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The passive micromixer is one of the essential devices that can be integrated into the Lab on Chip (LoC) system. Micromixer is needed to increase mixing efficiency. In this paper, two Koch fractal obstacle-based micromixer models of Secondary Snowflakes Fractal Micromixer (SSFM) and Tertiary Snowflakes Fractal Micromixer (TSFM) were designed. The effect of the Koch fractal resistance angles (15o, 30o, 45o, 315o, 330o, 345o) and the influence of the inlet (T and T-vortex) were studied in this paper using COMSOL Multiphysics numerical simulations. The results showed that the TSFM structure with a 30o angle on the T-vortex inlet is optimal. The deflection phenomena generated by the TSFM obstacle enhance the contact area between the two fluids and chaotic convection can be increased at Reynolds Number (Re) 0.05 and Re 100. This paper examines concentration curves along the channel ranging from 1 mol/L to 5 mol/L. This clearly shows that the fluid flow direction changes within the microchannel. This work provides a new design for the micromixer. [ABSTRACT FROM AUTHOR]

Hard pans, soil compaction, soil aggregation and stones create physical barriers that can affect the development of a root system. Roots are known to exploit paths of least resistance to avoid such obstacles, but the mechanism through which this is achieved is not well understood. Here, we combined 3D-printed substrates with a high-throughput live imaging platform to study the responses of plant roots to a range of physical barriers. Using image analysis algorithms, we determined the properties of growth trajectories and identified how the presence of rigid circular obstacles affects the ability of a primary root to maintain its vertical trajectory. Results showed the types of growth responses were limited, both vertical and oblique trajectories were found to be stable and influenced by the size of the obstacles. When obstacles were of intermediate sizes, trajectories were unstable and changed in nature through time. We formalised the conditions for root trajectory to change from vertical to oblique, linking the angle at which the root detaches from the obstacle to the root curvature due to gravitropism. Exploitation of paths of least resistance by a root may therefore be constrained by the ability of the root to curve and respond to gravitropic signals., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Scabies is found in crowded residential areas such as orphanages, dormitories, prisons, and Islamic boarding schools. In 2017, it was reported that scabies was among the 15 most common types of skin infections in Sumenep District, which reported 12,229 cases of scabies. Purpose: This study aims to analyze the relationship between the perception of individual susceptibility and barriers to treatment action in scabies patients at the Nasy’atul Muta’alimin Islamic Boarding School, Sumenep District, East Java. Methods: This research was an observational analytic study using a case-control design. The study population was patients with scabies in Nasy’atul Mutaalimin Islamic Boarding School, Sumenep District, East Java. The sample size was 70 people, consisting of 35 scabies patients who did not seek treatment as a case group and 35 scabies patients who did seek treatment as a control group. The sampling method used was simple random sampling. The two independent variables studied were the perception of individual susceptibility and barriers to treatment, while the dependent variable was treatment measures. The data analysis techniques employed were univariate and bivariate analysis. Results: This study shows that there are variables that have a relationship (p < 0.05) with the perception of individual susceptibility (OR = 99.00 95% CI 17.85 < OR < 548.86) and perceived barriers (OR = 29.00 95%, CI 7.968 < OR < 105.55). Conclusion: There is a relationship between the perception of individual susceptibility and barriers to treatment action in scabies patients.

This article uses the topological optimization method to optimize the flow field of radial proton exchange membrane fuel cells. Due to the high computational cost of this method, the model was simplified to a two-dimensional model, and the cathode flow field was studied under isothermal and steady-state conditions. Using the gradient-based algorithm SNOPT, the flow field evolves freely in the sector design domain to maximize battery power and minimize reaction energy loss. Perform 3D modeling of the obtained optimized model and optimize the longitudinal depth by applying different tilt angles and obstacles. The results indicate that the application of obstacles has a significant optimization effect on speed. Setting the gradient has a better effect on the oxygen concentration distribution. With the increase of the gradient, the uniformity of the oxygen concentration distribution is also increased. As the inclination increases, the pressure difference of the reaction gas gradually increases, and the pressure uniformly decreases. After setting obstacles, the pressure of the reaction gas decreases step by step after passing through each obstacle. The effect of increasing the inclination to increase the average current density is better than setting obstacles, and the comprehensive effect of setting an inclination of 2° is the best at working voltages of 0.5 V and 0.6 V.

This paper addresses the multi-drone formation capture in three-dimensional (3D) environments. The omni-directional minimum volume (ODMV) 3D-Voronoi diagram algorithm is proposed for the first time to achieve the two goals of (1) forming and keeping a capture and (2) planning the control action within its safe, collision region for each drone. First, we extend the traditional 2D Voronoi diagram to the 3D environment and use the non-overlapping spatial division property of 3D Voronoi diagram to inherently avoid the collision between drones. Second, we make improvements to the problem of capture angle in our minimum area strategy and propose an omni-directional minimum volume strategy to accomplish the effective capture of a target by constraining the capture angle. Finally, the wolf pack algorithm (WPA) with variable step size is introduced to provide a movement strategy for multi-drone formations. Thus, the proposed ODMV can also achieve dynamic target and multi target capture in environments with obstacles. The Optitrack motion capture system and Crazyflie drones are used to conduct the multi-drone capture experiment. Both simulation and experimental results are included to demonstrated the effectiveness of the proposed ODMV method.

