This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of t...This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of two dyes(TR+CG-H3G).The Cockle Shell(CS)was used as a natural bio-adsorbent.The characterizations of CS were investigated by Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and Brunauer–Emmett–Teller(BET).The adsorption potential of Cockle Shells was tested in two cases(single and binary system)and determined by:contact time(0–60 min),bio-adsorption dose(3–15 g/L),initial concentration(10–300 mg/L),temperature(22–61°C)and pH solution(2–12).The study of bio-adsorption(equilibrium and kinetics)was conducted at 22°C.The kinetic studies demon-strated that a pseudo-second-order adsorption mechanism had a good correlation coefficient(R2≥0.999).The Langmuir isotherm modeling provided a well-defined description of TR and CG-H3G bio-adsorption on cockle shells,exhibiting maximum capacities of 29.41 and 3.69 mg/g respectively at 22°C.The thermodynamic study shows that the reaction between the TR,CG-H3G dyes molecules and the bio-adsorbent is exothermic,spontaneous in the range of 22–31°C with the aleatory character decrease at the solid-liquid interface.The study of selectivity in single and binary systems has been performed under optimal operating conditions using the industrial textile rejection pH(pH=6.04).CG-H3G dye is found to have a higher selectivity than TR in single(0–60 min)and binary systems with a range of 6–45 min,as shown by the selectivity measurement.It was discovered that CS has the capability to remove both CG-H3G and TR dyes in both simple and binary systems,making it a superior bio-adsorbent.展开更多
The present study focuses on the flow of a yield-stress(Bingham)nanofluid,consisting of suspended Fe3O4 nanoparticles,subjected to a magnetic field in a backward-facing step duct(BFS)configuration.The duct is equipped...The present study focuses on the flow of a yield-stress(Bingham)nanofluid,consisting of suspended Fe3O4 nanoparticles,subjected to a magnetic field in a backward-facing step duct(BFS)configuration.The duct is equipped with a cylindrical obstacle,where the lower wall is kept at a constant temperature.The yield-stress nanofluid enters this duct at a cold temperature with fully developed velocity.The aim of the present investigation is to explore the influence of flow velocity(Re=10 to 200),nanoparticle concentration(ϕ=0 to 0.1),magnetic field intensity(Ha=0 to 100),and its inclination angle(γ=0 to 90)and nanofluid yield stress(Bn=0 to 20)on the thermal and hydrodynamic efficiency inside the backward-facing step.The numerical results have been obtained by resolving the momentum and energy balance equations using the Galerkin finite element method.The obtained results have indicated that an increase in Reynolds number and nanoparticle volume fraction enhances heat transfer.In contrast,a significant reduction is observed with an increase in Hartmann and Bingham numbers,resulting in quasi-immobilization of the fluid under the magnetic influence and radical solidification of this type of fluid,accompanied by the suppression of the vortex zone downstream of the cylindrical obstacle.This study sheds light on the complexity of this magnetically influenced fluid,with potential implications in various engineering and materials science fields.展开更多
Traffic forecasting with high precision aids Intelligent Transport Systems(ITS)in formulating and optimizing traffic management strategies.The algorithms used for tuning the hyperparameters of the deep learning models...Traffic forecasting with high precision aids Intelligent Transport Systems(ITS)in formulating and optimizing traffic management strategies.The algorithms used for tuning the hyperparameters of the deep learning models often have accurate results at the expense of high computational complexity.To address this problem,this paper uses the Tree-structured Parzen Estimator(TPE)to tune the hyperparameters of the Long Short-term Memory(LSTM)deep learning framework.The Tree-structured Parzen Estimator(TPE)uses a probabilistic approach with an adaptive searching mechanism by classifying the objective function values into good and bad samples.This ensures fast convergence in tuning the hyperparameter values in the deep learning model for performing prediction while still maintaining a certain degree of accuracy.It also overcomes the problem of converging to local optima and avoids timeconsuming random search and,therefore,avoids high computational complexity in prediction accuracy.The proposed scheme first performs data smoothing and normalization on the input data,which is then fed to the input of the TPE for tuning the hyperparameters.The traffic data is then input to the LSTM model with tuned parameters to perform the traffic prediction.The three optimizers:Adaptive Moment Estimation(Adam),Root Mean Square Propagation(RMSProp),and Stochastic Gradient Descend with Momentum(SGDM)are also evaluated for accuracy prediction and the best optimizer is then chosen for final traffic prediction in TPE-LSTM model.Simulation results verify the effectiveness of the proposed model in terms of accuracy of prediction over the benchmark schemes.展开更多
Managing sensitive data in dynamic and high-stakes environments,such as healthcare,requires access control frameworks that offer real-time adaptability,scalability,and regulatory compliance.BIG-ABAC introduces a trans...Managing sensitive data in dynamic and high-stakes environments,such as healthcare,requires access control frameworks that offer real-time adaptability,scalability,and regulatory compliance.BIG-ABAC introduces a transformative approach to Attribute-Based Access Control(ABAC)by integrating real-time policy evaluation and contextual adaptation.Unlike traditional ABAC systems that rely on static policies,BIG-ABAC dynamically updates policies in response to evolving rules and real-time contextual attributes,ensuring precise and efficient access control.Leveraging decision trees evaluated in real-time,BIG-ABAC overcomes the limitations of conventional access control models,enabling seamless adaptation to complex,high-demand scenarios.The framework adheres to the NIST ABAC standard while incorporating modern distributed streaming technologies to enhance scalability and traceability.Its flexible policy enforcement mechanisms facilitate the implementation of regulatory requirements such as HIPAA and GDPR,allowing organizations to align access control policies with compliance needs dynamically.Performance evaluations demonstrate that BIG-ABAC processes 95% of access requests within 50 ms and updates policies dynamically with a latency of 30 ms,significantly outperforming traditional ABAC models.These results establish BIG-ABAC as a benchmark for adaptive,scalable,and context-aware access control,making it an ideal solution for dynamic,high-risk domains such as healthcare,smart cities,and Industrial IoT(IIoT).展开更多
The self-healing properties of dual-component epoxy microcapsules are evaluated when incorporated into an epoxy coating.The performance of the coating was assessed under immersion in a saline solution,simulating seawa...The self-healing properties of dual-component epoxy microcapsules are evaluated when incorporated into an epoxy coating.The performance of the coating was assessed under immersion in a saline solution,simulating seawater conditions.Initially,synthesized microcapsules are incorporated into the epoxy coating.Then,the self-healing capabilities of the coating are studied under immersion using scanning vibrating electrode technique(SVET),open circuit potential(OCP),electrochemical impedance spectroscopy(EIS)and immersion corrosion test on coated samples with intentionally created artificial defects.The last three tests were conducted in a 3.5%NaCl solution.The adhesion of the coating is also studied by pull-off adhesion test.SVET analyses reveal lower ionic current densities in coated samples containing microcapsules during 24 h of immersion.EIS results demonstrate self-healing at the defect site for up to 12 h of immersion.After this time,the corrosion protection diminishes with prolonged immersion in the saline solution.Despite this,the coating with the microcapsules exhibits decrease in the corrosion process compared to the coating without the microcapsules.These results are consistent and complement the outcomes of the immersion tests conducted over 360 and 1056 h,which indicate that coated samples without microcapsules exhibit double the corroded areas around the scribes compared to coated samples containing the microcapsules.These findings offer a promising outlook for applying this coating on offshore carbon steel structures under immersion aiming for a longer lifetime with less maintenance intervention.展开更多
