Number Of Collisions Research Articles

Using a V2V- and V2I-based collision warning system to improve vehicle interaction at unsignalized intersections

Introduction: Unsignalized intersections are critical components of the road network where traffic collisions occur frequently. Method: This study aims to design a Vehicle-to-Vehicle (V2V)- and Vehicle-to-Infrastructure (V2I)-based unsignalized intersection collision warning system (UICWS) to improve driver performance and enhance driver safety at unsignalized intersections. A multi-user driving simulator experiment was conducted with 48 participants divided into 24 pairs. The dynamic interaction of each participant pair as they approached the intersection from straight-crossing directions was examined under different warning conditions (i.e., with vs without UICWS) and intersection field of view (IFOV) conditions (i.e., standard vs improved IFOV). Results and conclusions: The experimental results showed that the UICWS could effectively help drivers make appropriate operation decisions and reduce the number of right-angle collisions and near-collisions at unsignalized intersections. In the condition without UICWS, improved IFOV could prompt drivers to make crossing decisions in advance and adjust speed smoothly. Moreover, drivers’ crossing maneuvers changed with the relative distance between the subject and conflict vehicles and the intersection. The risks of collisions and near-collisions increased significantly when the two vehicles were at a similar distance to the intersection before they initiated any actions. Practical Applications: The findings show that the proposed UICWS can effectively reduce collisions or near-collisions at unsignalized intersections in a connected vehicle environment. On this basis, some active intervention strategies, such as specific speed guidance depending on the dynamics of the conflict vehicle, can be developed to ensure vehicles passing through unsignalised intersections safely.

Synthesis and Acidity Study of Na-ZSM-5 Zeolite

Zeolites are a special class of structured aluminosilicates with a developed inner surface and a large number of micropores, which allows them to be used as sorbents, membrane materials, and catalysts. Zeolite ZSM-5 is an aluminosilicate formed by parallel channels with a diameter of 5.3–5.6Å interconnected by sinusoidal channels with a diameter of 5.1–5.5Å. At the same time, the presence of aluminum atoms in the zeolite crystal lattice makes it possible to carry out dehydrogenation, esterification, isomerization, and aromatization reactions, and the presence of microchannels significantly increases the number of collisions of reacting compounds, which leads to a significant increase in the rate of chemical transformations in such systems. The synthesis of ZSM-5 zeolite using structure-directing agents has been known since the late 70s of the last centuries, while the high cost of structure-directing agents used and the long duration of hydrothermal synthesis and the need for subsequent post-synthetic procedures lead to a high cost of the resulting zeolite. One of the possible ways to reduce the cost of the synthesis of ZSM-5 zeolite is the direct use of ZSM-5 zeolite as a structure-forming agent, while the synthesis conditions play a decisive role in the structure of the resulting zeolite. The article presents the results of a study of the synthesis of ZSM-5 zeolite and a study of its acidic properties using locally produced reagents. Zeolite was prepared using pre-milled silica gel, sodium hydroxide, and sodium aluminate. The pre-weighed silica gel sample was filled with sodium hydroxide solution and stirred at 70 ℃ to form a colloidal solution, after which the pre-prepared sodium aluminate solution was added, and hydrothermal synthesis was carried out at 180 ℃ for 24 hours. During the synthesis, the Si/Al ratio was varied in the range from 7.5 to 2000, while the resulting acidity ranged from 0.002 to 0.265 mmol(NH3)/g(ZSM-5). It was found that the synthesis of ZSM-5 using pre-prepared reagent solutions is superior to the method using direct dissolution of solid reagents in an autoclave. An increase in the Si/Al ratio from 7.5 to 100 leads to a corresponding increase in surface acidity from 0.066 mmol(NH3)/g(ZSM-5) to 0.265 mmol(NH3)/g(ZSM-5). A further increase in the Si/Al ratio to 2000 leads to a decrease in surface acidity to 0.002–0.005 mmol(NH3)/g(ZSM-5). A reliable and simple method for the synthesis of ZSM-5 zeolite has been developed, providing a zeolite yield of up to 97%.

