Sink System Research Articles

Provenance of the Upper Carboniferous Yanghugou Formation in the Western Margin of the Ordos Basin, China: Constraints on Paleogeography and Basin Development

The Carboniferous Yanghugou Formation in the western margin of the Ordos Basin exhibits significant potential for oil and gas exploration. However, due to the influence of complex tectonic activities, there are substantial variations in stratigraphic thickness and depositional environments across the formation. The lack of a systematic source–sink comparative study has resulted in an unclear understanding of sediment sources and paleogeographic patterns, impacting the exploration for hydrocarbon accumulations. We conducted a comprehensive study of the source–sink system characteristics and paleogeography in the research area through field outcrop observations and drilling core sampling. By utilizing detrital zircon U–Pb geochronology and geochemistry, paleocurrent directions, lithofacies types, and sedimentary features, we delve into the understanding of the source–sink systems. Four major source–sink regions in the research area were identified: the Alxa, Yinshan, Alxa–Yinshan mixed and Qilian source–sink regions. The Alxa source–sink region formed a transitional delta-barrier-island sedimentary system. The northern part of the Yinshan source–sink region developed a transitional tidal-controlled delta-tidal-flat sedimentary system, while the southern deep-water area developed a shallow marine to semi-deep marine shelf sedimentary systems. The sediments of Alxa–Yinshan mixed source–sink region were deposited in a transitional tidal-controlled delta-tidal-flat barrier-island system. The Qilian source–sink region is characterized by small tidal-controlled delta-barrier-island system. From the analysis of the source–sink systems, it is inferred that the Alxa Block and the North China Craton had already merged before deposition of the late Carboniferous Yanghugou Formation. The delta sand bodies in the Alxa–Yinshan mixed source–sink region have the highest compositional and structural maturity, the best reservoir performance, and the great exploration potential.

Evaluating biomass sustainability: Why below-ground carbon sequestration matters

Biomass, as a raw material, has been identified as a crucial component of decarbonization strategies to mitigate climate change. Decisions on which biomass should be targeted for different purposes are dependent on variables such as availability, chemical composition, and sustainability. Consumer perception often positions non-wood sources, such as bamboo, as environmentally preferable feedstocks for fiber-based product production. Yet, this perceived environmental benefit lacks robust scientific substantiation and standardized methodologies. This study addresses this gap by conducting a cradle-to-gate life cycle assessment (LCA) of twelve biomass production systems encompassing tree plantations, dedicated crops, and agricultural residues for energy and bioproducts manufacture. The evaluated feedstocks include southern softwood, wheat straw, rice straw, rice husk, hemp hurd, sugarcane bagasse, switchgrass, biomass sorghum (United States), eucalyptus (Brazil), bamboo (China), and northern softwood (Canada). Incorporating a critical yet often overlooked factor, this LCA integrates the potential soil organic carbon sequestration (SOC) via below-ground biomass for each biomass type. This consideration significantly alters the estimated carbon intensity per ton of feedstock, potentially reshaping sustainability perceptions as certain systems emerge as carbon sinks. From a cradle-to-farm gate perspective, the assessed global warming potential for biomass production spans 12–245 kg CO2eq per oven-dry ton (ODt), factoring only anthropogenic emissions. However, when accounting for SOC sequestration, the range shifts to −170 to 228 kg CO2eq per ODt, highlighting the potential role of biomass to act as carbon sink systems. By illuminating the dynamic influence of SOC sequestration, this study contributes to a more comprehensive understanding of biomass-related carbon emissions, shedding light on pathways to mitigate environmental impact.