In an environment where demand for housing is growing and the supply from public authorities is virtually non-existent,several mechanisms for housing production are emerging in the formal,semi-informal and informal co...In an environment where demand for housing is growing and the supply from public authorities is virtually non-existent,several mechanisms for housing production are emerging in the formal,semi-informal and informal construction sectors.The project owner wonders how much it costs to construct a building to an acceptable standard.Cost forecasting in general faces a number of difficulties,including a lack of available information during the preliminary phase of the project.As such,estimation becomes a crucial task involving great responsibility,which can lead to either more convincing results or chaotic situations.This study proposes a quick and effective method for estimating the cost of a single-storey F4 residential building.The modelling is done using multiple linear regression based on a statistical approach applied to twenty(20)projects that have already been completed.The project data are collected from design offices in the city of Brazzaville.The method expresses the cost of an F4 construction by certain project tasks,representing five(5)variables,three(3)of which are related to structural work and two(2)to finishing work,which are easy to determine.This approach,known as MECSO(Cost Estimation Model by Sub-structure),gives good results in all statistical tests carried out with reasonable confidence intervals.This method is very practical for engineering professionals working on the evaluation and control of construction costs.展开更多
The productive evaluation of cocoa in this research is proposed through an assessment of soil quality and crop health in an organic production system(SPO)Taisha canton and a conventional production system(SPCv)Morona ...The productive evaluation of cocoa in this research is proposed through an assessment of soil quality and crop health in an organic production system(SPO)Taisha canton and a conventional production system(SPCv)Morona canton.Methodology:Altieri and Nicholls establish a diagnosis of chemical,physical,biological and health indicators,with weightings high(10),medium(5)and low(1).Results:SPO soil quality,reflects weights 10(high)for ammonium ion,zinc,copper,iron,manganese,moisture retention,biological activity,compaction,apparent density,residue status,color,organic matter,root development,erosion incidence,5(medium)potassium,phosphorus,calcium,sulfur,pH,texture,1(low)magnesium,boron,topsoil depth,for crop health values of 10(high)appearance,crop growth,stress resistance or tolerance,weed competition,agrosilvopastoral system,plant diversity and management system,5(medium)potential yield,incidence of pests and diseases.The SPCv soil quality presented a weighting of 10(high)for nitrogen,zinc,copper,iron,biological activity,compaction,bulk density,color,organic matter,root development,erosion incidence,5(medium)manganese,pH,texture,moisture retention,residue status,1(low)potassium,phosphorus,calcium,magnesium,sulfur,boron,topsoil depth,crop health 10(high)crop appearance and growth,stress resistance or tolerance,weed competition,agrosilvopastoral system,plant diversity,management system,potential yield,5(medium)incidence of pests and diseases,1(low)surrounding natural diversity.Conclusions:The SPO for soil quality:7.41 and for crop health:7.59 weighted as sustainable,while the SPCv for soil quality:6 and crop health:6.76,resulting in a moderately sustainable production system.展开更多
This research is an experimental study aimed at identifying and determining the physico-mechanical properties of various granular materials used in current concretes based on local aggregates (sands, gravels) from dif...This research is an experimental study aimed at identifying and determining the physico-mechanical properties of various granular materials used in current concretes based on local aggregates (sands, gravels) from different quarries, highlighting their intrinsic properties. The aim was also to test their specific influence on the cementitious matrix of hardened concrete. Several laboratory tests were conducted on samples from Brazzaville and Pointe-Noire. To develop a variety of concrete formulations meeting rheological criteria (deformability, bleeding, segregation) and create an optimal concrete formulation approach considering its microstructural and compacting matrix, a good granular distribution was planned, using two types of sand (rolled and crushed). This involved correcting the rolled sand with variable proportions (30% to 50%) of crushed sand. The results from the eight concrete formulations studied, using the Dreux-Gorisse method, showed that six formulations produced the expected results. Compressive strengths at 28 days ranged from 25 to 36.75 MPa. As a result, formulation 3 appears to be the best, with a mechanical strength of 36.75 MPa at 28 days, compared to formulation 1 (33.75 MPa), formulation 4 (27.25 MPa), and formulation 2 (26.65 MPa) for the Brazzaville locality. For the Pointe-Noire locality, formulation 8 was judged the best, with a characteristic mechanical strength of 29.70 MPa at 28 days, followed by formulation 7 (27.30 MPa), formulation 5 (22.80 MPa), and formulation 6 (18.30 MPa). In summary, the concretes formulated with raw sand showed better results than those with improved sands. The same was true for concrete formulations using rolled sand and gravel.展开更多
In the context of transitioning toward more sustainable construction materials,this study explores the impact of incorporating millet husks as an alternative to sand on the physical,mechanical,and thermal performance ...In the context of transitioning toward more sustainable construction materials,this study explores the impact of incorporating millet husks as an alternative to sand on the physical,mechanical,and thermal performance of lightweight concrete.Through a mixture design approach,five formulations were selected and thoroughly characterized.The analysis of iso-response curves enabled an in-depth assessment of the cross-effects between formulation parameters and their interactions on the final properties of the material.The results show that integrating millet husks leads to a significant reduction in density,reaching up to 21%,while maintaining notable mechanical performance.A balanced formulation of sand and fibers achieved a maximum compressive strength of 12.11 MPa,demonstrating that,under specific conditions,plant fibers actively contribute to the structural integrity of the composite.In tensile strength,the positive influence of fibers is even more pronounced,with a maximum resistance of 8.62 MPa,highlighting their role in enhancing material cohesion.From a thermal perspective,millet husks reduce both thermal conductivity and effusivity,thereby limiting heat transfer and accumulation within the composite.Iso-response curve analysis reveals that these effects are directly linked to the proportions of the constituents and that achieving an optimal balance between sand,fibers,and cement is key to maximizing performance.These findings demonstrate that the adopted approach allows moving beyond conventional substitution methods by identifying optimal configurations for the design of lightweight bio-based concretes that are both strong and insulating,thereby confirming the potential of millet husks in developing lightweight concretes suitable for sustainable construction applications.展开更多
Concentrating Solar Power(CSP)is one of the most promising solar technologies for sustainable power generation in countrieswith high solar potential,likeChad.Identifying suitable sites is of great importance for deplo...Concentrating Solar Power(CSP)is one of the most promising solar technologies for sustainable power generation in countrieswith high solar potential,likeChad.Identifying suitable sites is of great importance for deploying solar power plants.This work focuses on the identification of potential sites for the installation of solar power plants in Chad as well as a comparative analysis using the Analytical Hierarchy Process(AHP),Fuzzy Analytical Hierarchy Process(FAHP),and Full Consistency Method(FUCOM).The results show that 35%of the Chadian territory,i.e.,an area of 449,400 km2,is compatible with the implementation of Concentrating Solar Power.The North,North,East,Southeast,and East zones are the most suitable.The main criteria for influence are direct normal irradiation,the soil slope,and the water resource.FUCOM gave a weight of 41.9%for Direct Normal Irradiation(DNI)compared to 32.71%and 31.81%for AHP and FAHP.This method can be applied to other renewable energy technologies such as photovoltaics,wind power,and biomass.Combining its different analyses will be a valuable tool for planning any renewable energy project in Chad.This work should also facilitate the techno-economic analysis of future CSP plants in Chad.展开更多
