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We consider the semilinear problem Δ u = λ + (− log u +) 1 { u > 0 } − λ − (− log u −) 1 { u < 0 } in B 1 , where B1 is the unit ball in R n and assume λ + , λ − > 0. Using a monotonicity formula argument, we prove an optimal regularity result for solutions: ∇ u is a log-Lipschitz function. This problem introduces two main difficulties. The first is the lack of invariance in the scaling and blow-up of the problem. The other (more serious) issue is a term in the Weiss energy which is potentially non-integrable unless one already knows the optimal regularity of the solution: this puts us in a catch-22 situation. [ABSTRACT FROM AUTHOR]

In recent years, as one of the important technical tasks in the field of deep learning, object detection has broad prospects and applications in the field of road obstacle detection. However, in the real driving scene, there are many obstacles, serious occlusion, overlap and other problems, so that the existing obstacle detection algorithm can not effectively detect the obstacles on the road, so it can not guarantee the driving safety. In order to solve the above problems, this paper improves on the basis of Yolo V4 algorithm. Firstly, kmeans + + clustering is used to generate a priori box suitable for the data set to enhance the scale adaptability; Then, the ciou is used as the loss function of coordinate prediction to evaluate the coincidence degree of prediction frame and truth value frame more reasonably. Finally, a suitable target detection data set is constructed by preprocessing the public data set cityccaps. The experimental results show that the improved algorithm can achieve more than 90% accuracy for obstacles with large number of targets in the training set. Compared with the original Yolo V4, the average detection accuracy of the improved algorithm is improved by 2.03%. [ABSTRACT FROM AUTHOR]

This paper aims to present a numerical study of dam break flow in the presence of an obstacle. A model based on the modified Non-Linear Shallow Water Equations with cross section and a dispersive treatment was solved numerically using a momentum-conservative finite volume method on a staggered grid. To validate the numerical model, several benchmark tests were carried out. Comparison of the computed results with the analytical and experimental data shows that the numerical model here proposed the flow with high accuracy. Moreover, the effect of the obstacle’s dimensions on the water height was examined. The extension to different contraction geometries of the simulation channel was examined.

This paper aims to develop a new mobile robot path planning algorithm, called generalized laser simulator (GLS), for navigating autonomously mobile robots in the presence of static and dynamic obstacles. This algorithm enables a mobile robot to identify a feasible path while finding the target and avoiding obstacles while moving in complex regions. An optimal path between the start and target point is found by forming a wave of points in all directions towards the target position considering target minimum and border maximum distance principles. The algorithm will select the minimum path from the candidate points to target while avoiding obstacles. The obstacle borders are regarded as the environment’s borders for static obstacle avoidance. However, once dynamic obstacles appear in front of the GLS waves, the system detects them as new dynamic obstacle borders. Several experiments were carried out to validate the effectiveness and practicality of the GLS algorithm, including path-planning experiments in the presence of obstacles in a complex dynamic environment. The findings indicate that the robot could successfully find the correct path while avoiding obstacles. The proposed method is compared to other popular methods in terms of speed and path length in both real and simulated environments. According to the results, the GLS algorithm outperformed the original laser simulator (LS) method in path and success rate. With application of the all-direction border scan, it outperforms the A-star (A*) and PRM algorithms and provides safer and shorter paths. Furthermore, the path planning approach was validated for local planning in simulation and real-world tests, in which the proposed method produced the best path compared to the original LS algorithm.

