Uniform Drop Research Articles

Country and continent-wise trends in mortality rates of ovarian cancer from 1980-2021: An analysis of GBD study 2021.

148 Background: Ovarian cancer is one of the major causes of cancer related deaths in women worldwide. Early detection, primarily via ultrasound , can result in lower mortality and morbidity. We present a comprehensive evaluation derived from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, depicting the ovarian cancer associated mortality pattern from 1980 to 2021. Methods: Data were methodically retrieved from the Global Burden of Diseases (GBD) study, which included age-standardized death rates, Years of Lost Life (YLL), and disability-adjusted life years (DALYs). The dataset was stratified globally and categorized by continent, with Africa divided into Northern, Southern, Eastern, Western, and Central regions, and by World Bank income levels. Joinpoint Regression was employed to determine average annual percentage changes (AAPC). Results: Globally, the Age standardized death rates (ASDR) for ovarian cancer had an overall decline from 1980 to 2021. In 1980, the ASDR was 4.64 (95% UI: 4.3-5.14), and it declined to 4.05 (AAPC: -0.315; 95% CI: -0.35 to -0.27) in 2021. Globally, the disability-adjusted life-years (DALYs) rate was 132.4 (95% UI: 121.3–145.6) per 100,000 people in 1990, and it decreased to 115.14 (AAPC: -0.44; 95% CI: -0.52 to -0.36) in 2021. From 1990 to 2021, the age-standardized years of life lost (YLL) showed a uniform drop with an AAPC of -0.36 (95% CI: -0.40 to -0.31). However, in continent wise analysis, while the Americas and Europe had continuously declining ASDRs, Asia and Africa had an increasing trend throughout the predetermined time frame. From 1980 to 2021, America had an AAPC of -0.67 (95% CI: -0.69 to -0.65). Similarly, Europe also had a decreasing trend from 1980 to 2021 with an AAPC of -0.48 (95% CI: -0.50 to -0.45). The AAPC for Africa was 1.203 (95% CI: 1.19 to 1.21), showing a greater incline compared to the other continents. The AAPC for Asia was 0.54 (95% CI: 0.527 to 0.563). During further analysis of the African region, we observed that southern and eastern Africa had the highest ASDRs. According to World Bank income levels, low-income and lower-middle-income countries had increasing death rates, while high and upper-middle income countries had decreasing death rates from 1980 to 2021. Conclusions: The study disclosed a global decline in ovarian cancer fatality rates from 1980 to 2021. Although significant progress has been made in the Americas and Europe, mortality rates have risen in Asia and Africa, with southern and eastern Africa exhibiting particularly high rates. An increase in death rates is also observed in low- and lower-middle-income countries, contrasting with an overall decrease globally and in high-income nations.

Thermal management of counter terminal lithium-ion battery using Bio-based PCM

Research interest in applying Phase Change Materials (PCMs) for thermal management has been evident across various applications. In several studies, researchers have also suggested the use of PCMs for thermal management in lithium-ion batteries. The current study focuses on thermal management of lithium-ion batteries with terminal configurations positioned in a counter layout, comparing scenarios with and without the implementation of Bio-based PCM. Analysis has been conducted at various discharge rates (1C, 5C, and 10C) using the MSMD model in ANSYS Fluent software for transient analysis. Thermal performance has been numerically evaluated by analyzing temperature, voltage, and PCM’s liquid fraction. The results show that counter terminal lithium-ion batteries exhibit more uniform heat distribution compared to those with terminals in parallel configuration. At a 1C discharge rate, the maximum temperature peaks at 326.15 K, demonstrating a notable 6.23 % reduction with PCM integration. Similarly, at 5C and 10C discharge rates, the maximum temperatures peaks at 346.54 K and 372.99 K, respectively, witness reductions of 10.16 % and 12.44 % due to PCM utilization. Furthermore, the application of PCM facilitates a uniform drop in voltage during discharge, enhancing overall battery performance and longevity.