This research aimed to obtain accurate estimates of the productivity of eucalyptus plantations under different climate change scenarios without the need for additional fieldwork.Thus,we used tree growth data from 1,10...This research aimed to obtain accurate estimates of the productivity of eucalyptus plantations under different climate change scenarios without the need for additional fieldwork.Thus,we used tree growth data from 1,102research plots,existing spatially continuous environmental data,and the random forest(RF) algorithm to construct raster-based models.We constructed models to predict site index(SI) at landscape scale(250m·pixel^(-1)),which is useful for planning purposes and for analyzing the effect of climate change on productivity,and at forest plot scale(resolutions of 10,25,50,and 100 m-pixel^(-1)),which is essential for predicting plantation yields.All models explained~50% of site index variability,as is usual in this type of study.We found that the different spatial resolutions of predictor variables did not affect the amount of variability explained.This finding may be due to two opposing effects on the explained variability at finer scales:a positive effect,as finer scales enable capture of microscale landform variability through a high-resolution digital elevation model(DEM),and a negative effect due to the introduction of "noise" when downscaling the climatic and lithological information from coarser scales.Elevation and the climatic variables(mainly temperature) were the most important predictor variables:For every 100 m-increase in elevation,the productivity decreased by on average 0.3-0.9 m of site index(1-1.3 m^(3)·ha^(-1)·year^(-1) of maximum mean annual increment in volume) and for each degree-Celsiusincrease in annual mean temperature,productivity increased by about 2.2 m in site index(3 m^(3)·ha^(-1)·year^(-1)of maximum mean annual increment in volume).Due to the forecasted increase in temperatures under climate change,productivity is expected to increase significantly in Eucalyptus globulus plantations in northern Spain in the coming decades,by between 1.68% and 3.38% of the current average site index under the most pessimistic climate change scenario and between 1.79% and 2.48% of the current average site index for the moderate scenario.We conclude that currently available spatially continuous environmental data can be used to develop accurate raster data models for predicting site productivity for E.globulus without the need for fieldwork.The spatially explicit maps produced in the study provide support to forest planners,forest managers,private landowners and politicians,enabling well-founded decisions to be made regarding selection of the best sites for afforestation and providing accurate yield predictions for the plantations.展开更多
In the Republic of Benin,as in many other West African countries,urban areas have experienced rapid popula-tion growth in recent years.This situation has led to an increasing demand for sanitation facilities,necessita...In the Republic of Benin,as in many other West African countries,urban areas have experienced rapid popula-tion growth in recent years.This situation has led to an increasing demand for sanitation facilities,necessitating regular emptying of these systems.In a bid to reduce health risks and protect the surrounding natural environment,the manage-ment of the by-products from these systems has become a significant concern for decision-makers at various levels.This study aims to characterize fecal sludge at the Abomey-Calavi treatment station and suggest a mixed biological treatment approach.Fifteen sewage sludge samples were collected in 1,500 ml plastic bottles from Adjagbo’s Sewage Treatment Station,operated by SGDS-SA,a Waste Management and Sanitation company.Physico-chemical parameters were de-termined using spectrophotometric analysis.Colonies were enumerated using membrane filtration and inoculation.Cor-relation analysis was performed on sewage sludge samples.The main results indicate an alkaline character(pH>7)and a high organic pollutant load in the fecal sludge,with average concentrations of Chemical Oxygen Demand(COD)and Biochemical Oxygen Demand over 5 days(BOD_(5))at 18,730 mg O_(2).L^(-1)and 6,612 mg O_(2).L^(-1),respectively.The COD/BOD_(5) ratio of 2.83 suggests that the material is partially biodegradable.Furthermore,the nutrients exhibited high con-centrations of nitrates,with an average value of 4,786 mg.L^(-1),while nitrites,ammoniacal nitrogen,and orthophosphates had average concentrations of 22.48 mg.L^(-1),119.74 mg.L^(-1),and 239.0 mg.L^(-1),respectively.This study characterized fe-cal sludge at the Abomey-Calavi treatment station and suggests a mixed biological treatment approach.展开更多
The increasing adoption of Industrial Internet of Things(IIoT)systems in smart manufacturing is leading to raise cyberattack numbers and pressing the requirement for intrusion detection systems(IDS)to be effective.How...The increasing adoption of Industrial Internet of Things(IIoT)systems in smart manufacturing is leading to raise cyberattack numbers and pressing the requirement for intrusion detection systems(IDS)to be effective.However,existing datasets for IDS training often lack relevance to modern IIoT environments,limiting their applicability for research and development.To address the latter gap,this paper introduces the HiTar-2024 dataset specifically designed for IIoT systems.As a consequence,that can be used by an IDS to detect imminent threats.Likewise,HiTar-2024 was generated using the AREZZO simulator,which replicates realistic smart manufacturing scenarios.The generated dataset includes five distinct classes:Normal,Probing,Remote to Local(R2L),User to Root(U2R),and Denial of Service(DoS).Furthermore,comprehensive experiments with popular Machine Learning(ML)models using various classifiers,including BayesNet,Logistic,IBK,Multiclass,PART,and J48 demonstrate high accuracy,precision,recall,and F1-scores,exceeding 0.99 across all ML metrics.The latter result is reached thanks to the rigorous applied process to achieve this quite good result,including data pre-processing,features extraction,fixing the class imbalance problem,and using a test option for model robustness.This comprehensive approach emphasizes meticulous dataset construction through a complete dataset generation process,a careful labelling algorithm,and a sophisticated evaluation method,providing valuable insights to reinforce IIoT system security.Finally,the HiTar-2024 dataset is compared with other similar datasets in the literature,considering several factors such as data format,feature extraction tools,number of features,attack categories,number of instances,and ML metrics.展开更多
The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively ...The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively applying mono-capacitor positioning, multiple positioning and reconfiguration processes using GA-based algorithms implemented in a Matlab environment. From the diagnostic study of this network, it was observed that a minimum voltage of 0.90 pu induces a voltage deviation of 5.26%, followed by active and reactive losses of 425.08 kW and 435.09 kVAR, respectively. Single placement with the NSGAII resulted in the placement of a 3000 kVAR capacitor at node 128, which proved to be the invariably neuralgic point. Multiple placements resulted in a 21.55% reduction in losses and a 0.74% regression in voltage profile performance. After topology optimization, the loss profile improved by 65.08% and the voltage profile improved by 1.05%. Genetic algorithms are efficient and effective tools for improving the performance of distribution networks, whose degradation is often dynamic due to the natural variability of loads.展开更多
This study experimentally investigates the hydrodynamic characteristics,geometric configurations,fluttering motions of the codend,and the instantaneous flow fields inside and around the codend,with and without a liner...This study experimentally investigates the hydrodynamic characteristics,geometric configurations,fluttering motions of the codend,and the instantaneous flow fields inside and around the codend,with and without a liner,under varying catch sizes and inflow velocities.A proper orthogonal decomposition method is employed to extract phase-averaged mean properties of unsteady turbulent flows from flow measurement data obtained using an electromagnetic current velocity meter inside and around the codend.The results reveal that as catch size increases,the drag force,codend motion,Reynolds number,and codend volume increase while the drag coefficient decreases.Owing to the codend shape and pronounced motion,a complex fluid–structure interaction occurs,demonstrating a strong correlation between drag force and codend volume.The oscillation amplitudes of the hydrodynamic forces and codend motions increase with increasing catch size,and their oscillations mainly involve low-frequency activity.A significant reduction in the flow field occurs inside and around the unlined codend without a catch.The flow field is 5.81%,14.39%,and 27.01%lower than the unlined codend with a catch,the codend with a liner but without a catch,and the codend with both a liner and a catch,respectively.Fourier analysis reveals that the codend motions and hydrodynamic forces are mainly characterized by low-frequency activity and are synchronized with the unsteady turbulent flow street.Furthermore,the proper orthogonal decomposition results reveal the development of unsteady turbulent flow inside and around the codend,driven by flow passage blockage caused by the presence of the liner,intense codend motions,and the catch.Understanding the hydrodynamic characteristics and flow instabilities inside and around the codend,particularly those associated with its fluttering motions,is crucial for optimizing trawl design and improving trawl selectivity.展开更多
