Tubular Device Research Articles

Enhanced photothermoelectric conversion in self-rolled tellurium photodetector with geometry-induced energy localization

Photodetection has attracted significant attention for information transmission. While the implementation relies primarily on the photonic detectors, they are predominantly constrained by the intrinsic bandgap of active materials. On the other hand, photothermoelectric (PTE) detectors have garnered substantial research interest for their promising capabilities in broadband detection, owing to the self-driven photovoltages induced by the temperature differences. To get higher performances, it is crucial to localize light and heat energies for efficient conversion. However, there is limited research on the energy conversion in PTE detectors at micro/nano scale. In this study, we have achieved a two-order-of-magnitude enhancement in photovoltage responsivity in the self-rolled tubular tellurium (Te) photodetector with PTE effect. Under illumination, the tubular device demonstrates a maximum photovoltage responsivity of 252.13 V W−1 and a large detectivity of 1.48 × 1011Jones. We disclose the mechanism of the PTE conversion in the tubular structure with the assistance of theoretical simulation. In addition, the device exhibits excellent performances in wide-angle and polarization-dependent detection. This work presents an approach to remarkably improve the performance of photodetector by concentrating light and corresponding heat generated, and the proposed self-rolled devices thus hold remarkable promises for next-generation on-chip photodetection.

Abstract 2031: Supramolecularly Fabricated Non-thrombogenic Small Diameter Vascular Graft

Background: Small diameter (<6mm) arterial reconstruction often requires the use of autologous and synthetic vascular substitutes. While autologous conduits are the gold standard, because of their limited availability synthetic conduits are often used. However, synthetic conduits can lead to poor outcomes due to thrombosis and lumen occlusion occluding the lumen and result in graft failure. By modulating the biopolymer properties of the synthetic conduits, graft failure can be prevented. In this study, we present a thromboresistant synthetic vascular graft (zetagraft) fabricated with tunable biopolymers for small diameter arterial reconstructions. Methods: Zetagrafts were fabricated by the solvent extraction driven self-assembly using a concentric tubular assembly device using polyvinyl alcohol dissolved in dimethyl sulfoxide (15% w/v). We characterized the physicochemical and mechanical properties of zetagraft by fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), optical and scanning electron microscopy, and tensiometry. In-vitro studies were performed on the zetagraft using fibroblast, HUVEC and MVEC cell lines. Ex vivo hemocompatibility analysis was performed with fresh porcine blood. The zetagrafts were implanted in a rat aorta replacement model to evaluate its thromboresistance. Results: The zetagraft was uniform, highly stretchable, and self-healing when punctured with a needle. Blood circulation followed by FT-IR and XRD analysis showed no protein adsorption on the luminal surface. Immuno fluorescence staining revealed the absence of platelet and blood cell adsorption on the zetagraft lumen, demonstrating its thromboresistance. In vivo implantation of the zetagraft in rat abdominal aorta replacement model revealed the absence of thrombosis and other blood component adsorption on the zetagraft lumen. Conclusions: Advances in material science allow for fabrication of more tunable biocompatible small vascular grafts. In this study we demonstrated the development of a thromboresistant zetagraft. Our early results are very promising and zetagraft will provide a novel small vascular graft and thus fulfil an important unmet clinical need.

Structural design and performance optimization of Co/Bi0.5Sb1.5Te3 artificially tilted multilayer thermoelectric devices

Due to the complex principle of transverse thermoelectric conversion and the specific preparation technique, there are few studies on the three-dimensional structure of artificially tilted multilayer thermoelectric devices (ATMTDs), which also lags the development of ATMTDs for applications. It is necessary to optimize the three-dimensional structure of ATMTDs to satisfy the requirements of practical applications in thermal sensors, power generation, refrigeration, and so on. In this paper, Co/Bi0.5Sb1.5Te3 ATMTDs are selected as the research object. A COMSOL Multiphysics simulation analysis and experimental validation are used to establish the relationship between the structure and its thermal sensing, power generation, and cooling performance. Results indicate that increasing the length significantly improves the thermal response voltage. Increasing the length and width enhances output power while increasing the height of the ATMTD improves the thermoelectric conversion efficiency. The effective cooling temperature improves when the heat transfer area decreases or the height increases. Based on these findings, flexible thin-film thermal sensors, high-efficiency waste heat power generation tubular devices, and high-efficiency refrigeration pyramidal devices are designed. The results will lead to effective optimization and promote the multi-field application of ATMTDs.

