This work presents an advanced and detailed analysis of the mechanisms of hepatitis B virus(HBV)propagation in an environment characterized by variability and stochas-ticity.Based on some biological features of the vi...This work presents an advanced and detailed analysis of the mechanisms of hepatitis B virus(HBV)propagation in an environment characterized by variability and stochas-ticity.Based on some biological features of the virus and the assumptions,the corresponding deterministic model is formulated,which takes into consideration the effect of vaccination.This deterministic model is extended to a stochastic framework by considering a new form of disturbance which makes it possible to simulate strong and significant fluctuations.The long-term behaviors of the virus are predicted by using stochastic differential equations with second-order multiplicative α-stable jumps.By developing the assumptions and employing the novel theoretical tools,the threshold parameter responsible for ergodicity(persistence)and extinction is provided.The theoretical results of the current study are validated by numerical simulations and parameters estimation is also performed.Moreover,we obtain the following new interesting findings:(a)in each class,the average time depends on the value ofα;(b)the second-order noise has an inverse effect on the spread of the virus;(c)the shapes of population densities at stationary level quickly changes at certain values of α.The last three conclusions can provide a solid research base for further investigation in the field of biological and ecological modeling.展开更多
Nowadays, devices are connected across all areas, from intelligent buildings and smart cities to Industry 4.0 andsmart healthcare. With the exponential growth of Internet of Things usage in our world, IoT security is ...Nowadays, devices are connected across all areas, from intelligent buildings and smart cities to Industry 4.0 andsmart healthcare. With the exponential growth of Internet of Things usage in our world, IoT security is still thebiggest challenge for its deployment. The main goal of IoT security is to ensure the accessibility of services providedby an IoT environment, protect privacy, and confidentiality, and guarantee the safety of IoT users, infrastructures,data, and devices. Authentication, as the first line of defense against security threats, becomes the priority ofeveryone. It can either grant or deny users access to resources according to their legitimacy. As a result, studyingand researching authentication issues within IoT is extremely important. As a result, studying and researchingauthentication issues within IoT is extremely important. This article presents a comparative study of recent researchin IoT security;it provides an analysis of recent authentication protocols from2019 to 2023 that cover several areaswithin IoT (such as smart cities, healthcare, and industry). This survey sought to provide an IoT security researchsummary, the biggest susceptibilities, and attacks, the appropriate technologies, and the most used simulators. Itillustrates that the resistance of protocols against attacks, and their computational and communication cost arelinked directly to the cryptography technique used to build it. Furthermore, it discusses the gaps in recent schemesand provides some future research directions.展开更多
Explainable Artificial Intelligence(XAI)has an advanced feature to enhance the decision-making feature and improve the rule-based technique by using more advanced Machine Learning(ML)and Deep Learning(DL)based algorit...Explainable Artificial Intelligence(XAI)has an advanced feature to enhance the decision-making feature and improve the rule-based technique by using more advanced Machine Learning(ML)and Deep Learning(DL)based algorithms.In this paper,we chose e-healthcare systems for efficient decision-making and data classification,especially in data security,data handling,diagnostics,laboratories,and decision-making.Federated Machine Learning(FML)is a new and advanced technology that helps to maintain privacy for Personal Health Records(PHR)and handle a large amount of medical data effectively.In this context,XAI,along with FML,increases efficiency and improves the security of e-healthcare systems.The experiments show efficient system performance by implementing a federated averaging algorithm on an open-source Federated Learning(FL)platform.The experimental evaluation demonstrates the accuracy rate by taking epochs size 5,batch size 16,and the number of clients 5,which shows a higher accuracy rate(19,104).We conclude the paper by discussing the existing gaps and future work in an e-healthcare system.展开更多
The systematic method for constructing Lewis representations is a method for representing chemical bonds between atoms in a molecule. It uses symbols to represent the valence electrons of the atoms involved in the bon...The systematic method for constructing Lewis representations is a method for representing chemical bonds between atoms in a molecule. It uses symbols to represent the valence electrons of the atoms involved in the bond. Using a number of rules in a defined order, it is often better suited to complicated cases than the Lewis representation of atoms. This method allows us to determine the formal charge and oxidation number of each atom in the edifice more efficiently than other methods.展开更多
