检索结果-南通市图书馆

Microwave-Assisted Hydrolysis of Hemicellulose over Sulfonated Catalysts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2022年第11期12卷 306-322页

作者： Itidel Belkadhi Mohamed Achraf Bouabdellah Lassâad Ben Hammouda zouhaier ksibi Francesco Medina University Tunis-El Manar Tunisia Rovira I Virgili University Tarragona Spain

Sulfonated catalysts based on zirconia (SO3H-ZrO2), silica (SO3H-SBA-15) and zeolite (SO3H-ZSM-5) were studied in the catalytic hydrolysis reaction of hemicellulose in a microwave reactor. The prepared catalysts were characterized by various techniques (XRD, N2 physisorption at 77 K, SEM, TEM and NH3-TPD). The obtained results reveal that despite the differences in their structural and textural properties, the ZrO2, Al-SBA-15 and H-ZSM-5 supports show similar conversions. Doping supports with sulfonate species created hydrogen bonds between SO3H groups and increased the amount of weak acid sites, which enhanced the hydrolysis of hemicellulose. SO3H- ZSM-5 showed the highest catalytic activity followed by SO3H-SBA-15 while SO3H-ZrO2 exhibited a poor conversion. Furthermore, the catalytic hydrolysis of the hemicellulose leads to several interesting products, such as formic acid, acetic acid, lactic acid and xylan. The correlation between the catalytic performances and the acidic properties of the different samples indicates that the best catalytic performances were obtained with the least acidic solids and especially when the density of strong acid sites decreases.

关键词： ZrO2 Al-SBA-15 H-ZSM-5 SO3H Hemicellulose Microwave

Effect of Zirconium and Cerium Loadings on Aerogel Pd-Based Catalysts for Methane Combustion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2018年第3期8卷 105-119页

作者： Khouloud Sadouki Shemseddine Fessi zouhaier ksibi Mickael Capron Franck Dumeignil Abdelhamid Ghorbel Laboratoire de Chimie des Matériaux et Catalyse Département de Chimie Faculté des Sciences de Tunis Université Tunis-El Manar Campus Universitaire Tunis Tunisie Chemistry Department Faculty of Science and Arts University of Jeddah Jeddah Saudi Arabia Univ. Lille CNRS Centrale Lille ENSCL Univ. Artois UMR 8181-UCCS-Unité de Catalyse et Chimie du Solide Lille France

Aerogel Pd/(Ce0.33Zr0.66O2)SiO2 catalysts (CeZry) were prepared with variable Ce and Zr loadings (molar ratio Ce/Zr = 1/2) by combining sol-gel and impregnation methods. First, N2-physisorption was used to investigate the texture evolution. Then, H2-chimisorption and TEM were performed to study the effect on particle dispersion. After, TPR was used to determine the catalyst reducibility. Furthermore, XPS characterization was done to identify the palladium oxidation state and to evaluate the Pd-support interaction. Finally, the prepared catalysts were tested in methane combustion to assess their catalytic activity. The obtained results showed that, when the Zr and Ce loadings are varied between 0% and 8% and between 0% and 6% respectively, the BET surface area was increased from 615 to 744 m2/g, the porosity diameter from 45.7 to 83.6 Å, the Pd particle diameter from 5.2 to 7.0 nm, the CeO2 and ZrO2 particle size from 0 to 68 nm, the reduction temperature shift reached 16°C, the Pd binding energy shift attained 0.6 eV, but an optimum amounts of Zr (4 wt.%) and Ce (3 wt.%) are needed to maximize the PdO reducibility and to enhance the catalytic activity. In effect, 100% conversion of methane was reached at around 415°C on the CeZr4 catalyst.

关键词： Pd/(CexZr(1-x)O2)/SiO2 Catalysts Methane Combustion Catalytic Activity

τSQWRL:A TSQL2-Like Query Language for Temporal Ontologies Generated from JSON Big Data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Big Data Mining and Analytics 2023年第3期6卷 288-300页

作者： zouhaier Brahmia Fabio Grandi Rafik Bouaziz Department of Computer Science Faculty of Economics and ManagementUniversity of SfaxSfax 3029Tunisia. Department of Computer Science and Engineering University of BolognaBologna 40136Italy.