Propose of a low cost integrating sphere

This paper proposes the development of a low cost integrating sphere used for measuring flux characteristics and luminous spectrum lamps. The proposal provides the use of alternative materials as well the replacement of measuring high level equipment for more practical and common hardware accessories, providing a reduction in the cost of development. The objective is to minimize the cost of light sources assays, currently with a high cost, for research purposes, educational issues and the opportunity to use this alternative system for validation of new products, light bulbs and/or tubular daylighting devices for lighting indoors.

Dependence of changes in the nominal heat flow of tubular heating devices on their design features

The article is devoted to determining the nominal heat flow of a steel tubular heating device depending on the location of the pipes (vertical or horizontal), the number and diameter of pipes, as well as the value of the heat transfer coefficient. The main advantages and disadvantages of steel tubular heating devices are given. It has been determined that the mode of heat flow along the pipes in a tubular heating device changes from laminar to turbulent. As a result of the research, it was found that with a vertical arrangement of pipes in a heating device, when the coolant temperature in the pipes is 90-95°C, the height of the transition zone from laminar flow to turbulent flow varies in the range from 0.75 m to 1.25 m. If the tubular heating device is structurally made with horizontally located pipes, then the transition from the laminar flow regime to the turbulent regime is not observed. A dependence has been derived that allows one to determine the nominal heat flow of a steel tubular radiator depending on the height, number of sections, as well as the design features of the tubular heating device. A comparative analysis of changes in the nominal heat flow of a tubular heating device was carried out depending on the height, number of sections, design features, as well as the orientation of the pipes in the section. The nominal heat flux of a tubular radiator varies depending on the orientation of the pipes. It is shown that with a vertical arrangement of a tubular radiator, the value of the nominal heat flux exceeds the same value with a horizontal arrangement.

Comparative analysis of tubular daylighting device performance with acrylic and glass domes

Various materials have been utilized to enhance the performance of Tubular Daylighting Devices (TDDs) while maintaining cost-effectiveness. This study conducted a comparative experimental investigation to expose the relationship between dome materials and TDD performance. The experimentation took place during the summer in an arid region characterized by abundant sunlight and atmospheric pollutants. The results reveal that the glass dome experiences up to 13 % loss in incident daylight, while the acrylic dome demonstrates a more pronounced reduction at 30 %, which emphasizes the critical role of dome material in assessing TDD performance. Both dome types preserve the high-quality characteristics of daylight in terms of its spectrum. Moreover, the study reveals the complex interaction between solar altitude and transmittance ratio, showing how dome design can significantly shape this relationship. The transmittance patterns exhibited by both domes hold promise for optimizing daylight utilization across diverse scenarios, necessitating a careful balance between capturing low-angle sunlight and controlling high-angle sunlight entry. Given the arid environmental conditions of the experiment, the study also examined the impact of dust accumulation on TDDs performance. Over a span of 58 days, exposure to weather led to a notable reduction in illumination transmittance ranging from 26.6 % to 30.3 %. The glass dome displayed a 14 % greater reduction in transmittance ratio compared to the acrylic dome. This study emphasizes the pivotal role of dome materials in shaping TDD performance. The insights garnered from this research serve as a valuable guide for designing TDDs that maximize their potential in various applications and environmental contexts.

