Stable Zone Research Articles

Russia, NATO and the Arctic: Rivalry, Security, Possible Scenarios of Geopolitical Competition

The article is devoted to the analysis of key aspects of the geopolitical struggle for the Arctic region. The relevance of the research stems from the fact that due to climate change and the reduction of ice cover in the Northern Hemisphere, the Arctic is of increasing interest to world powers, which are competing for control over new deposits of natural resources and strategic dominance in the region. It is emphasized that the Arctic has become a region where leading states are trying to implement various geopolitical strategies. On the one hand, the four members of the Arctic Five under the auspices of NATO are trying to implement a scenario in which the polar zone is divided into stable zones of influence. On the other hand, there are the interests and position of Russia, which is concerned about the increased military activity of the United States and NATO in the region. The purpose of the article is to study the problems of the Arctic militarization, which will make it possible to identify challenges and threats in this region for Russias national strategy. The research methodology is based on theoretical analysis and dialectical method. In addition, the study used formal logical methods and various approaches to information processing (analysis, synthesis, induction, deduction). The forecasting method helped to determine the range of possible military and political trends in the region. The article identifies the potential interests of Russia, the United States and NATO in the context of increased attention to the Arctic region in recent years. The study reflects a comparative analysis of the policies and interests of the member states of the Arctic Five and NATO, namely Denmark, Canada, Norway and the USA, their practical steps in the High North. The author describes possible prospects for interaction and dialogue on countering the main threats to international security within the framework of a comprehensive strategy. Considering the role and rivalry between Russia and NATO in the Arctic, the article highlights the authors forecasts of further military and political presence of NATO in the Arctic and the necessary actions for Russia to defend its northern territories.

Sensitivity and Resolution of Controlled-Source Electromagnetic Method for Gas Hydrate Stable Zone

Natural gas hydrate is one of the most important clean energies and part of carbon cycle, due to the least carbon content. Natural gas hydrates depend on high pressure and low temperatures, located under seabed or permafrost. Small changes in temperature and pressure may lead gas hydrates to separate into water and gas, commonly as methane. As a powerful greenhouse gas, methane is much stronger than carbon dioxide. Therefore, it is necessary to detect the gas hydrates stable zone (GHSZ) before the methane gas escapes from GHSZ. Marine controlled source electromagnetic method (CSEM) is a useful tool to detect gas hydrate in offshore. The results from 3D CSEM method are a resistivity cube to describe the distribution of gas hydrates. In order to study the detectability of CSEM method, we simulate the sensitivity and resolution of marine CSEM synthetic data. By using the sensitivity and resolution, a simple statement may be quickly judged on the existence and occurrence range of the natural gas hydrate. In this paper, we compare the resolution of marine CSEM method with various transverse resistance. This information may help researchers find out whether the GHSZ exists or not.

Experimental Analysis and Numerical Simulation of the Stability of Geological Storage of CO2: A Case Study of Transforming a Depleted Gas Reservoir into a Carbon Sink Carrier.

Geological storage of CO2 is one of the most economical, feasible, and effective measures to slow down global warming. In this study, a combined long core model was designed to study the seepage characteristics of supercritical CO2 displacement. Moreover, the stability of permanent storage of cushion gas layers formed by supercritical CO2 injection has been systematically studied. The research results showed that in the supercritical temperature and pressure range of CO2, the front edge of CO2 displacement can form a relatively stable seepage zone. Supercritical CO2 displacement can achieve a high gas-storage rate and stable CO2 storage. At the same time, the recovery rate of remaining natural gas has been significantly improved. As the injection pressure increased, supercritical CO2 inhibited the reverse diffusion of natural gas molecules. Therefore, the breakthrough of the supercritical CO2 displacement front under a high pressure lagged behind. However, due to the increase in the density difference of gas molecules, the forward diffusion of supercritical CO2 has been enhanced. Temperature will not significantly affect the displacement and storage effects of supercritical CO2 in gas reservoirs. The increase in injection pressure and reasonable control of the injection rate can delay the breakthrough of supercritical CO2 displacement. These measures are conducive to the stable storage of CO2 and the improvement of remaining natural gas recovery. The implementation of CO2 geological storage is suitable for the later stage of gas reservoir depletion development. The high-density gravitational heterogeneity of supercritical CO2 enables the injected CO2 to form a stable high-density cushion gas layer in the gas reservoir, which can achieve stable CO2 storage for more than 100 years.

