Storage Capacity Research Articles

Elementi per la pianificazione di una transizione energetica sostenibile in Italia

Starting from analysing the Italian strategy for the ecological transition, this paper faces the sustainability of energy planning. While the need to decarbonise our economy is a matter of fact, the strategy to reach the carbon neutrality objective in 2050 must be more convincing. In particular, two aspects of renewable energy transition are analysed in this paper: spatial energy density and raw material consumption. The comparison between traditional fossil energy sources and renewable ones (in particular, solar and biomass energy), and related storage capacity demand through batteries or hydrogen generation, shows a much greater impact of the latter on land and raw materials consumption. The substantial implications reverberate on the techno-economical, environmental, social and political levels. The paper concludes with suggestions on integrating energy planning strategy with more sustainable solutions, including nuclear power plants.

CO2 Storage Capacity Classification and Compliance

CO2 Storage Capacity Classification and Compliance

Numerical simulation of the coupled thermal-hydro-mechanical fields for evaluating CO2 geo-sequestration storage in deep saline aquifers of Hainan Fushan Sag, China

Geo-sequestration storage of CO2 in saline aquifers is an important technological option to reduce carbon emissions in China in the future. The theory of geo-sequestration storage of CO2 in saline aquifers involves complex physical operations and chemical phenomena among reservoir stress, seepage, and temperature fields, and the numerical simulation models coupling thermal-hydro-mechanical (THM) fields are widely applied to analyze the evolution of multiphysical processes in CO2 reservoirs. Based on the geo-sequestration storage project of saline aquifer CO2 in Fushan Sag, Hainan Province, under the premise of considering the change of permeability and porosity after the mineralization of CO2 in the rock reservoirs, this study simulates the evolution of temperature, stress, and seepage fields during the sequestration process of saline aquifer Continuous CO2 injection wells clarifies the range of influence of the temperature field, seepage field, and the boundary of its stress field of saline aquifer Continuous CO2 injection wells in different sequestration periods. It reveals the influence mechanism of the fault structure on the reservoir CO2 sequestration pressure and capacity, and evaluates and estimates the CO2 injection storage capacity of Fu 1# well in Fushan Sag and on this basis. The THM numerical simulation model proposed in this study plays a crucial role in guiding theoretical evaluations of the CO2 geo-sequestration potential in saline aquifers and determining its technical parameters, thereby offering significant value for engineering applications.

Dual storage mechanism of Bi2O3/Co3O4/MWCNT composite as an anode for lithium-ion battery and lithium-ion capacitor

Bismuth oxide(Bi2O3) and cobalt oxide(Co3O4) are promising owing to their unique properties, high storage capacity, low cost, and eco-friendliness, making them ideal for lithium-ion batteries(LIBs) and lithium-ion capacitors(LICs) anodes. This study presents the synthesis and thorough characterization of Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT composites as potential LIB and LIC anode materials. The materials are synthesized using a hydrothermal process succeeded by annealing. Structural, morphological, and compositional studies were analyzed. Various tests evaluated electrochemical performance, including cyclic voltammetry(CV), confirming a dual storage mechanism like alloying and conversion reaction involved for better energy storage. Specific discharge capacities of 834 mAh/g and 1184 mAh/g were recorded for Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT composite electrodes at a current density of 100 mA/g, respectively. The composite material exhibited notably enhanced rate capability, with 31 % and 51 % discharge capacities for Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT, respectively. The cyclic stability assessment revealed that Bi2O3/Co3O4 and Bi2O3/Co3O4/MWCNT maintained a high coulombic efficiency of around 99 % over 250 charge–discharge cycles at a high current density of 1 A/g. The capacity retention was approximately 253 mAh/g for Bi2O3/Co3O4 and 439 mAh/g for the Bi2O3/Co3O4/MWCNT composite, indicating excellent cyclic stability and minimal energy loss during cycling. Moreover, the LICs assembly of Bi2O3/Co3O4/MWCNT//CB was investigated, revealing a power density of 200 W kg−1 alongside an energy density of 8.64 Wh kg−1. The cyclic stability assessment over 10,000 cycles exhibits a capacity retention of approximately 45 % under a high current density of 2 A/g.

