Safe Distance Research Articles

Characteristics of Forcible Entries into Objects and an Experimental Assessment of the Potential Impact of Fragments Scattering on Training Safety when Using Fence Charge

The article focuses on the characteristics of forcible entries into objects and the term "breaching", which is often used interchangeably with this activity. The article further addresses the issue of fragments scattering when using a charge to overcome chain-link fences. The introductory chapter describes the execution of training in this field using the exercise facilities that are built for this purpose in military training areas. When conducting explosive forcible entry training, the safe distance for intervening teams and non-participants is determined using given formulas. The purpose of the simulation, mathematical calculations and experiment was to assess the extent to which fragments scattering occurs during explosive overcoming of these fences and whether the procedures used to determine the safe distance for non-participants are sufficient.

Comprehensive assessment of emergency fire risks during oil and gas well drilling

The study aims to perform a comprehensive assessment of emergency fire risks when drilling oil and gas wells for open flowing of the well with gas flare combustion and the combustion caused by diesel fuel spills. The object is a well site of the oil and gas condensate field in the Irkutsk region. A retrospective analysis of emergency situations during oil and gas well drilling identified the most frequent types of accident - fires at oil and gas production facilities, open fountains and emissions from wells. Scenarios for these accidents were developed and event trees were built. Using them, options with the greatest possible damage caused by a fire were identified. The intensity of thermal radiation was estimated at various distances from the center of the flare with open flowing of the well with the gas flare combustion. The intensity of thermal radiation during a fire caused by diesel fuel spills was calculated for the destruction of three RVS-50 tanks. Safe distances from the accident site and possible fatal injuries to the personnel were identified.

Research on robot path planning with safe distance optimization

PurposeWith the development of technology, the application scenarios of mobile robots are becoming more and more extensive, accompanied by a variety of application scenarios suitable and safe path planning algorithms are indispensable for mobile robots.Design/methodology/approachThe purpose of this paper to improve the safety performance of your bot during the execution of tasks. The methods are synthesized in three main areas: setting appropriate safety distances based on the actual radius of the robot, turn penalty reduces the number of turns by applying an additional penalty to the number of turns in a heuristic function and path smoothing is used to improve path reliability by reducing the number of right-angle turns.FindingsA suitable safety distance greatly improves the safety of mobile robots and facilitates their development. Optimization of turns in the path of mobile robots improves the travel efficiency of robots. Enhancing the safety of mobile robots has become a research hotspot for path-planning algorithms.Originality/valueThis paper proposes a path planning scheme for mobile robots with safe distances, which provides readers with a comprehensive and systematic progress of path planning research. It helps readers to get inspiration from enhancing the safety of mobile robots.

Experimental and simulation investigation of jet characteristics during the accidental release of high-pressure CO2 with different diameter leakage orifice

Understanding the near-field characteristics of leakage is essential for safety distance calculations and risk assessment of emergency response to a pipeline leakage. This paper presents a small-scale experiment and computational fluid dynamics model designed to investigate the transient characteristics of near-field parameters. The study also analyzes the effects of leakage orifice diameter on the transient characteristics of the near-field. The results show that a pipeline leak starts with the formation of a compression wave, which causes the air at the front of the stream to be compressed, heated and pressurized. CO2 is then released at high pressure, creating a strong expansion wave that keeps the fluid pressure below local atmospheric levels. For full-hole and large-hole leaks, the temperature drop and rate show a negative linear correlation with the size of the leak hole. Conversely, for small hole leaks with the ratio of hole diameter to pipe diameter values below 0.2, the temperature drop shows an opposite trend. As the ratio of hole diameter to pipe diameter values increases, the maximum diameter of the barrel drum-shaped disk gradually increases, but the maximum expansion angle of the jet decreases. It is hoped that this work will contribute to the improvement of research models that assess the consequences of potential high-pressure pipeline rupture scenarios.

Large Pool Fires in the Process Industry. A Simple Model for Safety Distances Estimation

In recent years, the global production growth and the complexity of processes operation have increased safety concern, especially during the design project, considering potential accidental events as fires, explosions, and their related domino effects. Pool fire is one of the most frequent accidental events. Some procedures for safety distances estimation from pool fires were reported. However, there is a lack of adequate simple models to directly estimate safety distances covering a wide range of substances and pool diameters, considering a continuous interval of receptor vulnerabilities (from damage to people to domino effect prevention). In this paper, a simple model to estimate safety distances is proposed, suitable to be incorporated into complex models (e.g. safety management systems, layout optimization). A surrogate model is achieved by adopting a reference one. Methodologically, the main variables that play a key role modelling a pool fire were selected and their influence on the safety distance was analyzed to propose simple mathematical expressions. NLP optimization problems were solved to optimize the model parameters. A conservative, accurate and easy-to-use model was achieved with the aim of developing safer plants or for their safe operation by improving the optimal process design, or implementing safe management systems, considering risks.