AIS-based characterization of navigation conflicts along the US Atlantic Coast prior to development of wind energy

This study characterizes navigation conflicts in a region with a large traffic volume along the United States (US) Atlantic Coast, using an empirical approach that analyzes Automated Identification System (AIS) data for a full year (2010). The region includes areas proposed for wind energy development, and this characterization of vessel conflicts could be useful as a baseline to evaluating the effect of offshore wind areas on navigation conflicts and vessel collisions. There have been no collisions reported within the study area. This study analyzes the one year of AIS data to obtain vessel tracks and makes simultaneous pairwise comparisons to determine the number and rate of vessel encounters and near-misses (navigation conflicts). For vessel pairs in an encounter (3 nm distance; crossing, head-on, overtaking), a ‘blind vessel’ assumption was used to calculate the number of potential near misses and potential collisions. Graphical analysis of the frequency of vessels involved in potential near misses produced vessel response curves that provided the time of peak frequencies prior to the time of closest approach for each encounter type. These peak times were up to 600 s prior to the time of closest approach. The analyses of potential near misses and collision used the data during the period between the time of peak frequency and the time of closest approach to filter the data used in the calculation of the probability of potential collisions. The period included collsion avoidance maneuvering. Statistical analyses are made to estimate the point values and uncertainty of near miss rates and the probability of potential collisions for each type of encounter from which bounding estimates of the collision rates are made. These bounding collision rates are found to be comparable with estimates from previous studies. Causation probabilities were also estimated and compared with previous studies. The response curves may also have utility in the simulation of navigation conflicts. The use of surrogate data to evaluate the effect of wind energy areas is considered, though their usefulness depends on comparability of traffic density and the level and type of traffic control systems implemented.

Features of the Operation of a Three-Electrode Electrostatic Microgenerator in the Presence of Collisions between Electrodes

The results of studying the influence of impact interactions on the operation of a three-electrode two-capacitor microelectromechanical transducer (MEMT) and a microgenerator based on it are presented. The operation of the microgenerator in the impact periodic mode is analyzed for two extreme cases, when the movable electrode initially comes into contact with the limiters located on the left (LWC) or right (RWC) walls of the casing. The relationship between the system parameters and the characteristics of the external driving force source, which makes it possible to evaluate the possibility of implementing a periodic impact operation, is obtained. The dependences of the average generated power of the impact microgenerator on the number of collisions and the load are calculated. It is shown that a microgenerator with a three-electrode MEMT, in the case when the movable electrode initially comes into contact with the limiters located on the LWC, develops more power than in the case when the movable electrode initially touches the limiters located on the RWC. The efficiency of the microgenerator in impact and nonimpact modes is compared. It is shown that when using the impact mode, a gain by factors of 2 to 5 in the developed power is possible with a significant decrease of 1 to 2 orders of magnitude of the optimal load resistance compared to using an equivalent impact-free mode. In general, the analysis carried out and the developed approach make it possible to significantly narrow the range of the search for the necessary system parameters at the preliminary design stage and reduce the design time.

The mechanism investigation of ultrasonic roller dressing vitrified bonded CBN grinding wheel

To clarify the ultrasonic roller dressing mechanism of the vitrified bonded cubic boron nitride grinding wheel (V-CBN), the collision number model between the diamond dresser and CBN grits was established based on the geometric and kinematics analysis. The influence of each dressing parameter on the collision number was analyzed and discussed. The grinding experiment was performed on the bearing raceway with the dressed V-CBN grinding wheel, results obtained discovered that there was an inverse relationship between the collision number and the surface roughness and runout of the workpiece. Additionally, compared with conventional dressing, ultrasonic dressing has the advantage in improving the surface quality because it can produce more collision numbers and raise grit retention. In words, the collision number can be used to predict the dressing effect, which provides a reference for formulating an appropriate dressing process for V-CBN to improve the workpiece surface quality and production efficiency.