This research investigates dynamic earth processes within the South Setifian allochthonous ensemble,providing insights into landscape evolution and seismotectonic activity within the Tellian mountain chain.Focusing on...This research investigates dynamic earth processes within the South Setifian allochthonous ensemble,providing insights into landscape evolution and seismotectonic activity within the Tellian mountain chain.Focusing on the Jebel Gustar and Kef Lahmar area,which includes 14 sub-basins,this research uses a DEM-based technique to assess Holocene activities,lineament characteristics,and stream systems.Five geomorphic indices are used to assess relative active tectonics:the stream lengthgradient index(SL),drainage basin asymmetry(AF),valley-floor width to valley height ratio(VF),drainage basin shape(BS),and mountain front sinuosity(SMF).A weighted overlay of these five indices produces the Index of Relative Active Tectonics(IRAT)map.The findings reveal significant neotectonic activity in the study area,supported by profound basement faulting.This research highlights the morpho-structural processes and neotectonics activity in the Jebel Gustar,providing a framework for investigating the evolution of this structure.Additionally,it enhances comprehension of the interactions between the alpine range's internal zones in Eastern Algeria and the Atlasic domain.This study proposes a systematic approach to evaluate the tectonic and geomorphological dynamics of the South Setif region.展开更多
Studies show that contemporary teaching methodologies are based on skills and competences directed to different areas of professional practice,such as Architecture,Design and Computer Science.Collective learning space...Studies show that contemporary teaching methodologies are based on skills and competences directed to different areas of professional practice,such as Architecture,Design and Computer Science.Collective learning spaces gain strength,stimulating the development of new skills by users.The Digital Manufacturing Laboratories(Fab Labs)and Makerspaces are entering the school environment and starting a movement for change in traditional education.Although they are seen as potential drivers for higher quality education,the lack of specific training for teachers in the face of new digital information and communication technologies,especially in basic education,becomes limiting in the development of new active methodologies.Thus,this study aimed to develop a training dynamic for basic education teachers,addressing the use of tools and equipment for digital manufacturing and prototyping,2D and 3D modeling applications and software,and programming and electronics.The methodology consists of literature review,followed by the action research method with two workshops given through an online and synchronous platform.The importance of incorporating creative and innovative methodologies in education is understood,and above all,there is a dynamic,planned and effective structure,geared towards the orientation of teachers.展开更多
Despite the non-contact underwater explosion phenomena(UNDEX)have been studied for decades and several numerical methods have been proposed in literature,its effects on military structures,especially composite ones,ar...Despite the non-contact underwater explosion phenomena(UNDEX)have been studied for decades and several numerical methods have been proposed in literature,its effects on military structures,especially composite ones,are even nowadays matter of research.In early design phases,it is not always possible to verify the shock resistance of hull structures modelling the whole phenomenon,in which fluid,gas and solid properties must be properly set in a fully coupled fluid-structure interaction(FSI)numerical model.These ones are extremely complex to set,computationally demanding and certainly not suitable for everyday design practice.In this paper,a simplified finite element(FE)model,easy to use in an early design phase,is proposed.Both,the structure and the fluid are simulated.In this approximation,the fluid behaviour is simplified,using special finite elements,available in a commercial software environment.This choice reduces the computational time and numerical efforts avoiding the problem of combining computational fluid dynamics(CFD)and FE domains and equations in a fully coupled fluid-structure interaction model.A typical parallel body block of a minesweeper is modelled,using two-dimensional multi-layered shell elements to properly account for the composite materials behaviour.For the fluid instead,three dimensional volumetric elements,directly coupled to the structural elements,are placed.In addition,the same calculation is performed,modelling separately fluid in the CFD environment and structures in the finite element one.Thus,realizing a fully coupled fluid-structure interaction model.The results obtained by applying both numerical models are compared with the structural response measured on board of a composite ship during a full-scale shock test.The simplified proposed procedure provides results in satisfactory agreement with experiments,allowing the validation of the model.Approximations are discussed and differences with the real phenomenon and fully coupled CFD+FE method are shown,providing a better understanding of the phenomena.Eventually,the modelling strategy has been considered a valuable and cost-effective tool for the concept and preliminary design of composite structures subject to underwater explosions.展开更多
In this paper,an intelligent control method applying on numerical virtual flight is proposed.The proposed algorithm is verified and evaluated by combining with the case of the basic finner projectile model and shows a...In this paper,an intelligent control method applying on numerical virtual flight is proposed.The proposed algorithm is verified and evaluated by combining with the case of the basic finner projectile model and shows a good application prospect.Firstly,a numerical virtual flight simulation model based on overlapping dynamic mesh technology is constructed.In order to verify the accuracy of the dynamic grid technology and the calculation of unsteady flow,a numerical simulation of the basic finner projectile without control is carried out.The simulation results are in good agreement with the experiment data which shows that the algorithm used in this paper can also be used in the design and evaluation of the intelligent controller in the numerical virtual flight simulation.Secondly,combined with the real-time control requirements of aerodynamic,attitude and displacement parameters of the projectile during the flight process,the numerical simulations of the basic finner projectile’s pitch channel are carried out under the traditional PID(Proportional-Integral-Derivative)control strategy and the intelligent PID control strategy respectively.The intelligent PID controller based on BP(Back Propagation)neural network can realize online learning and self-optimization of control parameters according to the acquired real-time flight parameters.Compared with the traditional PID controller,the concerned control variable overshoot,rise time,transition time and steady state error and other performance indicators have been greatly improved,and the higher the learning efficiency or the inertia coefficient,the faster the system,the larger the overshoot,and the smaller the stability error.The intelligent control method applying on numerical virtual flight is capable of solving the complicated unsteady motion and flow with the intelligent PID control strategy and has a strong promotion to engineering application.展开更多
The issue of faecal sludge management in developing countries remains a significant challenge due to the indiscriminate discharge of sludge into the environment. This practice generates more environmental problems tha...The issue of faecal sludge management in developing countries remains a significant challenge due to the indiscriminate discharge of sludge into the environment. This practice generates more environmental problems than it solves. This study aims to assess the management of household faecal sludge in the communes of Abomey-Calavi and Natitingou, Benin, in order to optimise the best storage conditions for subsequent more effective treatment. To this end, a sociological survey was conducted among households in Abomey-Calavi and Natitingou, as well as among manual emptiers. The results of our studies revealed that two types of latrines are used in households. 20.55% of households use traditional latrines, while 59.83% use ordinary latrines. 7.97% of households use both types of latrine. Moreover, the depth of the latrines varies from 2.5 m to 7 m in Abomey-Calavi and from 2.5 m to 8 m in Natitingou. Among households with a latrine, 28.26% empty their pit at least once, while 71.74% have never emptied it. The emptying cost varies between 35,000 FCFA and 90,000 FCFA. The mixing of faecal sludge with solid waste, including plastic materials, makes emptying difficult due to the obstruction of the vacuum pump. The results obtained will serve as a reliable database to facilitate decision-making in the context of faecal sludge management.展开更多
基金supported by the University Salah Boubnider-Constantine 3 (Algeria).