After undergoing a total knee arthroplasty (TKA) procedure, patients are at a high risk of falling because they present with ineffective mobility within a complex environment, especially during obstacle crossing. Toe clearance (TC) is an important factor to quantify the risks of trip-related falls. The study aimed to investigate TC height and toe trajectory and joint kinematic changes occurring in the lower limb following TKA during obstacle crossing at the initial swing phase. Twenty TKA patients, including those in preoperative and postoperative stages (three and six months), performed obstacle-crossing tasks to compare their performance with 20 healthy controls. Participants walked at self-pace along an 8 m walkway with 2.5, 5, and 10 cm obstacles positioned along the center of the path. For each participant, body segment motions were traced using reflective markers and the kinematics of lower extremity, toe clearance, and gait parameters were analyzed using a 3D-motion analysis system. TKA patients had lower TC height and toe trajectory at six months, slower toe elevation than controls when swing toe crossed 5 and 10 cm obstacles (p < 0.05), and decreased hip and knee flexion (p < 0.05). These altered gait patterns with decreased TC height and toe trajectory were identified as tripping factors as the toe trajectory was close to the ground surface. TKA patients had acquired different lower limb kinematics to maintain adequate TC. At long-term follow-up, there was an increasing trend for patients to trip after surgery. Therefore, more focus is needed on the exercise prescription for rehabilitation programs to improve muscle strength and stepping control.

This paper proposes a new method that obstacles are attached to both the suction and pressure surfaces of the blades to suppress cavitation development. A centrifugal pump with a specific speed of 32 is selected as the physical model to perform the external characteristic and cavitation performance experiments. SST k − ω turbulence model and Zwart cavitation model were employed to simulate the unsteady cavitation flow in the pump. The results indicate that the numerical simulation results are in good agreement with the experimental counterparts. After the obstacles are arranged, the maximum head decrease is only 1.37%, and the relative maximum drop of efficiency is 1.12%. Obstacles have minimal impacts on the variations of head and efficiency under all flow rate conditions. The distribution of vapor volume in the centrifugal pump is significantly reduced after obstacles are arranged and the maximum fraction reduction is 53.6%. The amplitude of blade passing frequency decreases significantly. While obstacles decrease the intensity of turbulent kinetic energy near the wall in the impeller passages to effectively reduce the distribution of cavitation bubbles, and control the development of cavitation. After the obstacles are set, the strength of the vortex in the impeller passages is weakened significantly, the shedding of the vortex is suppressed, flow in the impeller becomes more stable. [ABSTRACT FROM AUTHOR]

In this study, the energy analysis of a solar air heater with an absorber plate made of different obstacles was made. Absorber plate of the solar air heater was created with porous steel wool. Three different absorber plates were used for the experimental study. Complex plate (Type I) was used as the first type of absorber plate, less complex plate (Type II) as the second type absorber plate, and flat plate (Type III) the third type absorber plate. On these plates, which are manufactured as three different absorber plates, steel wools are placed in a complex and less complex way. One absorber plate was left empty. In the experiments, the mass-flow rate of the air passing through the air passage channels was taken as 0.05 kg/s and 0.025 kg/s, and the optimum flow rate was found as 0.05 kg/s. In order to make heater efficiency calculations, heater inlet temperature, outlet temperature, absorber plate temperature, ambient temperature and solar radiation values were measured. Efficiency values for different absorber plate were found between 23% and 74%. [ABSTRACT FROM AUTHOR]

Children with disabilities are considered to be the group most excluded from basic education. While disability remains the strongest barrier to accessing education, studies have shown that appropriate policies can help to reduce barriers to education. This paper examines the determinants of school status for children with disabilities in four provinces and Ulaanbaatar in Mongolia. The results indicate that severe types of disabilities, preschool experience and parents' stated obstacles, as well as classmates' understanding, are strongly related to school enrolment. Furthermore, this study found that school status depends on the amount of human resource available within the family, such as grandparents' or siblings' abilities to accompany children with disabilities to school. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Economics & Finance (2437-0630) is the property of Association of Arab Universities and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to investigate the behavior and interaction of wet granular avalanches when hit an obstacle on the inclined plate. The cohesive contact model of discrete element method (DEM) is used to simulate the wet granular flow regimes after the avalanche occurred. The impact of surface energy and grain compositions to kinematic characters, deposit pattern and force on the obstacle of wet granular avalanches are discussed. The results show that after the wet granular avalanches hitting the baffle on the slope, the grain deposit forms symmetrical accumulated zones on the horizontal plate. With the increase of surface energy, the dispersed degree of wet granular flows becomes smaller, the longitudinal sliding distance is also shorter. Furthermore, the grain size and deposit compositions of initial source have little influence on final accumulated ranges and sliding average velocity of the wet granular avalanches when the surface energy is the same. Moreover, with the increase of surface energy, the cohesion between particles becomes stronger, lead to greater collision force to obstacle by the wet granular avalanches. These results highlight the capability of cohesion model in DEM for simulating avalanches of wet granular material with proper parameters. Some important conclusions about the cohesive contact model are obtained, which can be used to optimize defense structures in mountain regions. [ABSTRACT FROM AUTHOR]

