Inlet Device Research Articles

Improved determination of nitrate isotopes in irrigated agricultural areas and Bayesian mixing model quantification of nitrate sources and fate

Technological advancements in isotope techniques have been widely utilized in environmental pollution research, particularly for the monitoring of nitrate pollution in water. The utilization of pretreatment with an aqueous nitric acid solution offers numerous advantages in analyzing isotopic composition; however, there is still room for improvement regarding conversion efficiency, reduced reaction time, and cost control. In light of this, this study proposes an enhanced chemical conversion method that involves mitigating the interference caused by the nitrogen azide reaction during the pretreatment process, optimizing the purge gas to remove interfering factors, and improving the inlet device for measuring nitrous oxide. The improved method was applied to determine nitrate isotopes in the Ulansuhai Basin, Inner Mongolia and its reliability was verified through analytical results obtained from bacterial denitrification methods. The mean δ15N-NO3- and δ18O-NO3- values determined using the chemical transformation method were 4.85‰ and 23.44‰, respectively. Compared with the previous method, the improved method enhanced the maneuverability of precise control, the pretreatment time was reduced from 2 to 3 hours to 1.5 hours, and the experimental cost was scaled down to half of the original one. In addition, the contribution of each source was calculated by combining nitrate isotopes with a Bayesian stable isotope mixing model. It was found that manure sewage accounted for (50.1±22.6) % while soil nitrogen sources contributed (25.1±20.4) % to nitrate levels in Ulansuhai Lake's water. The chemical conversion methods successfully improved within this study can also be applied to other watersheds or regions. These research findings provide a valuable theoretical foundation for managing nitrogen sources within watersheds.

Mass transfer enhancement and flow field simulations for a Venturi bubble generator with multiple inlet tubes

The Venturi device plays a crucial role in the Filtered Containment Venting System (FCVS), effectively preventing the release of radioactive pollutants from nuclear reactor containment during overpressure events. Various configurations of the Venturi device yield different outcomes, with mass transfer efficiency being contingent on bubble size and overall gas holdup. This study examines the impact of varying numbers of inlet tubes on the Venturi device, while keeping the inlet area constant. Specifically looking at the gas–liquid flow field, bubble behavior, and mass transfer capacity in the diverging section. By comparing Single Inlet Tube Venturi Device (SITVD) and Double Inlet Tubes Venturi Device (DITVD), we have reached the following conclusions: (1) In SITVD, the liquid flow field is biased to one side, whereas in DITVD, the liquid flows along the axial direction, resulting in bubbles experiencing stronger shear forces. (2) DITVD exhibits a higher overall gas holdup compared to SITVD, with an average axial gas holdup of 0.0317, which is greater than SITVD's 0.0247. However, SITVD's gas holdup is more evenly distributed. (3) SITVD exhibits a higher turbulence dissipation rate of 545 m2/s3, while the bubble residence time in DITVD is comparatively longer. (4) The average bubble diameter of DITVD is 1.116 mm, which is higher than the 1.011 mm of SITVD. (5) DITVD has better mass transfer than SITVD. The proposed structure of the new Venturi scrubber in this study demonstrates a significant enhancement in mass transfer capacity and filtration efficiency. This discovery provides a solid basis for the design and optimization of FCVS, thereby ensuring the safe operation of nuclear reactors.

Вплив форми дозвукової частини надзвукового вхідного пристрою на коефіцієнт збереження повного тиску