Water is the most abundant liquid on the surface of the earth. It is a liquid whose properties are quite surprising, both as a pure liquid and as a solvent. Water is a very cohesive liquid: its melting and vaporizatio...Water is the most abundant liquid on the surface of the earth. It is a liquid whose properties are quite surprising, both as a pure liquid and as a solvent. Water is a very cohesive liquid: its melting and vaporization temperatures are very high for a liquid that is neither ionic nor metallic, and whose molar mass is low. Thus, water remains liquid at atmospheric pressure up to 100C while similar molecules such as H2S, H2Se, H2Te for example would give a vaporization temperature close to 80C. This cohesion is in fact ensured by hydrogen bonds between water molecules. This type of bonds between neighboring molecules, hydrogen bonds, is quite often found in chemistry [1] [2]. Any change in the state of aggregation of a substance occurs with the absorption or release of a certain amount of latent heat of transformation. Latent heat of fusion, vaporization or sublimation is the ratio of the energy supplied as heat to the mass of the substance that is melted, vaporized or sublimated. As a result of the reversibility of the processes, the fusion heat is equal to the heat released in the reverse process: crystallization and solidification heat. And likewise the heat of vaporization is equal to the heat of condensation. This equality of heat is often used to determine experimentally either of these quantities. There are two main measurement methods: 1) Direct measurement using the calorimeter, 2) Indirect measure based on the use of the VantHoff relationship. The objective of this work is to measure the latent heat of water vaporization and verify the compatibility of the experimental values with the values given by the tables using the indirect method.展开更多
Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-di...Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-dimensional structure with a high degree of anisotropy. The carbon atoms within each layer are linked together by strong covalent bonds, creating a strong, stable lattice structure. However, the layers themselves are held together by weak van der Waals forces, enabling them to slide easily over each other. The properties of carbon graphite are highly dependent on the orientation and alignment of the graphene layers. When the layers are aligned parallel to each other, the material exhibits high strength and stiffness along the alignment direction, but is weaker and more flexible in other directions. Carbon graphite is used in a variety of applications where high strength, rigidity and electrical conductivity are required. Some common applications include electrical contacts, electric motor brushes, and as a structural material in aerospace and defense applications. The aim of our work is to describe the structure of graphite, its physical and chemical properties and its applications.展开更多
This paper presents an extension of certain forms of the real Paley-Wiener theorems to the Minkowski space-time algebra. Our emphasis is dedicated to determining the space-time valued functions whose space-time Fourie...This paper presents an extension of certain forms of the real Paley-Wiener theorems to the Minkowski space-time algebra. Our emphasis is dedicated to determining the space-time valued functions whose space-time Fourier transforms(SFT) have compact support using the partial derivatives operator and the Dirac operator of higher order.展开更多
We have been pleased that our paper Geological mapping and mining prospecting in the Aouli inlier(Eastern Meseta,Morocco) based on remote sensing and geographic information systems(GIS) was of interest to our colleagu...We have been pleased that our paper Geological mapping and mining prospecting in the Aouli inlier(Eastern Meseta,Morocco) based on remote sensing and geographic information systems(GIS) was of interest to our colleagues who commented it in China Geology 5(2022) 1–4.展开更多
Mapping from remote sensing has become more effective in the field of geology, mainly in lithological discrimination and identification of hydrothermal alteration zones. The use of this technique consists in obtaining...Mapping from remote sensing has become more effective in the field of geology, mainly in lithological discrimination and identification of hydrothermal alteration zones. The use of this technique consists in obtaining information about the rock mass and the main ones existing in the inaccessible areas. Satellite data from the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor represent a favorable potential for detecting the spectral signatures of mineral zones and identifying their nature. These data are more reliable in places where the climate is arid with less abundant vegetation, as at the Oumjrane-Boukerzia mining district. This region which is part of the Eastern Anti-Atlas, is composed of several mineralized veins which still require detailed studies and exploration by the technique of remote sensing. In this work we applied several processing techniques on ASTER imagery such as Colored Composition, Principal Component Analysis and Ratio Bands. The use of the reports of the specialized Bands makes it possible to identify some hydrothermal alteration minerals within the mining district of Oumjrane Boukerzia. These minerals are represented mainly by iron oxides and hydroxides (Hematite, jarosite, limonite and goethite), carbonate minerals (dolomite, calcite), clay minerals (Illite, kaolinite and chlorite) and quartz minerals. This work allows us to produce a map of hydrothermal alteration zones which can be used as a valuable reference in the strategy of mining exploration for the base metals (Cu, Pb, Zn and Ba), in the mining district of Oumjrane-Boukerzia and in the entire Eastern Anti-Atlas.展开更多
Cosmetic companies are trying to include more sustainability in their strategies. But, showing commitment is always a challenge for them. This work consists in showing the degree of commitment of cosmetic companies in...Cosmetic companies are trying to include more sustainability in their strategies. But, showing commitment is always a challenge for them. This work consists in showing the degree of commitment of cosmetic companies in their marketing practices. The qualitative study carried out aims to determine the level of their commitment in terms of sustainability, based on 10 websites of “sustainable” cosmetics companies that sell their products online, and on defining sustainability criteria for each variable of the marketing mix. The results indicate that the majority of the companies analyzed are aware of the importance of sustainability and have taken measures to have a positive impact on the economy, society and the environment. The companies have made considerable efforts in “product” and “communication” strategies, but additional improvements can be envisaged for “price” and “distribution” strategies.展开更多