The numerical study of the flow and heat transfer in the two-phase mist flow over a single square obstacle is carried out using Eulerian two-fluid approach. The maximum value of the gas phase turbulence is obtained over the obstacle at x / h = -1–0, and it exceeds the values for the turbulence level before and after the obstacle by more than 50 %. The maximal turbulence suppression for the evaporating droplets in a turbulent stream is reached in the flow core of the channel and the minimal one is observed in the near-wall part. Turbulence suppression in the case of evaporating droplets is extremely low near the wall, and the level of turbulence tends to the corresponding value for the single-phase flow. Compared to the single-phase flow, an up to 15 % reduction in the gas turbulence is obtained. The predicted increase in heat transfer in the mist flow over the obstacle is over 1.5 times. [ABSTRACT FROM AUTHOR]

[Display omitted] • Boom stability was evaluated in a field sprayer with a secondary blower system, • A self-designed cable measurement system was used in the experiment, • The boom's stability states were described with a fuzzy logic model, • An experimental track with an obstacle was used in the experiment, • Boom stabilization time decreased with an increase in the sprayer's speed. During the application of plant protection products (PPP), the segments of a field sprayer's boom can be displaced from equilibrium, which can lead to uneven delivery of the sprayed liquid. Modern field sprayers are equipped with stabilization systems to eliminate this problem. However, these systems do not always operate correctly in all phases of a field sprayer's motion. Therefore, the aim of this study was to determine the influence of the speed at which a field sprayer crosses an obstacle on the displacement of the boom's terminal segments and the time after which the boom is stabilized. The experimental setup involved a field sprayer unit composed of a Claas AXOS 330 tractor and a mobile test bench – a detachable field sprayer with an air-assisted system and a boom with a working width of 21 m, which was equipped with a system for measuring boom displacement from equilibrium in two perpendicular planes. The boom's stability states were analyzed with the use of a fuzzy logic model developed by the authors. The measurements were performed in an experimental track with an obstacle. The displacement of boom tips in the horizontal and the vertical plane was registered during the experiment to determine boom stability. The experiment revealed that boom tips were displaced from equilibrium not only when the sprayer crossed the obstacle, but also when the tractor's front and rear wheels came into contact with the obstacle. Boom displacement was much greater in the horizontal than the vertical plane, and boom stabilization time was approximately three times longer in the horizontal than the vertical plane. The activation or deactivation of the air-assisted system had no significant effect on boom stability, but an increase in the sprayer's speed (from 4 to 12 km h−1) increased the time of unstable boom operation by around 50 %, decreased the time of semi-stable boom operation by around 34 %, and decreased boom stabilization time by around 45 %. [ABSTRACT FROM AUTHOR]

This paper is considered with a three-dimensional pyramidal traveling wave of the homogeneous reaction–diffusion equation with a compact obstacle in R 3. The long-time behavior of the entire solution derived from a pyramidal traveling wave after passing an obstacle is explored. Mainly relying on auxiliary functions, some new forms of super- and sub-solutions with good characteristics are proposed, and some properties of the pyramidal traveling wave are obtained. The results show that when the propagation of the entire solution is complete, the solution will recover to the same pyramidal traveling wave as before. [ABSTRACT FROM AUTHOR]

