Low Pressure Vessel Research Articles

Non-Invasive Hemodynamic Monitoring System Integrating Spectrometry, Photoplethysmography, and Arterial Pressure Measurement Capabilities.

Minimally invasive and non-invasive hemodynamic monitoring technologies have recently gained more attention, driven by technological advances and the inherent risk of complications in invasive techniques. In this article, an experimental non-invasive system is presented that effectively combines the capabilities of spectrometry, photoplethysmography (PPG), and arterial pressure measurement. Both time- and wavelength-resolved optical signals from the fingertip are measured under external pressure, which gradually increased above the level of systolic blood pressure. The optical channels measured at 434-731 nm divided into three groups separated by a group of channels with wavelengths approximately between 590 and 630 nm. This group of channels, labeled transition band, is characterized by abrupt changes resulting from a decrease in the absorption coefficient of whole blood. External pressure levels of maximum pulsation showed that shorter wavelengths (<590 nm) probe superficial low-pressure blood vessels, whereas longer wavelengths (>630 nm) probe high-pressure arteries. The results on perfusion indices and DC component level changes showed clear differences between the optical channels, further highlighting the importance of wavelength selection in optical hemodynamic monitoring systems. Altogether, the results demonstrated that the integrated system presented has the potential to extract new hemodynamic information simultaneously from macrocirculation tomicrocirculation.

A novel design of a low-pressure composite vessel with inspection opening – design, manufacturing and testing

Composite structures, especially pressure vessels, pipelines, and additional components such as tees, reductions, or inspection openings are more and more willingly used in the chemical industry. In this research, a novel design of a low-pressure composite vessel with an inspection opening is presented. The vessels are unsymmetrical considering the domes. On one side the opening is considerably bigger, around half of the cylindrical diameter of the vessel. This design requires a new approach to manufacturing such structures. In this study, a two-step analysis was performed. Firstly, small-size pressure vessels (S) were manufactured and the design of dome reinforcement was validated. Then, the final design of vessel (M) was produced, with a volume of around 700 litres. The vessels were initially calculated for 21 bars of burst pressure. During burst pressure tests, the strains were measured with optical fibres (FBG) and strain gauges. Additionally, the acoustic emission was utilized to predict the damage modes and locations. Finally, a microscopic evaluation of the specific parts of the vessels was performed. Conclusions were drawn, that the proposed novel design of dome reinforcement around the inspection opening fulfilled the strength and stiffness requirements.

Isobaric tanks system for carbon dioxide energy storage – The performance analysis

The paper presents the results of thermodynamic and economic analysis of a compressed carbon dioxide energy storage installation using a novel solution, i.e. isobaric carbon dioxide tanks. The solution assumes the installation of low-pressure and high-pressure vessels in such a way that they are isobaric so that during the process of compression and expansion of gas there will be no need to use throttling valves to establish a constant level of pressure before the compressor and expander. The throttling valves using decrease the round-trip efficiency of the system by generating losses in the energy balance. The article presents the results of calculations of tank main geometry features also the pressure dependence of carbon dioxide in the high-pressure tank to the low-pressure tank. Thermal energy storage and a single-stage compressor and expander are considered in the energy storage system. A thermodynamic analysis was carried out to determine the basic parameters of the installation, such as the maximum round-trip efficiency of the energy storage system, which was 76% for 220 kPa in low pressure and 28.2 MPa in a high-pressure tank. The maximum temperature calculated at the compressor outlet was 612 °C. Levelized cost of storage was determined at the level of 593.87€/MWh.