文摘This research aims to study the bio-adsorption process of two dyes,Cibacron Green H3G(CG-H3G)and Terasil Red(TR),in a single system and to bring them closer to the industrial textile discharge by a binary mixture of two dyes(TR+CG-H3G).The Cockle Shell(CS)was used as a natural bio-adsorbent.The characterizations of CS were investigated by Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and Brunauer–Emmett–Teller(BET).The adsorption potential of Cockle Shells was tested in two cases(single and binary system)and determined by:contact time(0–60 min),bio-adsorption dose(3–15 g/L),initial concentration(10–300 mg/L),temperature(22–61°C)and pH solution(2–12).The study of bio-adsorption(equilibrium and kinetics)was conducted at 22°C.The kinetic studies demon-strated that a pseudo-second-order adsorption mechanism had a good correlation coefficient(R2≥0.999).The Langmuir isotherm modeling provided a well-defined description of TR and CG-H3G bio-adsorption on cockle shells,exhibiting maximum capacities of 29.41 and 3.69 mg/g respectively at 22°C.The thermodynamic study shows that the reaction between the TR,CG-H3G dyes molecules and the bio-adsorbent is exothermic,spontaneous in the range of 22–31°C with the aleatory character decrease at the solid-liquid interface.The study of selectivity in single and binary systems has been performed under optimal operating conditions using the industrial textile rejection pH(pH=6.04).CG-H3G dye is found to have a higher selectivity than TR in single(0–60 min)and binary systems with a range of 6–45 min,as shown by the selectivity measurement.It was discovered that CS has the capability to remove both CG-H3G and TR dyes in both simple and binary systems,making it a superior bio-adsorbent.
文摘The present study focuses on the flow of a yield-stress(Bingham)nanofluid,consisting of suspended Fe3O4 nanoparticles,subjected to a magnetic field in a backward-facing step duct(BFS)configuration.The duct is equipped with a cylindrical obstacle,where the lower wall is kept at a constant temperature.The yield-stress nanofluid enters this duct at a cold temperature with fully developed velocity.The aim of the present investigation is to explore the influence of flow velocity(Re=10 to 200),nanoparticle concentration(ϕ=0 to 0.1),magnetic field intensity(Ha=0 to 100),and its inclination angle(γ=0 to 90)and nanofluid yield stress(Bn=0 to 20)on the thermal and hydrodynamic efficiency inside the backward-facing step.The numerical results have been obtained by resolving the momentum and energy balance equations using the Galerkin finite element method.The obtained results have indicated that an increase in Reynolds number and nanoparticle volume fraction enhances heat transfer.In contrast,a significant reduction is observed with an increase in Hartmann and Bingham numbers,resulting in quasi-immobilization of the fluid under the magnetic influence and radical solidification of this type of fluid,accompanied by the suppression of the vortex zone downstream of the cylindrical obstacle.This study sheds light on the complexity of this magnetically influenced fluid,with potential implications in various engineering and materials science fields.
文摘Traffic forecasting with high precision aids Intelligent Transport Systems(ITS)in formulating and optimizing traffic management strategies.The algorithms used for tuning the hyperparameters of the deep learning models often have accurate results at the expense of high computational complexity.To address this problem,this paper uses the Tree-structured Parzen Estimator(TPE)to tune the hyperparameters of the Long Short-term Memory(LSTM)deep learning framework.The Tree-structured Parzen Estimator(TPE)uses a probabilistic approach with an adaptive searching mechanism by classifying the objective function values into good and bad samples.This ensures fast convergence in tuning the hyperparameter values in the deep learning model for performing prediction while still maintaining a certain degree of accuracy.It also overcomes the problem of converging to local optima and avoids timeconsuming random search and,therefore,avoids high computational complexity in prediction accuracy.The proposed scheme first performs data smoothing and normalization on the input data,which is then fed to the input of the TPE for tuning the hyperparameters.The traffic data is then input to the LSTM model with tuned parameters to perform the traffic prediction.The three optimizers:Adaptive Moment Estimation(Adam),Root Mean Square Propagation(RMSProp),and Stochastic Gradient Descend with Momentum(SGDM)are also evaluated for accuracy prediction and the best optimizer is then chosen for final traffic prediction in TPE-LSTM model.Simulation results verify the effectiveness of the proposed model in terms of accuracy of prediction over the benchmark schemes.
文摘Managing sensitive data in dynamic and high-stakes environments,such as healthcare,requires access control frameworks that offer real-time adaptability,scalability,and regulatory compliance.BIG-ABAC introduces a transformative approach to Attribute-Based Access Control(ABAC)by integrating real-time policy evaluation and contextual adaptation.Unlike traditional ABAC systems that rely on static policies,BIG-ABAC dynamically updates policies in response to evolving rules and real-time contextual attributes,ensuring precise and efficient access control.Leveraging decision trees evaluated in real-time,BIG-ABAC overcomes the limitations of conventional access control models,enabling seamless adaptation to complex,high-demand scenarios.The framework adheres to the NIST ABAC standard while incorporating modern distributed streaming technologies to enhance scalability and traceability.Its flexible policy enforcement mechanisms facilitate the implementation of regulatory requirements such as HIPAA and GDPR,allowing organizations to align access control policies with compliance needs dynamically.Performance evaluations demonstrate that BIG-ABAC processes 95% of access requests within 50 ms and updates policies dynamically with a latency of 30 ms,significantly outperforming traditional ABAC models.These results establish BIG-ABAC as a benchmark for adaptive,scalable,and context-aware access control,making it an ideal solution for dynamic,high-risk domains such as healthcare,smart cities,and Industrial IoT(IIoT).
基金supported by CAPES scholarship-Brazil Coordination for the Improvement of Higher Education Personnel(No.88887.507764/2020-00)]by CNPq-Brazil National Council of Technological and Scientific Development(No.308564/2023-5).