C 2 HF 5 is not only a refrigerant but also a highly efficient fire extinguishing agent. The effect of obstacle on the concentration distribution of extinguishing agent is important in the design for a firefighting strategy. Based on the extinguishing agent concentration analyzer using the differential pressure principle, the fire extinguishing agent concentration under the influence of different wind speeds, blockage ratios, and obstacle types is measured. The fire extinguishing agent is brought into the recirculation zone by the mutual entrainment of the primary eddy and the secondary eddy. The concentration of fire extinguishing agent decreases with the increase of wind speed. The increase of blocking ratio makes the concentration of extinguishing agent decrease in the recirculation zone. In the recirculation zone, when the blockage ratio is small, the concentration of fire extinguishing agent in the baffle and the 45° backward facing step at different wind speeds is approximately equal. With the increase of blockage ratio, the concentration of fire extinguishing agent in the baffle is greater than 45° backward facing step in the recirculation zone. Through experimental analysis, the feasibility of discrete calculation of characteristic mixing time is proved. The characteristic mixing time of different obstacles is not equal under cold spraying condition. The calculation formula of characteristic mixing time of the baffle and 45° backward facing step is obtained by fitting analysis, the characteristic mixing time coefficients are 34.4 for the baffle and 30.7 for the 45° backward facing step. [ABSTRACT FROM AUTHOR]

In this case study, we describe an approach to dealing with a complicated, systemic, and multifaceted organizational issue: perceptions of obstetrical violence in the continuum of maternal care from antepartum care, birthing, to post-natal care. [ABSTRACT FROM AUTHOR]

This article deals with the kinematic analysis of trapezoidal suspension. Specifically, it focuses on the behaviour of the chassis when obstacle crossing was monitored. Our team is developing an autonomous mountain vehicle that will be equipped with different working adapters such as a cutter bar and a picker. The device was designed for work on slopes, hence, must be able to overcome certain natural obstacles. This implies the need to analyse the wheel suspension kinematics. The vehicle was built on a trapezoidal suspension, which has proven to be the most suitable option with respect to operating conditions. From the results obtained, it was possible to analyse the driving characteristics of the obstacle, track the rollover limits and overall safety of operation.

Lukana Preechasuk,1 Pornsri Sriussadaporn,1 Supawadee Likitmaskul1,21Siriraj Diabetes Center of Excellence, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand; 2Division of Endocrinology and Metabolism, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, ThailandPurpose: This study identified the obstacles to diabetes self-management education and support (DSMES) from healthcare professionals’ perspectives in Thailand.Patients and methods: A cross-sectional survey was conducted at 613 hospitals throughout Thailand from December 2016 to March 2017. A self-completion questionnaire on the characteristics of, and obstacles to, diabetes education was sent to administrators, doctors, and diabetes educators (DEs). The views of DEs at public and private hospitals on the characteristics of diabetes education were compared. The obstructing factors reported by administrators, doctors, and DEs were also analyzed.Results: The overall response was 76.6%; the response rates of DEs, doctors, and administrators were 85.6%, 58.9%, and 46.5%, respectively. Although the respondents reported that 75% of patients received diabetes education, only 30% of the DEs believed it was successful. An individual-patient education approach was used by 95.1% of public and 81.4% of private hospitals. The median durations of the individual education sessions were 15 (IQR 10, 28) and 30 (IQR 15, 30) minutes for public and private hospitals, respectively. The DE workload at public hospitals was 3 times heavier than at private hospitals (60 [IQR 30, 140] vs 20 [IQR 10, 33] patients per week; p