Landsat 8 Oli,ASTER,and Sentinel 2A satellite images processing was used to map geological formations,lineaments and hydrothermal alteration minerals in the Aouli inlier,as a case study to illustrate the application o...Landsat 8 Oli,ASTER,and Sentinel 2A satellite images processing was used to map geological formations,lineaments and hydrothermal alteration minerals in the Aouli inlier,as a case study to illustrate the application of digital images processing and Geographic Information System(GIS)in geological mapping and mining prospecting.Principal Component Analysis(PCA)applied to the Landsat images allowed good lithological discrimination and contributed to the updating of available geological maps.The Automatic lineament extraction from Sentinel images revealed the main tectonic structures affecting Aouli inlier.The ratio bands(b5+b7)/b6 and the false color composite(b4/b6,b2/b1,b3/b2)allowed the hydrothermal alteration minerals mapping from Aster images.Combined with available geological data and field observations,the satellite derived data were integrated and analyzed in a GIS software to establish mining prospecting guides.The results showed that the anomaly zones are intimately linked to NNE-SSW and NW-SE oriented faults and to highly fractured areas developing argillic and Fe rich alterations.Verified via field survey,this approach was successfully applied to the Aouli inlier to rapidly target potential areas to be explored in the tactical phase.This provides a model for future prospecting efforts for similar mineral deposits in other areas.展开更多
In the context of industrial competitiveness, taking into account the process design throughout the product life cycle is inevitable, from the expression of the need to recycle, the capitalization and knowledge manage...In the context of industrial competitiveness, taking into account the process design throughout the product life cycle is inevitable, from the expression of the need to recycle, the capitalization and knowledge management increasingly a target much sought after companies because of increased knowledge. Indeed, during the approval phase and use studies and scientific researches make have generated knowledge especially that concerning the reliability of system components. In this context, the capitalization and reuse of knowledge are necessary and have a particular interest in design and particularly in the preliminary design phase. Studies are already completed suggest a design process ranging from the need to solve the problem. At each phase of the process, structural characteristics are defined by the designer through the available knowledge already capitalized to make choice of component and their arrangement. This article proposes integrating the analysis of system reliability in this process. The objective is the use of knowledge in the vision safety and hazards of operating through the study of reliability and decision making for the selection of solution.展开更多
The decrease of wind velocity (wake losses) in downstream area of wind turbine is generally quantified using wake models. The overall estimated power of wind farm varies according to reliability of wake model used, ...The decrease of wind velocity (wake losses) in downstream area of wind turbine is generally quantified using wake models. The overall estimated power of wind farm varies according to reliability of wake model used, however it's unclear which model is most appropriate and able to give a high performance in predicting wind velocity deficit. In this subject, a qualification of three analytical wake models (Jensen, lshihara and Frandsen) based on three principal criteria is presented in this paper: (i) the parsimony which characterizes the inverse of model complexity, (ii) the accuracy of estimation in which wake model is compared with the experimental data and (iii) imprecision that is related to assumptions and uncertainty on the value of variables considered in each model. This qualitative analysis shows the inability of wake models to predict wind velocity deficit due to the big uncertainty of variables considered and it sensitivity to wind farm characteristic.展开更多
Identification of water potential areas in arid regions is a crucial element for the enhancement of their water resources and socio-economic development. In fact, water resources system-planning can be used to make va...Identification of water potential areas in arid regions is a crucial element for the enhancement of their water resources and socio-economic development. In fact, water resources system-planning can be used to make various decisions and implement manage- ment of water resources policies. The purpose of this study is to identify groundwater sto- rage areas in the high Guir Basin by implementing Geographic Information System (GIS) and Remote Sensing methods. The required data for this study can be summarized into five critical factors: Topography (slope), lithology, rainfall, rock fracture and drainage. These critical factors have been converted by the GIS into thematic maps. For each cri- tical parameter, a coefficient with weight was attributed according to its importance. The map of potential groundwater storage areas is obtained by adding the products (coeffi- cient × weight) of the five parameters. The results show that 50% to 64% of the total area of the High Guir Basin is potentially rich in groundwater, where most of fracture systems are intensely developed. The obtained results are validated with specific yield of the aqui- fer in the study area. It is noted that there is a strong positive correlation between excel- lent groundwater potential zones with high flows of water points and it diminishes with low specific yield with poor potential zones.展开更多