Acoustically driven orientation and navigation in enclosed spaces.

Awareness of space, and subsequent orientation and navigation in rooms, is dominated by the visual system. However, humans are able to extract auditory information about their surroundings from early reflections and reverberation in enclosed spaces. To better understand orientation and navigation based on acoustic cues only, three virtual corridor layouts (I-, U-, and Z-shaped) were presented using real-time virtual acoustics in a three-dimensional 86-channel loudspeaker array. Participants were seated on a rotating chair in the center of the loudspeaker array and navigated using real rotation and virtual locomotion by "teleporting" in steps on a grid in the invisible environment. A head mounted display showed control elements and the environment in a visual reference condition. Acoustical information about the environment originated from a virtual sound source at the collision point of a virtual ray with the boundaries. In different control modes, the ray was cast either in view or hand direction or in a rotating, "radar"-like fashion in 90° steps to all sides. Time to complete, number of collisions, and movement patterns were evaluated. Navigation and orientation were possible based on the direct sound with little effect of room acoustics and control mode. Underlying acoustic cues were analyzed using an auditory model.

Developing and implementing 20-mph speed limits in Edinburgh and Belfast: mixed-methods study

Background Transport initiatives such as 20-mph (≈30-km/h) speed limits are anticipated to result in fewer road casualties and improve perceptions of safety, leading to increases in active travel. Lower speeds may also lead to more pleasant environments in which to live, work and play. Objectives The main objective was to evaluate and understand the processes and effects of developing and implementing 20-mph speed limits in Edinburgh and Belfast. The focus was on health-related outcomes (casualties and active travel) that may lead to public health improvements. An additional objective was to investigate the political and policy factors (conditions) that led to the decision to introduce the new speed limits. Design This was a mixed-methods study that comprised an outcome, process, policy and economic evaluation of two natural experiments. Setting The study was set in Edinburgh, Scotland, and Belfast, Northern Ireland, from 2000 to 2018. Participants The whole population of each city were participants, as well as stakeholders involved in implementation and decision-making processes. Intervention The intervention was the implementation of 20-mph legislation, signage, enforcement, and education and awareness-raising in Edinburgh (citywide) and Belfast (city centre). Main outcome measures The main outcomes measured were speed; number, type and severity of road collisions; perceptions; and liveability. Data sources The following data sources were used – routinely and locally collected quantitative data for speed, volume of traffic, casualties and collisions, and costs; documents and print media; surveys; interviews and focus groups; and Google Street View (Google Inc., Mountain View, CA, USA). Results Collisions and casualties – the overall percentage reduction in casualty rates was 39% (the overall percentage reduction in collision rates was 40%) in Edinburgh. The percentage reduction for each level of severity was 23% for fatal casualties, 33% for serious casualties and 37% for minor casualties. In Belfast there was a 2% reduction in casualties, reflecting differences in the size, reach and implementation of the two schemes. Perceptions – in Edinburgh there was an increase in two factors (support for 20 mph and rule-following after implementation) supported by the qualitative data. Liveability – for both cities, there was a small statistical increase in liveability. Speed – mean and median speeds reduced by 1.34 mph and 0.47 mph, respectively, at 12 months in Edinburgh, with no statistically significant changes in Belfast. History, political context, local policy goals, local priorities and leadership influenced decision-making and implementation in the two cities. Limitations There was no analysis of active travel outcomes because the available data were not suitable. Conclusions The pre-implementation period is important. It helps frame public and political attitudes. The scale of implementation and additional activities in the two cities had a bearing on the impacts. The citywide approach adopted by Edinburgh was effective in reducing speeds and positively affected a range of public health outcomes. The city-centre approach in Belfast (where speeds were already low) was less effective. However, the main outcome of these schemes was a reduction in road casualties at all levels of severity. Future work Future work should develop a statistical approach to public health interventions that incorporates variables from multiple outcomes. In this study, each outcome was analysed independently of each other. Furthermore, population measures of active travel that can be administered simply, inexpensively and at scale should be developed. Study registration This study is registered as ISRCTN10200526. Funding This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 10, No. 9. See the NIHR Journals Library website for further project information.