With the widespread use of UAVs in daily life, there are many sensors and algorithms used to ensure flight safety. Among these sensors, lidar has been gradually applied to UAVs due to its stability and portability. However, in the actual application, lidar changes its position with the movement of the UAV, resulting in an offset in the detected point cloud. What's more, when the lidar works, it scatters laser light from the center to the surroundings, which causes the detected point cloud to be externally sparse and dense inside. This point cloud with uneven density is difficult to cluster using common clustering algorithms. In this paper, a velocity estimation method based on the polynomial fit is used to estimate the position of the lidar as it scans each point and then corrects the twisted point cloud. Besides, the clustering algorithm based on relative distance and density (CBRDD) is used to cluster the point cloud with uneven density. To prove the effectiveness of the obstacle detection method, the simulation experiment and actual experiment were carried out. The results show that the method has a good effect on obstacle detection.

One of susceptible area that occurs the conflagration is Kampung Rawa Mekar Jaya, Subdistrict of Sungai Apit, Siak Regency, Province of Riau where a big part of its area possesses peat moss. The conflagration can be caused some factors among others dry season, canal making in the peat moss soil and the deliberateness of human in speeding up the plantation open. For saving and preventing and coping with the environment and the conflagration needs to have the good environment proces and it certainly needs to get the support and the role and the society. In the village, there is an institution that focuses on the environment process, the pure from the society self-support is namely The Institution of The Caring Society of The Fire that has duty on the activity of the prevention, the extinguishing and the handling of postconflagration of the forest and the land. The research has goal to know the obstacle or the hindrance for the staff of The Institution of The Caring Society of The Fire in implementing the role. The research method that is used is descriptive qualitative in sampling in census namely as many 23 people. The data is obtained through the observation, the direct interview by using the questioner. Based on the research result, The obstacle of staff of the Caring Society of The Fire in implementing the role known from the work environment, the society environment, the nature environment and the lack of the support especially from the side of the government and the private.

Introduction In Cameroon, skepticism and neglect of doctors towards patients with mental disorders is noted. In order to change this, it was important to have an objective assessment. Depressive disorders are the most common form of mental disorders and Douala has the second largest number of general practitioners in the country. Thus, we proposed to evaluate the behaviour of general practitioners in Douala in front of patients with depressive disorders. Objectives Evaluate the frequency of depressive disorders in outpatient general consultation Evaluate the competence of general practitioners at diagnosing depressive disorders Evaluate the practices of general practitioners towards depressive disorders Evaluate obstacles faced by general practitioners regarding depressive disorders Methods We conducted a cross-sectional descriptive study from February to June 2017 in the outpatient department. For each general practitioner include, we had 3 patients who complete the patient health questionnaire to find out if the patient has depression. During each consultation, we filled out a clinical fact sheet to determine if the general practitioner had diagnosed a depressive disorder. If so, what care has he taken? Finally, we gave the general practitioner a questionnaire to know his difficulties when facing depression. Results We obtained a frequency of 32.5% of depressive disorders in consultation of general medicine in Douala and a rate of diagnosis by general practitioners of 1.92%. Diagnosed cases have just received counseling. Conclusions in Cameroon, despite the low interest in depressive disorders, they constitute a public health issue in Douala, and surely in Cameroon; Because of its frequency and the harm, they inflict on patients. Conflict of interest I don’t have any conflict of interest