Orbital stability of S-type circumbinary planets

Nowadays, more than 4,000 exoplanets have been discovered, including a hundred of circumbinary planets. In the following work, the orbital variations of 67 S-type circumbinary planets have been studied. Their orbital evolutions for a thousand years are simulated using the REBOUND package. The published physical and orbital parameters of the systems are used to computed the systems’ orbital instability limits: Roche limit and Hill’s sphere. From 67 systems, there are two unstable circumbinary systems: Kepler-420 and GJ 86. Kepler-420 Ab orbit passes into the system’s Roche limit due to its high orbital eccentricity. For GJ 86 Ab, the planet orbits outside its Hill’s sphere. The instability of GJ 86 Ab might be caused by an inaccurate measurement of GJ 86 A physical parameters. Using the GJ 86 A mass obtained from Farihi et al., the planet orbits in the stable orbit zone.

Optical limiting behavior, nonlinear optical studies, geometrical descriptors, chemical properties data, topology analysis on tetraethylammonium L-tartarate dihydrate crystals

The slow cooling technique was utilized to grow organic single crystals of tetraethylammonium L-tartarate dehydrate (EAT) with dimensions 20 × 4 × 4 mm3. The meta stable zone width was obtained via solubility curve. Structural confirmation was achieved using X-ray diffraction. EAT possesses noncentro symmetric P21 space group within the monoclinic crystal structure. Optical transmittance in the visible region reveals a strong transparency with lower cutoff wavelength of 261 nm. EAT crystal’s refractive index is 1.611. The EAT compound's thermal stability was found to be 115 °C, measured by TG-DTA experiments. EAT's specific heat capacity is be 3.670 g −1 K −1. The laser damage threshold of grown EAT crystal surface was measured at 0.3611 GW/cm2. Vicker's microhardness, Kurtz-Perry Powder Method evaluated the mechanical power, particle size based second harmonic generation efficiency (SHG) which identified phase matching in EAT. The SHG maker Fringes technique investigated the SHG of EAT. Optical limiting analysis showed transmitted output power rises linearly till 2.736 mW mm−2 of irradiance.

"Branch-First total arch replacement": a valuable alternative to frozen elephant trunk in acute type A aortic dissection?

The "Branch-First total arch replacement" technique has been used extensively in both elective and acute situations, including in type A aortic dissection. The focus of the Branch-First technique is to reduce the risk of neurological and end-organ dysfunction associated with arch replacement by optimising neuroprotection, distal organ perfusion and myocardial protection. The Branch-First technique is a valuable alternative to the frozen elephant trunk (FET) technique in type A aortic dissection, providing a stable landing zone for subsequent interventions on the distal aorta should they be required. Combining the Branch-First technique with FET in appropriate cases can further improve outcomes. We discuss the merits of the Branch-First technique, and contrast them to those of FET techniques for repair of type A aortic dissection.

Shape and stability characteristics of hydrogen-enriched natural-gas oxy-flames in a micromixer burner

ABSTRACT This study investigated experimentally the effects of H2-enrichment on premixed oxy-methane flames stabilized on a micromixer-like burner for clean energy production in gas turbines. The stable combustion zone was established over ranges of fuel hydrogen fraction (HF: 25–70% by vol.) and equivalence ratio (ϕ: 0.1–1) at fixed oxidizer oxygen fraction (OF = 30% by vol.) and fixed jet velocity (5.2 m/s). The blowout limit was plotted within the HF-ϕ space, superimposed on the contours of some operating parameters, namely adiabatic flame temperature (AFT), combustor power density (PD), jet Reynolds number (Re), and unburnt-mixture density (ρmix). Furthermore, images of visible flame shape were acquired at distinct points within the stable zone to study the effects of ϕ, HF, AFT, PD, Re, and ρmix on flame macrostructure. Results show that H2-enrichment extends the blowout limit from ϕ = 0.35 down to ϕ = 0.1, thereby widening the stable combustion zone. The blowout limit has little correlation with AFT and PD but correlates strongly with ρmix, i.e., occurs consistently at the same ρmix. The analyses of blowout limit and flame images were used to infer that the flames blow out possibly at constant ignition delay.