Characterisation of planar sensors for the inner tracker of the CMS experiment

The Compact Muon Solenoid (CMS) experiment is expected to collect an integrated luminosity of 3000 fb−1 during the High Luminosity phase of the Large Hadron Collider (HL-LHC). This scenario comes with a high number of collisions per bunch crossing, and in turn, a high level of radiation for the innermost layer of the CMS tracker. Simulations estimate a 1 MeV neutron equivalent fluence, Φeq, of 2.3 × 1016 cm−2 at a distance of 2.8 cm from the collision point. The inner tracker of the CMS detector is required to withstand this range of fluence and maintain tracking performance. Planar pixel sensors with an active thickness of 150 μm and pixel sizes of 25 × 100 μm2 or 50 × 50 μm2 have been produced by Hamamatsu Photonics (HPK) and Fondazione Bruno Kessler (FBK). The sensors were bump bonded to the RD53A readout chip prototype. The sensor-chip modules were irradiated with 23 MeV protons to the 1 MeV neutron equivalent fluence of up to 2.4 × 1016 cm−2 at the Zyklotron AG (ZAG).Non-irradiated and irradiated modules were tested in the DESY II beam test facility. The spatial resolution as a function of the incidence angle and hit efficiency as a function of the bias voltage of the sensors were determined from these measurements. It is shown that for the highest fluence, the planar modules still reach 98% hit efficiency at bias voltages below 800 V.

Visually-guided motion planning for autonomous driving from interactive demonstrations

The successful integration of autonomous robots in real-world environments strongly depends on their ability to reason from context and take socially acceptable actions. Current autonomous navigation systems mainly rely on geometric information and hard-coded rules to induce safe and socially compliant behaviors. Yet, in unstructured urban scenarios these approaches can become costly and suboptimal. In this paper, we introduce a motion planning framework consisting of two components: a data-driven policy that uses visual inputs and human feedback to generate socially compliant driving behaviors (encoded by high-level decision variables), and a local trajectory optimization method that executes these behaviors (ensuring safety). In particular, we employ Interactive Imitation Learning to jointly train the policy with the local planner, a Model Predictive Controller (MPC), which results in safe and human-like driving behaviors. Our approach is validated in realistic simulated urban scenarios. Qualitative results show the similarity of the learned behaviors with human driving. Furthermore, navigation performance is substantially improved in terms of safety, i.e., number of collisions, as compared to prior trajectory optimization frameworks, and in terms of data-efficiency as compared to prior learning-based frameworks, broadening the operational domain of MPC to more realistic autonomous driving scenarios.

Real-time tracking of colloidal stability based on collision behaviors probed by surface-enhanced Raman spectroscopy

HypothesisThe dynamic behaviors of colloidal particles have already been considered as one of the key issues in their practical application, such as aggregation and dispersion. However, it is still remained significant challenge in developing the real time techniques to capture their dynamic tracks. The nano/subnanometer scale gap generated during the colloidal collisions served as the critical location for amplifying the Raman signal, so called as gap (“hot spots”) based surface enhanced Raman spectroscopy (SERS). The alternating reversible “spike” of SERS intensity and irreversible step in baseline intensity are contributed to the preferred stability and the aggregation of colloid respectively. ExperimentsA facile approach is developed to track colloidal stability in real-time based on collisions and SERS. The effects of particle concentration, the dispersion medium, and solution pH on colloidal stability are systematically investigated, and the SERS intensity of a simulated single-like “hot spot” was calculated by combining a SEM position with SERS mapping technology to estimate the intensity of single-particle collision. FindingsThe colloidal particles exhibited higher stability in the solution with lower particle concentration, higher viscosity and neutral medium. The SERS intensity of single-particle collision was estimated to be about 2.06 × 10-7 counts, and the average number of collisions for the 0.13 mmol/dm3 SiO2@Ag solution was about 1.11 × 108 times/spike in the “spikes” with SERS intensity of 23.0 cps. It is believed that the SERS based strategy would be developed as a promising tool for obtaining the deeper insight into the nature of collisions in the colloidal science.