文摘The self-healing properties of dual-component epoxy microcapsules are evaluated when incorporated into an epoxy coating.The performance of the coating was assessed under immersion in a saline solution,simulating seawater conditions.Initially,synthesized microcapsules are incorporated into the epoxy coating.Then,the self-healing capabilities of the coating are studied under immersion using scanning vibrating electrode technique(SVET),open circuit potential(OCP),electrochemical impedance spectroscopy(EIS)and immersion corrosion test on coated samples with intentionally created artificial defects.The last three tests were conducted in a 3.5%NaCl solution.The adhesion of the coating is also studied by pull-off adhesion test.SVET analyses reveal lower ionic current densities in coated samples containing microcapsules during 24 h of immersion.EIS results demonstrate self-healing at the defect site for up to 12 h of immersion.After this time,the corrosion protection diminishes with prolonged immersion in the saline solution.Despite this,the coating with the microcapsules exhibits decrease in the corrosion process compared to the coating without the microcapsules.These results are consistent and complement the outcomes of the immersion tests conducted over 360 and 1056 h,which indicate that coated samples without microcapsules exhibit double the corroded areas around the scribes compared to coated samples containing the microcapsules.These findings offer a promising outlook for applying this coating on offshore carbon steel structures under immersion aiming for a longer lifetime with less maintenance intervention.
文摘In an environment where demand for housing is growing and the supply from public authorities is virtually non-existent,several mechanisms for housing production are emerging in the formal,semi-informal and informal construction sectors.The project owner wonders how much it costs to construct a building to an acceptable standard.Cost forecasting in general faces a number of difficulties,including a lack of available information during the preliminary phase of the project.As such,estimation becomes a crucial task involving great responsibility,which can lead to either more convincing results or chaotic situations.This study proposes a quick and effective method for estimating the cost of a single-storey F4 residential building.The modelling is done using multiple linear regression based on a statistical approach applied to twenty(20)projects that have already been completed.The project data are collected from design offices in the city of Brazzaville.The method expresses the cost of an F4 construction by certain project tasks,representing five(5)variables,three(3)of which are related to structural work and two(2)to finishing work,which are easy to determine.This approach,known as MECSO(Cost Estimation Model by Sub-structure),gives good results in all statistical tests carried out with reasonable confidence intervals.This method is very practical for engineering professionals working on the evaluation and control of construction costs.
文摘The productive evaluation of cocoa in this research is proposed through an assessment of soil quality and crop health in an organic production system(SPO)Taisha canton and a conventional production system(SPCv)Morona canton.Methodology:Altieri and Nicholls establish a diagnosis of chemical,physical,biological and health indicators,with weightings high(10),medium(5)and low(1).Results:SPO soil quality,reflects weights 10(high)for ammonium ion,zinc,copper,iron,manganese,moisture retention,biological activity,compaction,apparent density,residue status,color,organic matter,root development,erosion incidence,5(medium)potassium,phosphorus,calcium,sulfur,pH,texture,1(low)magnesium,boron,topsoil depth,for crop health values of 10(high)appearance,crop growth,stress resistance or tolerance,weed competition,agrosilvopastoral system,plant diversity and management system,5(medium)potential yield,incidence of pests and diseases.The SPCv soil quality presented a weighting of 10(high)for nitrogen,zinc,copper,iron,biological activity,compaction,bulk density,color,organic matter,root development,erosion incidence,5(medium)manganese,pH,texture,moisture retention,residue status,1(low)potassium,phosphorus,calcium,magnesium,sulfur,boron,topsoil depth,crop health 10(high)crop appearance and growth,stress resistance or tolerance,weed competition,agrosilvopastoral system,plant diversity,management system,potential yield,5(medium)incidence of pests and diseases,1(low)surrounding natural diversity.Conclusions:The SPO for soil quality:7.41 and for crop health:7.59 weighted as sustainable,while the SPCv for soil quality:6 and crop health:6.76,resulting in a moderately sustainable production system.
文摘This research is an experimental study aimed at identifying and determining the physico-mechanical properties of various granular materials used in current concretes based on local aggregates (sands, gravels) from different quarries, highlighting their intrinsic properties. The aim was also to test their specific influence on the cementitious matrix of hardened concrete. Several laboratory tests were conducted on samples from Brazzaville and Pointe-Noire. To develop a variety of concrete formulations meeting rheological criteria (deformability, bleeding, segregation) and create an optimal concrete formulation approach considering its microstructural and compacting matrix, a good granular distribution was planned, using two types of sand (rolled and crushed). This involved correcting the rolled sand with variable proportions (30% to 50%) of crushed sand. The results from the eight concrete formulations studied, using the Dreux-Gorisse method, showed that six formulations produced the expected results. Compressive strengths at 28 days ranged from 25 to 36.75 MPa. As a result, formulation 3 appears to be the best, with a mechanical strength of 36.75 MPa at 28 days, compared to formulation 1 (33.75 MPa), formulation 4 (27.25 MPa), and formulation 2 (26.65 MPa) for the Brazzaville locality. For the Pointe-Noire locality, formulation 8 was judged the best, with a characteristic mechanical strength of 29.70 MPa at 28 days, followed by formulation 7 (27.30 MPa), formulation 5 (22.80 MPa), and formulation 6 (18.30 MPa). In summary, the concretes formulated with raw sand showed better results than those with improved sands. The same was true for concrete formulations using rolled sand and gravel.
文摘In the context of transitioning toward more sustainable construction materials,this study explores the impact of incorporating millet husks as an alternative to sand on the physical,mechanical,and thermal performance of lightweight concrete.Through a mixture design approach,five formulations were selected and thoroughly characterized.The analysis of iso-response curves enabled an in-depth assessment of the cross-effects between formulation parameters and their interactions on the final properties of the material.The results show that integrating millet husks leads to a significant reduction in density,reaching up to 21%,while maintaining notable mechanical performance.A balanced formulation of sand and fibers achieved a maximum compressive strength of 12.11 MPa,demonstrating that,under specific conditions,plant fibers actively contribute to the structural integrity of the composite.In tensile strength,the positive influence of fibers is even more pronounced,with a maximum resistance of 8.62 MPa,highlighting their role in enhancing material cohesion.From a thermal perspective,millet husks reduce both thermal conductivity and effusivity,thereby limiting heat transfer and accumulation within the composite.Iso-response curve analysis reveals that these effects are directly linked to the proportions of the constituents and that achieving an optimal balance between sand,fibers,and cement is key to maximizing performance.These findings demonstrate that the adopted approach allows moving beyond conventional substitution methods by identifying optimal configurations for the design of lightweight bio-based concretes that are both strong and insulating,thereby confirming the potential of millet husks in developing lightweight concretes suitable for sustainable construction applications.
文摘Concentrating Solar Power(CSP)is one of the most promising solar technologies for sustainable power generation in countrieswith high solar potential,likeChad.Identifying suitable sites is of great importance for deploying solar power plants.This work focuses on the identification of potential sites for the installation of solar power plants in Chad as well as a comparative analysis using the Analytical Hierarchy Process(AHP),Fuzzy Analytical Hierarchy Process(FAHP),and Full Consistency Method(FUCOM).The results show that 35%of the Chadian territory,i.e.,an area of 449,400 km2,is compatible with the implementation of Concentrating Solar Power.The North,North,East,Southeast,and East zones are the most suitable.The main criteria for influence are direct normal irradiation,the soil slope,and the water resource.FUCOM gave a weight of 41.9%for Direct Normal Irradiation(DNI)compared to 32.71%and 31.81%for AHP and FAHP.This method can be applied to other renewable energy technologies such as photovoltaics,wind power,and biomass.Combining its different analyses will be a valuable tool for planning any renewable energy project in Chad.This work should also facilitate the techno-economic analysis of future CSP plants in Chad.
