The fact that Morocco is an agricultural country and the large volume of biodegradable waste produced by the population make composting so important.The degradation of organic matter is facilitated by faunal and flora...The fact that Morocco is an agricultural country and the large volume of biodegradable waste produced by the population make composting so important.The degradation of organic matter is facilitated by faunal and floral macro and micro-organisms that act in different stages of maturation;studies on this fauna are quite rare both nationally and internationally.On a sample of two tons of household waste,we documented invertebrates that colonized compost heaps and then assessed the changes in the structure of the invertebrate population during the different phases.Our study revealed the presence of several zoological groups colonizing the compost heaps during the different composting phases;we noted the presence of:(1)Macroscopic invertebrates,in order of number of individuals:insect larvae,ants,earthworms,sowbugs,spiders,springtails,and millipedes,and(2)Microscopic invertebrates,the most abundant in terms of individuals:mites and nematodes.As for the order of appearance,we observed that insect larvae were the first to colonize the compost heap from the very first days of installation,followed by woodlice observed during the thermophilic phase and disappearing towards the end of the process.Earthworms were observed during the end of the thermophilic phase,while springtails were observed more during the cooling and maturation phases.Our study revealed the presence of a good quality of fauna during the composting process,which are indicators of good compost quality and play a major role in the circulation of nutrients,thus ensuring the provision of essential elements for plant nutrition.展开更多
The aim of this work is to study and quantify the air mass flow exchanged between inside and outside of the greenhouse, in order to determine the ventilation openings layout and the design effect on greenhouse airflow...The aim of this work is to study and quantify the air mass flow exchanged between inside and outside of the greenhouse, in order to determine the ventilation openings layout and the design effect on greenhouse airflow and microclimate distribution. The study was conducted over a 945 m2 multi-chapels arched greenhouse with a polyethylene cover and has thirteen crop rows oriented from north to south;the greenhouse was equipped with side wall and roof vents openings. A simulation was performed using different arrangements and configurations of ventilation openings with the same wind direction. Numerical simulation has been adopted in three dimensions (CFD), using the Fluent computer code which relies on the resolution of the Navier-Stokes equations. These equations were solved in the presence of the turbulence model (k - ε) and the Boussinesq model equation adopted to incorporate buoyancy forces. The effects of solar and atmospheric radiation were included by solving the radiative transfer equation (RTE), using Discrete Ordinate (DO) model. The effects of the roof openings, the presence of anti-insect screens and crops orientation were investigated and quantified. In a 3-span greenhouse with an anti-aphid in-sect screen in the vent openings, combining roof and sidewall vents gave a ventilation rate per unit opening area that was 1.4 times more than with only side vents. In the latter case, the difference of temperature between the inside and the outside of the greenhouse was greater than 3°C. Numerical simulations with an anti-insect screen having a porosity of 56% showed that the air exchange rate with combined ventilation was reduced by 48%. Finally, the paper focused on the effect of vent arrangement on the efficiency of the ventilation and the distribution of the microclimate inside the greenhouse. Results showed that computed ventilation rates varied from 53.43 to 70.95 kg/s, whereas temperature differences varied from 7.15°C to 10.14°C. This study also showed that other characteristics such as climate heterogeneity must be investigated in order to define the best ventilation configuration.展开更多
DNA is the carrier of all cellular genetic information and increasingly used in nanotechnology. The study of DNA molecule achieved <em>in vitro</em> while submitting the DNA to all chemicals agent capabili...DNA is the carrier of all cellular genetic information and increasingly used in nanotechnology. The study of DNA molecule achieved <em>in vitro</em> while submitting the DNA to all chemicals agent capabilities to destabilize links hydrogen, such as pH, temperature. In fact, the DNA enveloped in the membrane cellular, so it is legitimate to study the influence of membrane undulations. In this work, we try to show that the fluctuations of the membrane can be considerate as a physics agent is also capable to destabilize links hydrogen. In this investigation, we assume that each pair base formed an angle <em>a</em><sub><em>n</em></sub> with the membrane’s surface. We have proposed a theoretical model, and we have established a relationship between the angle formed by the pair base <span style="white-space:nowrap;"><em><span style="white-space:nowrap;">θ</span></em><sub><em>eq</em></sub><em> </em></span> and <em>a</em><sub><em>n</em></sub> angle formed by the membrane and each pair base. We assume that DNA and biomembrane interact via a realistic potential of Morse type. To this end, use is made of a generalized model that extends that introduced by M. Peyrard and A. R. Bishop in the past modified by M. Zoli. This generalized model is based on the resolution of a Schr<span style="white-space:nowrap;">ö</span>dinger-like equation. The exact resolution gives the expression of the ground state, and the associated eigenvalue (energy) that equals the free energy, in the thermodynamic limit. First, we compute the denaturation temperature of DNA strands critical temperature. Second, we deduce all critical properties that mainly depend on the parameters of the model, and we quantify the effects of the membrane undulations. These undulations renormalize all physical quantities, such as harmonic stacking, melting temperature, eigenfunctions, eigenvalues and regular part of specific heat.展开更多