HEAT TRANSFER ANALYSIS OF A COMBINED PIEZOELECTRIC FAN–TRANSLATIONAL AGITATOR COOLING SYSTEM

This paper investigates the heat transfer characteristics of a channel system consisting of a finned heat sink and two piezoelectric devices, the piezoelectric fan (PF) and the piezoelectric translational agitator (PTA), both experimentally and computationally. In the proposed system, the mean flow is generated by a cantilevered PF, and the flow between the fins is agitated using a PTA. A single-channel system consisting of a PTA, the PF, and two fins is analyzed numerically using ANSYS Fluent software after validating numerical predictions against experimental measurements. The effect of design variables such as frequency ratio, phase difference, PF's tip distance from PTA, and squeezing fraction is explored. A PTA increases the heat transfer from the heated surfaces without incrementally aiding in the mass-flow rate. Velocity and temperature fields are plotted to understand the physics of the system for one complete cycle of a PTA blade. The concept of total Reynolds number that incorporates the effect of both axial and transverse fluid flow is used in this study. The Nusselt number increases with an increment in the total Reynolds number. It is noted that the integration of the PF and the PTA with the finned heat sink system has enhanced the heat transfer coefficient by 76.88% compared to the system with PTA and by 30.92% as compared to the system with the PF only.

Energy Transfer and Dissipation in Combined-Stiffness Nonlinear Energy Sink Systems

Abstract Nonlinear energy sinks (NES) are highly efficient vibration energy absorption and dissipation devices, and play an important vibration-suppression role in many types of structures. In this study, the influence of parameters on the combined stiffness nonlinear energy sink system is revealed from the perspective of energy, in which combined-stiffness terms are composed of piecewise linear stiffness and cubic stiffness. First, the slow-varying derivative of the combined-stiffness nonlinear energy sink system is calculated based on the complexification-averaging and multiscale methods. Second, an approximate expression for the extreme points on the slow-invariant manifold (SIM) of the system is derived by polynomial approximation, and the energy dissipation equation of the combined-stiffness nonlinear energy sink system is derived. The impacts of the stiffness gap, piecewise linear stiffness coefficient, and cubic stiffness coefficient on the system are analyzed by studying the energy transfer efficiency equation. Additionally, the relationship between the damping ratio of the primary structure and the dissipation time is analyzed.

Research on the optimal excitation threshold interval of targeted energy transfer for piezoelectric nonlinear energy sink

In this paper, in order to design a piezoelectric nonlinear energy sink system (NES), a coupling system of elastic plate and piezoelectric nonlinear energy sink is established. The nonlinear stiffness and damping are realized by the shunt circuit of piezoelectric materials. By using the harmonic balance method to analyze the forced vibration characteristics of the coupling system, it is found that within a certain range of harmonic excitation amplitude, the targeted energy transfer (TET) phenomenon occurs in the system. There is a threshold interval for the TET phenomenon of the system, where the TET does not occur when the excitation is less than the lower limit of the threshold. When the excitation exceeds the upper limit of the threshold, the system response appears a new high amplitude branch. The definite solution to the lower limit of the excitation threshold is determined, but when the system parameters are different, the high amplitude branch of the system response will appear above or below the amplitude of the platform. The results of this paper give the solution of the optimal TET excitation threshold interval in these two different cases and are helpful to design a NES for different applications.

Investigation on the thermal control and performance of PCM–porous media-integrated heat sink systems: Deep neural network modelling employing experimental correlations

Phase change material (PCM)-based heat sinks can offer reliable and effective thermal management (TM) solutions for increasingly sophisticated applications. A critical aspect of such heat sinks is determining how long it takes them to reach a set-point temperature. However, no generalised method exists in the literature that can predict and interpret the thermal performance of a wide range of PCM–porous media-integrated heat sinks. In this regard, this study examines the heat transfer characteristics of PCM-based heat sinks integrated with various metallic foams through experimental and deep learning (DL) techniques. The experiments are performed for transient TM analysis of various PCM-based heat sinks. Diverse variables, including foam porosity (0.95–0.97), PCM fraction (0.6–0.8), heat flux (0.8–2.4 kW/m2), foam materials (Fe–Ni alloy, Ni and copper) and PCM type (RT-35HC, RT-44HC, RT-54HC and paraffin wax), are investigated in this study. The experimental data are fed to the optimal DL model using the Bayesian surrogate model-tuned hyperparameters. Utilising a correlation analysis, as exemplified by the heat map and correlation plot, in conjunction with explainable artificial intelligence, it has been deduced that the thermal performance of the heat sink is principally influenced by factors such as PCM type, PCM fraction, foam material, foam porosity, and heat flux. Comparing the model's predicted data with the empirical findings, a good agreement was observed. Specifically, the mean absolute error (MAE) for the anticipated temperature and gradient registered at 0.0438 and 0.0054, whilst the mean square error (MSE) manifested values of 0.0579 and 0.0087, respectively. The proposed model can accurately assess the heat sink's thermal performance (correlation coefficient, R2 = 0.99) for various PCM types, fractions, foam materials, applied heat flux and foam porosity.