КОРОНАРНО-ПУЛЬМОНАЛЬНАЯ ФИСТУЛА

Coronary arteriovenous fistula (CAF) is a rare form of congenital heart disease. However, it is the most common type of congenital anomaly of the coronary arteries. [1] When there is the connection between the coronary artery and the chambers of the heart, it is called a coronary chamber fistula. The fistula may also be between a coronary artery and another adjacent vessel from the pulmonary or systemic circulation. An open fistula provides low-resistance flow by directing blood from an artery into a vein, heart chamber, or other low-pressure vessel such as the pulmonary artery. Patients with CAF may develop symptoms at birth or later in life, depending on the type of fistula and the presence of collateral circulation. Studies have reported an association between ventricular arrhythmias and sudden cardiac death syndromes in young adults and athletes with certain types of coronary anomalies, such as anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) [2-5]. The most common symptom is a myocardial ischemia. The purpose of this article is to present a clinical case of endovascular treatment of coronary pulmonary fistula. As a result of a modern diagnostic methods, such as CT angiography with three-dimensional reconstruction, it is not difficult to assess the degree and nature of the pathology. Having assessed the tactics, modern doctors are able to cope with coronary arteriovenous fistulas with great success using minimally invasive X-ray endovascular technologies.

Design and calculation of heat transfer of the passive cooling modules for low-pressure hydrogen vessels

This paper deals with the issue of improving the temperature management of a metal hydride tank to reduce the energy intensity of cooling. The problem of absorption and adsorption of hydrogen gas in metals, cooling of metal hydride tanks in the process of hydrogen absorption while protecting the current level of development of science and research for this area is analysed. The work also deals with numerical and experimental verification of a prototype metal hydride tank with passive cooling.

Design of Heat Exchanger for Low-Pressure Vessel for Hydrogen Storage

Design of Heat Exchanger for Low-Pressure Vessel for Hydrogen Storage

Quality Control in Manufacturing Process of Low and Medium Pressure Vessels

Quality Control in Manufacturing Process of Low and Medium Pressure Vessels

Finite Element Analysis of Glass Fiber Winding Molding of HDPE Pressure Vessel

Type IV low-pressure vessel formed by non-geometric winding of glass fiber composite materials are taken as the object. The number of winding layers, winding line type and thickness of the winding layer of the vessel are designed by the method of CADWIND numerical simulation. Finally, with finite element software for stress and strain analysis. The middle part of the pressure vessel is wound in a combination of hoop winding and spiral winding, and finite element modeling is carried out using CADWIND winding professional simulation software. According to the trajectory of non-geometric winding forming, the optimal winding parameters of the composite pressure vessel are determined; the design parameters such as fiber winding thickness, winding angle and number of winding layers are determined. The finite element model of the pressure vessel was established and exported on the basis of CADWIND simulation software, and the finite element simulation software was used to verify and analyze the thickness of the winding layer. The results show that when the internal pressure of 1.5MPa is applied, although the head is easily damaged, it is not enough to make the pressure vessel invalid. The research in this paper can provide reference for the design and use of glass fiber composite material low pressure vessel.

Radiological aspects during cutting and removal of L-08 coolant channel from the core of 540 MWe TAPS-4 nuclear reactor

The pressurized heavy-water reactors (PHWR) consist of a low-pressure horizontal reactor vessel, calandria, containing heavy water as moderator. The calandria is pierced by a large number of coolant tubes (also called pressure tubes [PTs], 392 in 540 MWe PHWR), which contains fuel bundles, and through which pressurized heavy-water coolant circulates. During biennial shut down in 2017, in-service inspection of coolant channels in Tarapur atomic power station-4 (TAPS-4) had been carried out and after the review of results of inspection, it was recommended by various groups of experts that channel L-08 should be removed for postirradiation examination at Bhabha Atomic Research Center (BARC). Before the channel removal job, one special shielding flask was designed to shift the removed channel to BARC. The integrity test of special shielding flask was carried out by safely placing cobalt-60 (source strength 851000 MBq) capsule source inside the shielding flask with the help of cranking unit mechanism followed by dose rate mapping on the outer surface of the flask. To establish the hydrogen pickup rates in L-08 PT, sliver samples were collected and separately sent to BARC. Four metallic sliver samples were obtained at four different distances from north E-face. The activity content present in each sliver sample was also estimated. The maximum activity estimated was 2313.24 MBq. Subsequently, L-08 coolant channel was cut from both sides using a chipless tool. Jobs involving heavy water (D2O) collection work were carried out with a ventilated plastic suit. Derived air concentration (DAC) of tritium at the work location was maintained below 1DAC during the entire activity. Particulate DAC was found below the detectable limit. Floor contamination checks and floor decontamination were conducted at regular intervals to avoid buildup of contamination. As a result of such high-quality radiological safety measures, only 25 workers, out of 270 radiation workers, have received a cumulative dose of more than 3 mSv in direct reading dosimeter with a maximum individual dose of 8.45 mSv and maximum individual uptake of 0.39 GBq/m3. Job was completed with a total collective dose of 324.35P-mSv which is 14.5% lower than estimated. This article highlights some of the critical tasks involved in the cutting and the removal of irradiated coolant channel from the core of 540 Mwe TAPS-4 reactor which is a first of kind activity in nature.