Digital transformation of higher education institutions (HEIs) is of paramount importance in today’s technology-driven world. However, there are numerous barriers that hinder the successful implementation of digital transformation initiatives in HEIs. In this article, we identify and classify these barriers based on a systematic literature review. The findings reveal twenty distinct barriers that inhibit digital transformation in higher education. These were then organised into six broad categories, namely environmental, strategic, organisational, technological, people-related and cultural. The study provides a comprehensive understanding of the barriers faced, facilitating the development of effective strategies and interventions. Our analysis provides valuable information for higher education institutions, policy makers and stakeholders involved in digital transformation initiatives.

Copyright of Szkoła Specjalna is the property of Akademia Pedagogiki Specjalnej im Marii Grzegorzewskiej 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.)

A composite hydraulic structure can be described as a discharge structure constructed inside a river or an open channel. This experimental study is targeted at investigating the performance of the composite hydraulic structure in consideration of the existence of the longitudinal obstacle in the downstream region of the composite hydraulic structure. This study adopts two different lengths of the longitudinal obstacle. In addition, three different cross-sectional areas of the obstacle in the lateral direction are adopted. Also, the gate of a composite structure has a half-ellipse shape, while the weir of a composite structure has rectangular, triangular, and parabolic shapes, respectively. Seven cases are investigated experimentally. Here, six cases included the longitudinal obstacle, while the last case was without it. The influence of downstream Froude number on the average downstream water depth, downstream flow velocity, upstream Froude number, Reynolds number, and actual discharge is investigated. Also, the relationship between Reynolds number and downstream flow velocity, actual discharge and downstream flow velocity, discharge coefficient and upstream Froude number, discharge coefficient and Reynolds number, discharge coefficient, and actual discharge is investigated, respectively. The results illustrated that the longitudinal obstacle has a moderate influence on the hydraulic characteristics of the composite hydraulic structure regardless of the obstacle length and the obstacle cross-section area. Finally, the hypothesis test is performed to demonstrate the feasibility of the longitudinal obstacle. [ABSTRACT FROM AUTHOR]

The interaction between granular flow and an array of obstacles is an important research subject in geological disaster prevention. We used a numerical model for the depth-integrated equations formulated in a bed-fitted coordinate system to simulate the runout and deflection of granular flow past an array of simple obstacles. Numerical simulations of granular flow encountering arrays of square columns and tetrahedral pyramids gave a lot of interesting and fascinating deposits. We then proposed a new dimensionless index called deflection efficiency (DE), together with the runout efficiency (RE) to quantify the comprehensive effects of the obstacle system on the runout and deflection behavior. There are three physical effects, a dissipation effect through bow shock, a deflection effect by splitting the granular flow, and a retention effect via trapping some granular mass, the combinations of which determine the mobility and deposit of granular flow. We found that RE decreases as either the height or number of rows of obstacles increases because of the dissipation effect, while DE increases as height increases due to the deflection effect for both tetrahedral and square column obstacles. However, if the retention effect was as important as the deflection effect, the DE could be reduced when the row numbers increase further. These findings provide some constructive help for the design of obstacle arrays and complement the understanding of subsequent flow after interaction between granular flow and obstacle arrays. [Display omitted] • Fascinating bow shocks, deflection and deposits found for granular flow past an obstacle system. • Dissipation, deflection and retention effects determine the flow and deposit behavior for granular flow-obstacle system interaction. • A new index deflection efficiency is proposed to characterize the deflection behavior for granular flow past an obstacle system. [ABSTRACT FROM AUTHOR]

The lateral overturning and backward rollover characteristics of a tractor driven on a hard surface were analysed depending on the ground slope angle and the shape and height of obstacles. The size and material properties of a tractor were used to create a 3D simulation model using a commercial dynamic simulation program. The simulation model was verified using tractor certification test results. For the simulations, ground slope was set to a maximum of 50° and four heights were applied to three different shapes of obstacle. Tractor driving speeds at which lateral overturning and backward rollover occurred were determined using each condition. The results revealed that the factor that contributed the most to the overturning and rollover of the tractor was ground slope, followed by the obstacle height and then obstacle shape. As the obstacle height and ground slope increased, the tractor became vulnerable to lateral overturning and backward rollover based on the height of its centre of mass and angular velocity in the rolling direction. Backward rollover occurred when the slope was mild and lateral overturning occurred above a certain slope angle. Depending on the obstacle shape, the sensitivity to lateral overturning and backward rollover varied with sinusoidal-shaped obstacles making the tractor relatively vulnerable to lateral overturning, whereas rectangular obstacles made it vulnerable to backward rollover. Therefore, on steep slopes, where lateral overturning occurs, sinusoidal-shaped obstacles are more risky, whereas on flat ground, where backward rollover occurs, rectangular obstacles are more risky. • Lateral slope angle and obstacle shape selected as main influencing factors. • Comprehensive analysis conducted on impact of slope angle and obstacle. • Three different obstacle shapes used: rectangular, right-triangular, and sinusoidal. • Ground slope maximum 50° and obstacle height maximum of 400 mm. • Speed of the tractor when overturning and rollover occurred determined. [ABSTRACT FROM AUTHOR]