The subject of this study is the total pressure conservation coefficient. The object of this study is the channel of the subsonic part of a supersonic input device of rectangular and oval shape, equivalent in size. The purpose of this study is to study the shape of the subsonic part of a supersonic external compression input device. To achieve this purpose, the following tasks were solved: modeling the flow in the subsonic part of a supersonic inlet external compression input device of rectangular and oval shape; calculation of the total pressure conservation coefficient in the subsonic part of the rectangular and oval supersonic inlet external compression input device. When studying the shape of the subsonic part of the supersonic inlet external compression device, the method of numerical experiment was used. The studies were conducted at an estimated altitude of 12 km and an estimated Mach number M = 2.5. The influence of the fuselage on the operation of the input device was not considered. To study the influence of the cross-sectional shape of the studied subsonic parts of the inlet device, the coefficient of conservation of total pressure in 7 cross sections along the length of the inlet device was calculated. To obtain the initial data for modeling the flow in a subsonic channel, an analytical calculation of the flow parameters in the supersonic part of the input device was performed. The results of flow modeling showed that the total pressure conservation coefficient of the subsonic part of the studied inlet devices when operating at an altitude of 12 km was 0.982 in the subsonic part of the supersonic inlet device with oval sections and 0.993 in the subsonic part of the supersonic inlet device with rectangular sections. The resulting visualization of streamlines in the studied channels demonstrates the presence of a paired vortex formed in the initial section of the channel with oval cross-sections, which leads to significant losses in total pressure. The scientific novelty and practical significance of this study lie in the fact that new data were obtained regarding the comparison of the total pressure conservation coefficient for equivalent subsonic parts of a supersonic oval and rectangular inlet device. Recommendations on the rational form of the subsonic part of the supersonic inlet external compression device were obtained.

Preliminary purification of the gas-liquid stream from hydrocarbon condensate, water and mechanical impurities

The paper discusses the process plan of the piston compressor package as well as the design of the gas separator. A technical proposal has been developed to improve the preliminary purification of the gas-liquid stream from hydrocarbon condensate, water and mechanical impurities. With the help of modern computer technologies, the design of the inlet device in the separator has been developed. The operation of the gas separator was simulated after the application developed by the devices. With the help of the program, the results of the study of the gas separator operation are presented.

Evaluation Method and Analysis on Performance of Diffuser in Heat Storage Tank

The diffuser is a critical component in a heat storage tank, and its structure has an important influence on the thermal performance of the heat storage tank. At present, research on the structure of diffusers often focuses on the change of one single parameter, which results in the need for a comprehensive structure analysis of diffusers in heat storage tanks. This paper comprehensively considers the inlet diameter, hole distance, and hole diameter of the diffuser and the inlet conditions of the heat storage tank. Then, a new evaluation index, namely the non-uniformity coefficient of the diffuser, is proposed. The experiments verify the accuracy of numerical calculation, and the related empirical formula is summarized finally. The results show that the diffuser with a small non-uniformity coefficient can achieve thin temperature stratification and higher exergy efficiency. In other words, the non-uniformity coefficient is in good agreement with temperature stratification and the exergy efficiency of the heat storage tank. When the flow rate of the inlet device is 0.5 m/s, the exergy efficiency increases by nearly 30 percentage points and the non-uniformity coefficient of the No. 4 diffuser is 3.39%. In contrast, that of the No. 8 diffuser is 75.17%. This evaluation index is suitable for different diffuser types with high accuracy. It provides the theoretical and experimental basis for the structural design and selection of diffusers for heat storage tanks.

Rotary thermal desorption technology for treatment of oil-based drilling cuttings in shale gas industry

Oil-based drilling cuttings are hazardous wastes in shale gas exploitation and need careful treatments to reduce environmental pollution and waste of resources. One of most widely employed waste-treatment technologies is the thermal desorption due to its high oil recovery efficiency. However, it usually suffers low heat exchange efficiency, thus leveraging operation costs and equipment instability. Toward the end of alleviating limitation, this study rationally designs the structure of the heating component under the guidance of the flat wall heat conduction theory, and uses numerical simulation to analyze the heat transfer of the structure. A rotary thermal desorption technology was thus developed and evaluated. The simulation results showed that given a short time of 800 s the temperature difference between device and cuttings became less than 5 K, indicating good heat exchange efficiency. Large inlet radius of device and high inlet velocity of heat transfer oil were critical parameters to maintain high heat transfer rate. Through industrial experiments verification, the 0.14–0.2 % oil content of treated cuttings qualified the environmental standards. The components of the recovered oil were recyclable C9-C23 alkanes, and the dichromate oxidizability of recovered water was less than 500 mg/L limit. Comparing with other technologies, the scores suggested that this technology was a promising candidate for treating oil-based drilling cuttings.