Towards a better understanding of detection properties of different types of plastic scintillator crystals using physical detector and MCNPX code

The purpose of this comprehensive research is to observe the impact of scintillator crystal type on entire detection process. For this aim, MCNPX (version 2.6.0) is used for designing of a physical plastic scintillation detector available in our laboratory. The modelled detector structure is validated using previous studies in the literature. Next, different types of plastic scintillation crystals were assessed in the same geometry. Several fundamental detector properties are determined for six different plastic scintillation crystals. Additionally, the deposited energy quantities were computed using the MCNPX code. Although six scintillation crystals have comparable compositions, the findings clearly indicate that the crystal composed of PVT 80% + PPO 20% has superior counting and detecting characteristics when compared to the other crystals investigated. Moreover, it is observed that the highest deposited energy amount, which is a result of the highest collision number in the crystal volume, corresponds to a PVT 80% + PPO 20% crystal. Despite the fact that plastic detector crystals have similar chemical structures, this study found that performing advanced Monte Carlo simulations on the detection discrepancies within the structures can aid in the development of the most effective spectroscopy procedures by ensuring maximum efficiency prior to and during use.

Comparing the Performance and Evaluation of Computer Experts and Farmers when Operating Agricultural Robots: A Case of Tangible vs Mouse-Based UIs

Tangible user interfaces (TUIs) integrate computer systems with the physical world as they allow interaction through physical objects and the human kinesthetic system. They have been studied in various domains, both by the designing and piloting of innovative applications, as well as by comparatively analyzing TUI against GUI interaction. In the human-robot interaction (HRI) field, TUIs are considered a promising approach as they make effective use of physical object affordances, but research is rather inconclusive about whether TUIs offer improved efficiency, lower error rates, increased intuitiveness, engagement, and user satisfaction. In this study, two prototype UIs were designed and evaluated to compare a TUI with a 2D mouse-based UI for remotely operating two agricultural robots used for vineyard spraying. Two different user groups played the role of the operator: computer experts and farmers leading to an experiment with a 2×2 setup, where two different types of UIs were evaluated by two different user groups. The formulated research questions concern the efficiency, accuracy, and user evaluation for each UI and for each group individually and combined. Analysis has shown that there were no statistically significant differences comparing the alternative UIs for each group in terms of time to complete the task, even though computers experts were faster, as expected. Also, the number of collisions, as well as the percentage of unsprayed and double sprayed area, revealed no significant differences, either for user groups or UIs. The TUI received more positive evaluations in terms of user preference, and users reported lower perceived error rates, especially in the case of farmers, who were also more willing to use the TUI in their daily job.

Forecasting seasonal peaks in roadkill patterns for improving road management

For several species, roadkill is not spatially aggregated on hotspots, having instead a more diffuse pattern along the roads. For such species, management measures such as road passages may be insufficient for effective mitigation, since a large part of the road crossings is likely to occur outside the influence of those structures. One complementary approach could be to implement temporary mitigation actions, such as traffic calming. This requires understanding when roadkill peaks may occur. We tested the feasibility of predicting seasonal peaks of roadkill using data from a 3-year systematic monitoring (78 surveys over ca. 960 km of roads) from eight non-flying vertebrate species from Mato Grosso do Sul, Brazil, with different body size and life history traits (ca. 6400 records from focal species). We modelled the time-series of the roadkill of these species at large scale (state level) using generalized additive mixed models (GAMMs). We used the data of the first 2 years as training datasets, and the information from the third year of surveys as testing datasets to evaluate the prediction performance of models. Overall, the models of species feed with a higher number of records were able to follow reasonably well the variations of roadkill over time, although they were not able to correctly predict the number of collisions. For species with fewer observations, the models presented a poorer goodness-of-fit and prediction ability. Our results suggest that, at least for those species with higher roadkill rates, it can be possible to forecast periods of higher probability of occurring hot-moments of mortality. Such models can provide valuable information to implement seasonal management actions.