The experimental simulation between the composite hydraulic structure and the found obstacles in the downstream region is a challenging process due to the energy losses and kinematic dissipation. The current work focuses on a comparative analysis of free flow conditions that exist without obstacles and submerged flow conditions that occur due to obstacles. It indicates the evaluation of hydraulic variables and geometrical variables of composite hydraulic structure for both flow conditions. In addition, it includes an investigation of the interaction among these variables. The hydraulic variables include actual discharge, flow velocity, flow cross-sectional area that crosses the gate, downstream water depth, discharge coefficient, Reynolds number and, Froude number, while the vertical distance between the weir and gate represents the geometry variable. The interference between the weir discharge and gate discharge plays a significant role in the result fluctuation and variation for both flow conditions, while the form and size of the obstacles only have a major effect on the submerged flow. For both flow conditions, the water depth is investigated; there would be a drastic increase in water depth by using obstacles in the downstream area as compared with not using the obstacles. This study adopts different obstacles in shape and size, therefore, the variation of maximum and minimum water levels related to the location will occur. [ABSTRACT FROM AUTHOR]

Aiming at the problems of low planning accuracy and long time-consuming in vehicle obstacle avoidance path planning method, a vehicle obstacle avoidance path planning method based on deep data mining is proposed. Firstly, the steering angle of obstacle vehicle is determined, the motion state is determined, and the obstacle data extraction is completed; Then, the obstacle operation data is placed in Cartesian coordinates to obtain a new state value and complete the preprocessing; Finally, determine the straight-line distance between the obstacle vehicle and the vehicle, build the vehicle obstacle avoidance path planning model with the help of deep data mining, input the obstacle data after training, output the path planning results, and introduce the error correction function to modify the output planning results to realize the vehicle obstacle avoidance path planning. The results show that the proposed method has high accuracy in obstacle avoidance path planning. [ABSTRACT FROM AUTHOR]

Wind energy is becoming one of the most widely used renewable energy sources in Romania as well. In order for production to be efficient and implicitly profitable, wind turbines are usually arranged in wind farms. The main purpose of the paper is to present intelligent criteria and tools for designing wind turbines. In the present study, the following are pointed out as topics of interest: the shading of the wind given by an obstacle, the height of the turbine hub, the distance between the obstacle and the turbine, the roughness class of the turbine location, the height and width of the obstacle and the porosity of the obstacle. These elements help to determine the variation of the wind front, the power of the wind captured by the turbines and the calculation of the energy captured. The results obtained using calculation programs are: wind speeds are in the range of 5-10 m / s in the predominant direction S-SE (between 2700 -3300) and V-NV (between 1500 -2100); power density function; Weibull distribution for wind speed; turbine power curve; Wind turbulence in the turbine area; power coefficient depending on wind speed; The amount of energy that the wind transfers to the rotor; Wind frequency curve; speed insurance curve. Finally, by using the modelling tools in Math Lab Simulink, the random speed distributions were obtained, which can be analyzed and then provided to obtain a maximum power, and consequently a maximum amount of energy. [ABSTRACT FROM AUTHOR]

In this article, contact problem with fractional derivatives is studied. We use fractional derivative in the sense of Caputo. We deploy penalty function method to degenerate the obstacle problem into a system of fractional boundary value problems (FBVPs). The series solution of this system of FBVPs is acquired by using the variational iteration method (VIM). The performance as well as precision of the applied method is gauged by means of significant numerical tests. We further study the convergence and residual errors of the solutions by giving variation to the fractional parameter, and graphically present the solutions and residual errors accordingly. The outcomes thus obtained witness the high effectiveness of VIM for solving FBVPs.

To investigate the excitation effects of different shapes and quantities of obstacles in dust-containing gas explosions, this study utilized an Euler-Lagrangian model. This model simulated explosions involving dust-laden gas, applying various governing equations to address the roles of coal dust at different combustion stages and its dynamic forces within the flow field. The research examined a 9.5 % gas concentration explosion with 5 g/m3 coal dust in a straight pipeline, assessing the impacts of spherical, regular tetrahedral, and cuboidal obstacles, as well as combinations of 1–3 cuboidal obstacles and three differently shaped obstacles on the explosion's flow field structure, overpressure, and flame propagation speed. Key findings include: dust-containing gas explosions result in more complex flow field structures, and the excitation effects of coal dust and obstacles on flame propagation speed exhibit mutual inhibition. Obstacles increase the maximum overpressure locally without affecting the overall trend of increasing overpressure with distance in closed conduits. Cuboidal obstacles show the most pronounced excitation effects, followed by regular tetrahedral and spherical obstacles, respectively. The number of obstacles also progressively enhances their excitation effects. When three obstacles of different shapes are present, cuboidal and regular tetrahedral obstacles primarily affect the flow field structure, with flame propagation speed and maximum explosion overpressure slightly lower compared to the presence of three cuboidal obstacles alone. These findings offer valuable insights into the destructive effects of gas explosions and the excitation effects of obstacles, providing theoretical support for disaster prevention and recommendations for underground equipment design and layout. [Display omitted] • A numerical method for biphasic explosions is proposed to investigate variations in flow field structure. • The study examines dust-gas explosion propagation under the influence of obstacles with varying shapes and quantities. • This study analyzes flow field structure to investigate how coal dust and obstructions stimulate gas explosions. • The study comprehensively considers the combustion characteristics of coal dust during its participation in gas explosions. [ABSTRACT FROM AUTHOR]

