Comparative analysis of thermodynamic and mechanical responses between underground hydrogen storage and compressed air energy storage in lined rock caverns

Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage processes.This study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock caverns.Gas thermodynamic responses are validated using additional simulations and the field test data.Temperature and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation modes.Hydrogen reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and pressure.Unlike steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing layer.In CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same areas.Our present research can provide references for the selection of energy storage methods.

Investigations of the mechanical response of dummy HTPB propellant grain under ultrahigh acceleration overload conditions using onboard flight-test measurements

In this paper,to study the mechanical responses of a solid propellant subjected to ultrahigh acceleration overload during the gun-launch process,specifically designed projectile flight tests with an onboard measurement system were performed.Two projectiles containing dummy HTPB propellant grains were successfully recovered after the flight tests with an ultrahigh acceleration overload value of 8100 g.The onboard-measured time-resolved axial displacement,contact stress and overload values were successfully obtained and analysed.Uniaxial compression tests of the dummy HTPB propellant used in the gunlaunched tests were carried out at low and intermediate strain rates to characterize the propellant's dynamic properties.A linear viscoelastic constitutive model was employed and applied in finite-element simulations of the projectile-launching process.During the launch process,the dummy propellant grain exhibited large deformation due to the high acceleration overload,possibly leading to friction between the motor case and propellant grain.The calculated contact stress showed good agreement with the experimental results,though discrepancies in the overall displacement of the dummy propellant grain were observed.The dynamic mechanical response process of the dummy propellant grain was analysed in detail.The results can be used to estimate the structural integrity of the analysed dummy propellant grain during the gun-launch process.

Influence of the boundary effect on the mechanical response test of pavement cushion under the wetting effect of silt

Through a self-developed model test system,the mechanical properties of silt and the deformation characteristics of airport runways were investigated during the period of subgrade wetting.Based on the test results,the reliability of the numerical simulation results was verified.Numerical models with different sizes were established.Under the same cushion parameter and loading width ranges,the effects of the cushion parameters and loading conditions on the mechanical responses of the cushion before and after subgrade wetting were analyzed.The results show that the internal friction angles of silt with different wetting degrees are approximately 34°.The cohesion is from 8 to 44 kPa,and the elastic modulus is from 15 to 34 MPa.Before and after subgrade wetting,the variation rates of the cushion horizontal tensile stresses with the same cushion parameters and loading width ranges are different under the influence of boundary effects.After subgrade wetting,the difference in the variation rates of the cushion horizontal tensile stresses under the same cushion parameter range decreases compared with that before subgrade wetting;however,this difference increases under the same loading width range.Before and after subgrade wetting,the influence of the boundary effect on the mechanical response evaluation of the cushion is not beneficial for optimizing the pavement design parameters.When the cushion thickness is more than 0.25 m,the influence of the boundary effect can be disregarded.

Mechanical response of bridge piles in high-steep slopes and sensitivity study

The bridge piles located in high-steep slopes not only endure the loads from superstructure, but also the residual sliding force as well as the resistance from the slope. By introducing the Winkler foundation theory, the mechanical model of piles-soils-slopes system was established, and the equilibrium differential equations of pile were derived. Moreover, an analytic solution for identifying the model parameters was provided by means of power series method. A project with field measurement was compared with the proposed method. It is indicated that the lateral loads have great influences on the pile, the steep slope effect is indispensable, and reasonable diameter of the pile could enhance the bending ability. The internal force and displacements of pile are largely based upon the horizontal loads applied on pile, especially in upper part.

