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Rock fragmentation is a key indicator for evaluating the effects of rock blasting and directly impacts subsequent excavation efficiency. However, predicting rock fragmentation outcomes is challenging due to the complex physical and chemical processes involved in explosive detonation. In this study, a simulation and analysis method for rock blasting fragmentation effects was developed by integrating the finite element method with image processing technology. To validate the reliability of this method, onsite blasting experiments were conducted. Furthermore, the rock blasting parameter of blast hole spacing was optimized based on this proposed method. The results showed that explosive blasting processes vary depending on the charge. Specifically, using water as a decoupling medium led to better blasting outcomes compared to air-decoupled charges. Due to the directional effects along the cylindrical charge, the explosive loading on the blast hole wall first increases and then stabilizes. The method’s feasibility is supported by the good agreement between the gradation curves of rock fragments obtained through onsite sieving tests and simulations in the 50–300 mm range. Additionally, the approach was used to optimize blasting parameters, ensuring that the fragment size distribution curve met the project requirements. Overall, this method can be used for research and analysis of rock blasting fragmentation.

The PELE (penetration with enhanced lateral efficiency) projectile is a new type of safe ammunition which can form a large number of fragments after perforating the target, and does not depend on any pyrotechnics. The damage characteristics of PELE projectile mainly include the penetration ability and fragmentation effect. There are many factors affecting the damage characteristics of PELE projectile, and this paper attempts to study the damage characteristics of PELE projectile, from the point of view of changing the single core material. Therefore, four different inner core combination types were designed in this paper, namely, zero gradient—I type (PE), zero gradient—II type (Al), positive gradient type (PE + Al), and negative gradient type (Al + PE). With the help of a more mature numerical simulation method, the studies were carried out from several aspects, such as the axial residual velocity of projectile, the radial scattering velocity of fragments, the radial scattering radius of fragments, and the residual length of projectile. The axial residual velocity of projectile can characterize the penetration ability of projectile, the radial scattering velocity and radial scattering radius of fragments can predict the damage area of fragments, and the residual length of projectile can reflect the fragment conversion rate of casing. The results indicate that the negative gradient inner core combination is superior to the other three combinations in terms of the penetration ability and fragmentation effect. Under the same impact velocity, the maximum radial velocity and radial scattering radius of fragments mainly depend on the front inner core material, and these two parameters will increase appropriately with the increase of the strength of front inner core material. Similarly, the residual length of projectile can be reduced, or the fragment conversion rate can be enhanced, by properly reducing the strength of rear inner core material. The conclusions obtained in this paper can provide a reference for engineering applications.

Background Habitat specialists living in human-dominated landscapes are likely to be affected by habitat fragmentation and human disturbances more than generalists. But there is a paucity of information on their response to such factors. We examined the effect of these factors on movement patterns of red pandas Ailurus fulgens , a habitat and diet specialist that inhabits the eastern Himalaya. Methods We equipped 10 red pandas (six females, four males) with GPS collars and monitored them from September 2019 to March 2020 in Ilam, eastern Nepal. We collected habitat and disturbance data over four seasons. We considered geophysical covariates, anthropogenic factors and habitat fragmentation metrics, and employed linear -mixed models and logistic regression to evaluate the effect of those variables on movement patterns. Results The median daily distance travelled by red pandas was 756 m. Males travelled nearly 1.5 times further than females (605 m). Males and sub-adults travelled more in the mating season while females showed no seasonal variation for their daily distance coverage. Red pandas were relatively more active during dawn and morning than the rest of the day, and they exhibited seasonal variation in distance coverage on the diel cycle. Both males and females appeared to be more active in the cub-rearing season, yet males were more active in the dawn in the birthing season. Two sub-adult females dispersed an average of 21 km starting their dispersal with the onset of the new moon following the winter solstice. The single subadult male did not disperse. Red pandas avoided roads, small-habitat patches and large unsuitable areas between habitat patches. Where connected habitat with high forest cover was scarce the animals moved more directly than when habitat was abundant. Conclusions Our study indicates that this habitat specialist is vulnerable to human disturbances and habitat fragmentation. Habitat restoration through improving functional connectivity may be necessary to secure the long-term conservation of specialist species in a human-dominated landscape. Regulation of human activities should go in parallel to minimize disturbances during biologically crucial life phases. We recommend habitat zonation to limit human activities and avoid disturbances, especially livestock herding and road construction in core areas.