Quasi-periodic oscillation characteristics of a nonlinear energy sink system under harmonic excitation

Quasi-periodic oscillation characteristics of a nonlinear energy sink (NES) system under harmonic excitation are studied in this work. It is found that there exist uniformly distributed sidebands in frequency spectra of quasi-periodic oscillations. The traditional incremental harmonic balance (IHB) method and the IHB method with two time-scales are used to obtain accurate frequency components and amplitudes of periodic responses and two different quasi-periodic oscillations of the system, respectively, with variations of the external excitation frequency and amplitude. The two different quasi-periodic oscillation characteristics are analyzed; energy absorption of the NES system under different excitation frequencies and amplitudes is also analyzed. Stability of quasi-periodic solutions obtained from the IHB method with two time-scales is analyzed by the Floquet theory. Analytical results obtained from the traditional IHB method and the IHB method with two time-scales agree very well with those from numerical integration using the fourth-order Runge–Kutta method. Results show that the efficiency of energy absorption of a strongly quasi-periodic oscillation is greater than those of a periodic response and a weakly quasi-periodic oscillation.

Multi-objective inverse design of finned heat sink system with physics-informed neural networks

This study proposes a new inverse design method that utilizes a physics-informed neural network (PINN) to parameterize the geometric and operating inputs, enabling the identification of optimal heat sink designs by starting with the desired objectives and working backward. A specialized hybrid PINN is designed to accurately approximate the governing equations of the conjugate heat transfer processes. On this basis, a surrogate model derived from the hybrid PINN is constructed and integrated with multi-objective optimization and decision-making algorithms. The results of an example finned heat sink system are presented, showcasing the accelerated search for Pareto-optimal designs. The proposed method nearly halved the search time to approximately 113.9 h in comparison with the traditional methods. Moreover, three representative scenarios—high-performance design, equilibrium design, and low-cost design —were compared to visualize the real-time changes in the multiphysics field, facilitating improved physical inspection and understanding of the optimal designs.

Autonomous Thermosiphon System of Passive Residual Heat Removal from the Primary Circuit of the Reactor Plant: Features of Operation, Characteristics and Basic Advantages

An autonomous system of passive removal of residual heat (PRRHS) of a reactor installation with VVER designed to ensure the safety of nuclear power plants in an accident with complete long-term blackout is considered. The system provides for the removal of heat directly from the first circuit of the reactor plant (PRRHS R). In order to increase the reliability and safety of the emergency heat sink, heat exchange equipment based on closed-type evaporation and condensation devices – two-phase thermosyphons – has been used in the system. The main feature of such heat exchangers is that their thermosiphon assemblies structurally separate the primary circuit and the auxiliary circuit of the PRRHS, which is removed outside the reactor compartment, and provide safe and efficient heat removal, reduce the risk of radioactive contamination spreading beyond safety barriers. Such autonomous passive systems will provide effective heat removal directly from the primary circuit by changing the chain of successive heat transfer sites from nuclear fuel to the final absorber and excluding from it such elements, as for example steam generators, the condition and operability of which in the emergency process of heat removal have a major impact on the safety of the reactor core. The article presents a diagram of an autonomous heat sink system; also, a description of its operation is given. The main characteristics of the course of the emergency process of removal of residual heat by the autonomous thermosiphon PRRHS R obtained by computational modeling have been considered. The advantages of an autonomous thermosiphon passive system in comparison with a passive heat removal system of a reactor installation with VVER through the second circuit are analyzed. The obtained results are proposed to solve the problems of diversification of passive safety systems of evolutionary reactor plants of nuclear power plants with VVER type reactors.

Mechanized shaft sinking system

Mechanized shaft sinking system

A review of applied research on low-carbon urban design: based on scientific knowledge mapping.