基金supported by the research project of code PID2020-112839RB-I00 funded by the Spanish State Research Agency(AEI)of the Ministry of Science and Innovation(MCIN/AEI/10.13039/501100011033)in receipt of a Severo Ochoa Fellowship from the Asturias Government(code BP21-125).
文摘This research aimed to obtain accurate estimates of the productivity of eucalyptus plantations under different climate change scenarios without the need for additional fieldwork.Thus,we used tree growth data from 1,102research plots,existing spatially continuous environmental data,and the random forest(RF) algorithm to construct raster-based models.We constructed models to predict site index(SI) at landscape scale(250m·pixel^(-1)),which is useful for planning purposes and for analyzing the effect of climate change on productivity,and at forest plot scale(resolutions of 10,25,50,and 100 m-pixel^(-1)),which is essential for predicting plantation yields.All models explained~50% of site index variability,as is usual in this type of study.We found that the different spatial resolutions of predictor variables did not affect the amount of variability explained.This finding may be due to two opposing effects on the explained variability at finer scales:a positive effect,as finer scales enable capture of microscale landform variability through a high-resolution digital elevation model(DEM),and a negative effect due to the introduction of "noise" when downscaling the climatic and lithological information from coarser scales.Elevation and the climatic variables(mainly temperature) were the most important predictor variables:For every 100 m-increase in elevation,the productivity decreased by on average 0.3-0.9 m of site index(1-1.3 m^(3)·ha^(-1)·year^(-1) of maximum mean annual increment in volume) and for each degree-Celsiusincrease in annual mean temperature,productivity increased by about 2.2 m in site index(3 m^(3)·ha^(-1)·year^(-1)of maximum mean annual increment in volume).Due to the forecasted increase in temperatures under climate change,productivity is expected to increase significantly in Eucalyptus globulus plantations in northern Spain in the coming decades,by between 1.68% and 3.38% of the current average site index under the most pessimistic climate change scenario and between 1.79% and 2.48% of the current average site index for the moderate scenario.We conclude that currently available spatially continuous environmental data can be used to develop accurate raster data models for predicting site productivity for E.globulus without the need for fieldwork.The spatially explicit maps produced in the study provide support to forest planners,forest managers,private landowners and politicians,enabling well-founded decisions to be made regarding selection of the best sites for afforestation and providing accurate yield predictions for the plantations.
文摘In the Republic of Benin,as in many other West African countries,urban areas have experienced rapid popula-tion growth in recent years.This situation has led to an increasing demand for sanitation facilities,necessitating regular emptying of these systems.In a bid to reduce health risks and protect the surrounding natural environment,the manage-ment of the by-products from these systems has become a significant concern for decision-makers at various levels.This study aims to characterize fecal sludge at the Abomey-Calavi treatment station and suggest a mixed biological treatment approach.Fifteen sewage sludge samples were collected in 1,500 ml plastic bottles from Adjagbo’s Sewage Treatment Station,operated by SGDS-SA,a Waste Management and Sanitation company.Physico-chemical parameters were de-termined using spectrophotometric analysis.Colonies were enumerated using membrane filtration and inoculation.Cor-relation analysis was performed on sewage sludge samples.The main results indicate an alkaline character(pH>7)and a high organic pollutant load in the fecal sludge,with average concentrations of Chemical Oxygen Demand(COD)and Biochemical Oxygen Demand over 5 days(BOD_(5))at 18,730 mg O_(2).L^(-1)and 6,612 mg O_(2).L^(-1),respectively.The COD/BOD_(5) ratio of 2.83 suggests that the material is partially biodegradable.Furthermore,the nutrients exhibited high con-centrations of nitrates,with an average value of 4,786 mg.L^(-1),while nitrites,ammoniacal nitrogen,and orthophosphates had average concentrations of 22.48 mg.L^(-1),119.74 mg.L^(-1),and 239.0 mg.L^(-1),respectively.This study characterized fe-cal sludge at the Abomey-Calavi treatment station and suggests a mixed biological treatment approach.
文摘The increasing adoption of Industrial Internet of Things(IIoT)systems in smart manufacturing is leading to raise cyberattack numbers and pressing the requirement for intrusion detection systems(IDS)to be effective.However,existing datasets for IDS training often lack relevance to modern IIoT environments,limiting their applicability for research and development.To address the latter gap,this paper introduces the HiTar-2024 dataset specifically designed for IIoT systems.As a consequence,that can be used by an IDS to detect imminent threats.Likewise,HiTar-2024 was generated using the AREZZO simulator,which replicates realistic smart manufacturing scenarios.The generated dataset includes five distinct classes:Normal,Probing,Remote to Local(R2L),User to Root(U2R),and Denial of Service(DoS).Furthermore,comprehensive experiments with popular Machine Learning(ML)models using various classifiers,including BayesNet,Logistic,IBK,Multiclass,PART,and J48 demonstrate high accuracy,precision,recall,and F1-scores,exceeding 0.99 across all ML metrics.The latter result is reached thanks to the rigorous applied process to achieve this quite good result,including data pre-processing,features extraction,fixing the class imbalance problem,and using a test option for model robustness.This comprehensive approach emphasizes meticulous dataset construction through a complete dataset generation process,a careful labelling algorithm,and a sophisticated evaluation method,providing valuable insights to reinforce IIoT system security.Finally,the HiTar-2024 dataset is compared with other similar datasets in the literature,considering several factors such as data format,feature extraction tools,number of features,attack categories,number of instances,and ML metrics.
文摘The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively applying mono-capacitor positioning, multiple positioning and reconfiguration processes using GA-based algorithms implemented in a Matlab environment. From the diagnostic study of this network, it was observed that a minimum voltage of 0.90 pu induces a voltage deviation of 5.26%, followed by active and reactive losses of 425.08 kW and 435.09 kVAR, respectively. Single placement with the NSGAII resulted in the placement of a 3000 kVAR capacitor at node 128, which proved to be the invariably neuralgic point. Multiple placements resulted in a 21.55% reduction in losses and a 0.74% regression in voltage profile performance. After topology optimization, the loss profile improved by 65.08% and the voltage profile improved by 1.05%. Genetic algorithms are efficient and effective tools for improving the performance of distribution networks, whose degradation is often dynamic due to the natural variability of loads.
基金sponsored by the National Natural Science Foundation of China(Grant No.32373187)the Research Fund for International Scientists of the National Natural Science Foundation of China(Grant No.32350410404)the Natural Science Foundation of Shanghai(Grant No.23ZR1427000).