PELE projectile is a new type of armor-piercing warhead and has a more obvious fragmentation effect, which solves the problem of insufficient after-effects of conventional armor-piercing projectiles. Reactive material is a new type of energetic material, which has some characteristics similar to the traditional explosives but has better mechanical properties. Reactive material is insensitive under normal conditions, and it can release huge energy under external impact loading. This paper hopes to study the application of reactive materials to the inner core of PELE projectiles to further improve the fragmentation effect of PELE projectiles. The fragmentation effect of PELE projectile is mainly reflected in the radial scattering velocity of fragments after it perforates the target plate. In this paper, three energy sources for the radial scattering of fragments were obtained by analyzing the penetration process of PELE projectile, that is, the axial kinetic energy of outer casing, the radial compression potential energy generated by the inner core to the outer casing, and the chemical energy released by the reactive core material. Based on the simplification and assumptions, the theoretical model of radial scattering velocity of fragments of the reactive core PELE projectile was established. In addition, numerical simulations were carried out to verify the theoretical model. The results show that the numerical simulation results are in good agreement with the theoretical calculation results, which indicates that the model established in this paper is scientific and reasonable. The reactive core PELE projectile has a more significant fragmentation effect, which further enhances the comprehensive damage power of traditional PELE projectile. The theoretical model established in this paper can quickly assess the power of reactive core PELE projectile’s fragmentation effect, which can be used to provide guidance and reference for engineering application.

The PELE (penetrator with enhanced lateral efficiency) projectile is a new type of penetrator, which has both penetration and fragmentation effects. The damage characteristics of the PELE projectile have never been studied from the perspective of changing the shape of the projectile structure until now. This paper hopes to improve the damage power by changing the structural shape of PELE projectile, and the concept of a truncated cone-shaped PELE projectile is first put forward. In order to compare and analyze the damage power of the truncated cone-shaped PELE projectile and the conventional PELE projectile, six sets of simulation conditions were designed, and the penetration ability and fragmentation effect were used as the main evaluation indicators. According to the known structural parameters of the PELE projectile, the range of angle α of the truncated cone-shaped PELE projectile was determined to be 86.2°–90°. In addition, there is little difference in penetration ability between the two different types of PELE projectile; the damage effect of the truncated cone-shaped PELE projectile on the after-effect target is better than that of the conventional PELE projectile. It is hoped that through further structural optimization, the truncated cone-shaped PELE projectile will have more extensive engineering application value.

Empirical findings suggest that forming Free Trade Agreement (FTA) could be an efficient way of attracting inward Foreign Direct Investment (FDI). With an aim to explore the mechanism of how FTA encourages FDI, this study detects its two FDI-promoting effects identified in theoretical studies. One is the effect of market expansion and the other is the effect of vertical fragmentation. This paper uses the ASEAN-China Free Trade Agreement (ACFTA) as a case study and detect its two effects through a sector-level examination of FDI in China’s manufacturing industry. Both effects are found with ACFTA. The finding suggests that the market expansion effect can assist sectors with international competitiveness in attracting more market-seeking FDI, while the vertical fragmentation effect can promote vertical FDI to sectors with intense trade in intermediate goods. A policy insight from this study is that the selection of FTA partners is important in the effect of FTA on FDI. Forming FTAs with big markets would bring market-seeking FDI, while forming FTAs with countries on the same production value chain can bring vertical FDI.

Question: What is the relative importance of area- and edge-effects on woody seedling diversity in old Afromontane forest fragments? Location: Mistbelt Afromontane forests, KwaZulu-Natal midlands, South Africa. Methods: Woody seedling abundance and species richness in 590 1-m2 plots were sampled at the forest edge (< 10 m from the edge) and interior in 31 old (> 60 a) Afromontane forest fragments (0.05 – 328.5 ha) with closed edges in an ancient grassland matrix. Results: Unlike young (< 20 a) Amazonian fragments, there was no edge- or area-effect on sample plot seedling density and species richness, although these increased significantly with increasing herb cover (less disturbance). Seedling density, but not species richness, declined significantly with herbivory of seedlings, regardless of forest size or plot location. Seedling community composition and richness did not differ significantly between the edge and interior of forests across the range of forest sizes (i.e. no edge-effect). Community composition was nested with small forests retaining a subset of the seedling flora of larger forests. Overall, cumulative seedling species richness increased with forest area (i.e. area-effect). Conclusions: Holocene climatic extinction filtering events and area-dependent species relaxation have potentially selected for tree species with convergent life histories adapted to local fragmentation-effects. Stable environmental conditions at old edges in these naturally fragmented forests cause similar regeneration conditions and seedling species composition between edge and interior. Consequently, seedling density and species richness are controlled more by response to gradients of local disturbance (habitat area, herb cover, herbivory) than by proximity to the edge. Large patches (> 50 ha) with intact edges had the highest tree seedling diversity and are a conservation priority. Although small patches contain no unique species they preserve landscape processes, have conservation value, and require protection. Conservation principles derived from recently created Amazonian fragments and that emphasize edge-effects, require critical evaluation for application to old Afromontane patches. Nomenclature: Arnold & de Wet (1993).

