications for practiceUnderstanding of the link between IR angle selection and image quality enhances current practice in the digital era to maximise the inclusion of breast tissue and minimise the potential of missed breast cancer.

Patient radiation risk reduction by controlling the tube start angle in single and dual source spiral CT scans: A simulation study.

Organ doses in spiral CT scans depend on the tube startangle. To determine the effective dose in single source CT (SSCT) and dual source CT (DSCT) scans as a function of tube start angle and spiral pitch value to identify the dose reduction potential by selecting the optimal startangle. Using Monte Carlo simulations, dose values for different tube positions with an angular increment of and a longitudinal increment of were simulated over a range of with collimations of , , and . The simulations were performed for the thorax region of six adult patients based on clinical CT data. From the resulting dose distributions, organ doses and effective dose were determined as a function of tube angle and longitudinal position. Using these per-view dose data, the individual organ doses, as well as the total effective dose, were determined for spiral scans with and without tube current modulation (TCM) with pitch values ranging from 0.5 to 1.5 for SSCT and up to 3.0 for DSCT. The dose of the best and worst tube start angle in terms of dose was determined and compared to the mean dose over all tube startangles. With increasing pitch and collimation, the dose variations from the effective dose averaged over all start angles increase. While for a collimation of , the variations from the mean dose value stay below for SSCT, we find that for a spiral scan with a pitch of 3.0 for DSCT with TCM and collimation of , the dose for the best starting angle is on average lower than the mean value and lower than the maximumvalue. Variation of the tube start angle in spiral scans exhibits substantial differences in radiation dose especially for high pitch values and for high collimations. Therefore, we suggest to control the tube start angle to minimize patientrisk.

High Resolution Computed Tomography Study of the Length, Width & Angle of Eustachian Tube in Normal Ear and in Chronic Otitis Media.

Eustachian tube is complex and inaccessible structure. It connects nasopharynx to middle ear. It is composed of cartilaginous and bony segments. Eustachian tube helps in pressure regulation, protection and clearance of the middle ear. Dysfunctions of Eustachian tube are either due to anatomical obstruction or functional failure. Whether variation of length, width of bony canal, isthmus, length of the cartilaginous canal and angulation of the Eustachian tube to horizontal plane affects overall pressure regulation, protection and mucociliary clearance leads to the spread of the infection to the middle ear are highlighted. A comparative prospective study design of 20 adults of both gender of normal ear computerized tomography done for some other cause and 20 adults of both gender with chronic otitis media (tubo-tympanic pathology). After obtaining consent, clinical examination, all patients had got computerized tomography study of the temporal bone and were evaluated to study the variation of length, width of bony canal, isthmus, length of the cartilaginous canal and angulation of the Eustachian tube to horizontal plane. In our series cartilaginous Eustachian tube length is 26.72mm in normal ear and 26.17mm in diseased ear. Long and reduced diameter of bony segment is the anatomical cause in the tubotympanic pathology along with inflammation and loss of ciliary moment. Normal ear bony width is 2.36mm; isthmus 1.18mm are comparatively more than diseased ear (bony width 2.13 & isthumus1.04). Whereas bony length of normal ear is 11.21mm and diseased ear is 11.62mm. Decreased Eustachian tube pretympanic diameter and Reid -plane ET angle can be used to predict Eustachian tube dysfunction. Angle to horizontal plane in our series in normal ear 44.670 whereas in diseased ear 45.10. The Eustachian tube plays an important role in the development of the tubotympanic pathology of the ear. Pre-existing Eustachian tube anatomical variation appears to be risk factor in developing tubotympanic pathology.

纵轴流玉米锥形脱粒装置优化设计与仿真分析

Aiming at the high crushing rate and impurity rate of corn kernel machine harvesting in the Huanghuaihai region, a longitudinal flow conical variable pitch threshing device is designed, which adopts the combined threshing element of "plate teeth + ribs" and the combined threshing concave plate of "leftward round tube type + vertical round tube type". The cob model was established, and the force analysis of the cob threshing process was carried out, and the type of threshing drum and the installation angle of the threshing concave plate round tube were determined as the main influencing factors, and the collision force on the corn cob was taken as the test index. Using EDEM discrete element simulation software, simulation tests were carried out on different types of threshing drums and threshing concave plates with different installation angles of round tubes with corn cobs, and the better threshing method was finally determined: a conical threshing drum at a drum speed of 450 r/min, and a combination of left-facing round-tube-type+vertical round-tube-type threshing concave plates with an installation angle of 10° (front-sparse and back-dense type) were used. Compared with the vertical circular tube type threshing concave plate, the corn cob contact force decreased from 313.5N to 247.3N, which was optimal for threshing in the range allowed by the corn kernel destructive force.