The recent increase in the use of artificial intelligence has led to fundamental changes in the development of training and teaching methods for executive education. However, the success of artificial intelligence in ...The recent increase in the use of artificial intelligence has led to fundamental changes in the development of training and teaching methods for executive education. However, the success of artificial intelligence in regional centers for teaching and training professions will depend on the acceptance of this technology by young executive trainees. This article discusses the potential benefits of adopting AI in executive training institutions in Morocco, specifically focusing on CRMEF Casablanca Settat. Based on the Unified Theory of Acceptance and Use of Technology (UTAUT) (Venkatesh et al., 2003), this study proposes a model to identify the factors influencing the acceptance of artificial intelligence in regional centers for teaching professions and training in Morocco. To achieve this, a structural equation modeling approach was used to quantitatively describe the impact of each factor on AI adoption, utilizing data collected from 173 young executive trainees. The results indicate that perceived ease of use, perceived usefulness, trainer influence, and personal innovativeness influence the intention to use artificial intelligence. Our research provides managers of CRMEFs with a set of practical recommendations to enhance the implementation conditions of an artificial intelligence system. It aims to understand which factors should be considered in designing an artificial intelligence system within regional centers for teaching professions and training (CRMEFs).展开更多
Magnetic hysteresis and compensation behavior of a mixed spin-（1, 3/2） Ising model on a square lattice are investigated in the framework of effective field theory based on a probability distribution technique. The e...Magnetic hysteresis and compensation behavior of a mixed spin-（1, 3/2） Ising model on a square lattice are investigated in the framework of effective field theory based on a probability distribution technique. The effect of random crystal field, ferromagnetic and ferrimagnetic exchange interaction on hysteresis loops and compensation phenomenon are discussed. A number of characteristic phenomena have been reported such as the observation of triple hysteresis loops at low temperatures and for negative values of random crystal field. Critical and double compensation temperatures have been also found. The obtained results are also compared to some previous works.展开更多
Mapping floods is crucial for effective disaster management. This study focuses on flood assessment in northern Morocco, specifically Tangier, Tetouan, and Larache. Due to the lack of a comprehensive flood inventory m...Mapping floods is crucial for effective disaster management. This study focuses on flood assessment in northern Morocco, specifically Tangier, Tetouan, and Larache. Due to the lack of a comprehensive flood inventory map, we used unsupervised learning techniques, such as K-means clustering and fuzzy logic algorithms, to predict flood-prone areas. We identified nine conditioning factors influencing flood risk: elevation, slope, aspect, plan curvature, profile curvature, land use, soil type, normalized difference vegetation index(NDVI), and topographic position index(TPI). Using Landsat-8 imagery and a Digital Elevation Model(DEM) within a Geographic Information System(GIS), we analyzed topographic and geo-environmental variables. K-means clustering achieved silhouette scores of 0.66 in Tangier and 0.70 in Tetouan, while the fuzzy logic method in Larache produced a Davies-Bouldin Index(DBI) score of 0.35. The maps classified flood risk levels into low, moderate, and high categories. This research demonstrates the integration of machine learning and remote sensing for predicting flood-prone areas without existing flood inventory maps. Our findings highlight the main factors contributing to flash floods and assess their impact, enhancing the understanding of flood dynamics and improving flood management strategies in vulnerable regions.展开更多
In this work, we study the stability of a class of materials obtained by printing a textile with conductive inks using a method called screen printing. Under the action of a certain external factors, the printed circu...In this work, we study the stability of a class of materials obtained by printing a textile with conductive inks using a method called screen printing. Under the action of a certain external factors, the printed circuit suffers deterioration and the conductivity decreases considerably. In this work, we propose to model the overall damage of the textile sheet in terms of the partial damages of the conductive lines. We also apply this approach to evaluate the damage of a system being made of transmission lines printed into nonwoven substrates using different conductive inks.展开更多