Performance study of air source heat pump system applying two types of distributors

Abstract Air source heat pump heating is the most effective way to solve heating problems, and gas-liquid two-phase refrigerant in the uniform distribution and pressure drop problem of finned heat exchanger branch tube are the main factors affecting the heat transfer ability. To study the effects of two types of manifolds applied in air-source heat pumps on the system performance and pressure drop when the system is in operation, an engineering-based test system for the actual operation of air-source heat pumps was constructed. The study shows that the difference between the venturi distributor and the rectifier nozzle distributor in the impact on the system performance is relatively small, while the rectifier nozzle distributor compared to the venturi distributor in the pressure drop on the effect is obvious. The evaporator pressure drop will be transferred to the distributor part of the reduction of pressure drop losses in the evaporator on the impact of heat transfer performance. This paper summarizes the performance study of two types of distributors applied to air source heat pumps, which provides a meaningful reference for similar studies.

Bulk-like phonon transport in multilayer graphene nanostructures with consecutive twist angles

We investigate phonon transport in consecutively twisted multilayer graphene (CTMG) via atomistic simulations, assuming the same twist angle between any adjacent layers. Intriguingly, the calculated temperature drop between each two layers along the cross-plane direction in CTMG appears nearly identical, indicating an ill-defined Kapitza length. Moreover, the bulk-like thermal resistance increases with rising temperature. Both phenomena suggest that heat conduction in CTMG more closely resembles that in bulk materials as compared to layered materials with an individual mismatched interface, such as twisted multilayer graphene (TMG). This peculiar behavior originates from the unique nanostructure of CTMG. First, the common twist angle creates a consistent charge distribution at each interface, leading to a higher binding energy and reduced mismatch of the phonon density of states across the interface, and therefore a more uniform temperature drop. Further, the continuum of interfaces induces strong scattering of low-energy acoustic phonons generated by emission processes at the interfaces, which results in a temperature dependence opposite to that of TMG. Our findings enable a better understanding of phonon transport in twisted multilayer graphene, and may also facilitate the exploration of other interface-engineered van der Waals nanostructures.

Comparative Analysis of Different Injection Molding Process Parameters through Injection Molding Flow Simulation for Various Gate Locations

This study deals with part quality concerning gate location on the part for injection molding. Through injection molding filling simulations, basic parameters such as injection pressure, bulk and surface temperature, shear rate, solidification, shrinkage, air entrapment, weld lines and others were analysed. The simulation was conducted on a fan blade model with Polycarbonate material. Polycarbonate is a commonly used polymer in the industry and is famous for its rigidity, strength-to-weight ratio and reliability in critical system. Simulation is done at six possible gate locations labelled A1 through A6. Injection molding filling simulations was performed to evaluate the performance of each gate location. Among the considered gate locations, gate A4 exhibited a considerably high pressure drop, while gate A5 exhibited a comparatively uniform pressure drop across the mould cavity, also gate A5 showed consistent and smooth filling along with uniform cooling implying less chance of defects. Gate A4 and A5 exhibit uniform distribution across the cavity in shear rate analysis. Gate locations A2, A3, A4, and A5 exhibited controlled solidification, indicating consistent part quality. However, Gate A6 exhibited problems with volume shrinkage, which requires process optimization. Gate A6 exhibited a significant reduction in air entrapment as compared to other gate locations.

Development and performance analysis of a compact counterflow dew-point cooler for tropics

Mechanical vapor compression coolers have dominated air conditioning systems since the invention of the refrigerant cycle. However, disadvantages such as huge energy consumption and environmental pollution are becoming increasingly prominent. Additionally, amid the Covid-19 pandemic, concerns have grown that current air conditioning systems can increase the spread of airborne diseases by circulating indoor air. In other words: a supply of fresh indoor air is necessary. Therefore, there is a need to develop alternative technologies. Among alternative technologies, dew point evaporative cooling technology is considered ideal due to its advantages. This paper reports the development of a compact air cooler based on a new method of indirect counterflow dewpoint evaporative cooling. A key component of this cooling system is the counterflow heat exchanger, which allows a portion of the air to flow from the dry channel to the wet channel without changing its direction. This results in uniform air flow and low pressure drop within the cooler's channels, resulting in high cooling efficiency, high cooling capacity, and high energy efficiency. The developed air cooler was tested in tropical weather conditions. The results show that within the air volume test range, the wet bulb efficiency, cooling capacity, and refrigeration COP are 85–114 %, 440–930 W and 6–51 % respectively. It is a sustainable solution that cools air by 3–7 °C and provides 100 % fresh air to improve indoor ventilation and reduce the risk of airborne diseases, including the Covid-19 virus.