Instability and breakup of rayleigh-plateau jets with capillary wave induced by electrowetting-on-dielectric

This paper discusses the lateral disturbances of vertical liquid flow enhancement using electrowetting-on-dielectric (EWOD) technique, which effectively reducing the breakup length of the liquid flow and minimizing the formation of satellite droplets. The EWOD technology is characterized by its minimal space occupation and low energy consumption. The successful implementation of the EWOD phenomenon relies on the formation of a three-phase contact line (TPCL) between the electrodes and the liquid, and the novel EWOD tube structure design provides an extended TPCL, enhancing the amplitude of capillary waves. Through experimental and theoretical analysis, this paper identifies key parameters affecting the liquid breakup process, such as the gap depth, angle of the EWOD tube, EWOD voltage amplitude, and frequency of the AC electrical signal. The research results indicate that the proposed EWOD tube responds rapidly and can consistently and stably manage liquid breakup and reduce the number of satellite droplets.

Numerical investigation of hydrogen ignition induced by unsteady flow phenomena

The purpose of the present study is to evaluate the possibility of using a gas dynamic heater as an igniter of the combustible gas mixtures. The impacts of some operating and geometrical parameters on average temperature of the gas dynamic heater are investigated by numerical simulation of axisymmetric turbulent flow in the resonance tube. The operating gas of the heater is air which is completely decoupled from the ignition chamber. The combustible mixtures under consideration is stoichiometric hydrogen-oxygen at atmospheric pressure, in which the ignition is studied solving the governing equations for one dimensional reacting flow using detailed chemistry. The finite volume method is used in the presently developed flow solver for numerical simulations. The results show that despite highly fluctuating temperature of the end wall of the resonance tube as a hot surface, it can provide proper condition for gas mixture ignition in the chamber, by adjusting an inlet pressure and geometry of the gas dynamic heater. The end wall average temperature depends on the nozzle inlet pressure and convergence angle of the resonance tube, and the results demonstrate that the characteristics of temperature time history of repeating cycles are so effective on ignition process.

Computational investigation and optimization of the bulb turbine for ultra-low head application

The Indian River, which is celebrated for its breathtaking beauty and diverse heritage of cultures, has an extensive amount of potential for producing green hydroelectric electricity. 7.5 % of the world's energy came from renewable sources in 2022, with India making up 36 % of the share and growing. India has nearly reached the 5 GW objective for small hydro projects and has reached 68 % of its 175 GW renewable energy ambition. At 90 % efficiency, bulb turbines are hydroelectric turbines that produce power from water, making them a perfect choice for high flow rates and low water head conditions. In order to optimize bulb turbines, this research investigates the use of computational fluid dynamics (CFD) to assess variables including the number of guiding vanes, the angle of the draft tube, and the design of the blades. According to studies, efficiency is increased when guiding vanes increase. The geometry of guiding vanes also has a significant impact on performance. Draft tubes, which restore kinetic energy from water entering the turbine, can enhance efficiency with proper design. Adding anti-cavitation capabilities to runner blades improves performance even further. CFD models verify these conclusions, with little variations from the field data. By fine-tuning important parameters such as 14 guiding vanes and adjusting the draft tube angle to 2.5°, the turbine's efficiency jumped from 87 % to 97 %.

Load–slip behavior of steel bearing–square reinforced concrete column connection joints with adhesive bonding and self-locking

The connection joint between a steel beam and a reinforced concrete (RC) column is crucial for strengthening and renovating the existing buildings; hence, designing simple, safe, and reliable connection joints is necessary. This study proposed a novel steel bearing–square RC column connection joint with adhesive bonding and self-locking and investigated seven half-scale connection joints with variable joint configurations under vertical loads. The typical failure modes, load–slip behavior, interfacial shear stress, and slip stiffness were analyzed through a parametric study of the taper angle of the square tube, the height of the steel bearing (i.e. contact area between the tube and the concrete), the structural adhesive, and the type of steel bearing surrounding the RC column. The results demonstrated that for a steel bearing–square RC column connection joint with adhesive bonding and self-locking, the typical failure process included at least two load fluctuations with multiple peaks. Moreover, the presence of adhesive bonding substantially improved the slip stiffness of the connection joint specimen relative to specimens with only self-locking. Additionally, the taper angle of the square tube influenced slip stiffness; however, the influence of the taper angle decreased with increasing contact area. Finally, regardless of the surrounding type and taper angle, the first peak load increased with the larger contact area, and the type of steel bearing surrounding the RC column had an obvious influence on slip stiffness. Furthermore, a finite element model was proposed to simulate the working performance of the proposed connection joint based on experimental data. The simulation showed that joint failure occurred mainly owing to the buckling of the vertical stiffeners and the outward deformation or tearing of the square rings, and the tilting of the joint due to local falling off of the structural adhesive must be prevented.