In this study, the dynamic behavior of the premixed syngas/air flames in enclosed ducts with obstacles at the blockage ratio of 0.5, as well as without obstacles, was studied via large eddy simulation and the turbulent flame speed closure model. The hydrogen volume fraction (hydrogen content in fuel) was set to 50 %. Results indicate that the simulation reproduced the flame shapes, flame speed and explosion overpressure observed in the experiments. In cases without obstacles, a "tulip" flame with a tulip cusp can be seen, and secondary cusps emerge on tulip lips due to the high-pressure zone ahead of "tulip" flame lips, leading to in a distorted "tulip" flame. In cases with obstacles, the flame develops hemispherical and finger shapes upstream of the obstacles and evolves into a "tulip" flame downstream of the obstacles due to vortices and adverse pressure gradients. The alteration of the flow direction within the unburned and burned zones results in intricate flame shapes. Flame speed and overpressure show a close relationship and exhibit oscillations following the generation of the "tulip" flame. Typically, the velocity, pressure and flow fields adjacent to the flame front can affect dynamic behaviors of premixed syngas/air flames. [ABSTRACT FROM AUTHOR]

[Display omitted] It has been experimentally shown that a complex obstacle consisting of two confusers oriented in opposite directions of a cylindrical vessel completely prevents the propagation of diluted methane – oxygen flames, i.e. , the obstacle is the most effective flame arrester; the theoretical predictions are consistent with the experiments. [ABSTRACT FROM AUTHOR]

In this paper, we propose four different numerical methods for solving the Non-Linear Shallow Water Equations (NSWE), which are used to study dam-break flow over an obstacle. The discrete equations are formulated by applying various finite difference methods with filter involving wet-dry procedure. To validate our numerical model, several benchmark tests are carried out. Comparison of the computed results with the analytical and experiment data shows that our numerical model reproduces the flow with high accuracy. Moreover, we examine the effect of the shape and dimensions of the obstacle on downstream water height. Rectangular obstacles reduce downstream water height more significantly than triangular and trapezoidal ones. Downstream water height decreases non-linearly as obstacle height and width are increased.

Well-structured pedestrian experiments in a long corridor have been carried out to explore the influence of obstacle shape and size on individual and crowd level pedestrian movement characteristics. Results indicate that for individual pedestrians, the number of right-turning pedestrians and the target drift angle show clear changes with the increase of the obstacle size, while the speed only changes significantly when the obstacle size is greater than 1.5 m. For the crowd movement scenarios, a small obstacle can speed up the pedestrian flow, then, with the increase of the obstacle size, the movement time increases. The increase rate has a relation with the obstacle shape. The obstacle shape influence becomes more obvious when the individual and crowd movement scenarios are compared. The results of this paper are expected to provide practical basis for modeling pedestrian under the influence of obstacle. [ABSTRACT FROM AUTHOR]

Coal is an indispensable fuel and plays an important role in the energy industry. However, coal mining is often accompanied by disasters such as gas explosion, which impose severe restrictions on the efficient exploitation of coal resources. The non-uniformity of combustible gases and obstructions in space are important factors that affect the intensity of explosions. In this study, an experimental investigation of non-uniform and uniform methane–air flame behavior in a duct containing obstacles with different opening scales was investigated. The results showed that for non-uniform methane–air mixtures, the speed of the velocity change under different opening scale obstacle configurations varied owing to the degree of non-uniformity. In addition, the explosion overpressure curves exhibited significant pressure peaks at extended diffusion times, with the largest pressure peak in the configuration with a barrier-opening scale of 50 mm. Furthermore, the backflow phenomenon after the flame passed through the obstacle only appeared in configurations with larger obstacle-opening scales or diffusion times. These findings offer insights into the prevention and management of gas explosions in coal mining and contribute to the efficient and safe development of coal resources. [Display omitted] • The effect of obstacle opening scale on the explosion flame behavior of non-uniform and uniform CH 4 -air mixtures was studied. • Flame velocity was affected by the degree of mixture non-uniformity for different open-scale obstacle configurations. • Backflow flames appear only in configurations with considerable obstacle opening scales or longer diffusion times. [ABSTRACT FROM AUTHOR]