Unveiling the mechanical response and accommodation mechanism of pre-rolled AZ31 magnesium alloy under high-speed impact loading

Split Hopkinson pressure bar(SHPB)tests were conducted on pre-rolled AZ31 magnesium alloy at 150–350℃ with strain rates of 2150s-1,3430s^(-1) and 4160s-1.The mechanical response,microstructural evolution and accommodation mechanism of the pre-rolled AZ31 magnesium alloy under high-speed impact loading were investigated.The twin and shear band are prevailing at low temperature,and the coexistence of twins and recrystallized grains is the dominant microstructure at medium temperature,while at high temperature,dynamic recrystallization(DRX)is almost complete.The increment of temperature reduces the critical condition difference between twinning and DRX,and the recrystallized temperature decreases with increasing strain rate.The mechanical response is related to the competition among the shear band strengthen,the twin strengthen and the fine grain strengthen and determined by the prevailing grain structure.The fine grain strengthen could compensate soften caused by the temperature increase and the reduction of twin and shear band.During high-speed deformation,different twin variants,introduced by pre-rolling,induce different deformation mechanism to accommodate plastic deformation and are in favor for non-basal slip.At low temperature,the high-speed deformation is achieved by twinning,dislocation slip and the following deformation shear band at different deformation stages.At high temperature,the high-speed deformation is realized by twinning and dislocation slip of early deformation stage,transition shear band of medium deformation stage and DRX of final deformation stage.

Mechanical response of transmission lines based on sliding cable element

In order to study the sliding characteristics when the cable is connected with the other rods in the transmission line structures,a linear sliding cable element based on updated Lagrangian formulation and a sliding catenary element considering the out-of-plane stiffness coefficient are put forward.A two-span and a three-span cable structures are taken as examples to verify the sliding cable elements.By comparing the tensions of the two proposed cable elements with the existing research results,the error is less than 1%,which proves the correctness of the proposed elements.The sliding characteristics should be considered in the practical engineering because of the significant difference between the tensions of sliding cable elements and those of cable element without considering sliding.The out-of-plane stiffness coefficient and friction characteristics do not obviously affect the cable tensions.

Quench characteristics and mechanical responses during quench propagation in rare earth barium copper oxide pancake coils

Quench and mechanical behaviors are critical issues in high temperature superconducting(HTS)coils.In this paper,the quench characteristics in the rare earth barium copper oxide(REBCO)pancake coil at 4.2K are analyzed,and a two-dimensional(2D)axisymmetric electro-magneto-thermal model is presented.The effects of the constituent materials,background field,and coil size are analyzed.An elastoplastic mechanical model is used to study the corresponding mechanical responses during the quench propagation.The variations of the temperature and strain in superconducting layers are compared.The results indicate that the radial strain evolutions can reflect the transverse quench propagation and the tensile hoop and radial stresses in superconducting layers increase with the quench propagation.The possible damages are discussed with the consideration of the effects of the background field and coil size.It is concluded that the high background field significantly increases the maximum tensile hoop and radial stresses in quenching coils and local damage may be caused.

External blast flow field evolution and response mechanism of single-layer reticulated dome structure

Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understanding of the behavior of single-layer reticulated dome structure under explosion.This paper investigates the fluid-structure interaction process and the dynamic response performance of the singlelayer reticulated dome under external blast load.Both experimental and numerical results shown that structural deformation is remarkably delayed compared with the velocity of blast wave,which advises the dynamic response of large-span reticulated dome structure has a negligible effect on the blast wave propagation under explosion.Four failure modes are identified by comparing the plastic development of each ring and the residual spatial geometric of the structure,i.e.,minor vibration,local depression,severe damage,and overall collapse.The plastic deformation energy and the displacement potential energy of the structure are the main consumers of the blast energy.In addition,the stress performance of the vertex member and the deep plastic ratio of the whole structure can serve as qualitative indicators to distinguish different failure modes.

Transcriptional activation of glucose transporter 1 in orthodontic tooth movement-associated mechanical response

The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1(GLUT1)—the primary glucose transporter in various cells—as a novel mechanosensitive gene in orthodontic tooth movement(OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells(PDLCs), showing a time-and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand(RANKL)/osteoprotegerin(OPG)system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.