Modeling the influence of coolant flow directions on thermal performance of PEM fuel cell cooling plates with serpentine and straight flow channels

The flow direction of the coolant in cooling channels relative to the reactant gasses is critical for thermal performance. Here, four different flow patterns for the serpentine channel and three different flow patterns for the straight channel are numerically studied based on index of uniform temperature (IUT), maximum temperature, and pressure drop. For the serpentine flow channel, the left-cross pattern has the lowest index of uniform temperature and maximum temperature, while the right-cross pattern has the highest. The parallel and left-cross patterns exhibits best and worst performances, respectively, in terms of cooling performance for the straight channel. Nearly the same pressure drops are obtained for all flow patterns of both channel configurations. When the parallel pattern is used instead of the counter pattern in the straight channel and the left-cross pattern is used instead of the right-cross pattern in the serpentine channel, the IUT improves by 55.45% and 27.39%, respectively.

Effect of the Catalyst Shapes and the Packed Bed Structure on the Efficiency of Steam Methane Reforming

One of the promising technologies for on-board hydrogen production is methane steam reforming in reactor with packed bed. The study of the effect of various catalytic packing arrangements on the steam methane reforming process is of considerable interest. The present article analyses the influence of catalyst shapes and packing arrangement on steam methane reforming reactions efficiency. The reformer tube contains several packings with a changing relative position; additionally, two forms of catalysts, a ball and a cylinder, are also used. The pressure drop depending on the packing location, methane conversion and hydrogen yield were analysed. It was found that the packing arrangement with spacing allows better distribution of the supplied heat. Due to the distance between the packing sections flow becomes more turbulent after each section, which intensifies the heat transfer and mixing of the mixture. The highest hydrogen yield is observed on catalytic packings located at a distance of 40 mm from each other and consisting of cylindrical catalysts. The most uniform pressure drop occurs at a packing arrangement without spacing. The increase in methane conversion observed with the increment in spacing distance, but the difference is insignificant. Therefore, the arrangement of catalysts with spacing can be used for the improvement of steam methane reforming process.

Design and Experimental Study of Intermittent Automatic Grouping Dropping Plug Seedling Mechanism of Fixed Seedling Cups

In a vegetable transplanting operation, if the seedling picking mechanism extracts the whole row of seedlings, the seedling separating mechanism needs to place the seedlings in groups. In this study, a seedling separating mechanism based on a fixed seedling cup was proposed to realize faster seedling grouping in a smaller volume. A collision model between the pot and the wall of the seedling dropping cylinder during the seedling dropping process was established. The duration of seedling dropping at different positions was analyzed. Subsequently, the calculation equations between the installation angle and the cam rotation speed and the dropping duration were derived. The net dropping duration of seedlings at different positions was measured. According to the measurement results, the installation angles of the driving cam at each position were calculated as 0°, 72°, 150°, 216°, and 288°, respectively. The seedling uniformity test was conducted according to the optimized installation angles. The test results revealed that the success rate of dropping seedlings was 100%, the coefficient of variation in dropping seedling interval at different positions was 6.25%, and the matrix damage rate was less than 10%, which verified the reliability of the dropping seedling principle. Finally, the stability tests results showed that the mechanism was able to complete the uniform seedling drop operation at a seeding frequency of 75~108 plants/(min · row) under the existing installation conditions. Therefore, the research results can provide a reference for the design and research of a subsequent traction-based automatic pot seedling transplanting machine.