We study the mixed spin-1 and spin-3/2 Blume-Capel model under crystal field in the tridimensional semi-infinite case. This has been done by using the real-space renormalization group approximation and specifically th...We study the mixed spin-1 and spin-3/2 Blume-Capel model under crystal field in the tridimensional semi-infinite case. This has been done by using the real-space renormalization group approximation and specifically the Migdal-Kadanoff technique. As a function of the ratio R of bulk and surface interactions and the ratios R<sub>1</sub> and R<sub>2 </sub>of bulk and surface crystals fields on the spin-1 and spin-3/2 respectively, we have determined various types of phase diagrams. Besides second- order transition lines, first-order phase transition lines terminating at tricritical points are obtained. We found that there existed nine main types of phase diagram showing a variety of phase transitions associated with the surface, including ordinary, extraordinary, surface and special phase transitions.展开更多
Nichel-phosphorus(Ni-P)coatings are deposited on mild steel by using an electroless plating process.The effect of three calix[4]arene derivatives,namely tetra methyl ester-P-tertbutyl calix[4]arene(Calix1),tetra acid-...Nichel-phosphorus(Ni-P)coatings are deposited on mild steel by using an electroless plating process.The effect of three calix[4]arene derivatives,namely tetra methyl ester-P-tertbutyl calix[4]arene(Calix1),tetra acid-P-tert-butyl calix[4]arene(Calix2)and tetra methyl P-tert-butyl-thicalix[4]arene ester(Calix3)on the deposition rate,the deposit composition,and the morphological surface was investigated and the study of growth mechanisms has delivered useful information about the surface properties of deposit.It is found that these additives modify the deposition rate and the nickel crystallization process.In fact,the Calix1 and Calix3 act as an accelerator,while Calix2 acts as an inhibitor for the nickel electroless.Furthermore,it is shown that the chemical bath is more stable with calix[4]arene derivatives addition and the obtained deposits are compact and adherent.It is observed also that the nickel content increases with additives.On the other hand,the X-ray diffraction showed that the orientation peaks are intensified at{111}in the presence of Calix2,confirming obtained results of EDAX spectrum.The cyclic voltammetry revealed that the tested additives strongly influence the cathodic process and slightly affect the hypophosphite oxidation.Finally,it is found that these compounds improve the anticorrosion efficiency of Ni-P coating on the mild steel substrate in 3%(mass)NaCl,where its polarization resistance increases with Calix2 and Calix3 addition.展开更多
The aim of this paper is to predict in details the distributed nocturnal climate inside a one hectare Moroccan canary type tomato-greenhouse equipped with continuous roof and sidewalls ventilation openings with fine i...The aim of this paper is to predict in details the distributed nocturnal climate inside a one hectare Moroccan canary type tomato-greenhouse equipped with continuous roof and sidewalls ventilation openings with fine insect screens, by means of 3D CFD (Computational Fluid Dynamics) simulations by using a commercial Software package CFD2000 based on the finite volumes method to solve the mass, momentum and energy conservation equations. The turbulent transfers were described by a k-ε model. Likewise, the dynamic influences of insect screens and tomato crop on airflow movement were modeled by means of the concept of porous medium with the Boussinesq assumption. Atmospheric radiations contribution was included in the model by customising the plastic roof cover temperature deducted from its energy balance. Also, the CFD code was customized in order to simulate in each element of the crop cover the sensible and latent heat exchanges between the greenhouse air and tomato crop. Simulations were carried out with a wind prevailing direction perpendicular to the roof openings (west-east direction). Simulations were later validated with respect to temperature and specific humidity field measurements inside the experimental greenhouse. Also, the model was verified respect to global sensible and latent heat transfers. Results show that, generally, greenhouse nocturnal climate distribution is homogeneous along the studies greenhouse area. The insect proof significantly reduced inside airflow wind speed. But there is no significant effect on the inside air temperature and specific humidity respect to outside.展开更多
Due to the rapid propagation characteristic of the Coronavirus(COVID-19)disease,manual diagnostic methods cannot handle the large number of infected individuals to prevent the spread of infection.Despite,new automated...Due to the rapid propagation characteristic of the Coronavirus(COVID-19)disease,manual diagnostic methods cannot handle the large number of infected individuals to prevent the spread of infection.Despite,new automated diagnostic methods have been brought on board,particularly methods based on artificial intelligence using different medical data such as X-ray imaging.Thoracic imaging,for example,produces several image types that can be processed and analyzed by machine and deep learning methods.X-ray imaging materials widely exist in most hospitals and health institutes since they are affordable compared to other imaging machines.Through this paper,we propose a novel Convolutional Neural Network(CNN)model(COV2Net)that can detect COVID-19 virus by analyzing the X-ray images of suspected patients.This model is trained on a dataset containing thousands of X-ray images collected from different sources.The model was tested and evaluated on an independent dataset.In order to approve the performance of the proposed model,three CNN models namely Mobile-Net,Residential Energy Services Network(Res-Net),and Visual Geometry Group 16(VGG-16)have been implemented using transfer learning technique.This experiment consists of a multi-label classification task based on X-ray images for normal patients,patients infected by COVID-19 virus and other patients infected with pneumonia.This proposed model is empowered with Gradient-weighted Class Activation Mapping(Grad-CAM)and Grad-Cam++techniques for a visual explanation and methodology debugging goal.The finding results show that the proposed model COV2Net outperforms the state-of-the-art methods.展开更多
