检索结果-南通市图书馆

3D hydrodynamics involving multiple eccentric impellers in unbaffled cylindrical tank

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2016年第5期24卷 572-580页

作者： Houari ameur Institut des Sciences et Technologies Centre Universitaire Salhi Ahmed CUN-SA

In this paper, the numerical predictions of 3D hydrodynamics and power consumption in a vessel stirred by mul- tiple eccentrically located impellers are presented. The vessel is a fiat-bottomed cylindrical one equipped with six-curved bladed impellers. Aqueous solutions of xanthan gum are used, which have a shear thinning behavior with yield stress. The influence of several parameters on the mixing efficiency has been investigated, namely： the stirring rate, fluid theology, impeller number and impeller clearance from the tank bottom. Our predicted results are compared with other experimental data and a satisfactory agreement is found.

关键词： Computational fluid dynamics Mixing Non-Newtonian fluids Laminar flow Eccentric impeller

Effect of the shaft eccentricity and rotational direction on the mixing characteristics in cylindrical tank reactors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2016年第12期24卷 1647-1654页

作者： Houari ameur Institute of Sdence and Technology University Center Ahmed Salhi Ctr Univ Naama 45000 Algeria

Strategy of the shaft eccentricity is introduced to enhance the mixing characteristics in a flat bottomed cylindrical vessel without baffles. The mixing is ensured by a six-curved blade impeller. Three solutions which are models of food emulsions are used as working fluids. These solutions have a shear thinning behavior modeled by the power-law. The effects of fluid properties, stirring rates, impeller rotational direction and impeller eccentricity on the 3D flow fields and power consumption are investigated. Three values of impeller eccentricity are considered, namely 0%, 24% and 48% of the vessel diameter. It is found that the opposite clockwise rotational direction reduces the power consumption, compared with the clockwise rotational direction. Also, the obtained results show that an impeller placed at an eccentric position between 24% and 48% of the vessel diameter and at the third of the vessel height may ensure the best mixing characteristics.

关键词： Numerical simulation Hydrodynamics Mixing Impeller eccentricity Non-Newtonian fluids

Effect of some parameters on the performance of anchor impellers for stirring shear-thinning fluids in a cylindrical vessel

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2016年第4期28卷 669-675页

作者： Houari ameur Institut des Sciences et Technologies Centre Universitaire Salhi Ahmed

The 3-D hydrodynamics of shear thinning fluids in a stirred tank with an anchor impeller were numerically *** using a computational fluid dynamics code（CFX 13.0）,the obtained results give a good prediction of the hydrodynamics such as the velocity fields and cavern *** multiple reference frames（MRF） technique was employed to model the rotation of the *** rheology of the fluid was approximated using the Ostwald *** validate the CFD model,some predicted results were compared with the experimental data and a satisfactory agreement was *** effects of impeller speed,fluid rheology,and some design parameters on the flow pattern,cavern size and power consumption were explored.

关键词： anchor thinning satisfactory rotation frames rheology validate hydrodynamics stirring corner

A formal model for plastic human computer interfaces

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2018年第2期12卷 351-375页

作者： Abdelkrim CHEBIEB Yamine AIT ameur Computer Science School for Engineers (ESI) Algiers 16270 Algeria IRIT-INPT-ENSEEIHT Toulouse 31071 France

The considerable and significant progress achieved in the design and development of new interaction devices between man and machine has enabled the emergence of various powerful and efficient input and/or output devices. Each of these new devices brings specific interaction modes. With the emergence of these devices, new interaction techniques and modes arise and new interaction capabilities are offered. New user interfaces need to be designed or former ones need to evolve. The design of so called plastic user interfaces contributes to handling such evolutions. The key requirement for the design of such a user interface is that the new obtained user interface shall be adapted to the application and have, at least, the same behavior as the previous （adapted） one. This paper proposes to address the problem of user interface evolution due to the introduction of new interaction devices and/or new interaction modes. More, precisely, we are interested by the study of the design process of a user interface resulting from the evolution of a former user interface due to the introduction of new devices and/or new interaction capabilities. We consider that interface behaviors are described by labelled transition systems and comparison between user interfaces is handled by an extended definition of the bi-simulation relationship to compare user interface behaviors when interaction modes are replaced by new ones.