Finite element simulation for mechanical response of surface mounted solder joints under different temperature cycling

Nonlinear finite element simulation for mechanical response of surface mounted solder joint under different temperature cycling was carried out. Seven sets of parameters were used in order to evaluate the influence of temperature cycling profile parameters. The results show that temperature cycling history has significant effect on the stress response of the solder joint. Based on the concept of relative damage stress proposed by the authors, it is found that enough high temperature holding time is necessary for designing the temperature cycling profile in accelerated thermal fatigue test.

Mechanical responses of the bio-nano interface: A molecular dynamics study of graphene-coated lipid membrane

Bio-nano interfaces between biological materials and functional nanodevices are of vital importance in relevant energy and information exchange processes, which thus demand an in-depth understanding. One of the critical issues from the application viewpoint is the stability of the bio-nano hybrid under mechanical perturbations. In this work we explore mechanical responses of the interface between lipid bilayer and graphene under hydrostatic coating provides remarkable resistance to the pressure or indentation loads, We find that graphene loads, and the intercalated water layer offers additional protection. These findings are discussed based on molecular dynamics simulation results that elucidate the molecular level mechanisms, which provide a basis for the rational design of bionanotechnology- enabled aoolications such as biomedical devices and nanotheraoeutics.

Alpine vegetation responses to snow phenology in the Chinese Tianshan mountainous region

Investigating the interrelation between snow and vegetation is essential to explain the response of alpine ecosystems to climate change.Based on the MOD10 A1 daily cloud-free snow product and MOD13 A1 NDVI(normalized difference vegetation index)data,this study analysed the spatial and temporal patterns of snow phenology including snow onset date,snow end date,snow cover days,and vegetation phenology including the start of growing season,the end of growing season and the length of growing season in the Chinese Tianshan Mountainous Region(CTMR)from 2002 to 2018,and then investigated the snow phenological effects on the vegetation phenology among different ecogeographic zones and diverse vegetation types.The results indicated that snow onset date was earlier at higher elevations and later at lower elevations,while snow end date showed opposite spatial distribution characteristics.The end of growing season occurred later on the northwest slope of the CTMR and the Yili Valley.The earliest end of growing season was in the middle part of the CTMR.A long growing season was mainly distributed along the northern slope and the Yili Valley,while a short growing season was concentrated in the middle part of the CTMR.The response of vegetation phenology to changes in snow phenology varied among vegetation types and ecogeographic zones.The effect of snow phenology on vegetation phenology was more significant in IID5(Yili Valley)than in the other ecogeographic zones.A negative correlation was observed between the start of growing season and snow end date in nearly 54.78%of the study area,while a positive correlation was observed between the start of growing season and the snow end date in 66.85%of the study area.The sensitivity of vegetation phenology to changes in snow cover varied among different vegetation types.Snow onset date had the greatest effect on the start of growing season in the four vegetation cover types(alpine meadows,alpine steppes,shrubs,and alpine sparse vegetation),whereas the snow cover days had the least impact.Snow end date had the greatest impact on the end of growing season in the alpine steppes and shrub areas.The study results are helpful for understanding the vegetation dynamics under ongoing climate change,and can benefit vegetation management and pasture development in the CTMR.

Acoustic Response and Micro-Damage Mechanism of Fiber Composite Materials under Mode-Ⅱ Delamination

Realizing the accurate characterization for the dynamic damage process is a great challenge. Here we carry out testing simultaneously for dynamic monitoring and acoustic emission （AE） statistical analysis towards fiber composites under mode-Ⅱ delamination damage. The load curve, AE relative energy, amplitude distribution, and amplitude spectrum are obtained and the delamination damage mechanism of the composites is investigated by the microscopic observation of a fractured specimen. The results show that the micro-damage accumulation around the crack tip region has a great effect on the evolutionary process of delamination. AE characteristics and amplitude spectrum represent the damage and the physical mechanism originating from the hierarchical microstructure. Our finding provides a novel aud feasible strategy to simultaneously evaluate the dynamic response and micro-damage mechanism for fiber composites.

