Train post‑derailment behaviours and containment methods:a review

Railway accidents,particularly serious derailments,can lead to catastrophic consequences.Therefore,it is essential to prevent derailment escalation to reduce the likelihood of severe derailments.Train post-derailment behaviours and containment methods play a critical role in preventing derailment escalation and providing passive safety protection and accident prevention in the event of a derailment.However,despite the increasing attention on this field from academia and industry in recent years,there is a lack of systematic exploration and summarization of emerging applications and containment methods in train post-derailment research.For this reason,this paper presents a comprehensive review of existing studies on train post-derailment behaviours,encompassing various topics such as post-derailment contact-impact models,dynamic modelling and simulation techniques,and the primary factors influencing post-derailment behaviours.Significantly,this review introduces and elucidates substitute guidance mechanisms(SGMs),which serve as railway-specific passive safety protection and accident prevention measures.The various types of SGMs are depicted,and their ongoing developments and applications are explored in depth.The review additionally points out several unresolved challenges including the adverse effects of SGMs,and proposes future research directions to advance the theoretical understanding and practical application of train post-derailment behaviours and containment methods.This review seeks to be a valuable reference for railway industry professionals in preventing catastrophic derailment consequences through post-derailment containment methods.

Suicidal Behaviours in Sickle Cell Patients at the Douala Sickle Cell Care Centre in Cameroon

Introduction: Sickle cell anaemia is a hereditary disease that combines physical and psychological manifestations, including suicidal tendencies. So far, to our knowledge, no study has been conducted on suicidal behaviours among people with sickle cell disease in Cameroon. This is what justifies our study on the prevalence and factors related to suicidal behaviors in our study population. Methods: We conducted a cross-sectional, analytical study of 171 sickle cell patients aged from 12 years upwards who came to the sickle cell disease care service of the Laquintinie Hospital in Douala, over a period of 6 months, that is, from 1 January to 31 June 2022. Data were collected using a structured questionnaire with questions on suicidal behaviours based on the “MINI” (Mini International Neuropsychiatric Interview). The data were processed using the SPSS 26.0 software. The related factors were studied in both a bivariate and multivariate analysis. Results: Female sickle cell patients accounted for 60.2% of the sample. The mean age was 23.36 ± 8.42 years. Suicidal ideation was prevalent in 56% of cases and 13% attempted suicide. The factors most associated with suicidal ideation were: primary level of education (OR = 0.08 (0.09 - 0.79);p = 0.03), feeling unworthy of life (OR = 0.40 (0.08 - 1.96);p = 0.02), not often being considered by those around them (OR = 2.97 (1.26 - 6.99);p = 0.01), lack of family support (OR = 0.34 (0.15 - 0.77);p = 0.01). Meanwhile, the factors associated with suicide attempts were: the fact of being rarely exposed to suicide-related media (OR = 4.17 (1.40 - 71.80);p = 0.03), and a constant feeling of sadness when returning home (OR = 18.02 (1.59 - 20.55);p = 0.01). Conclusion: More than half of sickle cell patients had had suicidal thoughts and 1/6 had made at least one suicide attempt, women and young adults being the most concerned. It is therefore necessary to ensure optimum psychological care for patients with sickle cell disease.

Mechanical behaviours of bedded sandstone under hydromechanical coupling

The combination of the dipping effect and hydromechanical(H-M)coupling effect can easily lead to water inrush disasters in water-rich roadways with different dip angles in coal mines.Therefore,H-M coupling tests of bedded sandstones under identical osmotic pressure and various confining pressures were conducted.Then,the evolution curves of stress-strain,permeability and damage,macro-and mesoscopic failure characteristics were obtained.Subsequently,the mechanical behaviour was characterized,and finally the failure mechanism was revealed.The results showed that:(1)The failure of the sandstone with the bedding angle of 45°or 60°was the structure-dominant type,while that with the bedding angle of 0°,30°or 90°was the force-dominant type.(2)When the bedding angle was in the range of(0°,30°)or(45°,90°),the confining pressure played a dominant role in influencing the peak strength.However,withinβ∈(30°,45°),the bedding effect played a dominant role in the peak strength.(3)With the increase in bedding angle,the cohesion increased first,then decreased and finally increased,while the internal friction angle was the opposite.(4)When the bedding angle was 0°or 30°,the“water wedging”effect and the“bedding buckling”effect would lead to the forking or converging shear failure.When the bedding angle was 45°or 60°,the sliding friction effect would lead to the shear slipping failure.When the bedding angle was 90°,the combination of the“bedding buckling”effect and shear effect would lead to the mixed tension-shear failure.The above conclusions obtained are helpful for the prevention of water inrush disasters in water-rich roadways with different dips in coal mines.