In this paper, we propose an age-structured viral infection model with general incidence function that takes account of the loss of viral particles due to their absorption into susceptible cells. The proposed model is...In this paper, we propose an age-structured viral infection model with general incidence function that takes account of the loss of viral particles due to their absorption into susceptible cells. The proposed model is described by partial differential and ordinary differential equations. We first show that the model is mathematically and biologically well-posed. Furthermore, the uniform persistence and the global behavior of the model are investigated. Moreover, the age-structured models and results presented in many previous studies are improved and generalized.展开更多
This paper presents an annual performance evaluation of three maximum power point tracking (MPPT) methods. The used MPPT techniques (Perturb and Observe, Incremental Inductance and Sliding mode) are evaluated under an...This paper presents an annual performance evaluation of three maximum power point tracking (MPPT) methods. The used MPPT techniques (Perturb and Observe, Incremental Inductance and Sliding mode) are evaluated under an annual data of atmospheric conditions of the target site. The main contribution of this work is to consider real fluctuation conditions of solar irradiations, ambient temperatures and wind velocities. It was found that the Sliding mode provides higher energy yields independently of the period. Compared to the basic P&O and the IC techniques, sliding mode has the potential of generating up to 8.18% more electrical energy than other techniques.展开更多
This paper studies the dynamical behavior of an HIV-1 infection model with satu- rated virus-target and infected-target incidences with Cytotoxic T Lymphocyte （CTL） immune response. The model is incorporated by two ...This paper studies the dynamical behavior of an HIV-1 infection model with satu- rated virus-target and infected-target incidences with Cytotoxic T Lymphocyte （CTL） immune response. The model is incorporated by two types of intracellular distributed time delays. The model generalizes all the existing HIV-1 infection models with cell-to- cell transmission presented in the literature by considering saturated incidence rate and the effect of CTL immune response. The existence and global stability of all steady states of the model are determined by two parameters, the basic reproduction number （R0） and the CTL immune response activation number （R1）. By using suitable Lyapunov functionals, we show that if R0≤1, then the infection-free steady state So is globally asymptotically stable; if R1≤1〈R0, then the CTL-inactivated infection steady state S1 is globally asymptotically stable; if R1〉1, then the CTL-activated infection steady state S2 is globally asymptotically stable. Using MATLAB we conduct some numerical simulations to confirm our results. The effect of the saturated incidence of the HIV-1 dynamics is shown.展开更多
We are interested in studying when the class of local modules is Baer- Kaplansky. We provide an example showing that even over a commutative semisimple ring R, we can find two non-isomorphic simple R-modules S1 and S2...We are interested in studying when the class of local modules is Baer- Kaplansky. We provide an example showing that even over a commutative semisimple ring R, we can find two non-isomorphic simple R-modules S1 and S2 such that the rings EndR（S1） and EndR（S2） are isomorphic. We show that over any ring R, the class of semisimple R-modules is Baer Kaplansky if and only if so is the class of simple R-modules.展开更多
A general nonlinear mathematical model for the viral infection with humoral immunity and two distributed delays is proposed and analyzed. Two bifurcation parameters, the basic reproduction number, R0 and the humoral i...A general nonlinear mathematical model for the viral infection with humoral immunity and two distributed delays is proposed and analyzed. Two bifurcation parameters, the basic reproduction number, R0 and the humoral immunity number, R1 are derived. We established a set of conditions on the general functions which are sufficient to determine the global dynamics of the model. Utilizing Lyapunov functions and LaSalle＇s invariance principle, the global asymptotic stability of all equilibria of the model is obtained. An example is presented and some numerical simulations are conducted in order to illustrate the dynamical behavior.展开更多
A module satisfying the descending chain condition on cyclic submodules is called coperfect.The class of coperfect modules lies properly bet ween the class of locally artinian modules and the class of semiartinian mod...A module satisfying the descending chain condition on cyclic submodules is called coperfect.The class of coperfect modules lies properly bet ween the class of locally artinian modules and the class of semiartinian modules.Let R be a commutative ring with identity.We show that every semiartinian Ti-module is coperfect if and only if R is a T-ring.It is also shown that the class of coperfect R-modules coincides with the class of locally artinian R-modules if and only if m/m^(2)is a finitely genera ted R-module for every maximal ideal m of R.展开更多