Heat transfer characteristics of the air-oil heat exchanger with spiral tube

The cooling problem of hot-end components has become an important factor restricting the aero-engine performance, life and reliability. In order to improve the cooling quality of the cooling air, the supercritical aviation kerosene was used as a heat sink to cool the cooling air in a spiral heat exchanger. The flow and heat transfer process of the air-oil heat exchanger with spiral tube were numerically simulated using Fluent software. The flow and heat transfer situation of air and aviation kerosene were analyzed in detail. The optimized spiral heat exchanger with the diaphragm was presented to enhance the heat transfer capacity of the air side. It is found that the heat transfer performance of the air-oil heat exchanger is greatly enhanced by the spiral tube due to the secondary flow effect. With the increase in the turning angle of the spiral tube, the effect of the secondary flow for the heat transfer enhancement is strengthened. The PEC index of the spiral heat exchanger increases with the increase in the air flow rate. The spiral heat exchanger with the diaphragm can effectively improve the heat transfer performance of the heat exchanger, and increase the PEC index of the air side by more than 20%.

Influence of the Tube Angle on the Measurement Accuracy of Peri-Implant Bone Defects in Rectangular Intraoral X-ray Imaging.

Intraoral radiography in the right-angle technique is the standard procedure to examine the peri-implant bone level in implant follow-up and implant-related studies. For the implementation of the right-angle or parallel technique, mostly ready-made image receptor holders are used. The aim of this experimental study is to analyze changes in the measurement of standardized peri-implant defects caused by a deviation in the position of the image receptor. Eleven Xive® implants (Dentsply Sirona, Bensheim, Germany) were placed in bovine bone, and peri-implant defects of varying depths were created. The preparations were fixed in a specially made test stand, and intraoral radiographs were taken using the right-angle technique with standard film holders at various horizontal and vertical projection angles. Defect measurement was carried out with the imaging software Sidexis 4 V 4.3 (Dentsply Sirona, Bensheim, Germany). With increasing angular deviation, larger deviations between the measured and the real extent of the defect occurred. Vertical tilting caused significant distortion, while horizontal rotation showed less effect. Intraoral radiography only provides a valid representation of the peri-implant bone level for follow-up or as a tool in implant-related studies if a reproducible projection direction is assured.

Tribocharging of granular materials flowing in grounded inclined tubes.

Granular materials charge as they flow through inclined tubes due to the triboelectric effect. This charging persists even when the tube is grounded and is influenced by the tube's angle. In this study, we demonstrate that the tribocharging of granular materials can be accurately replicated through numerical simulations using the patch model. Charge transfers occur between the grains and the tube from donor patches to acceptor patches, ensuring the tube does not retain charge to simulate grounded conditions. Interactions between the grains and the tube are modeled using the method of image charges. We conducted experiments to validate the numerical results. Our findings reveal that the density difference between donor patches on the grains and the tube determines the charge acquired by the granular materials. Additionally, we observed both in experiments and simulations that granular materials charge less with the tube when it is shorter or less tilted. We interpret the influence of the tube's angle and length using the patch model. This model offers valuable insights into the tribocharging mechanisms of various materials.

The Subdiaphragmatic Angle Of The Gastric Tube In Neonates – A Potential Predictor For Perforations?

Abstract Background Traumatic subdiaphramatic perforation of esophagus or stomach in neonates represents a rare clinical complication following the insertion of a gastric tube and is associated with high morbidity and mortality. The aim of the present study was to evaluate whether the angle of the gastric tube depicted on a plain radiograph may serve as a diagnostic tool to predict subdiaphragmatic traumatic (or iatrogenic) perforation. Patients and methods Thoraco-abdominal radiographs of 128 preterm and term neonates without perforation and 15 neonates with perforation of the esophagogastric junction or the stomach were retrospectively analysed. Results The angle of the gastric tube increases with postnatal age (p=0.0380). In the control group, the angle of the gastric tube varied between 13° and 48° (median: 31°), whereas the values ranged from -31° to 42° (median: 11°) in neonates with subdiaphragmatic perforation. Perforation should thus be suspected in cases with an angle of&lt;20° (sensitivity: 93.3%; specificity: 91.4%). Moreover, an unusual localization of the tip beyond the gastric bubble is highly indicative of perforation. Discussion The present study emphasizes the importance of verifying the correct course of an inserted gastric tube. Conclusions In daily clinical practice, an angle of&lt;20° should be followed by thorough physical examination, abdominal ultrasound and if applicable contrast medium examinations to exclude perforation.