When granular materials, colloidal suspensions, and even animals and crowds exit through a narrow outlet, clogs can form spontaneously when multiple particles or entities attempt to exit simultaneously, thereby obstructing the outlet and ultimately halting the flow. Counterintuitively, the presence of an obstacle upstream of the outlet has been found to suppress clog formation. For soft particles such as emulsion drops, clogging has not been observed in the fast flow limit due to their deformability and vanishing interparticle friction. Instead, they pinch off each other and undergo break up when multiple drops attempt to exit simultaneously. Similar to how an obstacle reduces clogging in a rigid particle system, we hypothesize and demonstrate that an obstacle could suppress break up in the two-dimensional hopper flow of a microfluidic crystal consisting of dense emulsion drops by preventing the simultaneous exit of multiple drops. A regime map plotting the fraction of drops that undergo break up in a channel with different obstacle sizes and locations delineates the geometrical constraints necessary for effective break up suppression. When optimally placed, the obstacle induced an unexpected ordering of the drops, causing them to alternate and exit the outlet one at a time. Droplet break up is suppressed drastically by almost three orders of magnitude compared to when the obstacle is absent. This result can provide a simple, passive strategy to prevent droplet break up and can find use in improving the robustness and integrity of droplet microfluidic biochemical assays as well as in extrusion-based three-dimensional printing of emulsion or foam-based materials. [ABSTRACT FROM AUTHOR]

In this study, the entrainment mechanisms of unconfined turbidity currents that interact with a linear rectangular obstacle will be investigated and compared with confined studies. Laboratory experiments will be performed in a lock exchange basin, where the width allows unconfined and partially unconfined flows, with varying initial current densities. Ambient fluid entrainment, based on the Morton-Taylor-Turner (MTT) hypothesis, was found to be comparable to previous confined studies; however, in situ current density decreased at a greater rate than the latter. It was shown that this was probably caused by the unconfined lateral spreading of the current before the obstacle. The entrainment parameter had a weak relationship with Froude, Reynolds, and Richardson numbers for nonobstructed tests, which was similar to previous studies. However, this was not the case for obstacle tests, which experienced a greater variance in entrainment velocity and head height. Of note, head height was less than that for equivalent confined tests, which suggested that in a practical setting, confined studies might overestimate the obstacle height needed to block current propagation. [ABSTRACT FROM AUTHOR]

Humans are able to perform very sophisticated reaching movements in a myriad of contexts based on flexible control strategies influenced by the task goal and environmental constraints such as obstacles. However, it remains unknown whether these control strategies can be adjusted online. The objective of this study was to determine whether the factors that determine control strategies during planning also modify the execution of an ongoing movement following sudden changes in task demand. More precisely, we investigated whether, and at which latency, feedback responses to perturbation loads followed the change in the structure of the goal target or environment. We changed the target width (square or rectangle) to alter the task redundancy, or the presence of obstacles to induce different constraints on the reach path, and assessed based on surface electromyography (EMG) recordings when the change in visual display altered the feedback response to mechanical perturbations. Task-related EMG responses were detected within 150 ms of a change in target shape. Considering visuomotor delays of ∼ 100 ms, these results suggest that it takes 50 ms to change control policy within a trial. An additional 30-ms delay was observed when the change in context involved sudden appearance or disappearance of obstacles. Overall, our results demonstrate that the control policy within a reaching movement is not static: contextual factors that influence movement planning also influence movement execution at surprisingly short latencies. Moreover, the additional 30 ms associated with obstacles suggests that these two types of changes may be mediated via distinct processes. NEW & NOTEWORTHY The present work demonstrates that the control strategies used to perform reaching movements are adjusted online when the structure of the target or the presence of obstacles are altered during movements. Thus, the properties of goal-directed reaching control are not simply selected during the planning stage of a movement prior to execution. Rather, they are dynamically and rapidly adjusted online, within ∼150 ms, according to changes in environment. [ABSTRACT FROM AUTHOR]

We show there exists a nontrivial H 0 1 solution to the steady Stokes equation on the 2D exterior domain in the hyperbolic plane. Hence we show there is no Stokes paradox in the hyperbolic setting. In fact, the solution we construct satisfies both the no-slip boundary condition and vanishing at infinity. This means that the solution is in some sense actually a paradoxical solution since the fluid is moving without having any physical cause to move. We also show the existence of a nontrivial solution to the steady Navier–Stokes equation in the same setting, whereas the analogous problem is open in the Euclidean case. [ABSTRACT FROM AUTHOR]