Crack propagation characterization of crumb rubber modified asphalt concrete using J-R curves

J-Resistance curves serve as a robust tool in characterizing the entire crack propagation trend of materials. Nevertheless, thus far, investigations on J-R curves of hot mix asphalt (HMA) have been very limited leading to scarce knowledge of post-peak fracture of the mixtures. In this research, mode I single-edge notched beam (SE(B)) fracture testing of unmodified and crumb rubber (CR) modified asphalt concrete mixtures was conducted with continuous monitoring of crack extension during the tests at 0 °C, −10 °C, and −20 °C. Modified HMA beams were fabricated incorporating 10% and 20% CR with 3% warm-mix additive. The CMOD-based elastic–plastic J-integral was computed incrementally during the tests and the J-R curve of each mixture could be determined. The results indicated that reducing the temperature increases the crack blunting energy from 0 °C to −10 °C while reducing the extents of the transition zone within blunting to unstable crack propagation of the unmodified mixtures. The unmodified mixtures undergo an unstable crack propagation as early as the macro crack initiates in −20 °C. At the same time, the incorporation of CR, could increase the blunting fraction of the R-curves at each temperature. Of vital importance, it could be detected that a 20% crumb rubber modification resulted in a more significant stable crack growth zone in the mixtures while developing a progressively rising R-curve in the post-peak region than the flat state in the unmodified mixtures at severely low temperatures.

Using a dynamic earthquake simulator to explore tsunami earthquake generation

SUMMARYObservations of historical tsunami earthquakes reveal that ruptures of these earthquakes propagate slowly at shallow depth with longer duration, depletion in high-frequency radiation and larger discrepancy of Mw–Ms than ordinary megathrust earthquakes. They can effectively generate tsunami and lead to huge damage to regional populated areas near the coast. In this study, we use a recently developed dynamic earthquake simulator to explore tsunami earthquake generation from a physics-based modelling point of view. We build a shallow-dipping subduction zone model in which locally locked, unstable patches (asperities) are distributed on a conditionally stable subduction interface at shallow depth. The dynamic earthquake simulator captures both quasi-static and dynamic processes of earthquake cycles. We find that earthquakes can nucleate on these asperities and propagate into the surrounding conditionally stable zone at slow speeds, generating tsunami earthquakes. A high normal stress asperity, representing a subducted seamount, can act as an asperity in some events but as a barrier in other events over multiple earthquake cycles. Low normal stress asperities typically act as asperities in tsunami earthquakes. The degree of velocity-weakening in the conditionally stable zone, which may sustain rupture at different speeds or stop rupture, is critical for tsunami earthquake generation and affects its recurrence interval. Distributed asperities may rupture in isolated events separated by tens of years, or in a sequence of events separated by hours to days, or in one large event in a cascade fashion, demonstrating complex interactions among them. The recurrence interval on a high normal stress asperity is much larger than that on low normal stress asperities. These modelling results shed lights on the observations from historical tsunami earthquakes, including the 1994 and 2006 Java tsunami earthquakes and 2010 Mentawai tsunami earthquake.

Storm emissions of macrophytes at the cape Martyan (Southern coast of Crimea, Black Sea)

Information about the peculiarities of the formation of storm emissions of macrophyte on the coast, at cape Martyan (the Southern coast of the Crimea) is presented. The studies were conducted from June 2019 to August 2020. Storm emissions on this part of the coast are formed with winds from the eastern (including north-eastern and south - eastern), southern and south-western directions and the corresponding direction of the waves. With north and west winds, the accumulated algae are carried back to the sea. Along the leveled coastal areas, storm emissions are distributed fairly evenly, without forming abundant accumulations. Stable zones accumulation of emissions are formed near the block heap, as well as at the bases of hydraulic structures. During one storm, cast ashore 40 kg to 7784 kg of phytomass. In total, 33061 kg of storm emissions were received on the shore during the year, which is about one percent of the annual production and a little more than two percent of the bottom vegetation reserves of the adjacent water area. The volume of storm emissions depends on the intensity of wave activity, the direction and strength of winds, on the morphology of the coast, as well as on seasonal phenomena in the life cycle of macrophytes.