Big Data (R)evolution in Geography: Complexity Modelling in the Last Two Decades

ABSTRACTThe use of data and statistics along with computational systems heralded the beginning of a quantitative revolution in Geography. Use of simulation models (Cellular Automata and Agent‐Based Models) followed in the late 1990s, with ontology and epistemology of complexity theory and modelling being defined a little less than two decades ago. We are, however, entering a new era where sensors regularly collect and update large amounts of spatio‐temporal data. We define this ‘Big Data’ as geolocated data collected in sufficiently high volume (exceeding storage capacities of the largest personal hard drives currently available), that is updated at least daily, from a variety of sources in different formats, often without recourse to verification of its accuracy. We then identify the exponential growth in the use of complexity simulation models in the past two decades via an extensive literature review (broken down by application area), but also notice a recent slowdown. Further, a gap in the utilisation of Big Data by modellers to calibrate and validate their models is noted, which we attribute to data availability issues. We contend that Big Data can significantly boost simulation modelling, if certain constraints and issues are managed properly.

A high-capacity and self-healable electrochromic system based on I0/CuI conversion reaction

Constructing electrochromic devices (ECDs) requires high-performance electrochromic electrodes with not only high color contrasts, but also large charge storage capacities. In this paper, a I0/CuI conversion-type electrochromic system is developed, achieving reversible and profound color switching between colorless transparent and dark brown, while delivering a large charge storage capacity of 246.7 mA h g−1. To improve switching durability, a multifunctional P10 (Polyquaternium-10) binder is introduced into the electrode, which can effectively confine the polyiodide intermediates and suppress the shuttle effect. At the same time, the CuI/Cu redox couple is further activated by controlling the applied voltage. The generated Cu from this couple can spontaneously react with residual I0 species and facilitate the conversion from I0 to CuI, and therefore in-situ rejuvenate the degraded electrochromic performance. Thanks to these rational designs, this electrochromic electrode achieves rapid response speeds (tcoloring: 14 s, tbleaching: 5 s), high optical modulation amplitude (73.4 % at 500 nm), decant coloration efficiency (57.0 cm2 C−1) and impressive cycle stability (without performance degradation after 150 cycles). This work provides a novel electrochromic system for the construction of high-performance electrochromic devices.

Giant energy storage capacity of graphene quantum dots prepared by facile method

Supercapattery technology focuses on high specific capacity with both high energy density and power density. In the present work, the electrochemical performance of Graphene quantum dots (GQDs) is compared with graphene oxide (GO). GO is synthesized by the modified Hummer's method. Less than 5 nm size of GQDs are synthesized by a facile chemical cutting method. High frequency vibrational mode of sp-sp2 bonded carbon at 2198 cm−1 is revealed from Raman analysis. The energy gap of GQDs of different sizes was calculated using the Quantum Espresso code based on Plane-Wave Self-Consistent Field (PWSCF). The forbidden gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels with the size of the GQDs cluster. The electrochemical results show that GQDs exhibit pseudocapacitor behavior with high specific capacity and energy density of 1516.7C/g and 425.9 Whkg−1 respectively at current density of 4 A/g. This is very high compared to the electric double layer capacitor (EDLC) behavior (115C/g) of GO. These results illustrate enhanced electrochemical performance, electrical conductivity and ion transport rate implying that the material can facilitate the movement of ions within the device, allowing for fast charging and discharging.

Toward high-integrity forest carbon market of ethnic minority groups in Dak Lak province, Vietnam

Forest carbon markets have demonstrated numerous benefits across economic, social, and environmental dimensions, while also advancing sustainable development goals. This study examines the primary policy mechanisms and conditions related to the development of high-integrity forest carbon markets in Dak Lak province, Vietnam. Utilizing a combination of SWOT analysis and the DPSIR framework, the study provides a comprehensive evaluation of the opportunities, challenges, driving forces, pressures, potential impacts, and responses associated with developing these markets. The Gold Standard method was also employed to estimate the potential contribution to carbon emission reductions through the new forest planting programs in the province. Data analysis from 202 households and in-depth interviews with fifteen experts revealed that local residents have limited information about the forest carbon market. While forest management officials at various levels are aware of the market, there is a lack of specific guidance, limited participation in training sessions and workshops, and insufficient instructional materials. Dak Lak holds significant potential for carbon emission reductions, with an estimated average forest carbon storage capacity of 7.5 tCO2/ha/year for an afforestation/reforestation (A/R) carbon project. This initiative is projected to contribute approximately $753,972 annually to the province's GRDP and generate 280 jobs for local communities. However, the technical and financial resources are challenging in the province. The study identifies critical issues and proposes appropriate solutions to support Dak Lak in developing high-integrity forest carbon markets in alignment with the national roadmap, ultimately contributing to the achievement of sustainable development goals.