Portable platform for leukocyte extraction from blood using sheath-free microfluidic DLD.

Leukocyte count is routinely performed for diagnostic purposes and is rapidly emerging as a significant biomarker for a wide array of diseases. Additionally, leukocytes have demonstrated considerable promise in novel cell-based immunotherapies. However, the direct retrieval of leukocytes from whole blood is a significant challenge due to their low abundance compared to erythrocytes. Here, we introduce a microfluidic-based platform that isolates and recovers leukocytes from diluted whole blood in a single step. Our platform utilizes a novel, sheathless method to initially sediment and focus blood cells into a dense stream while flowing through a tubing before entering the microfluidic device. A hexagonal-shaped structure, patterned at the device's inlet, directs all the blood cells against the channel's outer walls. The focused cells are then separated based on their size using the deterministic lateral displacement (DLD) microfluidic technique. We evaluated various parameters that could influence leukocyte separation, including different focusing structures (assessed both computationally and experimentally), the orientation of the tubing-chip interface, the effects of blood sample hematocrit (dilution), and flow rate. Our device demonstrated the ability to isolate leukocytes from diluted blood with a separation efficiency of 100%, a recovery rate of 76%, and a purity of 80%, while maintaining a cell viability of 98%. The device operates for over 30 min at a flow rate of 2 μL min-1. Furthermore, we developed a handheld pressure controller to drive fluid flow, enhancing the operability of our platform outside of central laboratories and enabling near-patient testing. Our platform can be integrated with downstream cell-based assays and analytical methods that require high leukocyte purity (80%), ranging from cell counting to diagnostics and cell culture applications.

Oxidation-free thiourea leaching of gold uthig sulphur dioxide

The paper summarizes research on gold recovery by the Carbon in Leach (CIL) process using thiourea by feeding sulphur dioxide by a hydroacoustic emitter. It was found that the use of such a device favors the formation of the radical OH*. The latter is the strongest oxidizing agent. One of the main regulated parameters of the plant is the pressure of pulp supply to the inlet device, which was studied. According to the results of the study, it was found that a high degree of gold recovery is achieved under the following conditions: initial concentration of H2SO4 – 0.5%, thiourea loading – 1.5 kg/t, coal loading 10 g/kg, sulphur dioxide feed –0.13 kg/t*min, ratio L:S – 1:3, slurry supply pressure to the inlet – 1.5 atm, CIL process time – 60 min. Thiourea consumption amounted to 0.57 kg/t, and sulphur dioxide – 8 kg/t. Gold recovery reached 93.5%.

Design of vortex-based cavitation devices/reactors: Influence of aspect ratio, number of inlets and shape

Vortex-based hydrodynamic cavitation devices are being used in a wide range of applications. However, adequate information on the design of such devices is not available. In this work, we have computationally investigated the influence of key design parameters such as the aspect ratio of the vortex chamber, the number of tangential inlets and the shape of the device on resulting flow characteristics and cavitation. Experiments were carried out to validate key findings from the computational studies. These investigations revealed that the aspect ratio of the vortex chamber as six may be considered as optimum. The performance of single and multiple inlet devices was found to be comparable at the same pressure drop (that is at same energy consumption per m3). Scale-up with a geometric similarity led to a reduction in the extent of cavitation for same energy consumption per m3. For facilitating scale-out option, an attempt was made to simplify the configuration of the vortex-based cavitation device. Computational results indicated that the cavitation performance of simplified configuration was not significantly inferior. A case of the formation of liquid–liquid emulsion was taken as a test case for evaluation of a modified cavitation device based on the present investigations. The droplet size distributions of emulsions generated by both the devices indicate that the proposed simplified configuration, which may facilitate fabrication and offer integrated scale-out options, performs almost at par with a complex configuration. The presented results will be useful for optimising designs of vortex-based hydrodynamic cavitation devices/ reactors.