Turbine specific fatigue life prediction model for wind turbine blade coatings subjected to rain erosion

The leading edge of a wind turbine blade is subjected to repeated impacts, by dust particles and rain droplets, leading to erosion. Hence, the surface of leading edge is painted or coated with protective coating materials to mitigate the erosion. However, even the coatings tend to fail and erode in fatigue under repetitive impact loading caused by these particles and water droplets. The numerical models available in the literature assume uniform tip velocity of the blade for fatigue life prediction of coatings. However, magnitude of rain drop impact induced erosion is dependent on the tip velocity, surface roughness and the rain intensities over the operating lifespan. The tip velocities of a turbine blade vary with the wind speed and the power characteristics of the turbine model. Thus, the wind velocity and tip velocity variation must be incorporated along with surface roughness for realistic estimation of erosion in wind turbine blade coatings. This paper presents a turbine specific computational framework to predict the fatigue life of the wind turbine blade coating against rain erosion using turbine power characteristics, annual wind velocity variation, blade profile and rain drop size distribution using finite element modelling. The coating surface is modelled for both smooth and rough surfaces to present the effect of surface roughness on the estimated fatigue life of the coating. It was found that the raindrop impact has no significant influence on the leading-edge erosion of a smooth coating surface. The obtained results show that the assumption of uniform tip velocity significantly overestimates the fatigue damage due to rain drop erosion. The surface roughness of the coating was found to be the most critical parameter in the rain induced erosion of the turbine coatings. Simulation results indicate a reduction in fatigue life with increased surface roughness and are qualitatively similar to experimental findings from literature. Results from the current study estimate the fatigue life of a coating with a surface roughness of 50 µm to be 1.36 years by considering an uniform drop diameter of 2.5 mm. This finding is in a good agreement with the on-site studies which report observations of erosion in turbine coatings between 1 and 3 years. The framework presented in this paper can be used for conducting realistic numerical and experimental investigations on the leading-edge erosion of the different turbine models and coatings. Furthermore, the numerical results presented can provide useful insights to wind turbine and turbine coating manufacturers in mitigating the leading-edge erosion.

Flow characteristics analysis for multi-path hydrogen supply within proton exchange membrane fuel cell stack

The flow rate distribution of hydrogen between single cells has a significant impact on the performance and durability of the entire proton exchange membrane fuel cell stack, especially for open-cathode stacks. However, few studies consider the effects of fuel distribution on output performance, pressure drop distribution, and temperature distribution simultaneously at the stack level. To investigate the effect of hydrogen distribution on the stack output characteristics, several different multi-path hydrogen supply modes are proposed and explored in this study through the combination of flow network models and experiments. Considering hydrogen reaction consumption in the calculation models. Parameters such as stack voltage, flow uniformity index, dimensionless pressure drop, and temperature uniformity index under different modes are quantitatively compared. The results show that Triple-path hydrogen supply mode has the highest stack voltage of 5.278 V at rated condition, 4% improvement over the lowest Z-shape mode. While Quad-path hydrogen supply mode has the best flow rate distribution and single-cell voltage uniformity, with a maximum voltage difference of only 0.073 V between single cells in the stack. Multi-path hydrogen supply modes provide more uniform pressure drop distribution over the conventional U and Z-shape (with a single path), but the relationship between output performance and the number of hydrogen supply paths is not simply linearly correlated. Furthermore, the whole stack temperature decreases with the increase of hydrogen supply path, but the temperature uniformity is not optimal with the maximum number of paths.

Investigation of liquid water behaviors inside a PEMFC cathode with a leaf-like biomimetic flow field design based on Murray’s Law

ABSTRACT Water management is the key to further improvement in the performance and durability of proton electrolyte membrane fuel cells (PEMFCs). The flow field inside the bipolar plates has a major role in managing the flooding process. Biomimetic flow field designs have been capturing the attention of researchers for their promising characteristics including uniform flow distribution and low pressure drop. Therefore, this study investigates liquid water behaviors inside a leaf-like biomimetic flow field design based on Murray’s Law using at the cathode of a PEMFC. The investigation is conducted using a computational simulation method utilizing the commercial software Ansys Fluent, in which the volume of fluid method is implemented for the three-dimensional, two-phase, unsteady flow simulation with the application of a dynamic contact angle model. The results are the general water transport process, the velocity, and pressure distribution inside the leaf-like biomimetic flow field design based on Murray’s Law.