Let R be a ring and n be a positive integer.Then R is called a left n-C2-ring(strongly left C2-ring)if every n-generated(finitely generated)proper right ideal of R has nonzero left annihilator.We discuss some n-C2 and...Let R be a ring and n be a positive integer.Then R is called a left n-C2-ring(strongly left C2-ring)if every n-generated(finitely generated)proper right ideal of R has nonzero left annihilator.We discuss some n-C2 and strongly C2 extensions,such as trivial extensions,formal triangular matrix rings,group rings and[D,C].展开更多
Nowadays,coronavirus disease 2019(COVID-19)poses a major threat to humanity which is caused by a novel coronavirus in Wuhan,China,at the end of December 2019.This novel coronavirus named the severe acute respiratory s...Nowadays,coronavirus disease 2019(COVID-19)poses a major threat to humanity which is caused by a novel coronavirus in Wuhan,China,at the end of December 2019.This novel coronavirus named the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)according to the International Committee on Taxonomy of Viruses(ICTV).It spreads directly through close contact with an asymptomatic(carrier)or symptomatic person who is coughing,sneezing,talking,singing and kissing.It also spreads indirectly through contact with an environment contaminated by viral particles of SARS-COV-2.In the absence of effective treatment against COVID-19,awareness can play an important role in reducing cases of COVID-19.In this study,we develop a mathematical model to better describe the dynamics of COVID-19 by taking into account the above modes of transmission and the prosocial awareness.The existence,uniqueness,positivity and boundedness of solutions of the model are discussed.All possible equilibrium points are determined.The local asymptotic stability of these equilibrium points is studied.Suitable Lyapunov functionals are constructed to investigate the global dynamics of the model.展开更多
文摘The fact that Morocco is an agricultural country and the large volume of biodegradable waste produced by the population make composting so important.The degradation of organic matter is facilitated by faunal and floral macro and micro-organisms that act in different stages of maturation;studies on this fauna are quite rare both nationally and internationally.On a sample of two tons of household waste,we documented invertebrates that colonized compost heaps and then assessed the changes in the structure of the invertebrate population during the different phases.Our study revealed the presence of several zoological groups colonizing the compost heaps during the different composting phases;we noted the presence of:(1)Macroscopic invertebrates,in order of number of individuals:insect larvae,ants,earthworms,sowbugs,spiders,springtails,and millipedes,and(2)Microscopic invertebrates,the most abundant in terms of individuals:mites and nematodes.As for the order of appearance,we observed that insect larvae were the first to colonize the compost heap from the very first days of installation,followed by woodlice observed during the thermophilic phase and disappearing towards the end of the process.Earthworms were observed during the end of the thermophilic phase,while springtails were observed more during the cooling and maturation phases.Our study revealed the presence of a good quality of fauna during the composting process,which are indicators of good compost quality and play a major role in the circulation of nutrients,thus ensuring the provision of essential elements for plant nutrition.
文摘The aim of this work is to study and quantify the air mass flow exchanged between inside and outside of the greenhouse, in order to determine the ventilation openings layout and the design effect on greenhouse airflow and microclimate distribution. The study was conducted over a 945 m2 multi-chapels arched greenhouse with a polyethylene cover and has thirteen crop rows oriented from north to south;the greenhouse was equipped with side wall and roof vents openings. A simulation was performed using different arrangements and configurations of ventilation openings with the same wind direction. Numerical simulation has been adopted in three dimensions (CFD), using the Fluent computer code which relies on the resolution of the Navier-Stokes equations. These equations were solved in the presence of the turbulence model (k - ε) and the Boussinesq model equation adopted to incorporate buoyancy forces. The effects of solar and atmospheric radiation were included by solving the radiative transfer equation (RTE), using Discrete Ordinate (DO) model. The effects of the roof openings, the presence of anti-insect screens and crops orientation were investigated and quantified. In a 3-span greenhouse with an anti-aphid in-sect screen in the vent openings, combining roof and sidewall vents gave a ventilation rate per unit opening area that was 1.4 times more than with only side vents. In the latter case, the difference of temperature between the inside and the outside of the greenhouse was greater than 3°C. Numerical simulations with an anti-insect screen having a porosity of 56% showed that the air exchange rate with combined ventilation was reduced by 48%. Finally, the paper focused on the effect of vent arrangement on the efficiency of the ventilation and the distribution of the microclimate inside the greenhouse. Results showed that computed ventilation rates varied from 53.43 to 70.95 kg/s, whereas temperature differences varied from 7.15°C to 10.14°C. This study also showed that other characteristics such as climate heterogeneity must be investigated in order to define the best ventilation configuration.