This article presents research and development of an interoperable platform to facilitate, monitor and coordinate groundwater data sharing. This system was orchestrated by a number of services described by Open Geospa...This article presents research and development of an interoperable platform to facilitate, monitor and coordinate groundwater data sharing. This system was orchestrated by a number of services described by Open Geospatial Consortium (OGC) such as Sensor Observation Service (SOS) and other services for the use of mapping data, Web Feature Services (WFS), Web Map Service (WMS), and catalogue services (CSW). An important activity for our project was the establishment of a portal for geographic data and services. Geoportal developed for this project will promote and facilitate access to groundwater data and share theme more openly. Otherwise our system has been designed to provide a powerful tool that enhances the ability of regional staff to monitor near real-time groundwater data (i.e.?piezometric level) and as a result will help provide a more effective response to environmental upsets.展开更多
<span style="font-family:Verdana;">In this article, the effect of temperature on the photovoltaic parameters of mono-crystalline silicon Photovoltaic Panel is undertaken, using the Matlab environment w...<span style="font-family:Verdana;">In this article, the effect of temperature on the photovoltaic parameters of mono-crystalline silicon Photovoltaic Panel is undertaken, using the Matlab environment with varying module temperature in the range 25°C - 60°C at constant solar irradiations 200 - 500 W/m</span><sup><span style="font-family:Verdana;">2</span><span></span></sup><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> The results show that the temperature has a significant impact on the various parameters of the photovoltaic panel and it controls the quality and performance of the solar panel</span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> The photovoltaic</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span><span style="font-family:Verdana;">parameters are the current of short circuit </span><i></i></span><i><i><span><span style="font-family:Verdana;">I</span><sub><span style="font-family:Verdana;">sc</span></sub></span></i><span></span></i><span style="font-family:Verdana;">, the open circuit voltage </span><i></i></span><i><i><span><span style="font-family:Verdana;">V</span><sub><span style="font-family:Verdana;">co</span></sub></span></i><span></span></i><span style="font-family:Verdana;">, the form factor FF, the maximum power </span><i><i><span><span style="font-family:Verdana;">P</span><sub></sub></span></i><i><span style="font-family:Verdana;"><sub>max</sub></span></i><i><span></span></i><span></span></i><span style="font-family:Verdana;"> as well as efficiency. The relative change of these photovoltaic parameters with temperature is also evaluated in this article. A DS-100M solar panel has been used as reference model. The results show also that the open circuit voltage, maximum power, fill factor and efficiency decrease with temperature</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> but the short circuit current increase</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> with temperature</span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> Th</span><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;"> results are in good agreement with the available literature.</span>展开更多
With their advantages, continuously variable transmissions have gained more popularity in the last decade by their use in mechanical transmission systems. The present paper aims to analysis the efficiency of the trans...With their advantages, continuously variable transmissions have gained more popularity in the last decade by their use in mechanical transmission systems. The present paper aims to analysis the efficiency of the transmission based on the mechanical efficiency of the planetary gear train integrated in such transmission. In this analysis, we consider the mechanical efficiency of the transmission has been determined considering how the efficiency of the CVT members changes as a function of the operating conditions. The efficiency of the planetary gear train as a function of the configuration, speeds in his three input/output shafts, and also with respect to the power flow type. Results are compared with those obtained from other methods performance evaluation of the transmission, available in the literature.展开更多
In our medical practice, in particular obstetrics, it is difficult to change certain consolidated dogmas, but the necessity and the current situation of our obstetrical exercise pushed us to find new technical support...In our medical practice, in particular obstetrics, it is difficult to change certain consolidated dogmas, but the necessity and the current situation of our obstetrical exercise pushed us to find new technical supports, to make the exercise of our specialty as stripped of pitfalls as possible. Our work is summarized in a prospective comparative study, aimed at evaluating the existence or not of a difference between the administration of oxytocin just before the hysterotomy in a cesarean section and its administration after fetal extraction. We used a set of criteria to include patients in our study. This study took place over a period of one year (2020) in the Mother and Child regional center, in Meknes Imperial city, Morocco, involving a total number of 364 patients. With a group A comprising 176 patients 48% (176/364) who received oxytocin just before the hysterotomy and a group B of 188 patients 52% (188/364) who received it classically after fetal extraction. The difference was very significant as detailed in the article. Conclusion: the very convincing results of our study and the difference between the two groups, allowed us to demonstrate the effectiveness of our process and to endorse its use in our routine practice, with the perspective of conducting a prospective randomized study on a larger series.展开更多