Community ambulation involves complex walking adaptability tasks such as stepping over obstacles or taking long steps, which require adequate propulsion generation by the trailing leg. Individuals post-stroke often have an increased reliance on their trailing nonparetic leg and favor leading with their paretic leg, which can limit mobility. Ankle-foot-orthoses are prescribed to address common deficits post-stroke such as foot drop and ankle instability. However, it is not clear if walking with an ankle-foot-orthosis improves inter-limb propulsion symmetry during adaptability tasks. This study sought to examine this hypothesis. Individuals post-stroke (n = 9) that were previously prescribed a custom fabricated plantarflexion-stop articulated ankle-foot-orthosis participated. Participants performed steady-state walking and adaptability tasks overground with and without their orthosis. The adaptability tasks included obstacle crossing and long-step tasks, leading with both their paretic and nonparetic leg. Inter-limb propulsion symmetry was calculated using trailing limb ground-reaction-forces. During the obstacle crossing task, ankle-foot-orthosis use resulted in a significant improvement in inter-limb propulsion symmetry. The orthosis also improved ankle dorsiflexion during stance, reduced knee hyperextension, increased gastrocnemius muscle activity, and increased peak paretic leg ankle plantarflexor moment. In contrast, there were no differences in propulsion symmetry during steady-state walking and taking a long-step when using the orthosis. Plantarflexion-stop articulated ankle-foot-orthoses can improve propulsion symmetry during obstacle crossing tasks in individuals post-stroke, promoting paretic leg use and reduced reliance on the nonparetic leg. • Ankle-foot-orthosis improved propulsion symmetry during obstacle crossing, post-stroke. • Improved propulsion symmetry can promote paretic leg use in community ambulation. • The orthosis also improved paretic leg kinematics and neuromuscular output. [ABSTRACT FROM AUTHOR]

Self-licensing and self-cleansing effects represent two aspects of the same self-regulatory mechanism that is based on the decision-making process. Building upon this background, the link of self-licensing with goal-oriented behaviour as one of the ways how self-regulation is explained is evident. In goal-directed behaviour, we perceive the maladaptive function of self-licensing as a possible obstacle causing a crisis in goal achievement, or the adaptive way how to resolve the self-regulatory conflict. In an action crisis, one considers several options - achieving the goal at all costs, giving up the effort to achieve it and identification of the alternative one. The objective of the study was the experimental examination of the relationships between self-licensing and self-cleansing, action crisis, goal disengagement and goal reengagement as two possible strategies for advancing the goal achievement process. The study was conducted on 195 participants divided into three conditions - self-licensing, self-cleansing and control group. The results did not show significant differences in action crisis, goal disengagement and goal reengagement between groups. The action crisis and goal disengagement were significantly more likely experienced while dealing with a subjective obstacle. Also, women were significantly more prone to goal reengagement than men. [ABSTRACT FROM AUTHOR]

Background: Overweight and obesity are significant global health concerns that involve deficits in gait and balance that affect daily activities. Although much is reported about the effect of overweight and obesity on gait during unobstructed walking, not much is known about how overweight and obesity could impact gait under more challenging conditions, such as environments with obstacles. Objective: The aim of this study is to systematically review and synthesize the available data regarding the effects of overweight and obesity on obstacle crossing during walking. Methods: This review will follow the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. PubMed, Web of Science, Scopus, and SPORTDiscus will be systematically searched with no limitations on publication date. Only full-text English-language articles published in a peer-reviewed journal will be included. Included articles must have compared obstacle crossing during walking in individuals with overweight or obesity to individuals of normal body weight. A total of 2 independent reviewers will select the articles and extract the following 4 sets of data: (1) study characteristics, (2) sample description, (3) obstacle crossing task protocol, and (4) main results obtained. If a considerable number of homogeneous papers are included, a meta-analysis will be conducted. A preliminary search was conducted in November 2021. Results: The results will include the article selection flowchart as well as tables and figures synthesizing the extracted data on the effects of overweight and obesity on obstacle crossing during walking. The preliminary search identified 73 original records, of which 5 articles met the inclusion criteria. Conclusions: This review will present researchers and clinicians with an overview of published studies that have compared the performance of obstacle crossing for individuals with overweight and obesity to those of normal body weight. Gaining insight into the control strategies adopted by individuals with overweight and obesity is critical for safe and successful obstacle crossing in this population. We therefore believe that our findings could be useful for identifying people at risk of falls and developing and implementing fall prevention programs for individuals with overweight and obesity. [ABSTRACT FROM AUTHOR]

We present a new approach to optimal design with state constraints based on active set optimization theory and implement it using a phase-field model. Our primary focus is on compliance minimization subject to inner and outer obstacles. We compare our approach to a classical penalization method and study the influence of initial guess, penalization parameters, and discretization. [ABSTRACT FROM AUTHOR]

The purpose of this study is to identify obstacles and success factors evident from empirical studies affecting strategy implementation and to provide an overview of the empirical literature. A systematic literature review (SLR) was used to analyze thirty-five peer-reviewed empirical articles. All of the 35 research papers selected in this review use primary data gathered from the organizations studied. This study of empirical research has identified 16 obstacles that can hinder strategy implementation and 18 success factors that can facilitate implementation. This study highlights factors that are dualistic, meaning that they contain both elements of obstacles and key success factors. The dualistic factors should therefore be considered in the strategy implementation process. Research gaps are identified. They include lack of studies on how to overcome obstacles to strategy on the one hand and on employee influence on implementation on the other. The differences among industries, countries, or cultures regarding implementation have not yet been explored at any depth. The paper adds to theoretical and practical knowledge based on the systematic overview it provides on strategy implementation from 1980 until 2020. The paper enriches the practical knowledge relevant to those implementing strategies, as it captures and identifies the dualistic factors affecting strategy implementation.