Temporal ontologies allow to represent not only concepts,their properties,and their relationships,but also time-varying information through explicit versioning of definitions or through the four-dimensional perdurantist *** are widely used to formally represent temporal data semantics in several applications belonging to different fields(e.g.,Semantic Web,expert systems,knowledge bases,big data,and artificial intelligence).They facilitate temporal knowledge representation and discovery,with the support of temporal data querying and ***,there is no standard or consensual temporal ontology query *** a previous work,we have proposed an approach namedτJOWL(temporal OWL 2 from temporal JSON,where OWL 2 stands for"OWL 2 Web Ontology Language"and JSON stands for"JavaScript Object Notation").τJOWL allows(1)to automatically build a temporal OWL 2 ontology of data,following the Closed World Assumption(CWA),from temporal JSON-based big data,and(2)to manage its incremental maintenance accommodating their evolution,in a temporal and multi-schema-version *** this paper,we propose a temporal ontology query language forτJOWL,namedτSQWRL(temporal SQWRL),designed as a temporal extension of the ontology query language—Semantic Query-enhanced Web Rule Language(SQWRL).The new language has been inspired by the features of the consensual temporal query language TSQL2(Temporal SQL2),well known in the temporal(relational)database *** aim of the proposal is to enable and simplify the task of retrieving any desired ontology version or of specifying any(complex)temporal query on time-varying ontologies generated from time-varying big *** examples,in the Internet of Healthcare Things(IoHT)domain,are provided to motivate and illustrate our proposal.

关键词： temporal ontology temporal big data temporal query language temporal OWL 2 from temporal JSON(τJOWL) Semantic Query-enhanced Web Rule Language(SQWRL) Temporal SQL2(TSQL2) Internet of Healthcare Things(IoHT)

τJOWL:A Systematic Approach to Build and Evolve a Temporal OWL 2 Ontology Based on Temporal JSON Big Data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Big Data Mining and Analytics 2022年第4期5卷 271-281页

作者： zouhaier Brahmia Fabio Grandi Rafik Bouaziz Faculty of Economics and Management University of SfaxSfax 3029Tunisia Department of Computer Science and Engineering University of BolognaBologna 40136Italy

Nowadays,ontologies,which are defined under the OWL 2 Web Ontology Language(OWL 2),are being used in several fields like artificial intelligence,knowledge engineering,and Semantic Web environments to access data,answer queries,or infer new *** particular,ontologies can be used to model the semantics of big data as an enabling factor for the deployment of intelligent *** data are being widely stored and exchanged in JavaScript Object Notation(JSON)format,in particular by Web ***,JSON data collections lack explicit semantics as they are in general schema-less,which does not allow to efficiently leverage the benefits of big ***,several applications require bookkeeping of the entire history of big data changes,for which no support is provided by mainstream Big Data management systems,including Not only SQL(NoSQL)database *** this paper,we propose an approach,namedJOWL(temporal OWL 2 from temporal JSON),which allows users(i)to automatically build a temporal OWL 2 ontology of data,following the Closed World Assumption(CWA),from temporal JSON-based big data,and(ii)to manage its incremental maintenance accommodating the evolution of these data,in a temporal and multi-schema environment.

关键词： big data JavaScript Object Notation(JSON) JSON schema temporal JSON ontology temporal ontology JSchema OWL

Germination and Photosynthetic Responses to Salinity and Alkalinity in Avicenna marina Propagules

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2022年第5期91卷 1015-1026页

作者： Abdallah Atia Ahmed Abdallah Hussain Barhoumi zouhaier Department of Biology College of Arts and Science Mahayel AsirKing Khalid UniversityAbha61413Saudi Arabia Research Unit Nutrition and Nitrogen Metabolism and Stress ProteinDepartment of BiologyFaculty of Sciences of TunisCampus Universitaire El Manar ITunis1068Tunisia Department of Biology King Khalid UniversityAbha61413Saudi Arabia Faculty of Science Abu HarazGezira UniversityWed Medani21111Sudan Laboratory of Extremophile Plants Biotechnology Center of Borj CedriaUniversity Tunis El ManarTunis1068Tunisia