РЕКОНСТРУКЦИЯ ПНЕВМАТИЧЕСКОГО ПЕРЕМЕШИВАЮЩЕГО УСТРОЙСТВА

The article analyzes the features of the use of pneumatic mixing in the chemical industry, the ad-vantages and disadvantages of this method. The basic designs of equipment for pneumatic mix-ing and its calculation are considered. A variant of reconstruction of a pneumatic mixing device in a reactor for bitumen production is being considered to improve the quality of mixing and re-duce energy and material costs. Instead of a tubular bubbling device, it is proposed to use a gas-lift type device

Feasibility Study of Tubular Daylighting Device for an Office Building at Pune

This paper depends on the reason that energy streamlining is conceivable in places of business through plan of daylighting the inspiration for the review was brought into the world of the way that in India, among all structure typologies, business structures burn-through the most extreme energy. This energy utilization is mostly for cooling of the building and lighting the inside spaces. Cooling and illuminating spaces creates heat in and around the structure, which again expands the cooling load. Out of the all-out electrical energy needed in the structure, around 20- 40% is utilized for lighting purposes. Not withstanding accessibility of sunlight during the functioning hours, fake lighting is utilized in workplaces that have tremendous inward spaces with enormous ranges. This paper points at understanding the elements identified with sunlight infiltration into place of business in various circumstances and creating rules for accomplishing greatest sunshine infiltration in enormous spaces.

Daylight performance of collector-diffuser combinations in light pipe systems at different geographical locations

Incorporating daylight inside occupied spaces has several benefits, including reduced lighting load, improved mental and physical health of occupants, and increased productivity during working hours. Several Innovative daylighting systems that utilize advanced technologies and design approaches are devised and tested to bring natural light into occupied spaces. Amongst them, the Tubular Daylighting Devices (TDD) have immense potential to trap the sunlight and carry it to enclosed/dimly lit areas, especially in tropical climates.The careful selection of system components dictates TDD's spatial and temporal illumination performance. The present study aims to analyze and correlate the performance of various TDD systems with different collector-diffuser configurations widely reported in the literature and used commercially. The study uses the Daily Useful Daylight Illuminance (DUDI) paradigm and uniformity criterion to assess the performance of carefully chosen collectors, namely, hemispherical dome, prismatic dome, and faceted collector, with the selected diffusers: flat plate acrylic, hemispherical dome, flat prismatic, and flat Fresnel lens. The study encompasses the identification, modeling, and simulation of different configurations throughout the year at four chosen cities in India. Results indicate that the maximum and average lighting level measured is high in the case of the hemispherical collector when paired with flat diffusers at all seasons and cities considered for the study. A matrix of different configurations of system components is tabulated for each location based on a predefined criterion. The increase in diameter of the tube improved the lighting level above 150 lx even at a distance of 1.5 m from the center, and splitting the light pipe into two pipes of an equivalent cross-sectional area improved the end illumination levels at the periphery of the room (10–25 %) making it better in terms of both illuminance and uniformity when paired with hemispherical/faceted collector and flat diffuser.

Miniaturized enantioselective tubular devices for the electromechanical wireless separation of chiral analytes

Chirality plays a crucial role in different research fields, ranging from fundamental physico-chemistry to applied aspects in materials science and medicine. In this context, enantioselective loading and pumping of chiral analytes for analysis, separation, and cargo delivery applications is an interesting scientific challenge. Herein, we introduce artificial chiral soft electromechanical pumps based on a bi-layer film built up by electrodepositing polypyrrole and an inherently chiral conducting oligomer at its internal surface. The enantioselective device can be driven by bipolar electrochemistry to act as a pump, allowing the selective loading and separation of different chiral analytes injected as pure enantiomers and in racemic form (i.e., doxorubicin, a chemotherapy drug, limonene, carvone, and a chiral ferrocene). The synergy between wireless electromechanical actuation and inherent enantiodiscrimination features makes these actuators excellent candidates for the controlled handling of chiral molecules in the frame of potential applications ranging from analysis to drug delivery.