文摘This study experimentally investigates the hydrodynamic characteristics,geometric configurations,fluttering motions of the codend,and the instantaneous flow fields inside and around the codend,with and without a liner,under varying catch sizes and inflow velocities.A proper orthogonal decomposition method is employed to extract phase-averaged mean properties of unsteady turbulent flows from flow measurement data obtained using an electromagnetic current velocity meter inside and around the codend.The results reveal that as catch size increases,the drag force,codend motion,Reynolds number,and codend volume increase while the drag coefficient decreases.Owing to the codend shape and pronounced motion,a complex fluid–structure interaction occurs,demonstrating a strong correlation between drag force and codend volume.The oscillation amplitudes of the hydrodynamic forces and codend motions increase with increasing catch size,and their oscillations mainly involve low-frequency activity.A significant reduction in the flow field occurs inside and around the unlined codend without a catch.The flow field is 5.81%,14.39%,and 27.01%lower than the unlined codend with a catch,the codend with a liner but without a catch,and the codend with both a liner and a catch,respectively.Fourier analysis reveals that the codend motions and hydrodynamic forces are mainly characterized by low-frequency activity and are synchronized with the unsteady turbulent flow street.Furthermore,the proper orthogonal decomposition results reveal the development of unsteady turbulent flow inside and around the codend,driven by flow passage blockage caused by the presence of the liner,intense codend motions,and the catch.Understanding the hydrodynamic characteristics and flow instabilities inside and around the codend,particularly those associated with its fluttering motions,is crucial for optimizing trawl design and improving trawl selectivity.
文摘This research investigates dynamic earth processes within the South Setifian allochthonous ensemble,providing insights into landscape evolution and seismotectonic activity within the Tellian mountain chain.Focusing on the Jebel Gustar and Kef Lahmar area,which includes 14 sub-basins,this research uses a DEM-based technique to assess Holocene activities,lineament characteristics,and stream systems.Five geomorphic indices are used to assess relative active tectonics:the stream lengthgradient index(SL),drainage basin asymmetry(AF),valley-floor width to valley height ratio(VF),drainage basin shape(BS),and mountain front sinuosity(SMF).A weighted overlay of these five indices produces the Index of Relative Active Tectonics(IRAT)map.The findings reveal significant neotectonic activity in the study area,supported by profound basement faulting.This research highlights the morpho-structural processes and neotectonics activity in the Jebel Gustar,providing a framework for investigating the evolution of this structure.Additionally,it enhances comprehension of the interactions between the alpine range's internal zones in Eastern Algeria and the Atlasic domain.This study proposes a systematic approach to evaluate the tectonic and geomorphological dynamics of the South Setif region.
基金the CAPES(Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil)-Finance Code 001,CNPq(National Council for Scientific and Technological Development)and Foundation for Research Support of the State of Rio Grande do Sul(FAPERGS).
文摘Studies show that contemporary teaching methodologies are based on skills and competences directed to different areas of professional practice,such as Architecture,Design and Computer Science.Collective learning spaces gain strength,stimulating the development of new skills by users.The Digital Manufacturing Laboratories(Fab Labs)and Makerspaces are entering the school environment and starting a movement for change in traditional education.Although they are seen as potential drivers for higher quality education,the lack of specific training for teachers in the face of new digital information and communication technologies,especially in basic education,becomes limiting in the development of new active methodologies.Thus,this study aimed to develop a training dynamic for basic education teachers,addressing the use of tools and equipment for digital manufacturing and prototyping,2D and 3D modeling applications and software,and programming and electronics.The methodology consists of literature review,followed by the action research method with two workshops given through an online and synchronous platform.The importance of incorporating creative and innovative methodologies in education is understood,and above all,there is a dynamic,planned and effective structure,geared towards the orientation of teachers.
文摘Despite the non-contact underwater explosion phenomena(UNDEX)have been studied for decades and several numerical methods have been proposed in literature,its effects on military structures,especially composite ones,are even nowadays matter of research.In early design phases,it is not always possible to verify the shock resistance of hull structures modelling the whole phenomenon,in which fluid,gas and solid properties must be properly set in a fully coupled fluid-structure interaction(FSI)numerical model.These ones are extremely complex to set,computationally demanding and certainly not suitable for everyday design practice.In this paper,a simplified finite element(FE)model,easy to use in an early design phase,is proposed.Both,the structure and the fluid are simulated.In this approximation,the fluid behaviour is simplified,using special finite elements,available in a commercial software environment.This choice reduces the computational time and numerical efforts avoiding the problem of combining computational fluid dynamics(CFD)and FE domains and equations in a fully coupled fluid-structure interaction model.A typical parallel body block of a minesweeper is modelled,using two-dimensional multi-layered shell elements to properly account for the composite materials behaviour.For the fluid instead,three dimensional volumetric elements,directly coupled to the structural elements,are placed.In addition,the same calculation is performed,modelling separately fluid in the CFD environment and structures in the finite element one.Thus,realizing a fully coupled fluid-structure interaction model.The results obtained by applying both numerical models are compared with the structural response measured on board of a composite ship during a full-scale shock test.The simplified proposed procedure provides results in satisfactory agreement with experiments,allowing the validation of the model.Approximations are discussed and differences with the real phenomenon and fully coupled CFD+FE method are shown,providing a better understanding of the phenomena.Eventually,the modelling strategy has been considered a valuable and cost-effective tool for the concept and preliminary design of composite structures subject to underwater explosions.
文摘In this paper,an intelligent control method applying on numerical virtual flight is proposed.The proposed algorithm is verified and evaluated by combining with the case of the basic finner projectile model and shows a good application prospect.Firstly,a numerical virtual flight simulation model based on overlapping dynamic mesh technology is constructed.In order to verify the accuracy of the dynamic grid technology and the calculation of unsteady flow,a numerical simulation of the basic finner projectile without control is carried out.The simulation results are in good agreement with the experiment data which shows that the algorithm used in this paper can also be used in the design and evaluation of the intelligent controller in the numerical virtual flight simulation.Secondly,combined with the real-time control requirements of aerodynamic,attitude and displacement parameters of the projectile during the flight process,the numerical simulations of the basic finner projectile’s pitch channel are carried out under the traditional PID(Proportional-Integral-Derivative)control strategy and the intelligent PID control strategy respectively.The intelligent PID controller based on BP(Back Propagation)neural network can realize online learning and self-optimization of control parameters according to the acquired real-time flight parameters.Compared with the traditional PID controller,the concerned control variable overshoot,rise time,transition time and steady state error and other performance indicators have been greatly improved,and the higher the learning efficiency or the inertia coefficient,the faster the system,the larger the overshoot,and the smaller the stability error.The intelligent control method applying on numerical virtual flight is capable of solving the complicated unsteady motion and flow with the intelligent PID control strategy and has a strong promotion to engineering application.
文摘The issue of faecal sludge management in developing countries remains a significant challenge due to the indiscriminate discharge of sludge into the environment. This practice generates more environmental problems than it solves. This study aims to assess the management of household faecal sludge in the communes of Abomey-Calavi and Natitingou, Benin, in order to optimise the best storage conditions for subsequent more effective treatment. To this end, a sociological survey was conducted among households in Abomey-Calavi and Natitingou, as well as among manual emptiers. The results of our studies revealed that two types of latrines are used in households. 20.55% of households use traditional latrines, while 59.83% use ordinary latrines. 7.97% of households use both types of latrine. Moreover, the depth of the latrines varies from 2.5 m to 7 m in Abomey-Calavi and from 2.5 m to 8 m in Natitingou. Among households with a latrine, 28.26% empty their pit at least once, while 71.74% have never emptied it. The emptying cost varies between 35,000 FCFA and 90,000 FCFA. The mixing of faecal sludge with solid waste, including plastic materials, makes emptying difficult due to the obstruction of the vacuum pump. The results obtained will serve as a reliable database to facilitate decision-making in the context of faecal sludge management.