Existence obstacles in terrain area and the mobility of the nodes in the network are the vital constrains that degrade the performance in Mobile Adhoc Network (MANET). To diminish the effect of such obstacles and mobility on the performance of MANET, the protocol used for routing must be efficient enough to handle both the factors. In the present work, we have considered the issues of Mobility and obstacle aware multipath communication in MANET. For avoiding obstacles, DeCasteljau Algorithm with Bezier curve concept has been applied. To the minimize impact of mobility, a speed based mobility prediction concept is used. Here optimal routing path across the obstacle is selected depending on its mobility prediction indicator, link duration, network connectivity and path availability. The performance of the suggested protocol is evaluated with Network Simulator-2. Simulation results confirm that the suggested protocol minimizes average energy consumption, network overhead, average delay and improves data deliverance in MANET.

Abstract 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.

Underground structures are normally located in highly-confined and congested spaces, which may lead to severe gas explosion accidents, with significant human and economic losses. For accurately evaluating the consequences of these explosions, a variety of influencing factors need to be considered, including concentrations of gas mixtures, vent conditions, obstacles, and ignition features. Moreover, a good review on these influencing factors is important for a better understanding of explosion behavior, e.g., the deflagration to detonation phenomenon. In this study, some critical influencing factors for gas explosions in underground or confined spaces are investigated, and the effects of the factors on such gas explosions are examined. The results are discussed, along with findings from literature. The present study provides a reference for future studies on safety management and consequence mitigation for underground gas explosions.

Background: The increased number of older adults living alone has created a substantial care need. However, the utilization rate of services and facilities to meet these needs are surprisingly low. Many of older adults experience difficulties accessing these services, although it remains unclear how these obstacles impede access to services. This study explored the obstacles and difficulties experienced by urban older adults in seeking community care.Methods: A phenomenological study was carried out and participatory observation and in-depth interviews were employed to investigate the process of seeking care of older adults in urban communities. A total of 18 urban community-dwelling older adults aged 75 years and over were included. Data collected were analysed by content analysis.Results: We identified the pathways by which senior-only households sought community care and encountered obstacles. (1) lack of community care information: older adults did not know where and how to get services, even though the care institutions scattered throughout the community; (2) limited mobility: older adults often suffered from various chronic diseases, which physically hindered their access to care resources; (3) complex process of achieving care: the functional fragmentation and geographical dispersion of care institutions made the care-seeking process challenging and confusing for older adults; (4) incomprehension of needs expression: limited interaction time and communication barriers between staff of institutions and the older adults were the final obstacle. Only by surmounting these obstacles one by one can older adults access the care resources effectively.Conclusions: When older adults in the community initiated calls for help, they encountered several obstacles. Their physiological and social disadvantages limited their ability to seek care physically. Lack of integration and clear guidance in the process of providing community care exacerbated these difficulties. Reform of care services should focus on the visibility and accessibility of services for older adults. [ABSTRACT FROM AUTHOR]

The DCRFoam solver (density-based compressible solver) built on the OpenFOAM platform is used to simulate the reflection and diffraction processes that occur when detonation waves collide with various objects. Static stoichiometric hydrogen–oxygen mixtures diluted with 70% Ar are used to form stable detonation waves with large cells, with initial conditions of 6.67 kPa pressure and 298 K temperature. The diameters of the cylindrical obstacle range from 6 mm to 22 mm, with x = 230 mm, x = 244 mm, and x = 257 mm being the chosen position. Cylindrical, square, triangular, and inverted triangular obstacles are used, and the quenched detonation re-initiation processes behind them are investigated. In the detonation diffraction process, four triple points exist at the same time due to the effect of cylindrical obstacles of smaller diameters. The re-initiation distance of the detonation wave increases with the increase of cylindrical obstacle diameter. Both the Mach reflection angle and the decoupled angle decrease as the diameter increases. When the location of the cylindrical obstacles is changed, the detonation wave dashes into the obstacles with its different front structures, it is easier to realize the detonation re-initiation when the weak incident shock at the front of a detonation wave strikes the obstacles, and the re-initiation distance decreases by 17.1% when compared with the longest re-initiation distance. The detonation re-initiation distance is shortest under the action of cylindrical obstacles, however the quenched detonation cannot be re-initiated when the inverted triangle and square obstacles are used. The suppression effects of inverted triangle and square obstacles on detonation waves are more evident. • Diffraction and re-initiation of detonations with large cell were simulated. • The DCRFoam solver built on the OpenFOAM platform was used. • Detonation waves with different front structures strike obstacles were studied. • Obstacles with different shapes and sizes were employed in this study. [ABSTRACT FROM AUTHOR]