When Fleeing Matters:Differences in Escape Behaviours of Three Northeast Asian Anurans

Prey species may have their own optimal escape strategy to balance predation risks and the energetic cost of fleeing.Some species have an advantage when maintaining a short fleeing distance,while others may favour an earlier escape based on microhabitat,size,or body condition.Here,we examined the escape behaviour of the three syntopic Northeast Asian anuran species:Mongolian toads(Strauchbufo raddei),Amur brown frogs(Rana amurensis),and Japanese treefrogs(Dryophytes japonicus)in Mongolia,Russia,China and DPR Korea.We examined flight initiation distance(FID;the distance from a potential predator to the point when the individual starts to flee)and distance fled(DF;distance between flight initiation and flight termination points)of each species and the effects of microhabitat,sex,and body size.Strauchbufo raddei and R.amurensis had a longer FID than D.japonicus,and S.raddei also had a longer DF than D.japonicus.These trends remained similar when dividing FID and DF by a size proxy(snout-vent length)for all individuals.This suggests that the treefrog D.japonicus used a strategy to stay immobile even when they were detected,and the toad S.raddei reacted quicker and more sensitively to predators despite the presence of toxin.Female S.raddei had a significantly longer FID than males suggesting that females are more sensitive to predation risk in this species,but body size was not significant for any of the three species.Our results indicate that the three sympatric species have different escaping strategies,likely related to differences in physiology and crypticity.

Wetting Behaviours of a Single Droplet on Biomimetic Micro Structured Surfaces

Natural surfaces with super hydrophobic properties often have micro or hierarchical structures.In this paper, the wettingbehaviours of a single droplet on biomimetic micro structured surfaces with different roughness parameters are investigated.Atheoretical model is proposed to study wetting transitions.The results of theoretical analysis are compared with those of experimentindicating that the proposed model can effectively predict the wetting transition.Furthermore, a numerical simulationbased on the meso scale Lattice Boltzmann Method （LBM） is performed to study dynamic contact angles, contact lines, andlocal velocity fields for the case that a droplet displays on the micro structured surface.A spherical water droplet with r= 15 μmfalls down to a biomimetic square-post patterned surface under the force of gravity with an initial velocity of 0.01 m·sand aninitial vertical distance of 20 μm from droplet centre to the top of pots.In spite of a higher initial velocity, the droplet can stillstay in a Cassie state; moreover, it reaches an equilibrium state at t≈17.5 ms, when contact angle is 153.16° which is slightlylower than the prediction of Cassie-Baxter’s equation which gives θ=154.40°.

Travel Behaviours of Sharing Bicycles in the Central Urban Area Based on Geographically Weighted Regression: The Case of Guangzhou, China