The construction of low-carbon cities is an essential component of sustainable urban development. However, there is a lack of a comprehensive low-carbon city design and evaluation system that incorporates "carbon sink accounting-remote sensing monitoring-numerical modelling-design and application" in an all-around linkage, multi-scale coupling, and localized effects. This paper utilizes the Citespace tool to evaluate low-carbon city design applications by analyzing literature in the Web of Science (WOS) core collection database. The results reveal that low-carbon cities undergo four stages: "measurement-implementation-regulation - management." The research themes are divided into three core clustering evolutionary pathways: "extension of carbon sink functions," "spatialisation of carbon sink systems," and "full-cycle, full-dimensional decarbonisation." Applications include "Utility studies of multi-scale carbon sink assessments," "Correlation analysis of carbon sink influencing factors," "Predictive characterisation of multiple planning scenarios," and "Spatial planning applications of urban sink enhancement." Future low-carbon city construction should incorporate intelligent algorithm technology in real-time to provide a strong design basis for multi-scale urban spatial design with the features of "high-precision accounting, full-cycle assessment and low-energy concept."

Assembly Device for Supermodules of Silicon Tracking System of the BM@N Experiment

The silicon tracking system of the BM@N experiment consists of four stations based on double-sided microstrip silicon sensors. The sensors make it possible to obtain a spatial resolution for tracks of secondary charged particles up to 17 μm. Two ASIC boards, the input channels of which are connected to the strips with ultralight (0.23% X0) aluminum flex cables, are used to readout and process signals from both sides of the sensor. Such an assembly is called a module. Silicon sensors are mounted on lightweight carbon-fiber support trusses in a way that the dead zones at the edges are overlapped due to the tiled layout. The frontend electronics are housed in metal containers with a heat sink system located at the rare ends of the carbon-fiber support truss. A set of modules attached to the carbon-fiber support truss with two containers with readout electronics at the ends is called a supermodule. The accuracy of the sensor positioning in the station plane plays a crucial role in limiting the degrees of freedom of the parameters determined by the software during the final alignment of the tracking system elements. A special device that allows mounting sensors on a carbon fiber truss with an accuracy of up to 15 µm on a 1200 mm base is developed to assemble supermodules. The results of testing the device are given.

Novel design of thermo-electric air conditioning system integrated with PV panel for electric vehicles: Performance evaluation

Traditional air conditioning may be inappropriate for electric vehicles due to its moving parts noise besides using chlorofluorocarbons that harm the environment. In addition, it consumes a significant portion of the stored energy in batteries, reducing the vehicle's driving range. So, in this paper, a novel design of thermo-electric cooling (TEC) system coupled with a photovoltaic (PV) panel replacing the vehicle roof is studied. This system consists of a sandwich of PV panel outside the vehicle and TEC inside with a heat sink system integrated between them. The air temperature variation in the cabin during the daytime is predicted by solving a complete mathematical transient thermal model of the whole system before and after mounting the cooling system. The air streams through the vehicle moving are exploited to improve the TEC and PV system performance. The system performance is investigated for different cases during the day with and without including the PV output power and for the vehicle parks inside or outside. The results indicate that, for each scenario, the number of used TEC modules influences the system performance where the best number varies between 128 and 98. Coupling the PV panel with the TEC system reduces the daily required energy from batteries by about 19%. Running the TEC system during parking from 8 to 10 am decreases the cabin air temperature from 47.5 to 34°C while the input power declines by about 45%, which reduces the interior temperature to 25°C in 10 min (transition time). The contribution of the PV panel based on the studied conditions can increase the range of the vehicle by 10.4 km/day and about 160kWh/year energy saving. The reduction in the input power during transition time reaches 27.8% when the vehicle speed increases from 30 to 60 km/h, while this ratio declines to 10.8% as the vehicle speed rises from 60 to 90 km/h. During vehicle moving, powering the TEC system by the PV panel only can prevent the cabin temperature from rising over 40°C, whereas during parking, there is an optimum fan air velocity that gives the maximum reduction of the cabin temperature.

Exploring meteorological droughts' spatial patterns across Europe through complex network theory

Abstract. In this paper we investigate the spatial patterns and features of meteorological droughts in Europe using concepts and methods derived from complex network theory. Using event synchronization analysis, we uncover robust meteorological drought continental networks based on the co-occurrence of these events at different locations within a season from 1981 to 2020 and compare the results for four accumulation periods of rainfall. Each continental network is then further examined to unveil regional clusters which are characterized in terms of droughts' geographical propagation and source–sink systems. While introducing new methodologies in general climate network reconstruction from raw data, our approach brings out key aspects concerning drought spatial dynamics, which could potentially support droughts' forecast.