Computational fluid dynamics comparison of the upper airway velocity, pressure, and resistance in cats using an endotracheal tube or a supraglottic airway device.

In veterinary medicine, airway management of cats under general anesthesia is performed with an endotracheal tube (ETT) or supraglottic airway device (SGAD). This study aims to describe the use of computational fluid dynamics (CFD) to assess the velocities, pressures, and resistances of cats with ETT or SGAD. A geometrical reconstruction model of the device, trachea, and lobar bronchi was carried out from computed tomography (CT) scans that include the head, neck, and thorax. Twenty CT scans of cats under general anesthesia using ETT (n = 10) and SGAD (n = 10) were modeled and analyzed. An inspiratory flow of 2.4 L/min was imposed in each model and velocity (m/s), general and regional pressures (cmH2O) were computed. General resistance (cmH2O/L/min) was calculated using differential pressure differences between the device inlet and lobar bronchi. Additionally, regional resistances were calculated at the device's connection with the breathing circuit (region A), at the glottis area for the SGAD, and the area of the ETT exit (bevel) (region B) and the device itself (region C). Recirculatory flow and high velocities were found at the ETT's bevel and at the glottis level in the SGAD group. The pressure gradient (Δp) was more enhanced in the ETT cases compared with the SGAD cases, where the pressure change was drastic. In region A, the Δp was higher in the ETT group, while in regions B and C, it was higher in the SGAD group. The general resistance was not statistically significant between groups (p = 0.48). Higher resistances were found at the region A (p = <0.001) in the ETT group. In contrast, the resistance was higher in the SGAD cases at the region B (p = 0.001). Overall, the provided CT-based CFD analysis demonstrated regional changes in airway pressure and resistance between ETT and SGAD during anesthetic flow conditions. Correct selection of the airway device size is recommended to avoid upper airway obstruction or changes in flow parameters.

Методика раціонального формування поверхонь гальмування плоского надзвукового вхідного пристрою

This article deals with methodological support for the design of effective supersonic flat external compression input devices. A concise analysis of the contribution of well-known scientists in the study of braking processes of supersonic flows of the working body in the system of sealing jumps is presented in the input devices. The proposed method of rational formation of the braking surfaces of a flat supersonic inlet device is based on the main provisions of the gas-hydraulic theory of sealing jump proposed by Rankin and Hugoniot. The main goal of this study is the development of a method of rational formation of braking surfaces of a supersonic flat input device of external compression according to the criterion of its efficiency, namely the maximum value of the coefficient of preservation of full pressure in sealing jumps. The choice of the value of the angle of inclination of the braking surfaces of the supersonic input device and the corresponding angles of inclination of the oblique jumps of the seal for a given calculated value of the number M consists in finding such values of the angles of inclination of the braking surfaces, at which the intensity of the oblique jumps of the seal is the same, under this condition the coefficient of preservation of full pressure is maximum. The mathematical formulation of the problem of determining the rational position of the braking surfaces of the supersonic flat input device of external compression is possible in the form of finding the angle of inclination of the first braking surface, which corresponds to the maximum value of the coefficient of preservation of full pressure for the determined value of the number M before the first oblique jump of the seal and at a constant intensity of the oblique jumps of the seal. This article outlines the main elements of the proposed methodology. Using the given methodology, a rational value of the angle of inclination of the first oblique jump of the seal was searched for the calculated value of the number M=2.5. In the supersonic input device operating at the specified design number M, three oblique sealing jumps and one direct-closing sealing jump are selected. The dependence of the full pressure preservation coefficient of oblique sealing jumps, direct jump, and total pressure preservation coefficient in the sealing jumps of the supersonic inlet device is obtained. It is shown that with an increase in the angle of inclination of the first braking surface and the corresponding values of the angles of inclination of the second and third braking surfaces, the coefficient of preservation of the full pressure of oblique jumps of the seal decreases, and that of direct jumps increases, which determines the presence of an extremum and makes it possible to determine the rational value of the angle of inclination of the first braking surface. This technique allows for any number of M before the first oblique jump of the seal to determine the rational values of the angles of inclination of the braking surfaces of the flat supersonic external compression input device.