In the present study, the effects of the square, circular and equilateral triangular cross-sectional obstacles placed on a backward-facing step on the flow-field were investigated numerically. Assumed to be fully turbulent, three-dimensional, steady and incompressible flow was solved by modified k-omega turbulence model. Obtained results were exhibited in terms of non-dimensional friction and non-dimensional pressure coefficients in addition to non-dimensional reattachment length. Apart from the geometric shapes of the obstacles, the influence of their heights (h) on the relevant parameters were presented for H/h=0.125, 0.25, 0.5 and 1 by dimensionalizing with the step height (H). Results obtained for the backward-facing step without any obstacles were compared with the experimental data of Driver and Seegmiller, 1985 to show the accuracy of the model. It was shown that in comparison with the step without the obstacles, not only the existence of the obstacles but their cross-sectional shapes also affect friction and pressure coefficients and the reattachment length. Regardless of the cross-sectional geometry of the obstacles, it was detected that the existence of the obstacles increases the length of the recirculation, however, the longest regions were obtained when equilateral triangular cross-sectional one was used. It was revealed that the effect of the height of the obstacle on the detached flow region is quite low for H/h=0.25. [ABSTRACT FROM AUTHOR]

Copyright of Journal of International Social Research is the property of Journal of International Social Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The micromixing performance in the micromixer is directly related to the selectivity and yield of the target product in the subsequent chemical reaction. In this paper, six kinds of mixer models with obstacles are designed by numerical simulation to improve the mixing efficiency. The four different obstacle shapes are square, round, left triangle and right triangle. Among these four different obstacle mixers, square obstacles are the best obstacle shape. The square obstacle mixer (SOM) is the most efficient mixer in four different obstacle shape mixers, because the chaotic convection effect produced by the SOM mixer is significantly higher than the other three. In order to improve the mixing efficiency, two different numbers of elliptical structure SOMs are designed. With the increase of the elliptical structure, the fluid passes the chaotic convection effect more and the mixing efficiency of the SOM5 mixer reaches over 95%, which achieves the purpose of improving the mixing efficiency. [ABSTRACT FROM AUTHOR]

Recently, in accordance with the 4 th industrial revolution, The use of autonomous mobile robots for flexible logistics transfer is increasing in factories, the warehouses and the service areas, etc. In large factories, many manual work is required to use Simultaneous Localization and Mapping(SLAM), so the need for the improved mobile robot autonomous driving is emerging. Accordingly, in this paper, an algorithm for mapless navigation that travels in an optimal path avoiding fixed or moving obstacles is proposed. For mapless navigation, the robot is trained to avoid fixed or moving obstacles through Deep Q Network (DQN) and accuracy 90% and 93% are obtained for two types of obstacle avoidance, respectively. In addition, DQN requires a lot of learning time to meet the required performance before use. To shorten this, the target size change algorithm is proposed and confirmed the reduced learning time and performance of obstacle avoidance through simulation. [ABSTRACT FROM AUTHOR]

In “The Science of Equality Volume 1: Addressing Implicit Bias, Racial Anxiety, and Stereotype Threat in Education and Health Care,” the Perception Institute, a national consortium of social scientists and legal scholars, begins a series of landmark reports to understand this challenge and to provide empirically tested solutions to address it.

The formation of explosive gas zones (EGZs) from flammable vapors, gases, or dust pose safety hazards to many industries. In many cases, explosions may occur in confined areas with obstacles in the path of flame expansion. By studying the effects of obstacle shape, turbulence model, and spark location on flame propagation and turbulence, a more complete understanding of the flame and fluid dynamics interaction has been achieved. Reynolds Averaged Navier-Stokes (RANS) models were tested to determine if these simplified turbulence models could capture the flame dynamics and propagation velocities using fewer computational resources compared to the higher fidelity Large Eddy Simulation (LES) turbulence model. Results showed that square obstacles caused faster flame propagation compared to hexagons and circles. The square had an average flame propagation velocity 26 % faster than the circle, and the hexagon was 16 % faster than the circle using a k-ω model. Modeling results indicate variation of spark location by as small as 10 % of the obstacle diameter can result in a difference of the flame propagation. Findings on turbulence model accuracy and computational time along with shape comparison can be applied in future modeling of large systems, providing crucial information for safety planning and explosion prevention. [ABSTRACT FROM AUTHOR]