Spatiotemporal Patterns of Cyclist Collisions in Germany: Variations in Frequency, Severity of Injury, and Type of Collision in 2019

Cycling has gained increasing interest in Germany in recent years due to its manifold environmental, societal, and economic benefits. However, the number of cyclist collisions resulting in injury or death remains high and little is known about regional variations in frequency, severity of injury, and type of collision. This study investigates spatial and temporal patterns and characteristics of cyclist collisions across Germany in 2019. Using a detailed cyclist collision dataset for most German federal states, we identified statistically significant regional differences in frequency, severity of injury, and type of collision. To facilitate this and future cyclist collision surveillance studies in Germany, we developed and published a custom R package to download and combine the collision data with geographical data. Our analysis reveals that densely populated regions exhibit higher collision rates and a higher share of collisions involving turns, but lower severity of injuries and a lower share of collisions whilst driving in a straight line, a higher collision frequency during the work week compared to weekends, and a higher collision frequency peak during morning rush hour. We also observed a markedly high share of fatal bicycle-truck collisions in densely populated regions. In contrast, rural regions show lower collision rates, but a higher share of severe collisions, a higher share of collisions whilst driving in a straight line, as well as higher collision frequencies during weekends and summer months. Our findings underscore the complex and multifaceted geographical variations in collisions involving cyclists. The results of this study suggest that a one-size-fits-all approach to collision prevention infrastructure and policy may be insufficient for addressing variations in risk, and that future efforts to improve cyclist safety should be tailored to the local geographical context.

Reproducing size distributions of swarms of barchan dunes on Mars and Earth using a mean-field model

We apply a mean-field model of interactions between migrating barchan dunes, the CAFE model, which includes spontaneous calving, aggregation, fragmentation, and mass-exchange, yielding a steady-state size distribution that can be resolved for different choices of interaction parameters. The CAFE model is applied to empirically measured distributions of dune sizes in two barchan swarms in the north circumpolar region of Mars, three swarms in Morocco, and one in Mauritania, each containing more than 1000 bedforms. When the sizes of bedforms are rescaled by the mean size in each zone two attractor states appear, with the Tarfaya zones all displaying a common distribution and the Martian and Mauritanian zones sharing a different distribution. Comparison of these attractor states with the outputs of the CAFE model reveals that the Tarfaya-type distribution results from a preference for aggregation and fragmentation interactions whereas the Mars–Mauritania distribution is more likely a result of exchange–dominated interactions. We observe that there appears to be a greater number of collisions happening in Tarfaya than in the other areas which is consistent with a greater rate of aggregation–fragmentation processes as suggested by our model. Our comparison with the CAFE model also predicts a universal rule for the outputs of the different types of interactions with exchange interactions favouring the production of two dunes roughly equal in size. Fragmentation interactions often result in three bedforms with volumes approximately in the ratio 1:1:2. Finally, we find that spontaneous calving of dunes does not play an important role in shaping the size distributions in barchan swarms.

The Effect of Metallicity on the Formation of Massive Black Holes through Stellar Collisions in Young Massive Star Clusters

Dynamical interactions facilitated by the high densities in massive star clusters can lead to large numbers of stellar collisions and unique stellar evolution pathways not possible for stars evolving in isolation. Using N-body cluster models, we study the role of stellar collisions in the formation of massive black holes, specifically studying the effect of stellar metallicity on this process. We show that at high metallicity (up to solar), the number of massive black holes formed may be reduced by up to a factor of ten compared to low-metallicity clusters. We also examine the role of collisions in the production of pair-instability supernovae and predict event rates of these transients in the local universe.