Feasibility of the Northern Sea Route: Impact of Sea Ice Thickness Uncertainty on Navigation

With the accelerated melting of the Arctic sea ice, the opening of the Northern Sea Route (NSR) of the Arctic is becoming increasingly accessible. The purpose of this paper was to examine the impact of uncertainty in sea ice thickness (SIT) data on the opening of the NSR and to quantify the extent of this impact, which is essential to the regularized operation of polar shipping. A quantitative assessment framework was proposed to examine the influence of SIT data uncertainty on navigational uncertainty through three aspects: the navigational spatiotemporal windows, the distribution of safe sailing speeds, and the uncertainty in optimal route planning by employing four distinct SIT datasets. Furthermore, the sensitivity of navigational spatiotemporal windows, the distribution of safe sailing speeds, and route planning to variations in SIT were also evaluated. Results show that experiment results based on CS2SMOS exhibit a more aggressive profile, while results based on CPOM are more conservative. The difference in SIT data has a significant impact on the proportion of operations subject to special consideration areas, such as safety speed, sailing time, and distance in NEP. A 0.1 m discrepancy in sea ice thickness data results in an approximate 0.067 change in the proportion of operations within special consideration areas. This discrepancy also leads to an approximate speed change of 0.89 knots, a navigation duration change of approximately 4 days, and a distance change of 152 km within specified limits.

The supinator approach to the lateral elbow: a technique description and literature review

We present the supinator approach for management of the lateral elbow which combines the principal features of the Kocher and Kaplan approaches. The Kaplan interval is connected to the Kocher interval by a transverse incision extending to the supinator crest. The supinator approach maintains a safe distance from the posterior interosseous nerve and is likely to avoid the insertional variations of the LUCL. In our experience, the supinator approach is reproducible, provides ample exposure of the radial head and lateral elbow and reduces the risk of instability and neurologic insult.

Calculating a conductor’s temperature-related sag as the limiting value for a Dynamic Line Rating

The ampacity — a term that refers to the maximum current in amperes — of existing overhead lines can be increased using Dynamic Line Rating (DLR) systems. Based on ambient online conditions and electrical power flow measurements, together with a forecast of future ambient conditions, the ampacity of overhead lines can be dynamically adjusted. In essence, the ampacity of an overhead line is determined by the operating temperature of the conductor that still guarantees the required safe distances to the objects under the overhead line. This paper presents a calculation algorithm for the sag of a conductor that addresses an unequal temperature of the conductor along the line as a response to an expected problem in the future, when increasing numbers of DLR sensors will be installed on or even near overhead lines. A novel approach to the sag-temperature calculation useful for a DLR is developed based on the linearization of cable equations. As a result, the computational costs are greatly reduced, which is an important factor when the DLR system includes a large number of overhead lines and processes them simultaneously. The presented methods are open and can be adapted for an arbitrary DLR system.

Morphometric evaluation of the anatomical relationships between the superior orbital fissure and the orbital structures based on computed tomography images with clinical implications.

To assist in surgical planning in endoscopic approaches, we analyzed the morphometric measurements of the superior orbital fissure (SOF) and optic canal (OC) by three-dimensional multislice computed tomography (3D MDCT) and evaluated them according to age, gender, and lateralization. The study analyzed 219 MDCT images (114 women, 105 men) from individuals aged 18-90. Measurements of SOF and OC were performed on 3D MDCT images in the axial plane and with 3D-Slicer software. The distance between the infraorbital foramen and the anterior entrance of the maxillary sinus (CBW) (p < 0.001), the distance between the CBW and the lateral point of the SOF (p = 0.001), and the Angle 1 (p = 0.028) were higher in women than in men. While the SOF length and on 3D the SOF width were higher in women than men (p < 0.001 and (p = 0.001, respectively), the lateral wall length OC was higher in men than women (p = 0.045). According to SOF classification, SOF length was highest in type II and lowest in type VIII (p = 0.025), SOF width was highest in type I and lowest in type VI (p < 0.001). No significant difference was found based on age groups and lateralization in all parameters. We found that as the SOF width increased, the SOF length also increased, and there was a statistically strong positive correlation. These findings can contribute to a more effective and safe operation by improving and updating surgeons' knowledge about safe distances to SOF in endoscopic procedures from a 3D MDCT perspective.