Experimental study on natural convection heat transfer performance of microencapsulated phase change material slurry in a square cavity

Microencapsulated phase change slurry (MicroEPCMS), consisting of microencapsulated phase change material (MicroEPCM) and base liquid, represents a novel latent heat functional fluid that can absorb a large amount of heat within its phase change temperature range. It has found widespread use as a functional liquid cooling medium for heat dissipation in batteries, electronic devices, and other devices. In this work, MicroEPCMS with different MicroEPCM concentration were prepared. The physical properties of MicroEPCMS including density, thermal conductivity, and dynamic viscosity were tested within different temperature ranges. The results showed that the MicroEPCMS exhibits a superior thermal energy storage capacity compared to water. In the phase change range of MicroEPCM, the MicroEPCMS has a higher thermal conductivity compared to water. In addition, the natural convection heat transfer characteristics of MicroEPCMS in a square cavity were investigated under varying heating power. The results indicated that MicroEPCMS can enhance natural convection heat transfer by absorbing heat with a minimal temperature rise during the phase change process compared to water. Moreover, higher heating power enables natural convection enhancement of MicroEPCMS in a square cavity. These results underscore the significant potential of MicroEPCMS as a functional liquid cooling medium for applications in thermal energy storage and thermal management.

Rational design of biofunctional borosilicate glasses: Tuning therapeutic ions and in vitro biological evaluation

Introducing therapeutic ions of bioactive glasses as scaffolds is appealing due to attractive architectural biomimicry of bone extracellular matrix and adjustable composition accompanied with soluble ions released for bone regeneration and remodeling. Herein, this strategy was expanded to develop biocomposites of borosilicate glasses incorporated with different therapeutic ions using a facile sol-gel technique and cetyltrimethylammonium bromide (CTAB) as the template. Mediating therapeutic ions (i.e., copper/selenium/strontium at the same content) in a SiO2–B2O3–CaO–P2O5 glassy system is effective and simple method for modifying structural-morphological features and physicochemical characteristics of the bioglasses. In vitro bioactivity measurements revealed that strontium/selenium-doped borosilicate glasses had faster apatite-formation ability compared to copper-doped borosilicate glasses. For in vitro drug release, rhodamine B (RB) storage and release showed that copper-doped borosilicate glasses had high storage capacities (79.42 %) and cumulated release rate (87.18 % at pH 1.2), and demonstrated sustained pH-sensitive drug release patterns. The RB release profiles also showed two-stage release mechanism following the Korsmeyer-Peppas model during the first release stage (the first 24 h), and the Weibull model during next stage (beyond 24 h). In subsequent bacterial studies, copper-doped borosilicate glasses could effectively inhibit (100 % at 2.5 mg mL−1) Escherichia coli and Staphylococcus aureus colonization. In vitro biocompatibility assays also showed that all bioglass samples were biocompatible. According to obtained data, present bicomponent composite strategy may pave the way for the design of bioglasses doped with functional ions tailored to induce biological activity that can heal infectious bone in vivo.

Experimental and theoretical study on high hydrogen storage performance of Mg(NH2)2-2LiH composite system driven by nano CeO2 oxygen vacancies