Assessment of genetic diversity of Moroccan cultivated almond (Prunus dulcis Mill.) grown from seed and cultivated at four eco-geographical regions was performed using 16 nuclear SSRs. 238 alleles were detected with a...Assessment of genetic diversity of Moroccan cultivated almond (Prunus dulcis Mill.) grown from seed and cultivated at four eco-geographical regions was performed using 16 nuclear SSRs. 238 alleles were detected with an average of 14.88 alleles per locus, ranging from 4 (locus BPPCT027) to 24 (locus CPSCT018). The size of alleles ranged from 84 bp (locus UDP96-003) to 253 bp (locus UDP96-018). A high genetic diversity of the local almonds is apparent and structured into three major clusters (Oasis cluster, High and Anti Atlas cluster, and Middle Atlas cluster). Compared to the Mediterranean genetic pools, from the East to West, the genetic diversity tends to be limited in Morocco which is the area of its extreme diffusion.展开更多
Operating in natural wind field, the horizontal axis wind turbines are subject to cyclical variation of aerodynamic loads. This cyclical loads fluctuation is a result of two aerodynamic phenomenon: the first one is th...Operating in natural wind field, the horizontal axis wind turbines are subject to cyclical variation of aerodynamic loads. This cyclical loads fluctuation is a result of two aerodynamic phenomenon: the first one is the advancing and retreating blade effect;the second one is related to the cyclical variation of induced velocity at the rotor plane. In these operating conditions, the correct prediction of this load variation is necessary to predict some important parameters linked to the fatigue and stability of free yawing turbines. The main objective of the present study is the evaluation of the azimuthal variation of normal force at different radial positions. To model the problem, the blade element momentum theory is used and wind turbine is supposed operate in yaw conditions. The aerodynamic coefficients are corrected using Chaviaropoulos and Hansen model to take into account the phenomenon of stall delay. A computer code was developed to obtain the numerical values and results are compared with measurements performed in the NASA Ames wind tunnel.展开更多
基金supported by the NSFC(12201557)the Foundation of Zhejiang Provincial Education Department,China(Y202249921).
文摘This work presents an advanced and detailed analysis of the mechanisms of hepatitis B virus(HBV)propagation in an environment characterized by variability and stochas-ticity.Based on some biological features of the virus and the assumptions,the corresponding deterministic model is formulated,which takes into consideration the effect of vaccination.This deterministic model is extended to a stochastic framework by considering a new form of disturbance which makes it possible to simulate strong and significant fluctuations.The long-term behaviors of the virus are predicted by using stochastic differential equations with second-order multiplicative α-stable jumps.By developing the assumptions and employing the novel theoretical tools,the threshold parameter responsible for ergodicity(persistence)and extinction is provided.The theoretical results of the current study are validated by numerical simulations and parameters estimation is also performed.Moreover,we obtain the following new interesting findings:(a)in each class,the average time depends on the value ofα;(b)the second-order noise has an inverse effect on the spread of the virus;(c)the shapes of population densities at stationary level quickly changes at certain values of α.The last three conclusions can provide a solid research base for further investigation in the field of biological and ecological modeling.
文摘Nowadays, devices are connected across all areas, from intelligent buildings and smart cities to Industry 4.0 andsmart healthcare. With the exponential growth of Internet of Things usage in our world, IoT security is still thebiggest challenge for its deployment. The main goal of IoT security is to ensure the accessibility of services providedby an IoT environment, protect privacy, and confidentiality, and guarantee the safety of IoT users, infrastructures,data, and devices. Authentication, as the first line of defense against security threats, becomes the priority ofeveryone. It can either grant or deny users access to resources according to their legitimacy. As a result, studyingand researching authentication issues within IoT is extremely important. As a result, studying and researchingauthentication issues within IoT is extremely important. This article presents a comparative study of recent researchin IoT security;it provides an analysis of recent authentication protocols from2019 to 2023 that cover several areaswithin IoT (such as smart cities, healthcare, and industry). This survey sought to provide an IoT security researchsummary, the biggest susceptibilities, and attacks, the appropriate technologies, and the most used simulators. Itillustrates that the resistance of protocols against attacks, and their computational and communication cost arelinked directly to the cryptography technique used to build it. Furthermore, it discusses the gaps in recent schemesand provides some future research directions.
文摘Explainable Artificial Intelligence(XAI)has an advanced feature to enhance the decision-making feature and improve the rule-based technique by using more advanced Machine Learning(ML)and Deep Learning(DL)based algorithms.In this paper,we chose e-healthcare systems for efficient decision-making and data classification,especially in data security,data handling,diagnostics,laboratories,and decision-making.Federated Machine Learning(FML)is a new and advanced technology that helps to maintain privacy for Personal Health Records(PHR)and handle a large amount of medical data effectively.In this context,XAI,along with FML,increases efficiency and improves the security of e-healthcare systems.The experiments show efficient system performance by implementing a federated averaging algorithm on an open-source Federated Learning(FL)platform.The experimental evaluation demonstrates the accuracy rate by taking epochs size 5,batch size 16,and the number of clients 5,which shows a higher accuracy rate(19,104).We conclude the paper by discussing the existing gaps and future work in an e-healthcare system.