文摘DNA is the carrier of all cellular genetic information and increasingly used in nanotechnology. The study of DNA molecule achieved <em>in vitro</em> while submitting the DNA to all chemicals agent capabilities to destabilize links hydrogen, such as pH, temperature. In fact, the DNA enveloped in the membrane cellular, so it is legitimate to study the influence of membrane undulations. In this work, we try to show that the fluctuations of the membrane can be considerate as a physics agent is also capable to destabilize links hydrogen. In this investigation, we assume that each pair base formed an angle <em>a</em><sub><em>n</em></sub> with the membrane’s surface. We have proposed a theoretical model, and we have established a relationship between the angle formed by the pair base <span style="white-space:nowrap;"><em><span style="white-space:nowrap;">θ</span></em><sub><em>eq</em></sub><em> </em></span> and <em>a</em><sub><em>n</em></sub> angle formed by the membrane and each pair base. We assume that DNA and biomembrane interact via a realistic potential of Morse type. To this end, use is made of a generalized model that extends that introduced by M. Peyrard and A. R. Bishop in the past modified by M. Zoli. This generalized model is based on the resolution of a Schr<span style="white-space:nowrap;">ö</span>dinger-like equation. The exact resolution gives the expression of the ground state, and the associated eigenvalue (energy) that equals the free energy, in the thermodynamic limit. First, we compute the denaturation temperature of DNA strands critical temperature. Second, we deduce all critical properties that mainly depend on the parameters of the model, and we quantify the effects of the membrane undulations. These undulations renormalize all physical quantities, such as harmonic stacking, melting temperature, eigenfunctions, eigenvalues and regular part of specific heat.
文摘The recent increase in the use of artificial intelligence has led to fundamental changes in the development of training and teaching methods for executive education. However, the success of artificial intelligence in regional centers for teaching and training professions will depend on the acceptance of this technology by young executive trainees. This article discusses the potential benefits of adopting AI in executive training institutions in Morocco, specifically focusing on CRMEF Casablanca Settat. Based on the Unified Theory of Acceptance and Use of Technology (UTAUT) (Venkatesh et al., 2003), this study proposes a model to identify the factors influencing the acceptance of artificial intelligence in regional centers for teaching professions and training in Morocco. To achieve this, a structural equation modeling approach was used to quantitatively describe the impact of each factor on AI adoption, utilizing data collected from 173 young executive trainees. The results indicate that perceived ease of use, perceived usefulness, trainer influence, and personal innovativeness influence the intention to use artificial intelligence. Our research provides managers of CRMEFs with a set of practical recommendations to enhance the implementation conditions of an artificial intelligence system. It aims to understand which factors should be considered in designing an artificial intelligence system within regional centers for teaching professions and training (CRMEFs).
文摘Magnetic hysteresis and compensation behavior of a mixed spin-（1, 3/2） Ising model on a square lattice are investigated in the framework of effective field theory based on a probability distribution technique. The effect of random crystal field, ferromagnetic and ferrimagnetic exchange interaction on hysteresis loops and compensation phenomenon are discussed. A number of characteristic phenomena have been reported such as the observation of triple hysteresis loops at low temperatures and for negative values of random crystal field. Critical and double compensation temperatures have been also found. The obtained results are also compared to some previous works.
文摘Mapping floods is crucial for effective disaster management. This study focuses on flood assessment in northern Morocco, specifically Tangier, Tetouan, and Larache. Due to the lack of a comprehensive flood inventory map, we used unsupervised learning techniques, such as K-means clustering and fuzzy logic algorithms, to predict flood-prone areas. We identified nine conditioning factors influencing flood risk: elevation, slope, aspect, plan curvature, profile curvature, land use, soil type, normalized difference vegetation index(NDVI), and topographic position index(TPI). Using Landsat-8 imagery and a Digital Elevation Model(DEM) within a Geographic Information System(GIS), we analyzed topographic and geo-environmental variables. K-means clustering achieved silhouette scores of 0.66 in Tangier and 0.70 in Tetouan, while the fuzzy logic method in Larache produced a Davies-Bouldin Index(DBI) score of 0.35. The maps classified flood risk levels into low, moderate, and high categories. This research demonstrates the integration of machine learning and remote sensing for predicting flood-prone areas without existing flood inventory maps. Our findings highlight the main factors contributing to flash floods and assess their impact, enhancing the understanding of flood dynamics and improving flood management strategies in vulnerable regions.
文摘In this work, we study the stability of a class of materials obtained by printing a textile with conductive inks using a method called screen printing. Under the action of a certain external factors, the printed circuit suffers deterioration and the conductivity decreases considerably. In this work, we propose to model the overall damage of the textile sheet in terms of the partial damages of the conductive lines. We also apply this approach to evaluate the damage of a system being made of transmission lines printed into nonwoven substrates using different conductive inks.