The magnesium based metal hydrogen storage composite system Mg(NH2)2-2LiH has a theoretical hydrogen storage capacity of 5.6 wt.% and is a promising hydrogen storage material for vehicles. However, its application is limited due to serious thermodynamic and kinetic barriers. Introducing efficient catalysts is an effective method to improve the hydrogen storage performance of Mg(NH2)2-2LiH. This article investigates for the first time the use of nano rare earth oxide CeO2 (∼44.5 nm) as an efficient modifier, achieving comprehensive regulation of the hydrogen storage performance of Mg(NH2)2-2LiH composite system through oxygen vacancy driven catalysis. The modification mechanism of nano CeO2 is also systematically studied using density functional theory (DFT) calculations and experimental results. Research has shown that the comprehensive hydrogen storage performance of the Mg(NH2)2-2LiH-5 wt.% CeO2 composite system is optimal, with high hydrogen absorption and desorption kinetics and reversible performance. The initial hydrogen absorption and desorption temperatures of the composite system were significantly reduced from 110/130°C to 65/80°C, and the release of by-product ammonia was significantly inhibited. Under the conditions of 170°C/50 min and 180°C/100 min, 4.37 wt.% of hydrogen can be rapidly absorbed and released. After 10 cycles of hydrogen release, the hydrogen cycle retention rate increased from 85% to nearly 100%. Further mechanistic studies have shown that the nano CeO2−x generated in situ during hydrogen evolution can effectively weaken the Mg–N and N–H bonds of Mg(NH2)2, exhibiting good catalytic effects. Meanwhile, oxygen vacancies provide a fast pathway for the diffusion of hydrogen atoms in the composite system. In addition, nano CeO2−x can effectively inhibit the polycrystalline transformation of the hydrogen evolving product Li2MgN2H2 in the system at high temperatures, reducing the difficulty of re-hydrogenation of the system. This study provides an innovative perspective for the efficient modification of magnesium based metal hydrogen storage composite materials using rare earth based catalysts, and also provides a reference for regulating the comprehensive hydrogen storage performance of hydrogen storage materials using rare earth catalysts with oxygen vacancies.

Reduced Na–S bond adsorption of WSSe enabling fast reaction kinetics in the sodium-ion battery

WS2, a two-dimensional layered material, is promising as sodium-ion batteries (SIBs) anode due to its large interlamellar spacing and high sodium storage capacity. However, its low electronic conductivity and high Na+ adsorption energy hinder reaction kinetics. Here we demonstrate that substituting Se for part of the S in WS2 reduces interlayer Na+ adsorption and increases electronic conductivity. Based on this finding, lamellar WSSe, grown in situ on peanut shell-derived carbon (PSDC/WSSe), is elaborately designed as a highly stable SIB anode with a fast kinetic. PSDC/WSSe with carbon matrix and Se substitution simultaneously provides fast electron transport channels and lowered Na+ transport barriers (0.22 eV). The PSDC/WSSe anode offers a considerable reversible sodium storage capacity (288.0 mAh g−1 after 1000 cycles at 1.0 A g−1) and a fast kinetic reaction. A SIB full-cell using a PSDC/WSSe anode and Na3V2(PO4)3 cathode achieves a 215.4 Wh kg−1 high energy density, and successfully powers LEDs. This work offers new strategies to lower sodium ion transportation barrier in two-dimensional layered materials.

Significantly enhanced high-temperature energy storage capacity for polyetherimide-based nanocomposites via energy level modulation and electrostatic crosslinking

In the field of electrostatic energy storage, polymers exhibit notable advantages, including high breakdown strength (Eb) and fast charge/discharge rates. However, at elevated temperatures, their discharge energy density (Ud) decreases due to reduced Eb and increased electrical conductivity losses. We herein integrate fluoro-functionalized polyimide (PFI) shell-modified Al2O3 nanoparticles (PFI@Al2O3) with polyetherimide (PEI) to form a trap-rich electrostatic crosslinked network. By energy level modulation and electrostatic crosslinking, the PFI layer enables to capture charges and acts as crosslinking sites, while the wide-bandgap Al2O3 introduces energy barriers that inhibit charge injection and migration. This sophisticated dual-interface design enhances Eb and facilitates dual capture of electrons and holes, thus effectively reducing leakage current and conduction losses. Surprisingly, the composites prepared using this method exhibit an energy density of 7.24 J/cm³ at 150 °C, with a charging-discharging efficiency of 83.58 %. Moreover, it maintains stability even after 105 extended charge-discharge cycles under harsh conditions (200 kV/mm and 150 °C). This work lays a solid foundation for electrostatic energy storage at elevated temperature.

Enhancing light energy harvesting and storage properties of cellulose acetate/azobenzene films through perylene photosensitization

This study presents a straightforward approach to enhancing the light energy capture and storage properties of cellulose acetate/azobenzene (CA/Azb) films through photosensitization with a perylene derivative (Py). The films' photoisomerization (trans-to-cis) and reverse isomerization (cis-to-trans) behaviors were evaluated under cold white LED light. Incorporating varying concentrations of perylene significantly improved the films' optical performance and energy storage capacity. Notably, the photoisomerization time of CA/Azb/Py films decreased by up to 30% compared to CA/Azb films. Furthermore, the energy storage half-life for films with the highest perylene content reached 70 minutes, substantially longer than that of CA/Azb films (24 minutes). Remarkably, the energy density of the film with the highest perylene content reached 240 J g⁻¹, which is more than 1.7 times higher than that of the CA/Azb film (138 J g⁻¹).