文摘The systematic method for constructing Lewis representations is a method for representing chemical bonds between atoms in a molecule. It uses symbols to represent the valence electrons of the atoms involved in the bond. Using a number of rules in a defined order, it is often better suited to complicated cases than the Lewis representation of atoms. This method allows us to determine the formal charge and oxidation number of each atom in the edifice more efficiently than other methods.
文摘Water is the most abundant liquid on the surface of the earth. It is a liquid whose properties are quite surprising, both as a pure liquid and as a solvent. Water is a very cohesive liquid: its melting and vaporization temperatures are very high for a liquid that is neither ionic nor metallic, and whose molar mass is low. Thus, water remains liquid at atmospheric pressure up to 100C while similar molecules such as H2S, H2Se, H2Te for example would give a vaporization temperature close to 80C. This cohesion is in fact ensured by hydrogen bonds between water molecules. This type of bonds between neighboring molecules, hydrogen bonds, is quite often found in chemistry [1] [2]. Any change in the state of aggregation of a substance occurs with the absorption or release of a certain amount of latent heat of transformation. Latent heat of fusion, vaporization or sublimation is the ratio of the energy supplied as heat to the mass of the substance that is melted, vaporized or sublimated. As a result of the reversibility of the processes, the fusion heat is equal to the heat released in the reverse process: crystallization and solidification heat. And likewise the heat of vaporization is equal to the heat of condensation. This equality of heat is often used to determine experimentally either of these quantities. There are two main measurement methods: 1) Direct measurement using the calorimeter, 2) Indirect measure based on the use of the VantHoff relationship. The objective of this work is to measure the latent heat of water vaporization and verify the compatibility of the experimental values with the values given by the tables using the indirect method.
文摘Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-dimensional structure with a high degree of anisotropy. The carbon atoms within each layer are linked together by strong covalent bonds, creating a strong, stable lattice structure. However, the layers themselves are held together by weak van der Waals forces, enabling them to slide easily over each other. The properties of carbon graphite are highly dependent on the orientation and alignment of the graphene layers. When the layers are aligned parallel to each other, the material exhibits high strength and stiffness along the alignment direction, but is weaker and more flexible in other directions. Carbon graphite is used in a variety of applications where high strength, rigidity and electrical conductivity are required. Some common applications include electrical contacts, electric motor brushes, and as a structural material in aerospace and defense applications. The aim of our work is to describe the structure of graphite, its physical and chemical properties and its applications.
基金supported by the Deanship of Scientific Research at King Khalid University,Saudi Arabia (R.G.P.1/207/43)。
文摘This paper presents an extension of certain forms of the real Paley-Wiener theorems to the Minkowski space-time algebra. Our emphasis is dedicated to determining the space-time valued functions whose space-time Fourier transforms(SFT) have compact support using the partial derivatives operator and the Dirac operator of higher order.
文摘We have been pleased that our paper Geological mapping and mining prospecting in the Aouli inlier(Eastern Meseta,Morocco) based on remote sensing and geographic information systems(GIS) was of interest to our colleagues who commented it in China Geology 5(2022) 1–4.
文摘Mapping from remote sensing has become more effective in the field of geology, mainly in lithological discrimination and identification of hydrothermal alteration zones. The use of this technique consists in obtaining information about the rock mass and the main ones existing in the inaccessible areas. Satellite data from the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor represent a favorable potential for detecting the spectral signatures of mineral zones and identifying their nature. These data are more reliable in places where the climate is arid with less abundant vegetation, as at the Oumjrane-Boukerzia mining district. This region which is part of the Eastern Anti-Atlas, is composed of several mineralized veins which still require detailed studies and exploration by the technique of remote sensing. In this work we applied several processing techniques on ASTER imagery such as Colored Composition, Principal Component Analysis and Ratio Bands. The use of the reports of the specialized Bands makes it possible to identify some hydrothermal alteration minerals within the mining district of Oumjrane Boukerzia. These minerals are represented mainly by iron oxides and hydroxides (Hematite, jarosite, limonite and goethite), carbonate minerals (dolomite, calcite), clay minerals (Illite, kaolinite and chlorite) and quartz minerals. This work allows us to produce a map of hydrothermal alteration zones which can be used as a valuable reference in the strategy of mining exploration for the base metals (Cu, Pb, Zn and Ba), in the mining district of Oumjrane-Boukerzia and in the entire Eastern Anti-Atlas.
文摘Cosmetic companies are trying to include more sustainability in their strategies. But, showing commitment is always a challenge for them. This work consists in showing the degree of commitment of cosmetic companies in their marketing practices. The qualitative study carried out aims to determine the level of their commitment in terms of sustainability, based on 10 websites of “sustainable” cosmetics companies that sell their products online, and on defining sustainability criteria for each variable of the marketing mix. The results indicate that the majority of the companies analyzed are aware of the importance of sustainability and have taken measures to have a positive impact on the economy, society and the environment. The companies have made considerable efforts in “product” and “communication” strategies, but additional improvements can be envisaged for “price” and “distribution” strategies.