文摘We study the mixed spin-1 and spin-3/2 Blume-Capel model under crystal field in the tridimensional semi-infinite case. This has been done by using the real-space renormalization group approximation and specifically the Migdal-Kadanoff technique. As a function of the ratio R of bulk and surface interactions and the ratios R<sub>1</sub> and R<sub>2 </sub>of bulk and surface crystals fields on the spin-1 and spin-3/2 respectively, we have determined various types of phase diagrams. Besides second- order transition lines, first-order phase transition lines terminating at tricritical points are obtained. We found that there existed nine main types of phase diagram showing a variety of phase transitions associated with the surface, including ordinary, extraordinary, surface and special phase transitions.
文摘Nichel-phosphorus(Ni-P)coatings are deposited on mild steel by using an electroless plating process.The effect of three calix[4]arene derivatives,namely tetra methyl ester-P-tertbutyl calix[4]arene(Calix1),tetra acid-P-tert-butyl calix[4]arene(Calix2)and tetra methyl P-tert-butyl-thicalix[4]arene ester(Calix3)on the deposition rate,the deposit composition,and the morphological surface was investigated and the study of growth mechanisms has delivered useful information about the surface properties of deposit.It is found that these additives modify the deposition rate and the nickel crystallization process.In fact,the Calix1 and Calix3 act as an accelerator,while Calix2 acts as an inhibitor for the nickel electroless.Furthermore,it is shown that the chemical bath is more stable with calix[4]arene derivatives addition and the obtained deposits are compact and adherent.It is observed also that the nickel content increases with additives.On the other hand,the X-ray diffraction showed that the orientation peaks are intensified at{111}in the presence of Calix2,confirming obtained results of EDAX spectrum.The cyclic voltammetry revealed that the tested additives strongly influence the cathodic process and slightly affect the hypophosphite oxidation.Finally,it is found that these compounds improve the anticorrosion efficiency of Ni-P coating on the mild steel substrate in 3%(mass)NaCl,where its polarization resistance increases with Calix2 and Calix3 addition.
文摘The aim of this paper is to predict in details the distributed nocturnal climate inside a one hectare Moroccan canary type tomato-greenhouse equipped with continuous roof and sidewalls ventilation openings with fine insect screens, by means of 3D CFD (Computational Fluid Dynamics) simulations by using a commercial Software package CFD2000 based on the finite volumes method to solve the mass, momentum and energy conservation equations. The turbulent transfers were described by a k-ε model. Likewise, the dynamic influences of insect screens and tomato crop on airflow movement were modeled by means of the concept of porous medium with the Boussinesq assumption. Atmospheric radiations contribution was included in the model by customising the plastic roof cover temperature deducted from its energy balance. Also, the CFD code was customized in order to simulate in each element of the crop cover the sensible and latent heat exchanges between the greenhouse air and tomato crop. Simulations were carried out with a wind prevailing direction perpendicular to the roof openings (west-east direction). Simulations were later validated with respect to temperature and specific humidity field measurements inside the experimental greenhouse. Also, the model was verified respect to global sensible and latent heat transfers. Results show that, generally, greenhouse nocturnal climate distribution is homogeneous along the studies greenhouse area. The insect proof significantly reduced inside airflow wind speed. But there is no significant effect on the inside air temperature and specific humidity respect to outside.
基金This research is funded by the Deanship of Scientific Research at King Khalid University through Large Groups.(Project under grant number(RGP.2/111/43)).
文摘Due to the rapid propagation characteristic of the Coronavirus(COVID-19)disease,manual diagnostic methods cannot handle the large number of infected individuals to prevent the spread of infection.Despite,new automated diagnostic methods have been brought on board,particularly methods based on artificial intelligence using different medical data such as X-ray imaging.Thoracic imaging,for example,produces several image types that can be processed and analyzed by machine and deep learning methods.X-ray imaging materials widely exist in most hospitals and health institutes since they are affordable compared to other imaging machines.Through this paper,we propose a novel Convolutional Neural Network(CNN)model(COV2Net)that can detect COVID-19 virus by analyzing the X-ray images of suspected patients.This model is trained on a dataset containing thousands of X-ray images collected from different sources.The model was tested and evaluated on an independent dataset.In order to approve the performance of the proposed model,three CNN models namely Mobile-Net,Residential Energy Services Network(Res-Net),and Visual Geometry Group 16(VGG-16)have been implemented using transfer learning technique.This experiment consists of a multi-label classification task based on X-ray images for normal patients,patients infected by COVID-19 virus and other patients infected with pneumonia.This proposed model is empowered with Gradient-weighted Class Activation Mapping(Grad-CAM)and Grad-Cam++techniques for a visual explanation and methodology debugging goal.The finding results show that the proposed model COV2Net outperforms the state-of-the-art methods.