Optimal scheduling of smart home appliances with a stochastic power outage: A two-stage stochastic programming approach

This study primarily concentrates on enhancing the scheduling of electric appliances within a smart home equipped with a photovoltaic solar array and a storage battery capable of redistributing excess electricity to the grid. Furthermore, the investigation takes into consideration the unpredictability of a power outage, analyzing the scheduling of these appliances to minimize consumer electricity expenses. To tackle this issue, a two-stage stochastic programming methodology is developed to effectively model the uncertainty surrounding both the onset time and duration of power outages. Additionally, a sample average approximation algorithm (SAA) is devised to efficiently address the problem. Through extensive computational experiments, the outcomes demonstrate that the SAA yields shorter CPU processing times, albeit without guaranteeing optimal solutions. The total average percent deviation of the SAA's upper bound from its lower bound and the optimal solution stands at 4.16 % and 4.5 %, respectively. Moreover, it is demonstrated that utilizing the stochastic approach, as opposed to the deterministic one, can enhance solution quality by 6.2 %. Furthermore, a comprehensive sensitivity analysis is provided, focusing on probability distribution functions of outage start time and duration, alongside an analysis of the solar panel and battery storage capacities. It is revealed that when adopting a Normal distribution instead of a Uniform distribution, the performance of the SAA experiences a slight decline.

Boosting the active sites of Cu/Ce0.8Zr0.2O2 catalysts through tailored precipitation method

A reverse co-precipitation method was employed to increase the surface area of Ce0.8Zr0.2O2, resulting in boosting the active sites of Cu catalysts in the water–gas shift reaction (WGS). Active Cu sites and oxygen vacancy have been systematically controlled through the modification of physical properties and geometric configuration via a reverse co-precipitation of Ce0.8Zr0.2O2 support. The catalytic activity in WGS is primarily dependent on the number of active Cu species and is partially on the oxygen storage capacity. The kinetic results with Cu loadings revealed that the efficiency of active metal utilization was effectively enhanced by a reverse co-precipitation method, compared to the normal precipitation method, owing to the moderate metal–support interactions. The turnover frequency values were independent of Cu dispersion, highlighting the structure-insensitivity of Cu/Ce0.8Zr0.2O2 catalysts. This work suggests the possibility of controlling metal–support interactions through support synthesis methods.

Effect of Fin Configuration on the Early Stage of the Melting Process of a Phase Change Material

Thermal storage systems are essential for optimizing energy resource utilization, particularly in the current context where sustainability and efficiency are critical. Phase Change materials (PCMs) offer a promising solution for improving thermal management efficiency without additional power consumption. Considering that the low thermal conductivity of phase change materials (PCMs) is a limiting factor for heat transfer, this study employs the enthalpy-porosity method to analyze the melting characteristics of a high-Prandtl number PCM. Additionally, this study investigated the effect of varying the number of fins in the heat sink on the heat transfer rate. The material melting process was modeled by considering buoyancy effects and treating the flow as incompressible, Newtonian, transient, and laminar. Lauric acid was selected as the working material with temperature-dependent properties that were incorporated into the simulations for greater accuracy. Three different heat sink configurations were analyzed, varying the number of fins from 5 to 10 and their lengths from 0.02 meters to 0.04 meters. The objective was to optimize the cooling performance using aluminum, which was selected for its excellent balance of lightweight properties and high thermal conductivity. This analysis aimed to assess how these variations in the fin count and dimensions affect the overall heat dissipation efficiency and thermal management of the system. The inclusion of a finned heat sink within a heat exchanger has demonstrated significant efficiency, particularly in regions with substantial boundary layer development, resulting in enhanced heat transfer. These findings highlight the effectiveness of using finned heat sinks in these regions. However, an interesting observation emerged regarding the effect of increasing the number of fins over long periods. Although initially beneficial, a larger number of fins eventually led to a reduced performance over time, notably affecting the thermal storage capacity and molten liquid mass production. Additionally, this study elucidates the influence of natural convection on thermal boundary layer development, highlighting the complexity of the heat transfer processes.