Anti-Rollover Control Based on Stable Zone Partition of Counterbalanced Forklift Trucks

Anti-Rollover Control Based on Stable Zone Partition of Counterbalanced Forklift Trucks

Effect of mode mixity, temperature, binder content, and gradation on mixed mode (I/II) R-curve of asphalt concrete at low temperatures

R-curves provide the means for in-depth analysis of crack propagation in engineering materials. However, due to experimental costs and difficulties, the application of this approach has been very limited in hot mix asphalt (HMA) investigations to date. In the present research, single edge notched beam (SE(B)) tests are conducted on asphalt concrete (AC) mixtures in pure mode I and mixed mode (I/II) states at low temperatures. Mode mixity is induced in the test setup by fabricating an asymmetric notch with varying relative offset values of 0.3, 0.47, and 0.67 from the centerline of the beam where the loading is situated. Mode I and mixed mode R-curves were constructed by plotting cumulative fracture energy versus crack extensions obtained from digital images during each test. Based on the R-curves, the mixed mode (I/II) crack propagation regime of the HMA with regards to temperature variations (+5 °C, 0 °C, −5 °C, −10 °C, −15 °C, and −20 °C in this research), binder contents (4%, 4.5%, and 5%), and the nominal maximum aggregate size (NMAS) of 19 mm and 25 mm were determined and studied. A considerable stable crack growth zone was observed in the mixtures as the contribution of shearing mode is increased and the mode I contribution is decreased. The stable crack growth region was proceeded by unstable crack propagation in all the cases and the instability outweighed in lower temperatures, particularly in −15 °C and −20 °C. Nevertheless, the mixtures exhibited greater resistance to post-peak crack propagation in higher mode mixites which could be inferred from the progressively rising R-curve in the instability phase. It was also observed that the NMAS value of 25 mm could increase the cohesive energy and the blunting work required to initiate macrocracking while amplifying unstable crack growth at −20 °C and −15 °C in comparison with NMAS 19 mm.

How to select the lowest instrumented vertebra in Lenke 5/6 adolescent idiopathic scoliosis patients with derotation technique.

To introduce and evaluate our lowest instrumented vertebra (LIV) selection criteria for Lenke type 5/6 adolescent idiopathic scoliosis (AIS) patients with de-rotation technique. There were 53 eligible Lenke 5/6 AIS patients with minimum 2-year follow-up enrolled in current study. The LIV selection criteria were: (1) the first vertebra touching the central sacral vertical line (CSVL) or the most cephalad vertebra which can return to stable zone under lateral bending position; (2) vertebral rotation no more than grade II by Nash-Moe rotation evaluation; (3) the lowest instrumented vertebra disc angle (LIVDA) could be reversed on lateral bending position. Demographic data, operation data and radiographic data were obtained and analyzed. Both clinical evaluation and radiographic data showed satisfactory outcome. The thoracolumbar/lumbar curve was improved from 53.4 ± 11.0° preoperatively to 6.9 ± 2.6° at the final follow-up. Two patients (3.8%) with adding on and two patients (3.8%) with coronal decompensation were identified at the final follow-up. LIV translation, LIV tilt and LIV disc angle were gradually improved after operation. The preoperative LIV tilt was positively correlated with Cobb angle (p = 0.010) and AVT (p = 0.030) at the final follow-up, and preoperative LIVDA was positively correlated with Cobb angle (p = 0.033) at the final follow-up. In Lenke 5/6 scoliosis, the current LIV selection criteria with de-rotation technique contribute to satisfactory correction rate of 87.1% and minimal alignment complications of 7.6%. LIV could be spontaneously and progressively improved after operation. Preoperative LIV tilt and LIVDA could predict postoperative correction and coronal balance.

Instability of a meandering channel with variable width and curvature: Role of sediment suspension

In this Perspective, we explore the instability of a meandering channel with variable width and curvature. The analysis employs the depth-averaged formulations for the flow and sediment transport. Unlike the conventional instability analysis that considers mainly the bedload transport, we consider the generic sediment transport including both the bedload and suspended load. The analysis addresses the variations of the near-bank excess azimuthal velocity and the bed topography deviation with the meander wavenumber for different pertinent parameters, such as Shields number, relative roughness number, channel aspect ratio, width-variation amplitude, and shear Reynolds number. The analysis detects a resonance phenomenon for certain critical values of the pertinent parameters and explores the sensitivity of the resonant wavenumber to the pertinent parameters. In a hydraulically smooth flow regime, the sediment suspension is found to play a stabilizing role. On the contrary, in hydraulically transitional and rough flow regimes, the sediment suspension offers a destabilizing effect. The stability diagrams reveal that the stable zone enlarges as the Shields number and relative roughness number increase, while it contracts with an increase in width-variation amplitude. For a given shear Reynolds number in a hydraulically smooth flow regime, the stability diagram predicts various stable zones. By contrast, for a given shear Reynolds number in hydraulically transitional and rough flow regimes, a unique stable zone exists.