基金We are very grateful and thank the handling editor and the referees for their helpful comments which led to important improvements in our original paper. Research of the author Yu Yang was supported by National Natural Science Foundation of China （No. 11501519）.
文摘In this paper, we propose an age-structured viral infection model with general incidence function that takes account of the loss of viral particles due to their absorption into susceptible cells. The proposed model is described by partial differential and ordinary differential equations. We first show that the model is mathematically and biologically well-posed. Furthermore, the uniform persistence and the global behavior of the model are investigated. Moreover, the age-structured models and results presented in many previous studies are improved and generalized.
文摘This paper presents an annual performance evaluation of three maximum power point tracking (MPPT) methods. The used MPPT techniques (Perturb and Observe, Incremental Inductance and Sliding mode) are evaluated under an annual data of atmospheric conditions of the target site. The main contribution of this work is to consider real fluctuation conditions of solar irradiations, ambient temperatures and wind velocities. It was found that the Sliding mode provides higher energy yields independently of the period. Compared to the basic P&O and the IC techniques, sliding mode has the potential of generating up to 8.18% more electrical energy than other techniques.
文摘This paper studies the dynamical behavior of an HIV-1 infection model with satu- rated virus-target and infected-target incidences with Cytotoxic T Lymphocyte （CTL） immune response. The model is incorporated by two types of intracellular distributed time delays. The model generalizes all the existing HIV-1 infection models with cell-to- cell transmission presented in the literature by considering saturated incidence rate and the effect of CTL immune response. The existence and global stability of all steady states of the model are determined by two parameters, the basic reproduction number （R0） and the CTL immune response activation number （R1）. By using suitable Lyapunov functionals, we show that if R0≤1, then the infection-free steady state So is globally asymptotically stable; if R1≤1〈R0, then the CTL-inactivated infection steady state S1 is globally asymptotically stable; if R1〉1, then the CTL-activated infection steady state S2 is globally asymptotically stable. Using MATLAB we conduct some numerical simulations to confirm our results. The effect of the saturated incidence of the HIV-1 dynamics is shown.
文摘We are interested in studying when the class of local modules is Baer- Kaplansky. We provide an example showing that even over a commutative semisimple ring R, we can find two non-isomorphic simple R-modules S1 and S2 such that the rings EndR（S1） and EndR（S2） are isomorphic. We show that over any ring R, the class of semisimple R-modules is Baer Kaplansky if and only if so is the class of simple R-modules.
文摘A general nonlinear mathematical model for the viral infection with humoral immunity and two distributed delays is proposed and analyzed. Two bifurcation parameters, the basic reproduction number, R0 and the humoral immunity number, R1 are derived. We established a set of conditions on the general functions which are sufficient to determine the global dynamics of the model. Utilizing Lyapunov functions and LaSalle＇s invariance principle, the global asymptotic stability of all equilibria of the model is obtained. An example is presented and some numerical simulations are conducted in order to illustrate the dynamical behavior.
文摘A module satisfying the descending chain condition on cyclic submodules is called coperfect.The class of coperfect modules lies properly bet ween the class of locally artinian modules and the class of semiartinian modules.Let R be a commutative ring with identity.We show that every semiartinian Ti-module is coperfect if and only if R is a T-ring.It is also shown that the class of coperfect R-modules coincides with the class of locally artinian R-modules if and only if m/m^(2)is a finitely genera ted R-module for every maximal ideal m of R.
文摘Let R be a ring and n be a positive integer.Then R is called a left n-C2-ring(strongly left C2-ring)if every n-generated(finitely generated)proper right ideal of R has nonzero left annihilator.We discuss some n-C2 and strongly C2 extensions,such as trivial extensions,formal triangular matrix rings,group rings and[D,C].
文摘Nowadays,coronavirus disease 2019(COVID-19)poses a major threat to humanity which is caused by a novel coronavirus in Wuhan,China,at the end of December 2019.This novel coronavirus named the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)according to the International Committee on Taxonomy of Viruses(ICTV).It spreads directly through close contact with an asymptomatic(carrier)or symptomatic person who is coughing,sneezing,talking,singing and kissing.It also spreads indirectly through contact with an environment contaminated by viral particles of SARS-COV-2.In the absence of effective treatment against COVID-19,awareness can play an important role in reducing cases of COVID-19.In this study,we develop a mathematical model to better describe the dynamics of COVID-19 by taking into account the above modes of transmission and the prosocial awareness.The existence,uniqueness,positivity and boundedness of solutions of the model are discussed.All possible equilibrium points are determined.The local asymptotic stability of these equilibrium points is studied.Suitable Lyapunov functionals are constructed to investigate the global dynamics of the model.