文摘Landsat 8 Oli,ASTER,and Sentinel 2A satellite images processing was used to map geological formations,lineaments and hydrothermal alteration minerals in the Aouli inlier,as a case study to illustrate the application of digital images processing and Geographic Information System(GIS)in geological mapping and mining prospecting.Principal Component Analysis(PCA)applied to the Landsat images allowed good lithological discrimination and contributed to the updating of available geological maps.The Automatic lineament extraction from Sentinel images revealed the main tectonic structures affecting Aouli inlier.The ratio bands(b5+b7)/b6 and the false color composite(b4/b6,b2/b1,b3/b2)allowed the hydrothermal alteration minerals mapping from Aster images.Combined with available geological data and field observations,the satellite derived data were integrated and analyzed in a GIS software to establish mining prospecting guides.The results showed that the anomaly zones are intimately linked to NNE-SSW and NW-SE oriented faults and to highly fractured areas developing argillic and Fe rich alterations.Verified via field survey,this approach was successfully applied to the Aouli inlier to rapidly target potential areas to be explored in the tactical phase.This provides a model for future prospecting efforts for similar mineral deposits in other areas.
文摘In the context of industrial competitiveness, taking into account the process design throughout the product life cycle is inevitable, from the expression of the need to recycle, the capitalization and knowledge management increasingly a target much sought after companies because of increased knowledge. Indeed, during the approval phase and use studies and scientific researches make have generated knowledge especially that concerning the reliability of system components. In this context, the capitalization and reuse of knowledge are necessary and have a particular interest in design and particularly in the preliminary design phase. Studies are already completed suggest a design process ranging from the need to solve the problem. At each phase of the process, structural characteristics are defined by the designer through the available knowledge already capitalized to make choice of component and their arrangement. This article proposes integrating the analysis of system reliability in this process. The objective is the use of knowledge in the vision safety and hazards of operating through the study of reliability and decision making for the selection of solution.
文摘The decrease of wind velocity (wake losses) in downstream area of wind turbine is generally quantified using wake models. The overall estimated power of wind farm varies according to reliability of wake model used, however it's unclear which model is most appropriate and able to give a high performance in predicting wind velocity deficit. In this subject, a qualification of three analytical wake models (Jensen, lshihara and Frandsen) based on three principal criteria is presented in this paper: (i) the parsimony which characterizes the inverse of model complexity, (ii) the accuracy of estimation in which wake model is compared with the experimental data and (iii) imprecision that is related to assumptions and uncertainty on the value of variables considered in each model. This qualitative analysis shows the inability of wake models to predict wind velocity deficit due to the big uncertainty of variables considered and it sensitivity to wind farm characteristic.
文摘Identification of water potential areas in arid regions is a crucial element for the enhancement of their water resources and socio-economic development. In fact, water resources system-planning can be used to make various decisions and implement manage- ment of water resources policies. The purpose of this study is to identify groundwater sto- rage areas in the high Guir Basin by implementing Geographic Information System (GIS) and Remote Sensing methods. The required data for this study can be summarized into five critical factors: Topography (slope), lithology, rainfall, rock fracture and drainage. These critical factors have been converted by the GIS into thematic maps. For each cri- tical parameter, a coefficient with weight was attributed according to its importance. The map of potential groundwater storage areas is obtained by adding the products (coeffi- cient × weight) of the five parameters. The results show that 50% to 64% of the total area of the High Guir Basin is potentially rich in groundwater, where most of fracture systems are intensely developed. The obtained results are validated with specific yield of the aqui- fer in the study area. It is noted that there is a strong positive correlation between excel- lent groundwater potential zones with high flows of water points and it diminishes with low specific yield with poor potential zones.
文摘This article presents research and development of an interoperable platform to facilitate, monitor and coordinate groundwater data sharing. This system was orchestrated by a number of services described by Open Geospatial Consortium (OGC) such as Sensor Observation Service (SOS) and other services for the use of mapping data, Web Feature Services (WFS), Web Map Service (WMS), and catalogue services (CSW). An important activity for our project was the establishment of a portal for geographic data and services. Geoportal developed for this project will promote and facilitate access to groundwater data and share theme more openly. Otherwise our system has been designed to provide a powerful tool that enhances the ability of regional staff to monitor near real-time groundwater data (i.e.?piezometric level) and as a result will help provide a more effective response to environmental upsets.