Avicenna marina(Forssk.)Vierh is a halophytic *** reproductive unit is green and has photosynthetic *** are naturally exposed to fluctuations in some abiotic factors at the soil surface,including salinity and *** objective of this study was to determine the effects of two salts including NaCl and NaHCO_(3)on germination processes and discuss the relationships between cotyledon photosynthesis and embryo axis growth in *** *** propagules came from Al Birk,located on the shoreline of the Saudi Red *** results showed that the studied salts did not affect neither the final germination percentage nor the embryo axis ***,rooting and root growth were delayed by both salts at 300 mM and were strongly inhibited by 600 mM NaHCO_(3).Both NaCl and NaHCO_(3)reduced the photosynthetic *** two salts did not affect the other photosynthetic parameters,including stomatal conductance,net transpiration,and intercellular CO_(2).Thereafter,the reduction in net photosynthesis was not related to any limitation of stomatal *** early germination phase was independent of cotyledon photosynthesis,whereas rooting and root growth may be limited by reduced photosynthesis under NaCl and NaHCO_(3).

关键词： Avicenna marina propagules cotyledons embryo growth germination photosynthesis alkalinity salinity

Evaluating the Potentials of PLSR and SVR Models for Soil Properties Prediction Using Field Imaging,Laboratory VNIR Spectroscopy and Their Combination

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2023年第8期136卷 1399-1425页

作者： Emna Karray Hela Elmannai Elyes Toumi Mohamed Hedi Gharbia Souham Meshoul Hamouda Aichi zouhaier Ben Rabah Center of Mapping and Remote Sensing Tunis1073Tunisia Department of Information Technology College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Digital Research Centre of Sfax Sfax3021Tunisia Higher School of Agriculture of Mograne LR03AGR02SPADDUniversity of CarthageCarthage1054Tunisia

Pedo-spectroscopy has the potential to provide valuable information about soil physical,chemical,and biological ***,wemay predict soil properties usingVNIRfield imaging spectra(IS)such as Prisma satellite data or laboratory spectra(LS).The primary goal of this study is to investigate machine learning models namely Partial Least Squares Regression(PLSR)and Support Vector Regression(SVR)for the prediction of several soil properties,including clay,sand,silt,organic matter,nitrate NO3-,and calcium carbonate CaCO_(3),using five VNIR spectra dataset combinations(%IS,%LS)as follows:C1(0%IS,100%LS),C2(20%IS,80%LS),C3(50%IS,50%LS),C4(80%IS,20%LS)and C5(100%IS,0%LS).Soil samples were collected at bare soils and at the upper(0–30 cm)*** data set has been split into a training dataset 80%of the collected data(n=248)and a validation dataset 20%of the collected data(n=61).The proposed PLSR and SVR models were trained then tested for each dataset *** to our results,SVR outperforms PLSR for both:C1(0%IS,100%LS)and C5(100%IS,0%LS).For Soil Organic Matter(SOM)prediction,it achieves(R^(2)=0.79%,RMSE=1.42%)and(R^(2)=0.76%,RMSE=1.3%),*** data fusion has improved the soil property *** highest improvement was obtained for the SOM property(R^(2)=0.80%,RMSE=1.39)when using the SVR model and applying the second Combination C2(20% of IS and 80%LS).