Mobile information and communication technologies(MICTs) have fully penetrated everyday life in smart societies;this has greatly compressed time, space, and distance, and consequently, reshaped residents’ travel behaviour patterns. As a new mode of shared mobility, the sharing bicycle offers a variety of options for the daily travel of urban residents. Extant studies have mainly examined the travel characteristics and influencing factors of public bicycles with piles, while the travel patterns for sharing bicycles and their driving mechanisms have been largely ignored. Using one week’s travel data for Mobike, this study investigated the spatial and temporal distribution patterns of sharing bicycle travel behaviours in the central urban area of Guangzhou, China;furthermore, it identified the influences of built environment density factors on sharing bicycle travel behaviours based on the geographically weighted regression method. Obvious morning and evening peaks were observed in the sharing bicycle travel patterns for both weekdays and weekends. The old urban area, which had a high degree of mixed function, dense road networks, and cycling-friendly built environments, was the main travel area that attracted sharing bicycles on both weekdays and weekends. Furthermore, factors including the point of interest(POI) for the density of public transport stations, the functional mixing degree, and the density of residential POIs significantly affected residents’ travel behaviours. These findings could enrich discourse regarding shared mobility with a Chinese case characterised by rapidly developing MICTs and also provide references to local authorities for improving slow traffic environments.

Critical behaviours and magnetic properties of three-dimensional bond and anisotropy dilution Blume-Capel model in the presence of an applied field

This paper studies the critical behaviours and magnetic properties of three-dimensional bond and anisotropy dilution Blume-Capel model （BCM） in the presence of an applied field within the effective field theory. The trajectory of tricritical point, reentrant transitions and degenerate patterns of anisotropy are obtained both for the bond and the anisotropy dilutions. The global phase diagrams demonstrate unusually reentrant phenomena. The temperature dependences of magnetization curves undergo remarkable spin glass behaviour at low temperatures, and transform from ferromagnetism to paramagnetism at high temperature in applied fields. Temperature dependence of magnetic susceptibility curve is in qualitative agreement with experimental result.

Effect of Pre-strain on the Transformation and Recovery Behaviours of a Ti_(44)Ni_(47)Nb_9 Shape Memory Alloy

The recovery strain, stress and transformation temperature of different pre-strained specimens of Ti44Ni47Nb9 were investigated by tensile test and electrical resistance measurement. The results indicated that pre-strain increases the reverse martensitic transformation temperature (A ' (s)) and hysteresis (A(s) - M-s). The recovery strain and stress are higher if the specimens are pre-strained between M-s and A(s) temperature than outside this temperature range. There exists an optimal pre-strain value, about 10%, at which the specimen exhibits maximum recovery strain and stress.

Numerical Investigations on Transient Behaviours of Two 3-D Freely Floating Structures by Using a Fully Nonlinear Method

Two floating structures in close proximity are very commonly seen in offshore engineering. They are often subjected to steep waves and, therefore, the transient effects on their hydrodynamic features are of great concem. This paper uses the quasi arbitrary Lagrangian Eulerian finite element method （QALE-FEM）, based on the fully nonlinear potential theory （FNPT）, to numerically investigate the interaction between two 3-D floating structures, which undergo motions with 6 degrees of freedom （DOFs）, and are subjected to waves with different incident angles. The transient behaviours of floating structures, the effect of the accompanied structures, and the nonlinearity on the motion of and the wave loads on the structures are the main focuses of the study. The investigation reveals an important transient effects causing considerably larger structure motion than that in steady state. The results also indicate that the accompanied structure in close proximity enhances the interaction between different motion modes and results in stronger nonlinearity causing 2hal-order component to be of similar significance to the fundamental one.

Effects of a flexible net barrier on the dynamic behaviours and interception of debris flows in mountainous areas

Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dynamic behaviours of debris flows with differences in volumes, concentrations(solid volume fraction), and travel distances after interception by a uniform flexible net barrier. A high-speed camera was used to monitor the whole test process, and their dynamic behaviours were recorded. A preliminary computational framework on energy conversion is proposed according to the deposition mechanisms and outflow of debris flow under the effects of the flexible net barrier. The experimental results show that the dynamic interaction process between a debris flow and the flexible net barrier can be divided into two stages:(a) the two-phase impact of the leading edge of the debris flow with the net and(b) collision and friction between the body of the debris flow and intercepted debris material. The approach velocity of a debris flow decreases sharply(a maximum of 63%) after the interception by the net barrier, and the mass ratio of the debris material being intercepted and the kinetic energy ratio of the debris material being absorbed by the net barrier are close due to the limited interception efficiency of the flexible net barrier, which is believed to be related to the flexibility. The energy ratio of outflow is relative small despite the large permeability of the flexible net barrier.