Reactive Collision Avoidance Control for Nonholonomic Vehicles and Obstacles of Arbitrary Shape

Abstract Potential field-based collision avoidance algorithms for mobile robots frequently assume vehicles and obstacles to have circular or spherical shapes. This assumption not only simplifies the analysis but also limits the mobility of agents in confined spaces, particularly for vehicles with elongated or irregular shapes. To increase mobility, this letter presents a decentralized collision avoidance framework for nonholonomic systems of unicycle type that considers the non-circular shape and relative orientation of vehicles and obstacles. The framework builds on the concepts of potential field and avoidance functions. However, it proposes using a non-constant minimum safe distance radius that changes based on the shape, relative position, and relative orientation of agents. The control framework is proven to guarantee collision avoidance at all times and is shown, via simulation, to increase the ability of agents to navigate through narrow spaces safely.

Ocena ryzyka przypadkowej inicjacji półfabrykatów zawierających artykuły pirotechniczne o przeznaczeniu technicznym w branży motoryzacyjnej

The identification of the danger of accidental initiation, respectively the establishment of the causes and the possibilities that can generate the triggering of pyrotechnic devices with a technical destination in the automotive field containing pyrotechnic articles of the P1 category, is carried out for each piece of equipment depending on the phases of the technological process of their manufacture. The protection against the accidental initiation of pyrotechnic devices intended for equipping auto vehicles is of particular interest for occupational safety in the manufacturing process of these types of products, because their triggering can endanger the life and health of workers as a result of the uncontrollable effects of functioning, with the generation of thermal and dynamic effects, as well as the emission of toxic reaction products that can affect the human component and/or destroy the work space. The paper highlights the way to analyse the risk of accidental initiation of pyrotechnic devices actuator type from the P1 category, using the latest generation technical-scientific tools in order to computerize the effects following their untimely triggering and establish the safety distances in relation to the amplitude of the degree of damage to the human component, respectively the destruction caused to the work space. In the case of pyrotechnic articles from category P1 type pyrotechnic actuator, the main risks of their accidental initiation are determined by the following technical factors: the production of an electrical discharge greater than 25 KV, the generation of a current with an intensity greater than 0.4 A at the terminals pyrotechnic device, their exposure to a temperature higher than 165°C. The main effects generated after the untimely initiations of these products are determined by: flame, thermal radiation, dynamic pressure waves, projected fragments and hazardous releases of chemical combustion products. Depending on the results obtained following the estimation and assessment of the assessed risks, preventive and countermeasures of a technical and organizational nature are established, in order to secure the predicTab. operations of specific operations with these types of products.

Research on the explosion vent external composite disaster induced by dust explosion inside the dust collector

With the help of computational fluid dynamics (CFD) technology, this research focuses on the quantitative effects of the explosion venting area (S), static opening pressure of the vent (Pstat) and dust cloud concentration (CD) on the explosion overpressure, high-speed airflow and high-temperature flame in the explosion venting zone. The results show that the explosion disaster along the explosion venting zone in general shows an oscillating fluctuating trend of attenuation, and the closer to the explosion vent explosion disaster is more serious. The increase of S will enhance the nonlinear change of explosion disaster, and the change law of explosion overpressure is completely opposite to that of high-speed airflow and high-temperature flame. With the increase of Pstat, the coupling effect of air intake pipe and dust collector is strengthened, which further aggravates the spread of explosion disaster. The change of CD has both promoting and restraining effects on the spread of explosion disaster. The maximum overpressure (P), maximum wind speed (V), maximum flame speed (Fs) and maximum flame distance (Fd) in the explosion venting zone are 0.022 MPa, 494.5 m/s, 112.9 m/s and 10.9 m, respectively, and the venting safety distance is more than 11 m. In addition, the degree of impact on explosion disaster is in the following order: Pstat > A > CD. This research can provide a reference basis for the effective prevention and control of the composite disaster external the explosion vent induced by dust explosion inside the dust collector.