Tunable thickness and uniform drop deposition of graphene oxide on porous anodic aluminum oxide and a reliable thickness measurement technique

The pinned contact line of sessile droplets containing micro/nanoparticles on a substrate results in nonuniform depositions with noncontrollable thicknesses, thereby producing the coffee-ring effect. In this study, we demonstrated that the thickness of graphene oxide (GO) films can be engineered using porous anodic aluminum oxide (AAO) substrates to fabricate uniform GO films. The outstanding thickness controllability and uniformity of GO films were obtained via tailorable hydrodynamic flow in a sessile droplet due to the pores of the AAO substrate. Furthermore, we developed a novel approach for measuring the micro/nanoscale thicknesses of GO films using an optical microscope. The thicknesses of the deposited GO film, measured via optical microscopy, demonstrated good agreement with those obtained via atomic force microscopy. These findings are beneficial for GO film applications, such as in wearable sensors, filtration, inkjet printing.

Wild Blueberry Fruit Drop: A Consequence of Seed Set?

Wild blueberry is a native plant managed as a crop in northeastern North America. Fruit drop in wild blueberry, Vaccinium angustifolium Aiton, was studied over 6 years (1996–1999, 2008 and 2011). Three hypotheses were tested regarding fruit drop mechanisms from plants (clones) sampled in the field: (1) proportional fruit drop; (2) constant or uniform fruit drop; and (3) pollen or resource limitation. In addition, the temporal rate of fruit drop was measured between the end of pollination (petal fall) and fruit maturity just prior to harvest (2008 and 2011). The dynamics of fruit drop were different in the two years. The role of pollination intensity in fruit drop was also assessed. Evidence for both proportional fruit drop and resource limitation at the clone level was found but only proportional drop at the field level. Low levels of seed set are associated with fruit drop. In a four-year study (1996–1999), fruit drop ranged from 23.3 to 49.4% of the total set fruit. Partitioning the variance in fruit drop between years, fields and clones (plant genotypes) showed that the highest variation is between stems within clones (37.4%) and clones (plant genotype) within fields (35.4%), followed by between fields (19.8%) and between years (7.4%).

Multiplexed electrospray emitters fabricated by rapid laser micromachining

This technical note documents the fabrication and performance of multiplexed electrospray emitters by rapid laser micromachining. A low cost 1064-nm fiber laser marker system is used to precisely, rapidly and selectively remove materials from a sheet of conductive silicone rubber, which is chemically inert. The laser pulse energy, scanning speed and machining path are judicially chosen to create clean and round micro posts that form external nozzle structures. This laser micromachining technique offers sufficient precision for ensuring uniform pressure drop across each fluid flow channel even at relatively low flow rate per nozzle. The uniformity of the operation from nozzle to nozzle is confirmed by measuring the diameter of each cone-jet. The results suggest that the laser micromachining is a rapid and convenient technique for fabricating multiplexed electrospray emitters.

Systematic assessment of the anode flow field hydrodynamics in a new circular PEM water electrolyser

In this work, we investigated the key underlying flow characteristics of a circular unit cell proton exchange membrane (PEM) water electrolyser. In particular, we focused on investigating anode flow field design using computational fluid dynamics (CFD) tool. Transient, 3D single phase fluid flow simulation results were presented, and in-house experiments were conducted for validation against CFD simulation data identifying key performance parameters of the PEM water electrolyser: uniform water distribution, pressure drop and hydraulic retention time. The effects of the water flow rate, inlet and outlet sizing and different number of inlet and outlet configurations were considered. The main observation from the study was discussed to provide insight into the factors affecting the flow pattern. Among the studied flow field design cases, it was found that the average pressure drop decreased with increase in number of inlets, also flow profile can be grouped into different set, depending on number of inlets. The correlation between pressure drop and mean velocity profile for different inlet and outlet configurations provides a useful basis to properly design the high performance PEM water electrolyser.

Uniform Spread of High-Speed Drops on Superhydrophobic Surface by Live-Oligomeric Surfactant Jamming.

Inkjet printing of water-based inks on superhydrophobic surfaces is important in high-resolution bioarray detection, chemical analysis, and high-performance electronic circuits and devices. Obtaining uniform spreading of a drop on a superhydrophobic surface is still a challenge. Uniform round drop spreading and high-resolution inkjet printing patterns are demonstrated on superhydrophobic surfaces without splash or rebound after high-speed impacting by introducing live-oligomeric surfactant adhesion. During impact, the live-oligomeric surfactant molecules aggregate into dynamic, wormlike micelle networks, which jam at the solid-liquid interface by entangling with the surface micro/nanostructures to pin the contact line and jam at the spreading periphery to keep the uniform spreading lamellar shape. This efficient uniform spreading of high-speed impact drops opens a promising avenue to control drop impact dynamics and achieve high-resolution printing.