关键词： formal modeling and verification ontology based modeling plastic user interfaces adaptive systems

Numerical study of the performance of multistage Scaba 6SRGT impellers for the agitation of yield stress fluids in cylindrical tanks

维普期刊数据库评论

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 Hydrodynamics 2015年第3期27卷 436-442页

作者： ameur Houari BOUZIT Mohamed GHENAIM Abdellah Laboratoire de Mécanique Appliquée Faculté de Génie MécaniqueUSTO-MB Institut de Technologie Université Ibn Khaldoun INSA de Strasbourg-24 Bd de la Victoire-67084 Strasbourg-France

The 3-D flow fields and power consumption in a vessel stirred by multistage Scaba 6SRGT impeller have been investiga- ted. The Xanthan gum solutions in water were used, which have a shear thinning behavior with yield stress. This study was carried out with the help of a CFD package （CFX 13.0, Ansys Inc.） which is based on the finite volume method to solve the momentum equations. The effects of stirring rate, fluid rheology, impeller number, impeller location and vessel size on the performance of such stirred system are presented. To validate the CFD model, our predicted results have been compared with other literature data and a satisfactory agreement has been found.

关键词： Scaba 6SRGT impeller multistage agitator yield stress fluid stirred tank power consumption

Effect of Agitator’s Types on the Hydrodynamic Flow in an Agitated Tank

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2020年第2期33卷 122-139页

作者： Mohammed Foukrach Mohamed Bouzit Houari ameur Youcef Kamla Mechanical Faculty of Engineering University of Sciences and Technology of Oran Mohamed Boudhief(USTO-MB)1505 El M’naouarOranAlgeria Institute of Science and Technology University Center of Naama(Ctr Univ Naama)BP 6645000 NaamaAlgeria Faculty of Technology University Hassiba Ben Bouali of Chlef(UHBC)Ouled FaresChlefAlgeria

The aim of this paper is to study the effect of agitator’s types on the turbulent flows in stirred tanks without and with *** hydrodynamics behavior induced by four different agitator’s types:a Rushton turbine(RT),a circular blade turbine(CBT),a diverging triangular blade turbine(DTBT)and converging triangular blade turbine(CTBT)are numerically predicted by solving the Navier-Stokes equations and RNGκ–εturbulent *** simulations are carried out using the Multi Reference Frame(MRF)*** numerical results showed good agreement with *** find that the agitator CTBT gives an important profit on the power consumption per report/ratio the others and DTBT give a good reduction of the vortex size of the impeller angles.

关键词： Mixing Baffled tanks Agitators Reynolds number Turbulent flow

A New Method for Sentiment Analysis Using Contextual Auto-Encoders

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2018年第6期33卷 1307-1319页

作者： Hanen ameur Salma Jamoussi Abdelmajid Ben Hamadou Multimedia Information Systems and Advanced Computing Laboratory Sfax University Sfax Technopole Sfa 3021 Tunisia

Sentiment analysis, a hot research topic, presents new challenges for understanding users＇ opinions and judg-ments expressed online. They aim to classify the subjective texts by assigning them a polarity label. In this paper, weintroduce a novel machine learning framework using auto-encoders network to predict the sentiment polarity label at theword level and the sentence level. Inspired by the dimensionality reduction and the feature extraction capabilities of theauto-encoders, we propose a new model for distributed word vector representation ＂PMI-SA＂ using as input pointwise-mutual-information ＂PMI＂ word vectors. The resulted continuous word vectors are combined to represent a sentence. Anunsupervised sentence embedding method, called Contextual Recursive Auto-Encoders ＂CoRAE＂, is also developed forlearning sentence representation. Indeed, CoRAE follows the basic idea of the recursive auto-encoders to deeply composethe vectors of words constituting the sentence, but without relying on any syntactic parse tree. The CoRAE model consistsin combining recursively each word with its context words （neighbors＇ words： previous and next） by considering the wordorder. A support vector machine classifier with fine-tuning technique is also used to show that our deep compositionalrepresentation model CoRAE improves significantly the accuracy of sentiment analysis task. Experimental results demon-strate that CoRAE remarkably outperforms several competitive baseline methods on two databases, namely, Sanders twittercorpus and Facebook comments corpus. The CoRAE model achieves an efficiency of 83.28% with the Facebook dataset and97.57% with the Sanders dataset.