In vivo evidence of IGF-I–estrogen crosstalk in mediating the cortical bone response to mechanical strain

Although insulin-like growth factor-I （IGF-I） and estrogen signaling pathways have been shown to be involved in mediating the bone anabolic response to mechanical loading, it is not known whether these two signaling pathways crosstalk with each other in producing a skeletal response to mechanical loading. To test this, at 5 weeks of age, partial ovariectomy （pOVX） or a sham operation was performed on heterozygous IGF-I conditional knockout （H IGF-I KO） and control mice generated using a Cre-loxP approach. At 10 weeks of age, a 10 N axial load was applied on the right tibia of these mice for a period of 2 weeks and the left tibia was used as an internal non-non-loaded control. At the cortical site, partial estrogen loss reduced total volumetric bone mineral density （BMD） by 5% in control pOVX mice （P=0.05, one-way ANOVA）, but not in the H IGF-I KO pOVX mice. At the trabecular site, bone volume/total volume （BV/TV） was reduced by 5%-6% in both control pOVX （P〈0.05） and H IGF-I KO pOVX （P=0.05） mice. Two weeks of mechanical loading caused a 7 %-8% and an 11%-13% （P〈0.05 vs. non-loaded bones） increase in cortical BMD and cortical thickness （Ct.Th）, respectively, in the control sham, control pOVX and H IGF-I KO sham groups. By contrast, the magnitude of cortical BMD （4%, P=0.13） and Ct.Th （6%, P〈0.05） responses were reduced by 50% in the H IGF-I KO pOVX mice compared to the other three groups. The interaction between genotype and estrogen deficiency on the mechanical loading-induced cortical bone response was significant （P〈0.05） by two-way ANOVA. Two weeks of axial loading caused similar increases in trabecular BV/TV （13%-17%） and thickness （17%-23%） in all four groups of mice. In conclusion, partial loss of both estrogen and IGF-I significantly reduced cortical but not the trabecular bone response to mechanical loading, providing in vivo evidence of the above crosstalk in mediating the bone response to loading.

Parametric Study on the Effect of Aspect Ratio of Selected Cooling Hole Geometries on the Mechanical Response of an Automobile Aluminium Alloy Wheel

Aluminium alloy wheels are increasingly popular for their light weight and good thermal conductivity. Cooling Holes (CH) are introduced to reduce their weight without compromising structural integrity. Literature is sparse on the effect of aspect ratio (AR) of CHs on wheels. This, work, therefore, attempts to undertake a parametric study of the effect of aspect ratio (AR) on the mechanical response of an aluminium alloy wheel with triangular, quadrilateral and oval-shaped CHs. Three-dimensional wheel models (6JX14H2ET42) with triangular, quadrilateral and oval shaped CH (each with CH area of 2229 mm2) were generated, discretized, and analyzed by FEM using Creo Elements/Pro 5.0 to determine the mechanical response at the inboard bead seat at different ARs of 1, 0.5, 0.33 and 0.25, each for quadrilateral-CH and oval-CH, at a static Radial Load of 4750 N and Inflation Pressures of 0.3 and 0.15 MPa, respectively. The study shows that the magnitude of stress and displacement is affected by shape and AR of CH. From the results, it could be established that oval-shaped-CH wheel at AR of 0.5 offers greater prospect in wheel design as it was least stressed and deformed and, that the CH combination with highest integrity was the oval-CH and quadrilateral-CH at AR of 0.5.

The mechanical response of multi-tower continuous-span suspension bridge deck pavement based on whole bridge analysis

The effect of multiple span suspension structure on the mechanical response of bridge deck pavement was studied, and finite element analysis (FEM) of stress and strain of pavement according to the bridge floor system features of super-long and high flexibility was made. Meanwhile, the FEM results were compared with those of the single span suspension structure. Three-stage analytic hierarchy process (AHP) is developed to analyze the mechanical response including whole bridge analysis, partial beams section analysis and orthotropic plate analysis. The most unfavorable load position was determined by the numerical solutions acquired from each stage to study the main mechanical index of multiple span suspension structure. The FEM results showed that the mechanical response numerical solutions by using the three-stage AHP are greater than those by simplified boundary condition, and the force condition of multiple span suspension structure is worse than that of the single span suspension structure.