We propose to numerically study the dispersion of pollutants emitted from a chimney bent around an obstacle. A numerical simulation of the dispersion of pollutants emitted from a chimney has been performed using the CFD code Fluent. The influence of the ratio (R) of the jet speed to the lateral wind velocity, the distance between the chimney and the obstacle and the height of the obstacle on the dispersion of the ejected pollutants was studied. The numerical method used to solve the flow equations is a finite volume method, the mesh size adopted is non-uniform, very close to the chimney and around the obstacle. The results show essentially that the dispersion of the pollutants is more pronounced for larger R-ratios. It is also shown that the location and height of the obstacle modify the flow, the further the chimney is from the obstacle the greater the dispersion of pollutants. Also, ejection at a higher chimney height generates a larger plume which favours dilution and dispersion. [ABSTRACT FROM AUTHOR]

Hydrogen has been utilized in FCV and leakage can cause safety issues. In this study, the vehicle is simplified as a cuboid enclosure with obstacles. The influence of obstacle locations on the hydrogen diffusion behavior is investigated with the iso-surfaces of 1% and 4% volume fraction of hydrogen. The time of the iso-surface of 4% volume fraction to reach the ceiling and the sidewalls without any obstacles is 1.42 and 1.25 times of that with an obstacle, respectively. Both height and the width of the flammable zone in the enclosure with an obstacle are greater than that without obstacles. The distance between the obstacle and the leakage affects significantly the hydrogen diffusion and the influence of the obstacle on the hydrogen diffusion strengthens with the decrease of the distance. Yet as the distance keeps same, the obstacle position relative to the leakage has no significant effect on hydrogen diffusion, and it makes little effect difference whether the obstacle is located in front of leakage or side of leakage. • Iso-surfaces of 4% and 1% are studied to explore the behavior of hydrogen diffusion. • The influences of the obstacle with different location are compared. • The effects of the obstacle on hydrogen diffusion of each stage are discussed. [ABSTRACT FROM AUTHOR]

This article has reviewed the behavior of gaseous detonation propagated in straight ducts and nonstraight ducts. Detonation limits are extended by low-velocity self-sustaining detonation in narrow gap and roughness pipe of straight ducts, which is caused by instability, while in obstacle-equipped ducts of straight ducts, detonation failure is led by diffraction and detonation reignition is led by reflection. Furthermore, the propagation mechanism of detonation around the obstacle is adopted in bend ducts and branch ducts. The objective of this study is to clarify the detonation behavior in complex structures, through the state of basic theories and typical experiment conclusions. [ABSTRACT FROM AUTHOR]

Heavy rain in a particular area can cause flooding in both the primary area and the surrounding area. A flood is an event where water is inundated in an area due to increased water volume. Due to high level of water and other hazards arising from flooding, flood victims need to move to a location prepared for evacuation. To get to that location prepared, the victims must get through a safe route. Searching for safe evacuation routes is important to save flood victims and bring them to the evacuation centre safely. Search for evacuation routes related to obstacles on the road to get through. Slippery roads, high puddles of water on the roads, rivers that are located close to the roads that flood victims will have to get through, drainage of waterways and the vulnerability of victims are taken into consideration in choosing a route to get to the evacuation location. There are several problems in choosing a safe route: (1) how to take into account the obstacles on the road to be passed (2) how to choose the priority of the route to be passed with the obstacles encountered. The proposed solution to deal with the problems encountered are (1) to take into account road obstacles by giving the obstacle weights. Fuzzy logic is used to calculate the value of obstacle weights (2) the problem of selecting route priorities will be solved using the firefly algorithm. The firefly algorithm is an algorithm inspired by the social life of fireflies. The priority route for evacuation of flood victims is sought using the method proposed in this study which is the optimal route. The optimal route referred to in this study is the route that has the smallest obstacle weight value. The simulation results show that the fuzzy logic integrated into the firefly algorithm (FuFA) provides a safe route priority, indicated by the smallest obstacle weight value. [ABSTRACT FROM AUTHOR]

Nan province, the biggest cultivation area of fresh mulberry fruit in Thailand is located in four districts: Chaloem Phra Kiat, Bor Klua, Tha Wang Pha, and Wiang Sa. The production yield of mulberry is about 848.6 kg/acre/year; however, it is mostly sold as frozen product. The Queen Sirikit Department of Sericulture intends to develop a new marketing channel for fresh mulberry fruit. The present study was to explore the current situation of mulberry fruit supply chain management in Nan province and to propose a new supply chain model for fresh mulberry. To gather information about supply chain management, the supply chain operation reference (SCOR) model was utilized to investigate four members of the mulberry supply chains, including growers, primary middlemen, secondary middlemen, and customers. The SCOR model possibly identifies critical points in the current supply chain and five obstacles in the distribution of fresh mulberries that are improperly handled, affecting market channels and product quality due to a lack of suitable knowledge and technology for postharvest handling. Active packaging technology of fresh mulberries from a previous study was introduced to design a new supply chain model, and it was found that this technology could extend the product’s shelf life and preserve its freshness. Although the cost of the active packaging technology leads to a much higher cost on the newly developed supply chain compared to that of the traditional supply chain, the developed model could enhance new market channels, including selling prices, and provide growers with more benefits than the traditional supply chain. [ABSTRACT FROM AUTHOR]