关键词： Soil VNIR field imaging spectroscopy PLSR SVR VNIR data combination

Effects of exotic and endogenous shrubs on understory vegetation and soil nutrients in the south of Tunisia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Arid Land 2015年第4期7卷 481-487页

作者： zouhaier NOUMI Department of Life Sciences Faculty of Sciences University of Sfax

This study was conducted in southern Tunisia in the growing seasons of 2013 and 2014, and aimed to compare the effects of exotic and endogenous shrub species （Haloxylon persicum and Retama raetam, respectively） on understory vegetation and soil nutrients. For each shrub species, the canopied sub-habitat （under the shrub crown） and un-canopied sub-habitat （in open grassland area） were distinguished. The concentrations of soil nutrients （organic matter, total nitrogen and extractable phosphorus） were found to be significantly higher （P〈0.05） under R. raetam canopy than under H. persicum canopy and in open area. The result also showed that the presence of shrubs improved all the values of understory vegetation parameters （floristic composition, density, total plant cover and dry matter） and all these values were significantly higher under endogenous species canopy than under exotic species canopy. These results highlighted the positive effect of endogenous shrubs on understory vegetation and soil nutrients compared to the exotic ones in the Saharan areas of Tunisia.

关键词： Saharan environment invasive species endogenous species vegetation soil enrichment

NUMERICAL STUDY OF FLOW AROUND AN OSCILLATING DIAMOND PRISM AND CIRCULAR CYLINDER AT LOW KEULEGAN-CARPENTER NUMBER

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第5期24卷 767-775页

作者： GHOZLANI Belgacem HAFSIA zouhaier MAALEL Khlifa Ecole Nationale d'Ingénieurs de Tunis Laboratoire de Modélisation en'Hydraulique et EnvironnementB.P.37.Le Belvédère1002 TunisTunisia

In order to identify the influence of shape comers on the instantaneous forces in the case of oscillating bodies, the simula- ted flow field is compared for two kinds of cross sections： diamond prism and circular cylinder. For these two flow configurations, the same Reynolds number and a Keulegan-Carpenter are considered. To compute the dynamic flow field surrounding the body, the Navier-Stokes transport equations in a non-inertial reference frame attached to the body are considered. Hence, a source term is added locally to the momentum equation to take into account the body acceleration. The proposed model is solved using the PHOENICS code. For the oscillating circular cylinder, the simulated results are in good agreement with the experimental data availa- ble in the litterature. After validation of this proposed model, flow field for diamond prism is determined. For both bodies, the pro- cess of the vortex formation is similar, with the formation of a recirculation zone in the near-wake containing a symmetric pair of vortices of equal strength and opposite rotation. The length of recirculation zone varies approximately linearly with time. However, the in-line force coefficient of the oscillating diamond prism is found to be greatest, since the recirculation zone is longer compared with that of the oscillating circular cylinder.

关键词： oscillating cylinder diamond prism body shape non-inertial frame numerical simulation in-line and transverse forcecoefficient

Numerical investigation of entropy generation and heat transfer of pulsating flow in a horizontal channel with an open cavity

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2017年第4期29卷 632-646页

作者： Fatma Zamzari zouhaier Mehrez Afif El Cafsi Ali Belghith Patrick Le Quéré Faculty of Sciences of Tunis Laboratory of Energy Heat and Mass Transfer (LETTM) Department of Physics El Manar University Computer Science Laboratory for Mechanics and Engineering Sciences (LIMSI)

In this study, the entropy generation and the heat transfer of pulsating air flow in a horizontal channel with an open cavity heated from below with uniform temperature distribution are numerically investigated. A numerical method based on finite volume method is used to discretize the governing equations. At the inlet of the channel, pulsating velocity is imposed for a range of Strouhal numbers Stpfrom 0 to 1 and amplitude Apfrom 0 to 0.5. The effects of the governing parameters, such as frequency and amplitude of the pulsation, Richardson number, Ri, and aspect ratio of the cavity, L/H, on the flow field, temperature distribution, average Nusselt number and average entropy generation, are numerically analyzed. The results indicate that the heat transfer and entropy generation are strongly affected by the frequency and amplitude of the pulsation and this depends on the Richardson number and aspect ratio of the cavity. The pulsation is more effective with the aspect ratio of the cavity L/H= 1.5 in terms of heat transfer enhancement and entropy generation minimization.

关键词： Pulsating flow entropy generation mixed convection heat transfer open cavity