Validation of a Simulation Tool for an Environmentally Friendly Aircraft Cargo Fire Protection System

One of the objectives of the CleanSky-2 project is to develop an Environmentally Friendly Fire Protection (EFFP) system to substitute halon for the aircraft cargo hold. For this, an aircraft demonstrator including the cargo hold was equipped with a nitrogen-based fire suppression system. The demonstrator is located in the Flight Test Facility (FTF) low-pressure vessel and can thus be subjected to realistic cruise pressure conditions and take-off and descent pressure profiles. As a design tool, a zonally refined simulation model to predict the local oxygen and nitrogen concentration distribution in the cargo hold has been developed using the Indoor Environment Simulation Suite (IESS). The model allows for fast transient simulations of the suppression system operation. This paper presents a model validation case of knockdown during cruising, followed by a holding phase and descent.

Validation of the simulation tool for environmentally friendly aircraft cargo fire protection system

One of the objectives of CleanSky-2 project is to develop an Environmentally Friendly Fire Protection (EFFP) system (halon free fire suppression system) for the aircraft cargo hold. For this, an Aircraft Demonstrator including the cargo hold has been equipped with a nitrogen suppression system. The demonstrator is located in the Flight Test Facility low pressure vessel and can thus be subjected to realistic cruise pressure conditions and take-off and descent pressure variations. As a design tool, a zonally refined simulation model to predict the local oxygen and nitrogen concentration distribution in the cargo hold has been developed using the Indoor Environment Simulation Suite (IESS). The model allows for fast transient simulations of the suppression system operation. This paper presents a model validation case of a knockdown during cruise, followed by a holding phase and descent (repressurization of the cargo hold).

Study of spray structure from non-flash to flash boiling conditions with space-time tomography

Flash boiling and plume interaction are common phenomena occurring in gasoline direct injection (GDI) spray at throttling and low load engine conditions. Combined with optical engines and low-pressure vessels, several optical techniques, such as backlight imaging, Mie-scattering, and laser sheet imaging have been employed to study the flash boiling morphology. However, in the 2D images resulting from these techniques (projection views or planar imaging), the 3D information is lost. Those methods are then incapable of providing satisfactory information, especially for the study of multi-plume interaction in flash boiling spray, since multi-plume interaction is not a 2D event. This paper reports the implementation of a 4D tomographic reconstruction method from multi-view diffused back illumination (DBI) images, used for the first time in spray characterization. This cost-effective and time-saving method with a simple experimental setup clarifies the 3D spray structure and fuel trajectory change from non-flashing conditions to flare flash conditions, and quantifies the 3D characteristics of individual plumes in non-flash conditions.

Integral role for lysyl oxidase-like-1 in conventional outflow tissue function and behavior.

Lysyl oxidase-like-1 (LOXL1), a vital crosslinking enzyme in elastin fiber maintenance, is essential for the stability and strength of elastic vessels and tissues. Variants in the LOXL1 locus associate with a dramatic increase in risk of exfoliation syndrome (XFS), a systemic fibrillopathy, which often presents with ocular hypertension and exfoliation glaucoma (XFG). We examined the role of LOXL1 in conventional outflow function, the prime regulator of intraocular pressure (IOP). Using Loxl1-/- , Loxl1+/- , and Loxl1+/+ mice, we observed an inverse relationship between LOXL1 expression and IOP, which worsened with age. Elevated IOP in Loxl1-/- mice was associated with a larger globe, decreased ocular compliance, increased outflow facility, extracellular matrix (ECM) abnormalities, and dilated intrascleral veins, yet, no dilation of arteries or capillaries. Interestingly, in living Loxl1-/- mouse eyes, Schlemm's canal (SC) was less susceptible to collapse when challenged with acute elevations in IOP, suggesting elevated episcleral venous pressure (EVP). Thus, LOXL1 expression is required for normal IOP control, while ablation results in altered ECM repair/homeostasis and conventional outflow physiology. Dilation of SC and distal veins, but not arteries, is consistent with key structural and functional roles for elastin in low-pressure vessels subjected to cyclical mechanical stress.