关键词： sentiment analysis recursive auto-encoder stacked auto-encoder pointwise mutual information deep embed-ding representation

Extracts from Marine Macroalgae and Opuntia ficus-indica Cladodes Enhance Halotolerance and Enzymatic Potential of Diazotrophic Rhizobacteria and Their Impact on Wheat Germination Under Salt Stress

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2018年第2期28卷 241-254页

作者： Abdelwahab RAI ameur CHERIF Cristina CRUZ Elhafid NABTI Département de Microbiologie Faculté des Sciences de la Nature et de la Vie Université Ferhat Abbas Sdtif-1 19000 (Algdrie) Universitg de Béjaia FSNV Laboratoire de Maitrise des Energies Renouvelables (LMER) Equipe de Biomasse et Environnement Targa Ouzemmour Béaia 06000 (Algérie) LR Biotechnology and Bio-Geo Resources Valorization Higher Institute for Biotechnology University of Manouba Sidi Thabet Biotechpole 2020 Sidi Thabet Ariana 2080 (Tunisia) cE3c-Centre for Ecology Evolution and Environmental Changes Campo Grande Bloco C-2 Piso 5 Sala 03 Lisboa 1749-016 CPor- tugal)

Soil salinity, which affects more than 6% of the earth’s land surface and more than 20% of its irrigated areas, is a major threat to agriculture. Diazotrophic bacteria are among the functional groups of soil microbiota that are threatened by this abiotic stress, as their activity is mostly inhibited by salt stress. Seventy bacterial strains with distinct characteristics were isolated from soils by using N-free Jensen’s selective medium. Based on their ability to produce metabolites of agricultural interest, four strains were selected and identified as Flavobacterium johnsoniae, Pseudomonas putida, Achromobacter xylosoxidans, and Azotobacter chroococcum. The selected strains were grown at different NaCl concentrations (0–600 mmol L^(-1) in N-free broth and 0–2 000 mmol L^(-1) in Luria-Bertani medium) in the presence and absence of glycine betaine (GB), aqueous and hydro-alcoholic extracts from marine macroalgae, Ulva lactuca and Enteromorpha intestinalis, and Opuntia ficus-indica cladodes. The selected bacterial strains, GB, and the aforementioned extracts were tested for their ability to promote the germination of wheat (Triticum durum) seeds at 0–300 mmol L^(-1) NaCl. Compared with the results obtained with the synthetic osmoprotectant GB, the extracts from O. ficus-indica, U. lactuca, and E. intestinalis significantly promoted bacterial growth and seed germination under salt stress.

关键词： glycine betaine Ulva lactuca Enteromorpha intestinalis plant growth-promoting rhizobacteria (PGPR) seed germi-nation Triticum durum

Effect of the Inclination of Baffles on the Power Consumption and Fluid Flows in a Vessel Stirred by a Rushton Turbine

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第4期30卷 1008-1016页

作者： Youcef Kamla Mohamed Bouzit Houari ameur Mohammed Ilies Arab Abdessalam Hadjeb Faculty of Mechanical Engineering University of Scienceand Technology USTO-MB1505 E1 M'naouarOranAlgeria Institute of Science and Technology University Center Ahmed Salhi(Ctr-Univ Naama)BP 6645000 NaamaAlgeria

The role of baffles in mechanically stirred tanks is to promote the stability of power drawn by the impeller and to avoid the fluid swirling, thus enhancing mixing. The present paper numerically investigates the baffles effects in a vessel stirred by a Rushton turbine. The geometric factor of interest is the baffle inclination which is varying between 25°, 32.5°, 45°, 70° and 90° at different impeller rotational speeds. The impeller rotational direction has also been varied. The vortex size and power consumption were evaluated for each geometrical configuration. It was found that the best configuration is the baffle inclination by = 70° at a negative angular velocity.

关键词： Stirred tanks Power consumption Baffles Rushton turbine CFD simulation