Comprehensive investigation on lighting and energy-saving performance of lighting/heating coupled tubular daylighting devices integrated with nanofluids

Feasible regulation of the solar visible and infrared spectrum is a promising technology for energy-efficient buildings. Our recently published work has proposed a lighting/heating coupled tubular daylighting devices (LH-TDDs) integrated with nanofluids to track the trade-off between indoor visible light gain and near-infrared shielding and demonstrated its excellent lighting/heating decoupling performance. To further evaluate the application potential of the LH-TDDs, the present work develops a comprehensive evaluation method that considers both lighting and energy-saving performance. In detail, the LH-TDDs system was investigated using both the numerical models and Energyplus software. The results on lighting performance demonstrate that the filtration of nanofluids hardly affects the lighting quality of LH-TDDS, but will instead enhance lighting uniformity and lessen glare risk. Meanwhile, the energy consumption simulations indicate that LH-TDDs achieve energy saving from three approaches, namely, lighting energy saving, thermal energy output, and air-conditioning energy-saving, and 100 ppm nanofluid can improve the total energy-saving amount by 43.6 % in Harbin, China. The findings of this paper can accelerate the application of LH-TDDs, and the evaluation system elaborated in this work may provide some useful clues for the assessment of other nanofluids-based transparent envelopes.

Gestational environmental enrichment prevents chronic social stress induced anxiety- and ethanol-related behaviors in offspring

Epidemiological surveys have shown a strong relationship between maternal stress and offspring's mood disorders. Growing evidence suggested that environmental enrichment (EE) improves cognitive function in models of psychiatric and neurological disorders. However, the potential protective effects of gestational EE on social stress-elicited mood disorders in offspring have not been studied. Knowing that the undeveloped brain is more sensitive to gestational environmental stimuli, we hypothesized that initiating cognitive stimulation, during gestation, would protect against social stress-induced behavioral alterations in adulthood. Therefore, the present study aimed to investigate the effects of gestational EE on social stress-elicited anxiety- and ethanol-related behaviors in adult offspring. EE consisted of free access, of dams, to tubular devices of different shapes, colors, and sizes that were changed regularly. After birth and weaning, young adult offspring were exposed to 19 days of social stress and anxiety-like behavior was evaluated by elevated plus maze, open field, and marbles burying tests. The two-bottle choice (TBC) drinking paradigm was used to assess stress-induced ethanol intake. Results showed that gestational EE prevented social stress-elicited anxiogenic-like effects with no differences in spontaneous locomotor activity. Moreover, in the TBC paradigm, mice pre-exposed to EE consistently showed a significantly decreased consumption and preference for ethanol with no effects on tastants' intakes. Interestingly, gestational EE increased serum BDNF levels, which showed a correlation with measures of anxiety- and ethanol-related behaviors. These findings indicate that some neurodevelopmental changes associated with prenatal EE may counteract adult social stress-induced behavioral alterations through a BDNF mechanism. Therefore, we propose that gestational EE has significant protective and beneficial effects on social stress-induced cognitive impairment. It can also alleviate anxiety-like behavior and subsequent excessive alcohol consumption.

Wave energy conversion using a small tubular free-floating device

Wave energy conversion using a small tubular free-floating device

Influence Analysis of Impeller-Guide Vane Matching on Energy and Pressure Pulsation in a Tubular Pump Device

Tubular pump devices offer advantages such as low hydraulic losses, a simple structure, and easy maintenance. They find extensive application in areas such as irrigation, flood control, and water diversion. The performance and security of the pump are directly impacted by the contact between the impeller and guide vane. The matching relationship between the number of impeller blades and guide vanes significantly influences this interaction in tubular pump devices. To explore this impact, a Very-Large-Eddy Simulation turbulence model was employed to simulate the 3D flow fields of six different number matching relationships in a shaft tubular pump device. The analysis focused on the energy performance of the different schemes, the flow distribution of the guide vanes, and the velocity circulation at the guide vanes’ outlet. Entropy theory and energy gradient theory were employed to understand how the number matching relationship influences energy performance. Additionally, pressure pulsations were analyzed at the impeller and guide vanes for different matching configurations. The results indicate that although increasing the number of impeller blades can lead to higher water circulation, increased energy, and potentially unstable water flow, an increase in impeller blades number results in improved flow distribution in each guide vane groove, leading to an overall enhancement in the efficiency of the pump device. Similarly, increasing the number of guide vanes may increase the non-uniformity of the guide vane flow rate, but it also enhances the ability of the guide vanes to regulate water circulation and recover energy, thereby benefiting the overall efficiency.