This study analyzes the effects of listing changes within NASDAQ market segments during the period of 1998 to 2005. We find that firms phased up from the NASDAQ Small Capital Market (SmallCap) to the NASDAQ National Market (NNM) experienced significant declines in bid-ask spreads, the volatility of returns, and the probability of informed trading, and firms that phased down from NNM to the SmallCap experienced decreases in bid-ask spreads, but insignificant changes in the volatility of returns and the probability of informed trading. We also estimate simultaneous equations models of bid-ask spreads, return volatility, and trading volume for both groups of firms. The results confirm that improved liquidity is associated with the listing changes for the phase-up firms. However, the simultaneous equations model suggests that the decreases in bid-ask spreads for the phase-down firms are caused by the changes in share prices.

Microwave energy can be used to assist mechanical rock breakage for civil and mining engineering operations. To assess the industrial applicability of this technology, microwave heating of basalt specimens in a multi-mode cavity (a microwave chamber) at different power levels was followed by conventional mechanical strength and fragmentation effect tests in the laboratory. X-ray diffraction and scanning electron microscopy/energy-dispersive X-ray spectroscopy were used to determine the mineral composition and distribution of the basalt, to aid interpretation of crack propagation patterns and the associated strength reduction mechanism. These analyses demonstrated that cracks mainly occurred around olivine grains, primarily as intergranular cracks between olivine and plagioclase grains and intragranular cracks within olivine grains. Strength reduction during microwave fracturing of basalt is driven by heat from enstatite (a microwave-sensitive mineral) and volumetric expansion of olivine (a thermally expansive mineral). Uniaxial compressive, Brazilian tensile, and point load strengths all decreased with increasing microwave irradiation time at rates that were positively related to the power level. For a given power level, mechanical strength reduction can be estimated from linear relationships with irradiation time. On the other hand, a power function best described burst time (the irradiation time at which the specimen burst into fragments) vs. power level (for a given specimen size) and burst time vs. specimen size (for a given power level) relationships. Microwave-induced hard rock fracturing can be an integral part of new methods for rock breakage and tunnel excavation.

ContextWhen human-made barriers impact wildlife by limiting habitat connectivity, simulation can reveal movements lost to fragmentation, strategies to restore corridor function, and potential benefits of corridor restoration.ObjectivesGuided by previous genetic research, we examined desert bighorn sheep movement near two highways that restrict gene flow and modelled their movement and habitat selection behavior. The ultimate goal was to simulate movement without highway barriers as a means to site crossing structures that mitigate fragmentation and to reveal their benefits for habitat reachability.MethodsWe fit integrated step selection functions (iSSFs) to GPS data from 9 bighorn populations near highways in California. After comparing iSSF simulations to validation data, we simulated 8200 bighorn-years of movement—200 year-long tracks each for 41 individuals—on a landscape with and without highways. We derived utilization distributions (UD) from simulations to identify probable high-use locations along the highways, compare these locations to previously predicted genetic corridors and roadkill events, and estimate changes in habitat reachability and elevation without these barriers.ResultsSimulation UDs correlated well with observed bighorn movements. Barrier-free simulations indicated preferred corridors across highway-blocked valleys, often at the same locations predicted by landscape genetics models (4 of 6 genetic-based corridors matched simulation-based corridors), and where bighorn roadkill events occurred (3 of 3 roadkill events occurred at simulation-predicted corridors). Relative to barrier-present simulations, barrier removal increased accessible habitat for 8 of 9 populations, with increases ranging from 7 to 138% per population. Barrier-free conditions allowed movement to higher elevations in two populations.ConclusionAnimal movement simulation can effectively assess fragmentation impacts and reveal mitigation options when other data sources are scarce. Our simulations confirm previously predicted corridors, provide detailed locations for targeted mitigation, and suggest certain corridors pose greater habitat-related benefits.