Design and mathematical modeling of a pyrotechnically actuated water inlet device

Pyrotechnically actuated devices(PADs) rely on combustion of energetic materials to achieve various functions and are widely used in aerospace fields. In this paper, based on the basic principle of the PADs, a piston-type water inlet device is designed, which can make underwater weapon sink into the seabed to self-destruct when there is an abnormality, and prevent the weapon from accidentally acting or being captured. A segmented mathematical model was established to study the kinematic characteristics of the device, and the functional experimental was carried out. The results show that the water inlet device works reliably and can be applied to a variety of underwater weapons. The mathematical model can predict the performance parameters of the water inlet device during the movement process, providing support for the engineering application and optimal design of the device.

Life Cycle Assessment of Magnetite Production Using Microfluidic Devices: Moving from the Laboratory to Industrial Scale

Magnetite nanoparticles (MNPs) have important applications in several industrial and scientific fields for the remediation of contaminated soil and water, for instance. Emerging technologies such as microfluidic techniques have been adapted to continuously synthesize MNPs showing appealing results, such as a narrower size distribution. Therefore, this approach might become important for producing MNPs to meet industrial requirements. In this study, a life cycle assessment (LCA) is conducted to analyze and evaluate the impacts of the synthesis of MNPs performed in microfluidic devices. This LCA considers all of the steps required for MNP production at a laboratory and possible industrial scales. The LCA results showed that the rivets suitable for device inlets and outlets and the chemicals required for the synthesis process have the highest contribution to all impact categories, i.e., 80 and 90%, respectively. These results thus contribute to determining the overall environmental performance of each step during the synthesis of MNPs. The contribution analysis reveals that the manufacturing stage has a contribution of 97% at the lab scale, while the operation stage shows a contribution of 82% at the industrial scale. Finally, a sensitivity analysis is performed to identify the possible scenarios for replacing rivets required to manufacture microfluidic devices.

Natural and forced convection heat transfer characteristics of single-phase immersion cooling systems for data centers

Improving power usage effectiveness (PUE) in data centers becomes a key challenge for carbon neutrality and carbon peaking strategies. In this context, this paper investigates the single-phase immersion cooling (SPIC) system that promises to improve PUE. Three-dimensional mathematical models of pump-driven and buoyancy-driven immersion cooling tanks are established and numerically solved. The thermal characteristics, flow resistance, and energy consumption levels of immersion cooling tanks in three operating modes are investigated. Moreover, the roles of volume flow rate, inlet temperature, and device power in immersion cooling characteristics are analyzed. The results indicate that the heat dissipation of buoyancy-driven SPIC systems is less effective than pump-driven ones. Compared to buoyancy-driven SPIC systems, the average temperature of immersion coolants and PUE in pump-driven SPIC systems reduces by 55.5 and 11.6%, respectively. Interestingly, although natural convection in mixed convection operation enhances convective disturbance, it induces temperature stratification that weakens temperature homogeneity. Increases in inlet temperature and device power both worsen the immersion cooling performance. However, increasing inlet temperature improves temperature uniformity and reduces flow resistance losses, while increasing device power has the opposite effect. Besides, the increased flow rate enhances the convective heat transport and temperature uniformity but increases the flow resistance loss.

Development of a 1D/2D Urban Flood Model Using the Open-Source Models SWMM and MOHID Land

Urban pluvial floods are the outcome of the incapacity of drainage systems to convey the runoff generated by intense rainfall events. Cities have been struggling to control such hazards due to several pressures, such as urbanization increase, more frequent experiences of extreme rainfall events, and increases in tide levels. Such pressures demand the study of adaptation strategies, which conventional one-dimensional drainage models fall short of simulating. Thus, 1D/2D models have been emerging with the aim of allowing better integration of key processes for flood modeling, namely, runoff interception by stormwater inlet devices and manhole overflows. The current paper presents a 1D/2D urban flood model based on an offline coupling procedure between the 1D model SWMM and the 2D model MOHID Land. The SWMM/Land model is applied to a synthetic street case study and to a real case study in downtown Albufeira, Portugal. The results obtained for the real case study are coherent with local observations of past flooding events, and the model shows potential for better decision-making regarding urban flood risk management.