Long-Term Dynamics of Chlorophyll in Plankton of Different Sites in a Large Plain Reservoir

On the basis of field observations in 2009–2019, the seasonal and long-term dynamics of chlorophyll at six standard stations of the Rybinsk Reservoir is considered. The fluorescence method is used to determine chlorophyll. The average chlorophyll content at stations varies from the minimum 3.5–10.8 to the maximum 16.9–40.5 μg/L in different years and from 12.0 at station 5 (Sredny Dvor) up to 21.6 μg/L at station 2 (Mologa) on average for the entire period. The seasonal dynamics of chlorophyll is characterized by spring; summer; and, in some years, autumn maxima. With the same type of seasonal dynamics, the change in chlorophyll at the stations is to varying degrees coupled in the years of observation and is most often correlated in neighboring areas. Significant differences in the amount of chlorophyll at the stations are observed during surveys carried out within one day and are determined by the complex hydrological structure of the reservoir; active dynamic processes; and, in the spring, by the thermal regime. The presence of stable large circulation zones smoothes out the spatial differences of chlorophyll, the average seasonal concentrations of which do not differ significantly at all six stations in years with an average water level, and at four stations of the Main Reach in extremely high-water years. A close correlation in long-term dynamics is revealed for the average chlorophyll concentrations for the growing season at six stations, as well as at each station and the reservoir as a whole. The results of the work confirm the reliability of the data obtained for assessing the ecological state of the Rybinsk Reservoir.

Research on the Corrosion Fatigue Property of 2524-T3 Aluminum Alloy

The 2524-T3 aluminum alloy was subjected to fatigue tests under the conditions of R = 0, 3.5% NaCl corrosion solution, and the loading cycles of 106, and the S-N curve was obtained. The horizontal fatigue limit was 169 MPa, which is slightly higher than the longitudinal fatigue limit of 163 MPa. In addition, detailed microstructural analysis of the micro-morphological fatigue failure features was carried out. The influence mechanism of corrosion on the fatigue crack propagation of 2524-T3 aluminum alloy was discussed. The fatigue source characterized by cleavage and fracture mainly comes from corrosion pits, whose expansion direction is perpendicular to the principal stress direction. The stable propagation zone is characterized by strip fractures. The main feature of the fracture in the fracture zone is equiaxed dimples. The larger dimples are mixed with second-phase particles ranging in size from 1 to 5 μm. There is almost a one-to-one correspondence between the dimples and the second-phase particles. The fracture mechanism of 2524 alloy at this stage is transformed into a micro-holes connection mechanism, and the nucleation of micropores is mainly derived from the second-phase particles.

A non-Darcy gas flow model for coalbed methane in mine gobs

The expected extraction efficiency of coalbed methane (CBM) depends significantly on the laws considered to govern its gas flow. This study applies a non-Darcy gas flow model to describe the CBM migration in mine gobs; by mine gob, we mean that it is a fractured zone along with massive cracks and the primary place where gas flows after mining activities. A permeation experiment involving crushed sandstone is first conducted to prove the CBM undergoes Forchheimer-type non-Darcy flow. Subsequently, the three-dimensional continuous distribution functions of the permeability parameters are determined. The non-Darcy flow model includes the influence of inertial force on the gas flow, which is neglected in the Darcy model. A coupling model is established based on the experimental results and the gas flow characteristics in different regions. Thereafter, the model and distribution functions are applied to a series of numerical simulations of CBM extraction at the Sihe coal mine in China, to ascertain the most appropriate location for a ground borehole. These simulations involve boreholes placed in three different zones: the natural accumulation zone (NAZ), the load affected zone (LAZ), and the compaction stable zone (CSZ). The simulation results show that the total extraction quantity expected from the borehole in the NAZ is 2.4 and 13.5 times that from the boreholes in the LAZ and CSZ, respectively. This confirms that the NAZ is the most suitable zone for a borehole. This research ultimately provides a realistic gas flow model for CBM extraction from mine gobs.