Причины различий между коэффициентами упора винта при работе за корпусом судна и в свободной воде на швартовых

Object and purpose of research. The object of research is the results of self-propelled ship tests in bollard-pull conditions. The purpose is to analyse the hydrodynamic sources giving rise to differences between propeller thrust coefficient in open-water and behind-hull conditions. Materials and methods. Analysis based on the ideal propeller theory shows that the velocity ΔV of inflow on propeller operating behind ship hull in bollard-pull conditions caused by a system of sinks, ensuring flow attachment to hull surface, has a finite value and is actually the effective wake. The wake velocity for an open-water propeller is equal to the behind hull velocity. The open-water propeller thrust coefficient at advance ratio (formula) is due to the opposed jet of its reversal. It is shown that the thrust coefficient deviations at self-propelled tests in open-water has to do with the specifics of propeller thrust variations in the operating area adjacent to bollard-pull conditions. Boundaries of the operating area where the opposed jet affects the propeller curve at self-propelled tests are defined. Practical conclusions and recommendations are given following from the obtained data. Main results. The source of discrepancies between self-propelled test results for open-water propeller in bollard pull conditions and close operating area has been found. Recommendations are given on updating the test procedures for propeller and self-propelled model tests Conclusion. The paper is expected to be useful for understanding the ambiguity of self-propelled test results.

Thermal and hydrodynamic management of a finned-microchannel heat sink applying artificial neural network

Thermal management of microelectronic circuits will be one of the most difficult challenges facing engineering processes in the near future. High operating temperatures in these devices can degrade the reliability of the components and reduce their life. Therefore, effective cooling technologies that can disperse the significant heat load from the surface of microelectronic equipment are required. An appropriate microchannel heat sink (MCHS) system with optimized geometry can be one of the reliable choices. In the current work, an artificial neural network (ANN) is exerted to optimize the geometry of a finned-MCHS. The distance of fins from the inlet in the second row (l), the distance of fins from the side walls in the first and third rows (t), and the angle of hexagons (θ) are the input parameters. According to the obtained results, the ANN model with a coefficient of determination of 0.999 performed well in predicting the Nusselt number (Nu) and pressure drop (ΔP). Among the investigated input parameters, the variations of the parameter of t affected the thermal and hydrodynamic properties of the device noticeably. Besides, the ANN model suggested that when the optimum values of input parameters (i.e., l = 7.636 mm, t = 4 mm, and θ = 140) are used for the hexagonal fins inside a microchannel, the maximum relative efficiency index of 1.491 can be acquired.

PV-TEG output: Comparison with heat sink and graphite sheet as heat dissipators

This paper finds that PV-TEG systems are well-researched. Different techniques are applied to regulate the heat (or dissipate the heat) in these systems. However, the research shows insufficient data regarding TEG as a heat-utilizing and heat-to-electrical energy-converting agent. So, this paper shows the usage of graphite sheets and heat sinks with PV-TEG systems and their comparison. The investigation demonstrates that at 823 W/m2 of solar irradiation, PV-TEG without heat dissipators transforms PV backside heat into TEG DC voltage of 0.727 V; PV-TEG with graphite sheet TEG voltage is 0.889 V; and PV-TEG with heat sink TEG voltage is 1.476 V. The PV-TEG with graphite sheet system improves TEG voltage up to 0.241 V and DC voltage gain up to 0.75 times for TEG alone. In addition, the temperature difference between the hot side and cold side is up to 3.92 C. PV-TEG with a heat sink system improves TEG voltage up to 0.749 V, provides a DC voltage gain of up to 1.78 times for TEG alone, and increases the temperature difference between the hot side and the cold side up to 5.96 °C.