Research on Vehicle AEB Control Strategy Based on Safety Time–Safety Distance Fusion Algorithm

With the increasing consumer focus on automotive safety, Autonomous Emergency Braking (AEB) systems, recognized as effective active safety technologies for collision avoidance and the mitigation of collision-related injuries, are gaining wider application in the automotive industry. To address the issues of the insufficient working reliability of AEB systems and their unsatisfactory level of accordance with the psychological expectations of drivers, this study proposes an optimized second-order Time to Collision (TTC) safety time algorithm based on the motion state of the preceding vehicle. Additionally, the study introduces a safety distance algorithm derived from an analysis of the braking process of the main vehicle. The safety time algorithm focusing on comfort and the safety distance algorithm focusing on safety are effectively integrated in the time domain and the space domain to obtain the safety time–safety distance fusion algorithm. A MATLAB/Simulink–Carsim joint simulation platform has been established to validate the AEB control strategy in terms of safety, comfort, and system responsiveness. The simulation results show that the proposed safety time–safety distance fusion algorithm consistently achieves complete collision avoidance, indicating a higher safety level for the AEB system. Furthermore, the application of active hierarchical braking minimizes the distance error, at under 0.37 m, which meets psychological expectations of drivers and improves the comfort of the AEB system.

An artificial potential field approach for event-triggered cooperative control of multiple high-speed trains with free initial states

ABSTRACT In this paper, a multi-algorithm-fusion-based cooperative tracking control strategy is proposed for high-speed trains to achieve the control objectives of reference speed trajectory tracking and adjacent safety distance maintenance simultaneously. First, the multiple high-speed train (MHST) system is formulated as a multi-agent system (MAS) with a virtual leader. Second, a coordination controller that considers the dynamic tracking performance and input saturation is designed by combining the MAS leader-follower consensus algorithm and the improved artificial potential field (APF) method. In addition, within the train-to-train (T2T) communication network, an event-triggered mechanism is introduced in the continuous state transmission process to address the communication channel capacity protection limitation issue. Third, the closed-loop stability of the MHST system is ensured by the comprehensive analysis of a novel log-type Lyapunov function. Finally, the effectiveness of the proposed event-triggered cooperative tracking control strategy is verified through a numerical example of the MHST system on a typical line.

Rapid Primary Sulfate Aerosol Generation Observed With OP‐FTIR in the Eruptive Plume of the Fagradalsfjall Basaltic Eruption, Iceland, 2021

AbstractOpen‐Path Fourier‐Transform Infrared (OP‐FTIR) absorption spectroscopy is a powerful method for remote characterization of volcanic plume composition from safe distances. Many studies have used it to examine the composition of volcanic gas emitted at the surface, which is influenced by initial volatile contents and magma ascent/storage processes, and help to reveal the dynamics controlling surface activity. However, to evaluate the health hazard threats associated with volcanic emissions and their potential impact on wider atmospheric conditions, near‐source particle measurements are also key. Here we present a forward model and fitting algorithm which allows quantification of particle size and abundance. This was successfully applied to radiometrically uncalibrated OP‐FTIR spectra collected with a highly dynamic radiation source during the Fagradalsfjall eruption, Iceland, on 11 August 2021. Quantification of plume temperatures ranging from 350 to 650 K was essential to characterize the emission‐absorption behavior of SO2, enabling retrievals of particulate matter in the thermal infrared spectral window (750–1250 cm−1) in each spectrum. For the first time, we observe the rapid formation of primary aerosols in young plumes (only a few seconds old) with OP‐FTIR. Temperature‐dependent SO2/SO42− molar ratios range from 100 to 250, consistent with a primary formation mechanism controlled by cooling and entrainment of atmospheric gases. This novel aerosol spectrum retrieval opens new frontiers in field‐based measurements of sulfur partitioning and volcanic plume evolution, with the potential to improve volcano monitoring and quantification of air quality hazard assessments.

Analytical formulations with experimental validation for determining the incident heat flux from firefronts

Any target exposed to a heat source receives a certain amount of heat flux, depending on the distance, view factor, characteristics of the source, and environmental properties. Incident heat flux is mainly characterized by firefront properties, e.g., flame dimensions, and its thermal attributes by fuel properties, topography, and meteorological factors. Predicting the incident heat flux from the firefronts is crucial for fire risk management and analytical and numerical fire modelling. Based on this specification, safe zones can be defined for elements such as unprotected individuals, firefighters, and buildings. Since the contribution of radiation and convection varies with the fire evolution, it is essential to specify them as a function of distance and slope. This study elaborates determination of radiation and convection for firefronts. Sets of laboratory-scale experiments were conducted using fuel beds of straw with a load of 1.5 kg/m2 on the slopes of 0°, 20°, and 40° measuring the incident radiative and total heat fluxes. The proposed methodology was validated using available approaches and correlations between the flame length and the acceptable safety distance (ASD) were established. Unlike the existing models, a nonlinear correlation between convection and radiation during the firefront evolution is proposed.