Assessing the Soil Infiltration Rate of Alpine Meadows Using the Electrolyte Tracer Method

ABSTRACTGrassland on the Qinghai‐Tibet Plateau is highly susceptible to climate change and human activities, and vegetation degradation can affect biodiversity and soil erosion. Soil infiltration is a crucial water flow process that determines the amount of runoff and water storage capacity, and it is of great importance in maintaining biodiversity. This research investigated the effects of vegetation degradation and soil rates on soil infiltration rate and processes using the electrolyte tracer method. This technique accurately calculated soil infiltration rate by tracking continuous changes in the solute concentration change process throughout the experimental period and did not require calibration. Findings indicate that vegetation type, root mass, soil water content and soil porosity significantly affect soil infiltration rate. In particular, root mass was found to have a negative effect on soil infiltration rate. Soil moisture content initially dominated soil infiltration, but subsequently, soil porosity became increasingly influential in affecting infiltration in degraded meadow. Soil infiltration capacity varied more with vegetation type than with surface runoff. Shrub meadows had the highest infiltration rate followed by normal alpine meadows and degraded meadows, indicating the importance of vegetation on soil infiltration. The research also shows that mixed shrub and meadow can improve the ecological environment by introducing a more complex root system and increasing the infiltration rate. The electrolyte tracer method was used as an alternative to other methods that can be used in different environments than the one studied in this research.

Hydrogen storage in a novel BCC-structured TiCrW alloys

Body-centered cubic (BCC)-type alloys possess a high theoretical hydrogen storage capacity, yet their high cost, limited effective hydrogen storage capacity, and poor cyclic properties remain challenges. In this work, a novel and cost-effective (Ti0.44Cr0.56)94W6 BCC phase alloy was successful prepared by W doping and heat treatment. The alloy exhibits an effective hydrogen desorption capacity of 2.44 wt% with minimal 9 % degradation over 300 cycles. The microstructural analysis shows that W doping inhibits the formation of Ti-rich phase and Laves phase in the alloy, and makes the alloy form a single BCC phase structure with higher hydrogen storage sites. After heat treatment, the alloy exhibits remarkable hydrogen de-/absorption kinetics and superior plateau characteristics, which reduces the plateau slope factor from 5.32 to 0.18, and increases the effective hydrogen desorption capacity from 1.09 to 2.44 wt%. This alloy’s activation energy and enthalpy change in dehydrogenation process are determined to be 11.64 and 44.31 kJ/mol, respectively. First-principles simulations further illuminated that the incorporation of W doping diminished the migration energy barrier of hydrogen and compromised the structural stability of the hydride. Furthermore, the structural evolution during de-/hydrogenation was analyzed, elucidating the mechanism of the alloy’s cyclic performance decay. These findings offer theoretical insights that guide the development of novel solid state hydrogen storage materials.

Research on the relationship between thermal aging of lubricating grease outside the contact area of bearing rolling elements and bearing lubrication failure

This study examines the lubrication and tribological performance of lithium-based grease subjected to varying degrees of thermal aging. The paper elucidates the degradation in anti-oxidant, rheological, and tribological performance of the grease, shedding light on the lubrication failure mechanism of lithium-based grease under thermal influence. At the molecular level, lithium-based greases undergo chemical degradation due to the thermal oxidation of their base oil. This process produces macromolecular polymers and oxygenated organic substances that accumulate as the degree of aging increases, progressively reducing the original lubrication efficiency and chemical stability of the grease. From a microstructural viewpoint, persistent thermal effects lead to a gradual reduction in the helical structure of the ribbon fibers within the thickener. This leads to the increased fiber diameter and its breakage, reduced binding capacity of the base oil, heightened oil separation, and a continuous decrease in structural strength and recovery capability. The rapid evaporation of the base oil reduces the grease oil storage capacity. As the aging process advances, aged grease soap fibers fragment and re-aggregate into bundles. This aggregated thickener structure hardens the remaining grease, and reduces its oil supply capacity. The friction pair surface is not adequately replenished with oil, which leads to direct contact at the interface and causes the surface contact fatigue damage. The friction process generates more wear products, which in turn cause the abnormal vibrations and noise. The combined degradation of grease performance and the deterioration of the friction pair surface conditions exacerbate bearing vibration failure.