Comparison of Trapping Effects of Different Traps and Monitoring the Occurrence Dynamics of Spodoptera litura in Soybean Fields of Dangtu, Anhui Province, China

In order to clarify the trapping efficiency of different types of sex pheromone traps on populations of Spodoptera litura in soybean fields, three kinds of conventional traps, called YL-VT, YL-HEMT and YL-NMT, and types of traps equipped with a automatic catch monitoring mechanism, called AIM and AIM-lite-A, have been tested. These last two allow monitoring the diurnal and seasonal rhythms of the catches. From 5 August to 5 October 2020, each YL-VT trap caught an average of 84.4 heads of S. litura moths per day, which was significantly higher than the YL-HEMT (11.8 heads), YL-NMT (16.5 heads) and AIM (9.7 heads), which did not show significant differences between them. The half-life of pheromone attraction effect in YL-VT trap is about 17–20 days. Considering the number of trapping and the duration of pheromone attraction effect, YL-VT trap is the best. For efficient monitoring, the validity period is approximately 15 days. Among the causes that could explain its higher capture rate and efficiency, the YL-VT trap has the smallest and largest number of inlet devices, and in it, the lure core is located inside of the insect inlet device. Under different occurrence numbers of S. litura, the accuracy of the automatic count of AIM-lite-A is 90% greater than in the AIM trap. The diurnal rhythms of S. litura observed by AIM-lite-A show that S. litura have two active periods that are from 18:00 to 21:00 and from 23:00 to 4:00 at night and that the first active period may be affected by sunshine and temperature. The annual activity rhythm of S. litura monitored by AIM showed that the activity of S. litura was related to temperature, there were approximately 6 generations of S. litura in a year and that the activity peak was from August to September in Dangtu, China. AIM and AIM-lite-A can be used for the annual monitoring of S. litura population in soybean fields because of their automatic counting function. AIM can simultaneously record a variety of meteorological data, AIM-lite-A has higher accuracy and a lower cost, which can be selected according to different situations. In conventional traps, the trap YL-VT can be used for the population monitoring of S. litura in soybean fields and pest control in the field, especially in greenhouses and net rooms where organic soybeans are grown, due to its low cost and efficient trapping ability.

Аbout the influence of the use of «zaezdok» type nets on the passing of the Рacific salmon producers to the springing territories in the Аmur and Аmur liman

Materials are presented on the study of the technology of harvesting Pacific salmon, using fixed seines of the «zaezdok» type in the Amur estuary and the river. Amur, in order to ensure the passage of spawners of Pacific salmon during passing days without dismantling the wings and the trap, but only by closing the inlet device of the reservoir. The results of the conducted studies showed that the design of a fixed seine of the «zaezdok» type does not prevent the passage of fish to spawning grounds, does not allow it to be bound and does not cause damage to the prey object. During periods of skipping spawners («passing days»), it is sufficient to close the entrance to the seine trap and raise its netting. This ensures the unhindered exit of fish from the fishing area of the prey tool. Installation of additional structural elements (windows, etc.) is not required to ensure the passage of fish.

Comparative evaluation of the efficiency of the ring-type and bucket inlet devicesfor a power plant with a turbopropfan engine