The effect of composition variations on the response of steels subjected to high fluence neutron irradiation

A set of low alloy model reactor pressure vessel steels, with systematic variations in their Mn, Ni, and Si contents, were neutron-irradiated to high fluence (1.4 × 1020 n/cm2) in the Advanced Test Reactor at Idaho at 290°C and a flux of 3.6 × 1012 n/cm2s. The alloys were analysed using atom probe tomography and solute clusters were observed in each alloy, including in one alloy that contained low nominal levels of Mn (0.04 at. %) and Si (0.06 at. %). Changes in the mechanical properties of the alloys were correlated with cluster volume fractions. Whilst the effect of nominal composition was observed to influence cluster composition, cluster nucleation site was not observed to affect composition. Several grain boundaries were also analysed and the segregation behaviour of certain elements is discussed.

Study of the influence of the pressure and rotational motion of 3D substrates processed by magnetron sputtering: A comparative study between Monte Carlo modelling and experiments

Over the last ten years, low pressure plasma solutions for materials surface treatment have been remarkable. Nevertheless, the deposition of films with a uniform thickness on 3D complex shapes is still a challenge for various deposition systems. In several cases, concavities and different substrate orientations and motions lead to macroscopic shadowing and affect the thickness uniformity. The objective of this work is to describe a modelling method able to predict the layer thickness on any surface of 3D substrates in motion and subject to vapour transported in a low pressure vessel. The meshing of objects with Delaunay-triangulation enables the modelling of complex shapes. The deposition process consists of several Monte Carlo simulations involving first the computing of the angular and energy particles distribution from the source, second their transport through the chamber and last the deposition on a meshed substrate. The algorithm is optimised with a “cell-list-linked-like” method and differs from existing models by the computation speed.The benchmarking between simulation and experimental results for Cr, Ag and Ta deposition at various pressures and on moving complex substrates with several shadowed faces is presented. Moreover, particle energy distribution will be discussed for each sample surface, mode and pressure.

A novel method to estimate the fracture toughness of pressure vessel ferritic steels in the ductile to brittle transition region using finite element analysis and Master Curve method

Fracture toughness is a key parameter in the structure integrity assessment for pressure vessels. Several experiments must be performed to obtain the accurate fracture toughness of pressure vessel steels. However, these experiments are both time-consuming and money-consuming. It is difficult to conduct these experiments in practical engineering projects due to this reason. In this paper, an effective method is proposed to estimate the fracture toughness of pressure vessel ferritic steels in the ductile to brittle transition region. This method is based on the finite element analysis and the Master Curve method. A load P vs. load–line displacement VLL curve, critical J-integral values and reference temperature T0 are obtained using this method. To validate this method, the tensile test and the fracture toughness test of Chinese low temperature pressure vessel ferritic steel, 16MnDR steel, are conducted. The applicability of involved methods, Compliance Changing Rate method and Chaouadi's equation, are evaluated with experimental data. It is found that the predicted results agree well with the experimental results and have a certain conservatism. The method provides a good solution to obtain accurate fracture toughness of pressure vessel ferritic steels by using minimal number of experiments for practical engineering projects.