Injection Treatment for Tunneling Excavation in Sandy Soils with High Fines Content

Instability and high permeability are two of the problems facing tunnelling excavations in soils with high fines content. Among the different techniques used to improve these soils, the injection of cement grouts stands out. In this work, a grouting treatment is designed to ensure the stability of the ground during the construction of two tunnels linking two municipalities in the north of Spain in Biscay, and to reduce the inflow of water from the aquifer located in the vicinity of these tunnels. First of all, the rock mass is analysed and the material to be injected is selected on the basis of the authors’ experience as well as setting time and compressive strength. Subsequently, with a test device designed by the DinRock research group of the University of Oviedo, two types of laboratory tests are carried out in order to analyse the effect of fines migration and washing on the water flows and the effect of re-injections of grouts with different densities on the permeability value. The results show that, in sandy materials, obtaining high degrees of waterproofing together with large stable zones can only be achieved by a combination of treatments and stages with different materials and densities. In addition, maximum values for both injection pressure and flow rate must be established depending on the type of grout and the permeability of the soil. Once the problem has been analysed, the injection treatment is designed and executed. The treatment consists of one pre-injection in four stages with 30 boreholes drilled in the top heading, 19–20 boreholes drilled in the bench, and one post-injection with boreholes drilled around the perimeter of the tunnel in those areas where the pre-injection does not achieve the desired degree of waterproofing.

Improvement of ecological and economic mechanism of recreational tourism management in the context of European integration

The article describes the current state of development of recreational and tourist activities. The role of European integration in the context of the tourism industry is defined. The functions and properties of the Ukrainian tourist business are considered. Opportunities and risks of development of recreational and tourist activity are specified, and also roles of recreation and tourism are defined. The role of state regulation and management in increasing the level of development of recreational and tourist activities is described. The parameters of formation and increase of the level of development of recreational tourism are indicated. The ecological and economic mechanism of recreational and tourist activity in the context of European integration processes is formed. Features of functioning ecological and economic mechanism of management of development of recreational tourism are considered, and also importance of development of programs on development of recreational and tourist activity is considered. It is noted that recreation and tourism play one of the main roles in formation and development of rest physical and mental condition. Obtained a high level of efficiency from recreational tourism, people can only due to temporarily living in remote, away from home, tourist areas of recreation. European integration and globalization processes have a positive impact on the development of recreational tourism and gaining competitive advantages, providing the above components. Investment reserves have been identified as a method of increasing the competitiveness of recreational and tourist activities in Ukraine in the context of European integration. Certain tourist complexes in Ukraine form stable economic zones and development of regions of recreational and tourist activity. An important issue remains the creation of favorable investment flows for both foreign and domestic investors, which, in turn, stabilizes working conditions given the rational use of investment on a long-term basis. Thus, these problems increase the relevance of the need to improve the mechanism for the management of recreational and tourist activities, primarily by government agencies. European integration processes in Ukraine require the formation and implementation of a model of relations between recreational areas and governance structures, which should meet the requirements of regional policy of the European Union, which in the future provided more prospects for cooperation, interregional and international cooperation.

Hierarchical Model Predictive Control for Autonomous Collision Avoidance of Distributed Electric Drive Vehicle with Lateral Stability Analysis in Extreme Scenarios

This paper proposes an active collision avoidance controller based on a hierarchical model predictive control framework for distributed electric drive vehicles (4IDEV) considering extreme conditions. In this framework, a two-layer strategy is developed. The upper layer is the path replanning controller based on nonlinear MPC (nMPC), from which a collision-free path including the optimal lateral displacement and yaw angle can be obtained in real-time while encountering the obstacles. The lower layer is the path tracking controller based on hybrid MPC (hMPC), and the coordinated control inputs (yaw moment and the front wheel steering angle) are solved by a Mixed-Integer Quadratic Programming (MIQP) with the piecewise affine (PWA) tire model considering tire saturation region. Moreover, to improve the lateral stability when tracking, the stable zone of lateral stability in the high-risk condition is analyzed based on the phase portrait method, by which the constraints of vehicle states and inputs are derived. The verification is carried out on the MATLAB and CarSim co-simulation platform, and the simulation results show that the proposed active collision avoidance controller can track the reference path accurately and prevent vehicle instability in extreme scenarios.