Stochastic finite-fault method controlled by the fault rupture process and its application to the Ms 7.0 Lushan Earthquake

Fast and precise estimation of strong ground motion is important for seismic hazard responses and engineering purposes. Stochastic finite-fault methods are effective ground-motion time-series simulation methods using stochastic models of point-source spectra and considering physical parameters on finite faults. We propose two main modifications of current stochastic finite-fault methods to control the simulations. We replace the predetermined time function with different source time functions for each subfault to improve low-frequency results including the envelopes of accelerations and velocities. We replace the uniform stress drop with a distribution of non-uniform stress drops to reduce the dependence of simulated results on a single stress drop. The two modifications are applied to simulate ground motions of the 2013 Ms 7.0 Lushan earthquake. The simulation results agree with the observations in terms of acceleration, velocity, and pseudo-spectral acceleration (PSA). Damage estimates based on the simulated PSA also agree with the post-earthquake disaster investigation.

Detrimental effects of low-rank coal utilization to the operational condition of large capacity updraft moving-bed gasifier

ABSTRACT The feedstock of updraft Fixed-Bed Gasifier must meet very strict criteria such as low fragmentation, non-caking property and high ash fusion temperature (AFT), which represent the general characteristic of medium rank coal. In this paper, the properties of low-rank coal were carefully selected according to literature recommendations such as high AFT (above 1500°C), low grindability (HGI 55), swelling index (FSI 1) and lump size ranging from 30 to 80 mm. Thermal fragmentation was also evaluated by using sieve analysis and show Fd value of 0.81. After 90 h of service time, the temperatures of the vessel body declined gradually and 580 kg/h gasifier reactor was forced to shut down after 300 h. The rotating grate was found severely damaged with a large deposit of char. The OES, SEM, EDS and XRD analysis results confirmed each other that rotating grate has experienced excessively high temperature during gasification. It is likely that high breakage during devolatilization is the root cause of all operational problems. It causes melting of the cone, block the air exit ports, localize pressure drop, aggravate bed channeling, and so on. It is possible that FSI value is not necessarily to be low to maintain uniform pressure drop of the gasifier.

Transport and release of electron donors and alkalinity during reductive dechlorination by combined emulsified vegetable oil and colloidal Mg(OH)2: Laboratory sand column and microcosm tests

Emulsified vegetable oil combined with colloidal Mg(OH)2 (EVO-CM) can slowly release electron donors and OH– into groundwater and is therefore regarded as a promising amendment for enhanced in situ treatment of chlorinated solvents, such as tetrachloroethene (PCE) and trichloroethene (TCE). However, its migration ability in different porous media and the simultaneous release of electron donor and pH buffer during enhanced reductive dechlorination (ERD) have never been evaluated in detail. In this study, EVO-CM with uniform drop size and desirable stability was prepared. Laboratory-scale column tests were conducted to investigate the transport and spatial distribution of the EVO-CM in different porous media. Batch microcosm experiments were carried out to study the dechlorination efficiency under different EVO:Mg(OH)2 ratios. Experimental results indicate that prepared EVO-CM emulsions can be transported effectively through different porous media with grain size ranging from 0.1–1.0 mm. The emulsified vegetable oil (EVO) and colloidal Mg(OH)2 showed synchronous movement through the porous media column systems, providing both electron donor and alkalinity at the same location. The retention degree of EVO-CM is greater in the finer grained media and decreases with increasing distance from the inlet. The injection of EVO-CM lead to a significant mobilization of TCE in the column. The reductive dechlorination of TCE in the microcosms was remarkably enhanced in the presence of EVO-CM. The coaddition of sufficient colloidal Mg(OH)2 effectively limits the deleterious pH decline caused by acid release. The microcosm achieves an optimum dechlorination efficiency when the EVO:Mg(OH)2 ratio is 1:1.