The increase in losses in the inlet device leads to an increase in specific fuel consumption. When integrating the inlet device and the propeller or propfan, it is necessary to take into consideration their interaction to ensure the maximum efficiency of the power plant. The object of this study is a coaxial propfan with the channel of the inlet device. The results reported here are of practical value: a methodology for designing a bucket S-shaped channel of the inlet device of a power plant with a turboprop engine has been developed. The dependence of the coefficient of preservation of the total pressure of the inlet device on the height and speed of flight was obtained, which makes it possible to take into consideration the influence of the propfan of a turboprop engine. A comparison of the characteristics of the ring-type and bucket S-shaped channel of the inlet device of the power plant with the turboprop engine was carried out. Specifically, it was found that the change in flight conditions has a less significant effect on the change in the coefficient of preservation of the total pressureof the ring-typeinlet device than the bucket one. A comparative assessment of the obtained results of mathematical modeling of the flow in the bucket S-shaped channel of the inlet device, taking into account the influence of the propfan, with the results of flight tests of the ring-type inlet device of the prototype is given. The comparative evaluation shows that the use of a bucket inlet device, instead of a ring-type inlet device, makes it possible to increase the full pressure recovery factor by 5–7 %. Thus, there is reason to argue that replacing the ring-type with a bucket inlet device will minimize hydraulic losses at the inlet to the engine and reduce the uneven flow at the inlet. That, in turn, will improve engine efficiency.

Аналіз впливу кривизни S-подібного каналу та умов польоту на ефективність ковшового вхідного пристрою

When creating a modern aircraft, the principle of optimal integration of the power plant and the aircraft is used to ensure the maximum target function, determined by its functional purpose. The specific fuel consumption and specific thrust of the power plant depend significantly on the loss of the total air pressure in the inlet device, which is characterized by the total recovery factor. The change in pressure along the diameter of the propfan affects the efficiency of the inlet of the power plant. When using the inlet ring device, its efficiency decreases, due to low pressure in the area of the root part of the propfan blades. The use of a bucket inlet allows air to be supplied to the channel from the area located near the middle part of the blade height and this is the main factor influencing the reduction of pressure losses in the air supply channel. When using a bucket inlet, curvature and constriction are important factors influencing the effectiveness of S-channels. The influence of the curvature of the S-shaped channel on the total pressure recovery coefficient at a constant value of its narrowing is studied in this work. The study S-shaped channel in its geometric parameters is equivalent to the channel of the annular inlet device of a power plant with a turbofan engine. The total pressure recovery coefficient of an S-shaped channel is calculated from the flow parameters in the sections of the S-shaped channel by solving the Navier-Stokes equations using the Florian Menter two-layer turbulence model (SST Transitional No. 4 Gamma Theta) and the combined finite element model at the entrance to the channel and in the channel itself - hexahedral, at the exit tetrahedral. An analysis of the dependence of the total pressure recovery coefficient of the S-shaped channel on the M number and the channel curvature shows that, up to a curvature of 0.002, the total pressure recovery coefficient is not significantly affected. A further increase in the channel curvature has a significant effect on the change in the total pressure recovery coefficient, which is associated with flow separation and losses from the vortex formation.

Improvement in sensitivity for lateral flow immunoassay of ferritin using novel device design based on gold-enhanced gold nanoparticles

This work introduces a low-cost adhesive tape combined with a hydroxylamine/polyvinyl alcohol/polyethylene oxide (HA/PVA/PEO) blend film to fabricate novel devices for improving sensitivity of gold nanoparticle (AuNP)-based lateral flow immunoassays (LFIAs) via two platforms: (1) LFIA device with integrated gold enhancement and (2) LFIA device with two independent sample inlets. The detection of ferritin has been used for proof-of-concept. The adhesive tape inserted in the devices assists to separate two solutions independently flowing from two different inlets toward a nitrocellulose membrane. On-device gold enhancement was achieved by the enlargement of AuNPs via the catalytic reaction of KAuCl4 and HA using the HA/PVA/PEO blend film easily prepared via a solution-casting technique, which could delay the flow of HA released from the film for 180s and improve storage stability of the device. Under optimal conditions evaluated by naked eyes, the gold enhancement (LOD = 0.5 ng/mL) and double-sample inlet (LOD = 2 ng/mL) devices exhibited 20-fold and fivefold higher sensitivity respectively than a conventional device, verifying the sensitivity improvement. Furthermore, the proposed device was successfully detected ferritin in human serum samples within 10 min via naked-eye observation, exhibiting rapidity and simplicity of use, and the capability to perform on-site assays.