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Flame acceleration and the deflagration to detonation transition (DDT) are important physical phenomena in combustion theories. The main objective of this work is to provide a comprehensive understanding of the effect of the positions of obstacles when a flame propagates in obstructed confined channels, using two-dimensional direct numerical simulations (DNSs) with the detailed chemical kinetics mechanism of H2. The underlying mechanism for the flame propagation and detonation, affected by the obstacles with the flame-shockwave and flame–vortex interactions, is investigated. In 1000 K cases, two different detonation modes associated with flame propagation are observed, where for the case with obstacles near the ignition kernel, autoignition takes place in the end-gas region as predicted, while for the case with obstacles far away from the ignition kernel, autoignition occurs, instead, in front of the flame and triggers a DDT immediately. Both of two modes consist three processes: flame propagation stages, flame-pressure wave/shockwave interaction, and detonation development. The evolutions of centerline temperature and pressure are employed to explicitly demonstrate the detonation process. The differences in the shockwave formation, peak temperature, and pressure values can be clearly observed. The mechanisms of the different detonation modes induced by different obstacle positions are analyzed in detail for the first time. The results indicate that the compressed and preheated temperature of the unburned mixture determines the detonation combustion mode. The conclusion is further proved in the flame-shockwave number variation and detonation modes transition when initial temperature is changed. This study will provide new insight into the DDT and detonation phenomena in engines. [ABSTRACT FROM AUTHOR]

To investigate the actual gas explosion and propagation laws in the roadway of an underground mine, experiments were conducted in a standard 19-L tube of rectangular section to provide a comprehensive understanding of the effects of carbon monoxide (CO) addition and obstacles placed on the flame propagation of explosions from methane–air mixtures at different conditions. The flame structure, flame propagation speed, heat loss, and explosion pressure were used to reflect the explosion behaviors of the premixed flame. The experimental results indicate that the enhancement and attenuation of the explosion pressure wave are significantly influenced by an obstacle. The existence of obstacles changed the trend of classical pressure rise, thus forming a first pressure peak. In addition, the position close to the obstacle presented a higher explosion pressure. Under 7 vol.% and 9.5 vol.% CH4 conditions, the increase of CO (from 0 vol.% to 2 vol.%) promoted explosion flame propagation. However, the CO exhibited a clear negative effect on the rate of flame propagation due to exacerbated O2 depletion of 11 vol.% CH4, and the negative effect enhances with CO increased. Besides, when the CO addition increased, the flame tended to more instability and more brightly. For heat loss, with the increase of CO content in mixed gases, there was a slight promoting, constant and inhibiting effect for 11 vol.%, 9.5 vol.%, and 7 vol.% CH4, respectively. These results are of fundamental importance for the prevention and mitigation of gas explosion in underground mines and other industrial scenarios. [ABSTRACT FROM AUTHOR]

To address the coal gangue fracture heat transfer problem, the law of heat transfers and temperature distribution in the coal gangue fracture is studied. The temperature distribution in a coal gangue fracture under 12 conditions (with or without the obstacle, and various heat flows) is simulated via Fluent numerical simulation. The results show that the heat flow velocity, temperature and obstacle are important factors in inhibiting heat transfer oxidation spontaneous combustion in the coal gangue fracture. When the heat flow temperature is constant, the low-velocity heat flow causes a large temperature drops in the coal gangue fracture; when the heat flow velocity is constant, the high-temperature heat flow also produces a large temperature drops effect; when the obstacle is present and the heat flow produces vortex pass through the obstacle, increasing the energy loss in the coal gangue fracture, causing the temperature in the coal gangue fracture to drop rapidly, and reach the lowest in the position of the obstacle. Obstacles can effectively inhibit the heat transfer characteristics in the coal gangue fracture and reduce the risks of oxidation spontaneous combustion of gangue after grouting. [ABSTRACT FROM AUTHOR]

Direct ink writing (DIW), as an additive manufacturing method, can effectively mould ceramic parts. The single screw extruder is used here to extrude viscous SiC slurry. The deposits caused by the low viscosity and the agglomerations resulting from the nonuniform mixing, form the obstacles in the channel, which affect the normal theoretical flow of the slurry, and interaction with other printing parameters. Therefore, it is necessary to explore the effect mechanism of the obstacles on the flow. The obstacles are always irregular, which makes it difficult to directly analyse them. The irregular geometries are always composed of linear and/or arcuate elements; therefore, the obstacles can be simplified into regular geometries. In the previous work, linear elements have been analysed first. As the continuous work, arcuate elements are investigated in the current research. To conduct the required simulations, an improved MRT LBM (multiple relaxation time lattice Boltzmann method) with a pseudo external force is proposed. The above numerical method is combined with the rheological model to analyse cases with two obstacles, and the obtained results are used to reveal the general mechanism in cases with multiple obstacles. The results show that the central angles, radii, and positions of the obstacles are important factors affecting the flow. To obtain a stable and controllable slurry flow, it is recommended that the central angle and the radius should be small enough. The number of obstacles should be minimized, and the position of the last obstacle is expected to be far away from the outlet to avoid the negative velocity. In addition, the adjacent obstacles should maintain a certain distance to ensure the full development of the vortex and avoid affecting the following obstacles or back vortices. [ABSTRACT FROM AUTHOR]