Health-Promoting Behaviours of University Nursing Students in Jordan

The purpose of this study was to determine health-promoting behaviours of university nursing students in Jordan. This descriptive cross-sectional study used convenient sampling technique to recruit 167 undergraduate nursing students in Jordan. Data were collected by using an Arabic version of Health-Promoting Lifestyle Profile II. The study results revealed that the mean item score for total Health-Promoting Lifestyle Profile II was (127.24 ± 21.03). The students obtained highest scores in spiritual growth (25.04 ± 4.70) and lowest in physical activity subscales (16.27 ± 5.21). Significant difference was found between Health-Promoting Lifestyle Profile II subscales (stress management, health responsibility, and interpersonal relations) and students’ age and gender.

NUCLEATION BEHAVIOURS OF SILVER ON GLASSY CARBON MICROELECTRODES

The initial stage of silver deposition has been investigated using the microelectrode technique A disc shaped nucleus can be obtained on glassy carbon microelectrodes and the instanta. neous nucleation model applies for the process

The coupled hydro-mechanical behaviours of compacted crushed Callovo-Oxfordian argillite

Callovo-Oxfordian （COx） argillite obtained from the excavation of high-level radioactive waste geological disposal has been evaluated as an alternative sealing/backfill material in France. This paper presents an experimental investigation into the hydro-mechanical behaviour of compacted crushed COx argillite. A series of oedorneter compressive tests including various loading-unloading cycles were conducted on COx argillite powders at different initial water contents. After reaching the desired dry density （2.0 Mg/m^3）, the vertical stress was reduced to different levels （7.0 and 0.5 MPa） and the compacted sample was then flooded under constant volume conditions while measuring the changes in the vertical stress. It was found that the initial water content significantly affects the compressive behaviour. The measured saturated hydraulic conductivity is less than 1×10^-10m/s.

Behaviours in Attachment-Detachment Cycles of Geckos in Response to Inclines and Locomotion Orientations

Geckos can move quickly in various environments by efficiently controlling their complex adhesive toe pads.The locomotion behaviours observed in the attachment-detachment(A-D)cycle of their toe pads in response to changes in their environment should be studied to understand the adaptive behavioural characteristics of such toe pads.The lack of systematic research on the entire A-D cycle,including the release,swing,contact,and adhesion stages,limits the comprehension of the adhesive locomotion mechanism.The A-D cycle of Gekko gecko that facilitates the foot locomotion on inclined and vertical surfaces was investigated to clarify the locomotion behaviours in different stages.Results show that the change trends of foot locomotor angles(yaw and pitch)during the entire A-D cycle remain unchanged in response to various substrates.The bending angles(fore 41°;hind 51°)and contact time percentages(fore 7.42%;hind 7.44%)in the contact stage as well as the forefoot angle ranges(yaw:163.09°;pitch:308.68°)in the A-D cycle also remain constant across all substrates.These invariant foot locomotion behaviours during the swing and contact stages suggest that the foot behaviours are weakly related to the forces acting on the foot,which change according to the environment.Furthermore,the forefoot and hindfoot have different anatomical structure and functional demands,thus,the angle range of forefoot locomotion is larger than that of hindfoot locomotion,and the pitch angle change trend of the forefoot is opposite to that of the hindfoot.The diverse and complex locomotion control of the adhesive toe pads for various environments is reduced by the consistent behaviours in the gecko’s A-D cycle,such as the constant postures in the swing and contact stages.This study provides insight into the adhesive locomotion mechanism of geckos and can facilitate further research on the effective design and control of adhesion robots.