文摘<span style="font-family:Verdana;">In this article, the effect of temperature on the photovoltaic parameters of mono-crystalline silicon Photovoltaic Panel is undertaken, using the Matlab environment with varying module temperature in the range 25°C - 60°C at constant solar irradiations 200 - 500 W/m</span><sup><span style="font-family:Verdana;">2</span><span></span></sup><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> The results show that the temperature has a significant impact on the various parameters of the photovoltaic panel and it controls the quality and performance of the solar panel</span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> The photovoltaic</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span><span style="font-family:Verdana;">parameters are the current of short circuit </span><i></i></span><i><i><span><span style="font-family:Verdana;">I</span><sub><span style="font-family:Verdana;">sc</span></sub></span></i><span></span></i><span style="font-family:Verdana;">, the open circuit voltage </span><i></i></span><i><i><span><span style="font-family:Verdana;">V</span><sub><span style="font-family:Verdana;">co</span></sub></span></i><span></span></i><span style="font-family:Verdana;">, the form factor FF, the maximum power </span><i><i><span><span style="font-family:Verdana;">P</span><sub></sub></span></i><i><span style="font-family:Verdana;"><sub>max</sub></span></i><i><span></span></i><span></span></i><span style="font-family:Verdana;"> as well as efficiency. The relative change of these photovoltaic parameters with temperature is also evaluated in this article. A DS-100M solar panel has been used as reference model. The results show also that the open circuit voltage, maximum power, fill factor and efficiency decrease with temperature</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> but the short circuit current increase</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> with temperature</span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;"> Th</span><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;"> results are in good agreement with the available literature.</span>
文摘With their advantages, continuously variable transmissions have gained more popularity in the last decade by their use in mechanical transmission systems. The present paper aims to analysis the efficiency of the transmission based on the mechanical efficiency of the planetary gear train integrated in such transmission. In this analysis, we consider the mechanical efficiency of the transmission has been determined considering how the efficiency of the CVT members changes as a function of the operating conditions. The efficiency of the planetary gear train as a function of the configuration, speeds in his three input/output shafts, and also with respect to the power flow type. Results are compared with those obtained from other methods performance evaluation of the transmission, available in the literature.
文摘In our medical practice, in particular obstetrics, it is difficult to change certain consolidated dogmas, but the necessity and the current situation of our obstetrical exercise pushed us to find new technical supports, to make the exercise of our specialty as stripped of pitfalls as possible. Our work is summarized in a prospective comparative study, aimed at evaluating the existence or not of a difference between the administration of oxytocin just before the hysterotomy in a cesarean section and its administration after fetal extraction. We used a set of criteria to include patients in our study. This study took place over a period of one year (2020) in the Mother and Child regional center, in Meknes Imperial city, Morocco, involving a total number of 364 patients. With a group A comprising 176 patients 48% (176/364) who received oxytocin just before the hysterotomy and a group B of 188 patients 52% (188/364) who received it classically after fetal extraction. The difference was very significant as detailed in the article. Conclusion: the very convincing results of our study and the difference between the two groups, allowed us to demonstrate the effectiveness of our process and to endorse its use in our routine practice, with the perspective of conducting a prospective randomized study on a larger series.
基金This study was made in the PRAD Project No.10-06,supported by“Centre d’Ecologie Fonctionnelle et Evo-lutive”,UMR CEFE(Montpelier,France)and“Institut National de la Recherche Agronomique Meknès”,INRA-CRRMKS(Meknès,Maroc).
文摘Assessment of genetic diversity of Moroccan cultivated almond (Prunus dulcis Mill.) grown from seed and cultivated at four eco-geographical regions was performed using 16 nuclear SSRs. 238 alleles were detected with an average of 14.88 alleles per locus, ranging from 4 (locus BPPCT027) to 24 (locus CPSCT018). The size of alleles ranged from 84 bp (locus UDP96-003) to 253 bp (locus UDP96-018). A high genetic diversity of the local almonds is apparent and structured into three major clusters (Oasis cluster, High and Anti Atlas cluster, and Middle Atlas cluster). Compared to the Mediterranean genetic pools, from the East to West, the genetic diversity tends to be limited in Morocco which is the area of its extreme diffusion.
文摘Operating in natural wind field, the horizontal axis wind turbines are subject to cyclical variation of aerodynamic loads. This cyclical loads fluctuation is a result of two aerodynamic phenomenon: the first one is the advancing and retreating blade effect;the second one is related to the cyclical variation of induced velocity at the rotor plane. In these operating conditions, the correct prediction of this load variation is necessary to predict some important parameters linked to the fatigue and stability of free yawing turbines. The main objective of the present study is the evaluation of the azimuthal variation of normal force at different radial positions. To model the problem, the blade element momentum theory is used and wind turbine is supposed operate in yaw conditions. The aerodynamic coefficients are corrected using Chaviaropoulos and Hansen model to take into account the phenomenon of stall delay. A computer code was developed to obtain the numerical values and results are compared with measurements performed in the NASA Ames wind tunnel.