Spatiotemporally Controllable Chemical Delivery Utilizing Electroosmotic Flow Generated in Combination of Anionic and Cationic Hydrogels

AbstractSpatiotemporally controlled chemical delivery is crucial for various biomedical engineering applications. Here, a novel concept of electrically controllable delivery utilizing electroosmotic flow (EOF) generated in a combination of anionic and cationic hydrogels (A‐ and C‐hydrogels) is reported. The unique advantages of the A/C‐hydrogel combination are demonstrated utilizing a flexible sheet‐shaped and a thin tubular devices. Since the directions of EOF in the A‐ and C‐hydrogels are opposite to each other, the ionic current for EOF generation flows inside the delivery devices, enabling chemical delivery without accompanying external ionic current that could stimulate target cells and tissues. A thin tubular device, which can be inserted into narrow in vivo structures and be integrated with other flexible devices, exhibits high robustness and repeatability thanks to the flexibility and water retentivity of hydrogels. The EOF devices with A/C‐hydrogels combination show high controllability superior to the pumping with a conventional syringe; the volumetric flow rate is able to be controlled proportionally to the current applied, for example, ≈0.4 µL (mA min)−1 for the tubular device. The developed EOF‐based devices are versatile for delivery of most chemicals regardless of their charge and size, and have great potential for both biomedical researches and therapeutics.

Research on Optimization of the Bulb Form of the Bulb Tubular Pump Device for a Low-Head Agricultural Irrigation Pumping Station

A bulb tubular pump unit is a horizontal tubular pump unit composed of a water pump and bulb with an electric motor installed. Electric motors, transmission equipment, and bearings are usually placed in the bulb. The bulb is located in the flow channel and has a relatively narrow space. Therefore, the shape of the bulb has a significant influence on the flow pattern and pump efficiency in the flow channel. In this study, the CFX 19.2 software was employed to optimize the bulb hydraulically according to its geometry and parameters. The research results indicate that the flow pattern at the tail of the elliptical bulb was better, the hydraulic loss at the bulb section was small, and the device efficiency was higher than that at the tail, which was round. The streamlined support had small flow resistance, minimal hydraulic loss, and a high pump unit head and efficiency. Nine schemes were selected, and the geometrical characteristics and parameters of the bulb were determined as follows: the shape of the tail of the bulb was oval, the bulb ratio was 0.96, and the shape of the support parts was streamlined. The results hold important reference significance to improve efficiency and broaden the operating conditions of bulb tubular pump devices.

Hemodynamic effects of a dielectric elastomer augmented aorta on aortic wave intensity: An in-vivo study

Dielectric elastomer actuator augmented aorta (DEA) represents a novel approach with high potential for assisting a failing heart. The soft tubular device replaces a section of the aorta and increases its diameter when activated. The hemodynamic interaction between the DEA and the left ventricle (LV) has not been investigated with wave intensity (WI) analysis before. The objective of this study is to investigate the hemodynamic effects of the DEA on the aortic WI pattern. WI was calculated from aortic pressure and flow measured in-vivo in the descending aorta of two pigs implanted with DEAs. The DEAs were tested for different actuation phase shifts (PS). The DEA generated two decompression waves (traveling upstream and downstream of the device) at activation followed by two compression waves at deactivation. Depending on the PS, the end-diastolic pressure (EDP) decreased by 7% (or increased by 5–6%). The average early diastolic pressure augmentation (Pdia¯) increased by 2% (or decreased by 2–3%). The hydraulic work (WH) measured in the aorta decreased by 2% (or increased by 5%). The DEA-generated waves interfered with the LV-generated waves, and the timing of the waves affected the hemodynamic effect of the device. For the best actuation timing the upstream decompression wave arrived just before aortic valve opening and the upstream compression wave arrived just before aortic valve closure leading to a decreased EDP, an increased Pdia¯ and a reduced.WH.