Impact of train speed on the mechanical behaviours of track-bed materials

For the 30,000 km long French conventional railway lines(94% of the whole network),the train speed is currently limited to 220 km/h,whilst the speed is 320 km/h for the 1800 km long high-speed lines.Nowadays,there is a growing need to improve the services by increasing the speed limit for the conventional lines.This paper aims at studying the influence of train speed on the mechanical behaviours of track-bed materials based on field monitoring data.Emphasis is put on the behaviours of interlayer and subgrade soils.The selected experimental site is located in Vierzon,France.Several sensors including accelerometers and soil pressure gauges were installed at different depths.The vertical strains of different layers can be obtained by integrating the records of accelerometers installed at different trackbed depths.The experimentation was carried out using an intercity test train running at different speeds from 60 km/h to 200 km/h.This test train was composed of a locomotive(22.5 Mg/axle) and 7 'Corail'coaches(10.5 Mg/axle).It was observed that when the train speed was raised,the loadings transmitted to the track-bed increased.Moreover,the response of the track-bed materials was amplified by the speed rise at different depths:the vertical dynamic stress was increased by about 10% when the train speed was raised from 60 km/h to 200 km/h for the locomotive loading,and the vertical strains doubled their quasistatic values in the shallow layers.Moreover,the stressestrain paths were estimated using the vertical stress and strain for each train speed.These loading paths allowed the resilient modulus Mrto be determined.It was found that the resilient modulus(M_r) was decreased by about 10% when the train speed was increased from 100 km/h to 200 km/h.However,the damping ratio(D_r) kept stable in the range of speeds explored.

Chaotic behaviours and control of chaos in the p-Ge photoconductor

The chaotic behaviours in the p-Ge photoconductor system are studied by changing the photo-excitation coefficient and the routes and parameter conditions are given for chaos generation in this system. A scheme for controlling chaos in the p-Ge photoconductor is presented by adding an ac bias current. Numerical simulations show that this scheme can be effectively used to control chaotic states into stable period states for this system. Moreover, the different period states with diifferent period numbers can be obtained by appropriately adjusting the amplitude, frequency, and initial phase of the additional ac current.

TRANSIENT AERODYNAMIC BEHAVIOURS ASSOCIATED WITH STEPWISE INCIDENCE VARIATION OF AIRFOILS

Transient aerodynamic characteristics of airfoil are important for the safety of airplanes, the development of helicopter rotors and many other applications of unsteady aerodynamics. For a better understanding of these phenomena, it is necessary to investigate the simultaneous relation between the characteristics and the flow field. The purpose of the present study is to clarify experimentally the fundamentals of the aerodynamic behaviours associated with stepwise incidence variations from 0 to some certain values, including high angles of attack, of symmetric airfoils at low speeds, Reynolds number being of the order of 104. Temporal variations of surface pressure distribution, lift, drag and . pitching moment, and the observation of the flow field will be discussed.

ELECTROCHEMICAL BEHAVIOURS OF CYANOETHENYL ANILINE DERIVATIVES

The redox behaviours of the donor-acceptor model compounds, cyanoethenyl aniline derivatives were investigated by cyclic voltammetry and the mechanism of the electrode reaction was studied in detail.

Importance of Metal－Oxide Support Wettingandinteractions on Understanding of Physical and Chemical Behaviours of Supported Metal Catalysts

It has been generally recognised that the metal catalysts supported on oxide ceramic and non-oxide ceramic supports exhibit completely different characteristics as compared with the homogeneous ones. The na-ture of bonding and interactions occurring at the metal / ceramic interfaces are believed to be of importancefor the characteristics of such catalysts. The recently developed microscopic theory of adhesion and wettingin metal/ ceramic systems is briefly presented here with the emphasis on the ionocovalent oxide ceramics.and its consequence on the understanding of the physical and chemical behaviours of supported metal cata-lysts is exploited.

Dietary Knowledge, Behaviours and Attitudes of Students of Public School in a Northeastern City in Brazil

This quasi-experimental intervention was conducted with 10- to 14-year-old students enrolled in public schools in Teresina, Brazil, to evaluate the effects of a nutritional education program on the students’ knowledge, behaviour and attitudes towards nutrition. The dietary attitudes were evaluated in terms of food tastes/preferences and food behaviours. The participants in the study included 126 students from four schools. Differences between before and after the intervention were found regarding knowledge about the “food pyramid”, “healthy eating” and “nutrients”