First-passage-driven boundary recession

We investigate a moving boundary problem for a Brownian particle on the semi-infinite line in which the boundary moves by a distance proportional to the time between successive collisions of the particle and the boundary. Phenomenologically rich dynamics arises. In particular, the probability for the particle to first reach the moving boundary for the nth time asymptotically scales as . Because the tail of this distribution becomes progressively fatter, the typical time between successive first passages systematically gets longer. We also find that the number of collisions between the particle and the boundary scales as ln ln t, while the time dependence of the boundary position varies as t/ln t.

Changing patterns of Oral & Maxillofacial injuries before and during COVID-19 pandemic: A retrospective study

IntroductionOral and maxillofacial injuries can be defined as injuries involving soft and hard tissue structures of the facial region and oral cavity, including the teeth and vital structures of the head and neck area as a result of trauma. The maxillofacial injuries are multifactorial and vary from one country to another and even from region to region. Despite, societal restrictions imposed by the government in the form of lockdowns and curfews, patients still experienced trauma and required significant healthcare services for management. MethodsPatients of either gender reporting to the emergency department of Lata Mangeshkar Hospital with maxillofacial injuries, attended by residents of OMFS from October 2019 to August 2020 were included in the retrospective study. The demographic data about age, gender and status pertaining to under the influence of alcohol was recorded. The aim of this retrospective study was to evaluate the changing patterns of the maxillofacial injuries during the Covid-19 pandemic. ResultsIn the present study, the road traffic accidents were 72.50% pre-lockdown which reduced to 47.37% during the alcohol ban and nationwide lockdown and gradually increased to 63.83% post-lockdown. The second most common cause of maxillofacial injury was falls which showed a significant increase from 22.50% before the lockdown to 31.58% during the lockdown and decreased to 26.6% after lockdown during the pandemic. There was an increase in the number of assaults from 2.50% pre-lockdown to 15.79% during the lockdown and again a decrease to 6.38% post-lockdown. DiscussionOur study demonstrates the impact of nationwide lockdown in the month of April and May 2020, may have an association with the significant statistical decrease in the monthly average number of trauma admissions. There was a significant decrease in the number of road traffic collisions and falls during the “lockdown period”. ConclusionThe etiology and pattern of maxillofacial injuries reflect the trauma pattern within the community. We need more coordinated strategies of action to minimize maxillofacial injuries and its implication on physical and psychological wellbeing of patients.

Spatio-temporal modeling of traffic accidents incidence on urban road networks based on an explicit network triangulation

ABSTRACT Traffic deaths and injuries are one of the major global public health concerns. The present study considers accident records in an urban environment to explore and analyze spatial and temporal in the incidence of road traffic accidents. We propose a spatio-temporal model to provide predictions of the number of traffic collisions on any given road segment, to further generate a risk map of the entire road network. A Bayesian methodology using Integrated nested Laplace approximations with stochastic partial differential equations (SPDE) has been applied in the modeling process. As a novelty, we have introduced SPDE network triangulation to estimate the spatial autocorrelation restricted to the linear network. The resulting risk maps provide information to identify safe routes between source and destination points, and can be useful for accident prevention and multi-disciplinary road safety measures.

“On the Foundation of Transport-Driven Diffusion for Neutron Transport Problems”

The article presents the foundation of a novel methodology developed for the solution of the neutron transport equation, named the transport driven-diffusion approach, which can be considered as an evolution of the classic multiple collision method. The idea behind this method is based on the expansion of the full solution in terms of the contributions of the particles emitted by successive collisions plus a residual term, accounting for particles which have undergone more than a predefined number of collisions. In order to determine the contribution at each collision order, a transport equation with a source term is solved, while the estimation of the residue is based on a diffusion theory model. The physical rationale for the choice of the diffusion model for the residue is discussed and justified, as physics suggests that the diffusion assumptions become more applicable for the description of the particles having suffered a certain number of collisions rather than to the original transport problem. Some results are presented for a set of steady-state and time-dependent test cases. Their analysis shows the remarkable advantage of the method proposed in terms of accuracy and computational time, when compared to standard diffusion and multiple collision at the same order.