From Nature to UAV - A Study on Collision Avoidance in Bee Congregation

Insects engage in a variety of survival-related activities, including feeding, mating, and communication, which are frequently motivated by innate impulses and environmental signals. Social insects, such as ants and bees, exhibit complex collective behaviors. They carry out well-organized duties, including defense, nursing, and foraging, inside their colonies. For analyzing the behavior of any living entity, we selected honeybees (Apis Mellifera) and worked on a small portion of it. We have captured the video of honeybees flying close to a hive (human-made artificial hive) while the entrance was temporarily sealed which resulted in the” bee cloud”. An exploration of the flight trajectories executed and a 3D view of the” bee cloud” constructed. We analyzed the behaviors of honeybees, especially on their speed and distance. The results showed that the loitering honeybees performed turns that are fully coordinated, and free of sideslips so thus they made no collision between themselves which inspired us to propose a method for avoiding collision in unmanned aerial vehicle. This paper gives the collective behavioral information and analysis report of the small portion of data set (honeybees), that bee maintains a safe distance (35mm) to avoid collision.

Transforaminal posterior lumbar interbody fusion microscopic safe operating area: a three-dimensional model study based on computed tomography imaging

BackgroundEndoscopic spine lumbar interbody fusion (Endo-LIF) is well-regarded within the academic community. However, it presents challenges such as intraoperative disorientation, high rates of nerve damage, a steep learning curve, and prolonged surgical times, often occurring during the creation of the operative channel. Furthermore, the undefined safe operational zones under endoscopy continue to pose risks to surgical safety. We aimed to analyse the anatomical data of Kambin’s triangle via CT imaging to define the parameters of the safe operating area for transforaminal posterior lumbar interbody fusion (TPLIF), providing crucial insights for clinical practice.MethodsWe selected the L4–L5 intervertebral space. Using three-dimensional (3D), we identified Kambin’s triangle and the endocircle within it, and recorded the position of point ‘J’ on the adjacent facet joint as the centre ‘O’ of the circle shifts by angle ‘β.’ The diameter of the inscribed circle ‘d,’ the abduction angle ‘β,’ and the distances ‘L1’ and ‘L2’ were measured from the trephine’s edge to the exiting and traversing nerve roots, respectively.ResultsUsing a trephine with a diameter of 8 mm in TPLIF has a significant safety distance. The safe operating area under the TPLIF microscope was also clarified.ConclusionsThrough CT imaging research, combined with 3D simulation, we identified the anatomical data of the L4–L5 segment Kambin’s triangle, to clarify the safe operation area under TPLIF. We propose a simple and easy positioning method and provide a novel surgical technique to establish working channels faster and reduce nerve damage rates. At the same time, according to this method, the Kambin’s triangle anatomical data of the patient’s lumbar spine diseased segments can be measured through CT 3D reconstruction of the lumbar spine, and individualised preoperative design can be conducted to select the appropriate specifications of visible trephine and supporting tools. This may effectively reduce the learning curve, shorten the time operation time, and improve surgical safety.

Modelling Air Pollution from Steel Plants and Determining the Safety Distance for the Surrounding Area in Phu My Town, Ba Ria - Vung Tau Province, Vietnam

Modelling Air Pollution from Steel Plants and Determining the Safety Distance for the Surrounding Area in Phu My Town, Ba Ria - Vung Tau Province, Vietnam

The Impact of Pit Latrines on the Pollution of Groundwater in the District of Rwamagana, Rwanda

The composition and condition of a water body change over time and across different locations due to internal and external factors. In many rural and peri- urban communities in Rwamagana, the lack of treated water has increased reliance on groundwater for various household and community needs. Groundwater sources are essential for meeting the water demand in these regions. An investigation was carried out in the Rwamagana district of the eastern province of Rwanda to evaluate the influence of pit latrines on groundwater quality. The research examined the water quality of four boreholes with hand pumps and 18 improved springs located near pit latrines. The evaluation specifically looked at total coliforms (TC), electrical conductivity (EC), turbidity, and pH. The proximity of the pit latrines to the boreholes or springs was considered in order to determine the presence of fecal coliforms in the groundwater, with the goal of establishing a minimum safe distance between the pit latrines and water sources. The physicochemical indicators of the water samples met the drinking water quality criteria set by the World Health Organization (WHO). However, the levels of biological contaminants exceeded the WHO's drinking water quality standards. The highest coliform counts detected in the study were 99cfu/100ml of water. The research findings suggest a clear relationship between fecal microbes from pit latrines and their impact on groundwater quality, with the contamination effect extending up to 322.4m for improved springs and 266.2m for boreholes with hand pumps.