Earthquake Emergency Response System of High-speed Railway by Least Square Method

This paper studies the Least Square Method to define high-speed railway(HSR) earthquake risk and solve the problem of its emergency response mechanism. Based on the construction of a monitoring system for HSR earthquake emergency response, the technical operational procedures for HSR seismic emergency response are proposed. The quantity, scale, and location of HSR earthquake emergency response mechanism are defined, and the corresponding emergency response system is built. In particular, the earthquake emergency response system can conduct real-time continuous dynamic monitoring of seismic activity along the railway. When earthquake occurs, the intensity of the ground motion is detected by the system. When the earthquake monitoring value reaches the earthquake alarm threshold, it will send an alarm signal to the dispatch center, and the emergency power supply will be forced to cut off. The earthquake emergency response system will continue to monitor the follow-up ground motion acceleration. The system provides the operation scheduling center with a basis for train operation control to resume operation after stopping. The monitoring result of the system reduces the disaster, and the secondary disaster is caused by the earthquake. This paper improves the HSR response mechanism in detecting earthquake disasters. The result improves the ability of HSR to deal with earthquake disasters, and reduces casualties and economic and property loss caused by earthquake disasters.

Risk and Response of China Overseas Hydropower Projects--A Vision of Corporate Social Responsibility

Recent years, with the quickening of global economic integration and the rapid development of our country, more and more Chinese enterprises begin to implement internationalization strategy and actively develop overseas business. However, the internationalized process of Chinese enterprises is not progressing smoothly. The paper systematically analyzes the risks of China overseas hydropower projects from two aspects： international environment risks and internal risks of hydropower enterprises and points out that effectively fulfilling corporate social responsibility by using Guidance on Social Responsibility （ISO26000） could help Chinese hydropower enterprises to deal with overseas risks. In order to help Chinese hydropower enterprises to improve the CSR （Corporate Social Responsibility） implementation level, the paper integrates the characteristics of hydropower enterprises with the core subjects of ISO26000, examines the key problems on the CSR work of Chinese hydropower enterprises according to requirements of ISO26000 and puts forward effective advices.

A Preliminary Study on Mechanisms of Well Water Temperature Responses Based on the Modes of Stress Loading

Based on the studies of the predecessors, and contrasting the modes of stress loading with water level and water temperature response characteristics of a well-aquifer system, this paper draws a preliminary conclusion on the mechanisms of water temperature responses in a well caused by three modes of stress loading, i.e. gas escape, heat dispersion and cold water penetration mechanisms for elastic seismic wave stress loading; the fracture seepage mechanism for seismic wave stress loading and the hydrodynamic mechanism for earth tide stress loading and stress-dissipative heat mechanism for long period slow stress loading in the earthquake preparation stage. This paper illustrates the typical observation examples for each mode of stress loading and makes a preliminary study on their mechanisms.

A review of in situ carbon mineralization in basalt

Global warming has greatly threatened the human living environment and carbon capture and storage(CCS)technology is recognized as a promising way to reduce carbon emissions.Mineral storage is considered a reliable option for long-term carbon storage.Basalt rich in alkaline earth elements facilitates rapid and permanent CO_(2) fixation as carbonates.However,the complex CO_(2)-fluid-basalt interaction poses challenges for assessing carbon storage potential.Under different reaction conditions,the carbonation products and carbonation rates vary.Carbon mineralization reactions also induce petrophysical and mechanical responses,which have potential risks for the long-term injectivity and the carbon storage safety in basalt reservoirs.In this paper,recent advances in carbon mineralization storage in basalt based on laboratory research are comprehensively reviewed.The assessment methods for carbon storage potential are introduced and the carbon trapping mechanisms are investigated with the identification of the controlling factors.Changes in pore structure,permeability and mechanical properties in both static reactions and reactive percolation experiments are also discussed.This study could provide insight into challenges as well as perspectives for future research.