Numerical simulation of heat transfer performance of spiral wound heat exchanger under sloshing condition

LNG floating production storage and offloading (FPSO) unit is a new type of floating production unit developed for offshore natural gas fields. It performs the functions of natural gas extraction, pretreatment, liquefaction, and storage. In this study, the heat transfer characteristics of a spiral-wound heat exchanger were studied using numerical simulations, which provides a basis for equipment selection and structural optimization of spiral-wound heat exchangers. The main research contents and conclusions are as follows. Under land-based simulation conditions, the heat transfer coefficient of the shell side of the spiral-wound heat exchanger decreases with an increase in the winding angle of the heat exchange tube, decreases with an increase in the spacing of the heat exchange tube, and increases with an increase in the outer diameter of the heat exchange tube. When the winding angle increased from 5° to 8°, the heat transfer coefficient decreased by 6.70%. The heat transfer coefficient of the shell side decreased by 13.21% when the heat exchange tube spacing increased from 14 to 17 mm. The heat transfer coefficient of the shell side increased by 22.89% when the outer diameter of the heat exchange tube increased from 9 to 12 mm. When the sloshing angle is constant, the heat transfer coefficient of the spiral-wound heat exchanger decreases with an increase in the winding angle and spacing of the heat exchange tubes, and increases with an increase in the outer diameter of the heat exchange tubes. When the structural parameters of the heat exchanger are constant, the heat transfer coefficient decreases as the sloshing angle increases. When the sloshing angle was less than 3°, the sloshing promoted heat transfer on the shell side. When the sloshing angle was higher than 7°, the heat transfer effect of the shell side deteriorated considerably, which weakened the heat transfer performance of the heat exchanger. When the sloshing period is constant, the heat transfer coefficient of the wound heat exchanger decreases with an increase in the winding angle and spacing of the heat exchange tubes, and increases with an increase in the outer diameter of the heat exchange tubes. When the structural parameters of the heat exchanger are constant, the heat transfer coefficient increases with sloshing period. When the sloshing period was greater than 15 s, the influence of sloshing on the heat transfer on the shell side of the heat exchanger was relatively weak.

Energy spectrum measurement of scattered X-rays during IVR procedure.

With the increase of the number of interventional radiology (IVR) procedures, the occupational exposure of operators and medical staff has attracted keen attention. The energy of scattered radiation in medical clinical sites is important for estimating the biological effects of occupational exposure. Recent years have seen many reports on the dose of scattered radiation by IVR, but few on the energy spectrum. In this study, the energy spectrum of scattered X-rays was measured by using a cadmium telluride (CdTe) semiconductor detector during IVR on several neurosurgical and cardiovascular cases. The cumulated spectra in each case were compared. The spectra showed little changes among neurosurgical cases and relatively large changes among cardiovascular cases. This was assumed to be due to the change of X-ray tube voltage and tube angle was larger in cardiovascular cases. The resulting energy spectra will be essential for the assessment of detailed biological effects of occupational exposure.

Simulation and experimental research on luminance uniformity in full-field electroretinogram stimulators

Full-field electroretinogram (ERG) is a technique to study the function of the retina. The Ganzfeld is the stimulator used to provide uniform light for light input to the visual system. This study aims to design an improved stimulator and study the effects of its illumination geometric parameters on luminance uniformity. The developed Ganzfeld model was simulated in software ASAP, and then built in the laboratory. An illumination tube with variable parameters was mounted on the integrating sphere to investigate the effects on luminance uniformity. A linear regression method was applied to predict the relationship between luminance uniformity and illumination geometric parameters using ANOVA analysis. The simulated results were verified by the experiments, showing no significant difference (p < 0.05). Illumination tube diameter and angle show positive effects on the luminance uniformity, while height negatively affects the luminance uniformity. An equation indicating the parameter effects was obtained, and optimized luminance uniformity was calculated.

Torsional mechanical properties and damage mechanism of glass fiber-ramie hybrid circular tube

Compared with other green natural fibers, ramie has higher mechanical properties and lower cost. In this study, ramie and glass fiber are made into composite circular tubes by two-dimensional braiding, and their torsional mechanical properties and damage mechanisms are investigated. The results show that under the unit wall thickness, compared with the pure glass fiber circular tube, the maximum torsion angle of the hybrid circular tube with ramie and glass fiber spindle ratio of 1:3 increases by 78%, the weight is reduced by 22%, the cost is reduced by 14%, the maximum torque is increased by 10% and the torsional stiffness is reduced by 18.75%. When the loading direction is the same as the implantation direction with more glass fiber content, the failure is caused by buckling. When the loading direction is the same as the implantation direction with more ramie content, the failure is caused by matrix fracture or fiber fracture. The numerical simulation results of the damage model are consistent with the experimental data and the damage morphology, which verifies the effectiveness of the finite element model. These conclusions provide a reference for the engineering application of composite circular tubes with environmental protection, lightweight and anti-torsion failure ability.