Well connection optimization in integrated subsurface and surface facilities: an industrial case study

Optimizations of oil productions in current practices have been done separately in both subsurface and surface facilities. This approach might not lead to an optimum state when the whole system is interconnected. In this work, a superstructure model of an existing integrated subsurface and surface facilities was developed and evaluated to maximize the oil productions. In subsurface facilities, well performance data were taken from PROSPER well simulations. Operating variables such as downstream pressures of choke valves and gas lift flowrates, which influence the flow of oil, gas, and water from reservoirs, were considered. Based on these variables, performance correlations of the wells were then developed. On the evaluated surface facility, three pressure levels of vessels on the platform (high-, medium-, and low-pressure vessels) and their current designs were also considered. The optimization result shows that to reach optimum oil production, one well should be connected to the high-pressure vessel, four wells to the medium-pressure vessel, and the rest goes to the low-pressure vessel. Several choke valves and gas lift flowrates also need to be adjusted accordingly.

Phenomenological modelling of flow behaviour of 20MnMoNi55 reactor pressure vessel steel at cryogenic temperature with different strain rates

Abstract In the present study a phenomenological constitutive model is developed to describe the flow behaviour of 20MnMoNi55 low carbon reactor pressure vessel (RPV) steel at sub-zero temperature under different strain rates. A set of uniaxial tensile tests is done with the variation of strain rates and temperature ranging from 10−4 s−1 to 10−1 s−1 and -80 °C to −140 °C respectively. From the experimental data, family of flow curves at different temperatures and strain rates are generated and fitted exponentially. The strain rate and temperature dependence of the coefficients of the exponential flow curves are extracted from these curves and characterised through a general phenomenological constitutive coupled equation. The coefficients of this coupled equation are optimised using genetic algorithm. Finite element simulation of tensile tests at different strain rates and temperatures are done using this coupled equation in material model of Abaqus FEA software and validated with experimental results. The novelties of proposed model are: (a) it can predict precisely the flow behaviour of tensile tests (b) it is a simple form of equation where fitting parameters are both function of strain rate ratio and temperature ratio, (c) it has ability to characterize flow behaviour with decreasing subzero temperatures and increasing strain rates.

Stress and thickness calculation of a bolted flat cover with double metal sealing rings

The design of a bolted flat cover is extremely important for the structural integrity of pressure vessels. The present design codes provide the thickness calculation equations for a bolted flat cover with single metal gasket. However, the rules for a bolted flat cover with double metal sealing rings are not developed to date. In the study, a new thickness calculation equation for the bolted flat cover with double metal sealing rings is proposed. First, the theoretical stress solution for bolted flat cover with the double metal sealing rings is obtained, based on the theory of simply supported circular plate and then verified using the results from finite element analyses. The results indicate that the influence of double metal sealing ring on the stress of the flat cover is more serious compared to single metal gasket. Second, a more accurate and reasonable equation is proposed to calculate the thickness of bolted flat cover with double metal sealing rings based on the derived theoretical equations of maximum stress. Finally, the influence of linear load and the spacing between rings on the thickness are discussed. Subsequently, a few suggestions are provided to design low-pressure or atmosphere pressure vessels. The study provides a theoretical foundation to develop design codes of pressure vessels in nuclear reactors.

Estimation of fracture toughness of 16MnDR steel using Master Curve method and Charpy V-notch impact energy

16MnDR steel is widely used as a low temperature pressure vessel steel in China. However, the fracture toughness of this steel significantly decreases with the decrease of temperature in the ductile to brittle transition region. To prevent the occurrence of brittle fracture, the methods which can precisely estimate the fracture toughness of 16MnDR steel are of great practical significance. In this paper, the Master Curve method, and empirical formulas between Charpy V-notch impact energy and fracture toughness are applied to estimate the fracture toughness of 16MnDR steel in the transition region. The reference temperature T0 values are determined using both single-temperature and multi-temperature method from fracture toughness test data and Charpy impact test data. The T0 values determined from different combinations of test temperatures are compared. It is found that the fracture toughness of 16MnDR steel can be well estimated using the Master Curve method in the transition region and lower shelf region. The predicted fracture toughness values obtained by empirical formulas cannot be directly used in structural integrity assessment of 16MnDR steel. The effective methods to accurately estimate fracture toughness in the transition region under the differenttestconditions are proposed for 16MnDR steel.