Study on the Energy Loss Characteristics of Shaft Tubular Pump Device under Stall Conditions Based on the Entropy Production Method

This study aimed to reveal the energy loss characteristics of each part of the shaft tubular pump device (STPD) under stall conditions. Numerical simulations were conducted by using the SST k-ω turbulence model with curvature correction, and the reliability of the simulation results was verified by a model test. The entropy production method was used to evaluate and visualize the energy loss. The results show that turbulent entropy production (TEP) is the main source of energy loss in each component of the STPD, and the TEP increases significantly with the deterioration of stall. The energy loss in the impeller is mainly concentrated near the shroud and hub, while in the guide vanes it is mainly concentrated near the shroud and suction surface of the blades. In addition, with the deterioration of stall, the energy loss in the inlet of the impeller and guide vanes increases significantly. Influenced by the backflow from the impeller, there is a significant amount of energy loss at the outlet segment of the inlet passage, and the location of the high-energy-loss region is consistent with the backflow region. Affected by the flow separation vortex at the tail of the guide vanes, the energy loss in the outlet passage is mainly concentrated at the inlet segment.

Study of Energy Loss Characteristics of a Shaft Tubular Pump Device Based on the Entropy Production Method.

The unstable flow of a shaft tubular pump device (STPD) leads to energy loss, thereby reducing its efficiency. The aim of this study is to investigate the distribution pattern of energy loss in STPDs. This paper reveals that the two components with the highest proportion of energy loss are the impeller and the outlet passage. Furthermore, turbulent entropy production is the primary cause of energy loss. Due to the wall effect, the energy loss in the impeller mainly occurs near the hub and shroud. Additionally, the presence of a tip leakage vortex near the shroud further contributes to the energy loss in the region near the shroud. This results in the energy loss proportion exceeding 40% in the region with a volume fraction of 14% near the shroud. In the outlet passage, the energy loss mainly occurs in the front region, with a volume fraction of 30%, and the energy loss in this part accounts for more than 65%. Finally, this study reveals the locations of the vortex in the STPD under different flow-rate conditions, and when the distribution of energy loss is visualized, it is found that the energy loss occurs high in the vortex regions.

Leakage Flow Characteristics in Blade Tip of Shaft Tubular Pump

The shaft tubular pump device is widely used in various water diversion projects because of its ultra-low head and large flow characteristics. Due to the tip clearance between the blade and the shroud, it is easy to cause hydraulic mechanical performance changes, induced vibration, and noise, which seriously affects the safe and stable operation of the pump. Steady and unsteady three-dimensional flow field numerical simulations of a shaft tubular pump device were carried out using computational fluid dynamics to investigate the impeller flow properties of the device under various flow conditions, including the tip clearance leakage flow (TCLF) and change rule of pressure pulsation. The TCLF, vortex morphology evolution, and pressure pulsation properties of the impeller tip clearance were analyzed. The results show that with an increase in the flow rate, the influence of the tip clearance size on the tip clearance flow decreases, the TCLF decreases, and the axial velocity of the water flow at the tip clearance increases. When the flow rate increases, the swirling strength of the tip leakage vortex decreases, and the distance between the tip leakage vortex and the suction surface of the blade increases. With the increase in flow rate, the pressure pulsation amplitude at the tip clearance increases first and then decreases. The focus of this study is to analyze the variation of tip clearance flow field and pressure pulsation under multiple working conditions, aiming to provide some help for improving the performance of the pump device and ensuring its safe operation.