We currently have only a minimal understanding of energy‐saving strategies of fish in unsteady flows. In this study, we found that obstacle shape can affect swimming ability of fish: our results suggested that a half cylinder improved critical swimming speed of silver carp (Hypophthalmichthys molitrix) compared with swimming downstream of a full cylinder, square tube or for free‐flow conditions. We also discovered how silver carp alter their locomotory behavior in response to turbulent flow caused by varying flow velocities around obstacles. At a flow velocity of 1 BL/s (body length per second), the fish spent similar percentages of time between holding station and moving forward behind the half cylinder: their motions resembled freestream swimming behavior. The greatest percentage of time spent downstream of the half cylinder occurred at a flow velocity of 5 BL/s. Fish were unstable and displayed irregular body motions with large lateral displacement at 5 BL/s. However, the fish held station for a long time and moved forward steadily behind the half cylinder at 3 BL/s. In holding station behind the half cylinder, fish maintained constant tail‐beat frequency and tail‐ beat amplitude when flow velocity was increased from 1 to 3 BL/s. In moving forward behind the half cylinder, fish increased tail‐beat frequency and tail‐beat amplitude while maintaining constant ground swimming speed, swimming acceleration and ground stride when flow velocity was increased from 3 to 5 BL/s. Moreover, fish positioned their snouts in a small area approximately 1–3 BL downstream from the half cylinder at 3 BL/s. These behaviors support the hypothesis that turbulence behind a half cylinder was a suitable location for fish to conserve energy at 3 BL/s. Our results indicate that the combined effect of obstacles and flow velocity influence fish locomotory behavior, and some combinations may be beneficial to fish energy expenditure swimming in unsteady flow. [ABSTRACT FROM AUTHOR]

High-speed train may collide with many obstacles, which can cause serious occupant injury. This study aims to investigate the dynamic characteristic of occupant during the frontal collision between high-speed train and obstacle. The finite element method was used to establish the collision model between the head vehicle of the train and obstacle. The frontal collision simulation tests under three collision conditions were established. The dynamic characteristics of occupants under different collision speeds and collision angles were explored. According to the above research, the influences of collision angle and speed on occupant injuries were systematically studied, and the risk boundaries for Railway Group Standard GMRT2100: Rail Vehicle Structures and Passive Safety (GM/RT2100) and Abbreviated injury scale ≥ 3 (AIS 3 + ) injury risk ≤ 5 % were finally proposed. The results show that the occupant injuries increased with the increase of collision speed, and most of the injury values at the collision angle of 20° were the minimum. The risk boundary for AIS 3 + injury risk ≤ 5 % was higher than that for GM/RT2100. The findings in this study are helpful to understand the occupant injury mechanism during the frontal collision between high-speed train and obstacle., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Porcine circovirus type 3 (PCV3) is a novel circovirus identified in sows with PDNS-like clinical signs and reproductive failure. The capsid protein (CAP) of PCV3 is expected to be an effective vaccine candidate. Here, we expressed the original capsid protein, truncated capsid protein without anterior highly repetitive arginine (ΔCAP) and their codon-optimized counterparts in E. coli. These results showed that lots of repeated arginine could severely lower the expression of PCV3 capsid protein in E. coli. At the same time, the recombined truncated PCV3 capsid protein forms typic virions. The efficient expression of capsid protein is expected to serve the development of PCV3 vaccines and other studies of PCV3 capsid protein. [ABSTRACT FROM AUTHOR]