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This study employed Virtual Reality (VR) technology to investigate the influence of corridor directional configuration on evacuation wayfinding behavior in underground spaces. The study designed two virtual underground space fire evacuation scenarios with different forms of intersections, and recruited 115 volunteers to participate in the experiment.The results indicated that corridor directional configuration significantly affected participants' fire evacuation wayfinding behavior. At Y-shaped and T-shaped intersections with left and right turning options, participants showed a preference for choosing the right-side corridor. At ┡-shaped and ┩-shaped intersections with straight and turning options, participants tended to choose the straight path. Individual factors (such as gender, evacuation experience, and professional background) did not demonstrate significant effects on wayfinding choices in this study, though they may produce different evacuation outcomes in various scenarios. In practical evacuation design, corridor directional configuration should be organically integrated with other environmental factors to reinforce directional preferences and more effectively guide evacuation. The findings provide scientific evidence for underground space evacuation route design, which can be used to optimize evacuation signage and path configuration, thereby improving evacuation efficiency and safety. Future research could be conducted in more complex environments, considering additional variables to gain a more comprehensive understanding of evacuation behavior. [ABSTRACT FROM AUTHOR]

High-Ti basalts are commonly believed to represent parental magmas leading to the formation of mafic-ultramafic layered intrusions, such as Late Permian Panzhihua and Hongge in the Emeishan Large Igneous Province (SW China). Consequently, elucidation of the crystallisation and crustal differentiation of high-Ti basalts is critical for our understanding of the petrogenesis of these layered intrusions and the associated oxide ore mineralisation. Here, we present the results of crystallisation experiments carried out in internally heated pressure vessels using a primitive high-Ti basaltic composition. The experiments were conducted at 100 and 300 MPa, in the temperature interval of 950–1200 °C and with water activities (a H2O) from 0 to 1. The oxygen fugacity (f O2) was controlled and varied from FMQ −1 to FMQ +3.3 log units (FMQ corresponds to fayalite-quartz-magnetite buffer). The main mineral phases are olivine, clinopyroxene and plagioclase, accompanied by Cr-Fe-Ti-oxides, orthopyroxene, apatite and amphibole, depending on the conditions. Redox conditions primarily influence the stability fields of Cr-Fe-Ti oxides. Clinopyroxene, orthopyroxene and amphibole are pressure-dependent and have larger stability fields under high pressure conditions. The olivine→orthopyroxene and olivine→amphibole peritectic reactions are observed. Comparisons of phase equilibria between this study and experiments conducted with parental magma of Skaergaard layered intrusion demonstrate the effect of bulk system composition. For instance, ilmenite crystallisation is determined not only by intrinsic parameters such as f O2 but also by additional compositional parameters (e.g. melt Ti, Fe, Al and Mg content). Although COMAGMAT and MELTS modelling results generally reproduce the crystallisation sequence, only the stability field of clinopyroxene and its composition are perfectly modelled. The comparison of experimental results with the rocks from the lowest units of Panzhihua and Hongge layered intrusions are applied to constrain storage conditions in the magma reservoirs. Compared to Hongge, we conclude that the Panzhihua magma chamber was probably located at a shallower depth (~3–6 km), that magma crystallisation started at lower temperatures (~1125–1100 °C), higher f O2 (~FMQ + 1 to FMQ + 2) and that its initial melt H2O content was lower (~0.5–1 wt. %). [ABSTRACT FROM AUTHOR]

Pedestrian evacuation is an important measure to ensure disaster safety in central retail districts, the efficiency of which is affected by the synergy of road network planning indices. This paper established the typical forms of central retail district (CRD) road networks in terms of block form, network structure and road grade, taking China as an example. The experiment was designed using the orthogonal design of experiment (ODOE) method and quantified the evacuation time under different road network planning indices levels through the Anylogic simulation platform. Using range and variance analysis methods, the synergy of network density, network connectivity, road type and road width on pedestrian evacuation efficiency were studied from the perspectives of significance, importance and optimal level. The results showed that the type of CRD will affect the importance of network planning indices, and that the network connectivity is insignificant (P 0.477/0.581) in synergy; networks with wide pedestrian primary roads (30.1~40.0 m), medium secondary roads (3.1~5.0 m/side) and high density (11.0~13.0 km/km2) have the highest evacuation efficiency. From the perspective of evacuees, this paper put forward urban design implications on CRD road networks to improve their capacity for disaster prevention and reduction. [ABSTRACT FROM AUTHOR]

Magma mixing is a widespread magmagenic process. However, its significance in the formation of ultrapotassic magmas has been largely overlooked so far as they are commonly thought to originate directly from the mantle and ascend rapidly through the crust. The Hezhong ultrapotassic lavas in Western Yunnan (SW China) are (basaltic) trachy-andesitic in composition. These rocks display porphyritic textures with olivine, clinopyroxene (Cpx), spinel, and phlogopite occurring as both phenocryst and glomerocryst. Disequilibrium textures and complex zonation of crystals are commonly observed. Specifically, based on the textural and compositional characteristics, olivines can be classified into three different populations: two populations are characterized by highly to moderately magnesian olivines with normal chemical core-rim zonation (Fo~94–86 to Fo~89–79 and Fo~91–89 to Fo~86–84, respectively). The third population lacks obvious crystal zonation, but individual crystals exhibit some compositional variety at lower Fo contents (Fo83–76). Similarly, four populations of Cpx and two populations of spinel phenocrysts are recognized in terms of texture and composition. Notably, Cpx with reverse zoning contains a 'green-core' surrounded by a colourless mantle and rim. Hence, based on the variations of mineral assemblage, types of inclusions, and chemical compositions, all phenocryst/glomerocryst minerals can be divided into three groups. Mineral Group I (MG I) consists of high Fo cores of olivine, cores of the zoned spinel, and phlogopite. MG II only includes the green cores of reversed zoned Cpx (green-core Cpx), and MG III is composed of micro phenocrysts without obvious zoning and rims of large phenocrysts. Comparing these mineral groups with relevant minerals occurring in typical temporally and spatially associated igneous rocks, we suggest that the MG I and II could have been derived from magmas with compositions resembling an olivine lamproite and a trachyte, respectively. The overall bulk-rock geochemical and isotopic features of Hezhong lavas also agree with a mixing process between these two endmembers. Hence, we infer that mixing between these two magmas played a key role in the petrogenesis of the ultrapotassic Hezhong lavas and that the MG III crystallized from the mixed magmas. Our study highlights the complex formation of ultrapotassic magmas inferring that caution must be taken when using bulk chemical magma compositions are to deduce source signatures. [ABSTRACT FROM AUTHOR]