Design and Simulation Analysis of Semi-Active Lifting and Sinking Compensation System

The lifting and sinking motion generated by the drilling platform causes large fluctuations in the suspension tension of the large hook, which affects the stability of the drilling pressure acting on the rock at the bottom of the well, greatly reduces the efficiency of drilling and decreases the service life of the drill bit and the drill column under the action of cyclically varying loads, causing an increase in the overall drilling cost. In order to avoid the above situation, a nonlinear model of a semi-active lift-sink compensation system is designed and a method to improve the compensation efficiency of the system is proposed. Firstly, the relevant physical model of the hydraulic system is established, and then its simulation model is built according to the working principle of the semi-active lift and sink compensation system. Then the effects of different factors are added to the simulation model of semi-active lifting and sinking compensation, and finally the effects of different factors on the compensation efficiency of the active lifting and sinking system are compared. The simulation results show that a regular sinusoidal wave with a peak value of 6.5 m and a period of 10 s as the ship's lifting and sinking displacement input will reduce the compensation efficiency of the semi-active lifting and sinking compensation system, while the smaller the stiffness of the wire rope, the better the compensation effect of the drill column and the higher the compensation accuracy. The proposed method can effectively improve the compensation efficiency of semi-active lifting and sinking compensation system.

Strong diurnal variability of carbon dioxide flux over algae-shellfish aquaculture ponds revealed by eddy covariance measurements

Aquaculture ponds represent a biogeochemical hotspot of the global carbon cycle. However, accurate estimations of their carbon budgets are hindered by a limited understanding of the temporal variability of carbon fluxes across time scales. In this study, the eddy covariance (EC) approach was applied to quantify net ecosystem CO2 exchange (NEE) over algae-shellfish aquaculture ponds (razor clam cultivation) in Zhangjiang Estuary of Southeast China from January 2020 to June 2022, aiming to assess the diurnal variability of NEE during various management periods. The EC-based NEE over the ponds showed strong diurnal variations with daytime sink and nighttime source, mainly controlled by photosynthetically active radiation and air temperature, respectively. The ponds acted as a net sink system during razor clam (daily mean flux of −0.42 μmol m−2 s−1) and shrimp-crab (−0.50 μmol m−2 s−1) farming periods with a stronger daytime sink than a nighttime source, while it was the opposite during the drainage period acting as a net source (0.40 μmol m−2 s−1). The strength of sink/source also differed between the early and late stages of the razor clam farming period, with much larger (∼ 16 times) net carbon uptake in the late stage as a result of the strong daytime sink and near-neutral nighttime flux. The diurnal variability of NEE over the ponds was overall larger than other aquatic ecosystems and tended to increase with air temperature. Previous estimates of daily NEE from discrete daytime-only samplings might have biased the actual carbon budgets if no diurnal correction was applied in the temporal aggregation. The confirmed strong temporal variability of NEE across time scales highlighted the importance and necessity of continuous and high-frequency flux measurements in assessing the carbon budgets of algae-shellfish aquaculture ponds.

Research progress on calculation method and impact factors of carbon sequestration capacity in urban ecosystems

Achieving carbon neutrality is an urgent, complex and arduous task in China. How to effectively exert carbon sequestration and improve carbon sequestration capacity of urban ecosystems should be solved. Compared with other terrestrial ecosystem types, frequent anthropogenic activities lead to more abundant carbon sink elements of urban ecosystems and more complex factors affecting their carbon sequestration capacity. Based on researches at multiple spatial and temporal scales, we analyzed key factors affecting the carbon sequestration capacity of urban ecosystems from different perspectives. We illuminated the composition and characteristics of carbon sinks of urban ecosystems, summarized the methods and characteristics of carbon sequestration capacity of urban ecosystems, and revealed the impact factors of carbon sequestration capacity of different carbon sink elements and the comprehensive impact factors of carbon sinks of urban ecosystems under the influence of human activities. With the continuous improved understanding of carbon sinks of urban ecosystems, it is necessary to further improve the accounting method of carbon sequestration capacity of artificial carbon sink systems, explore the key impact factors of comprehensive carbon sequestration capacity, change the research method from global to spatially weighted, discover the spatial coupling relationship between artificial and natural carbon sink systems, find out the optimal artificial-natural spatial configuration to achieve carbon sequestration capacity enhancement, break the limitations of increasing carbon sink of urban ecosystems, and finally contribute to the achievement of the urban carbon neutrality goal.