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Steam Methane Reforming(SMR)Combined with Ship Based Carbon Capture(SBCC)for an Efficient Blue Hydrogen Production on Board Liquefied Natural Gas(LNG)Carriers 被引量:1
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作者 Ikram Belmehdi Boumedienne Beladjine +2 位作者 Mohamed Djermouni Amina Sabeur Mohammed El Ganaoui 《Fluid Dynamics & Materials Processing》 2025年第1期71-85,共15页
The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methaner... The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint. 展开更多
关键词 Carbon dioxide(CO_(2))emissions blue hydrogen boil-off gas(BOG) steam methane reforming(SMR) ship-based carbon capture(SBCC)
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Feynman Perturbation Series for the Morse Potential
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作者 Boudjedaa Badredine Meftah Mohamed Tayeb Chetouani Lyazid 《Journal of Modern Physics》 2014年第5期177-185,共9页
In this paper we give an alternative treatment of the Schrodinger equation with the Morse potential, which based on the exact summation of the Feynman perturbation series in its original form. Using Fourier transform ... In this paper we give an alternative treatment of the Schrodinger equation with the Morse potential, which based on the exact summation of the Feynman perturbation series in its original form. Using Fourier transform we establish a recurrence equation between terms of the perturbation series. Finally, by the inverse Fourier transform and some technical tools of the ordinary differential equations of the second order, we can compute the exact sum of the perturbation series which is the Green’s function of the problem. 展开更多
关键词 MORSE Potential Green’s Function PROPAGATOR Path INTEGRAL PERTURBATION Series FOURIER Transform
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X-ray diffraction analysis of cold-worked Cu-Ni-Si and Cu-Ni-Si-Cr alloys by Rietveld method 被引量:3
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作者 A.KHEREDDINE F.HADJ LARBI +3 位作者 L.DJEBALA H.AZZEDDINE B.ALILI D.BRADAI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第3期482-487,共6页
Cold worked and annealed supersaturated Cu-2.65Ni-0.6Si and Cu-2.35Ni-0.6Si-0.6Cr alloys were studied. The microstructural parameters evolution, including crystallite size, root mean square strain and dislocation dens... Cold worked and annealed supersaturated Cu-2.65Ni-0.6Si and Cu-2.35Ni-0.6Si-0.6Cr alloys were studied. The microstructural parameters evolution, including crystallite size, root mean square strain and dislocation density was analyzed using Materials Analysis Using Diffraction software (MAUD). The parameters for both alloys have typical values of cold deformed and subsequently annealed copper based alloy. A net change of the crystallite size, root mean square strain and dislocation density values of the alloys aged at 450 °C for 2.5-3 h seems corresponding to the recovery and recrystallization processes. Addition of Cr as quaternary element did not lead to any drastic changes of post deformation or ageing microstructural parameters and hence of recovery-recrystallization kinetics. 展开更多
关键词 Cu-Ni-Si alloy microstructure XRD line profile analysis Materials Analysis Using Diffraction software
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Technological Valorization of Algerian Dates Downgraded from <i>Deglet Nour</i>Variety to Semi-Candied Dates in Dates Syrup
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作者 Férial Aziza Benyahia-Krid Elheyfa Khemissat +4 位作者 O. Aissaoui Zitoun Kaouther Djafri Meriem Bergouia Batoul Meghzili Lamia El-Mechta 《Food and Nutrition Sciences》 2021年第6期627-642,共16页
The objective of this study is the valorization of downgraded dates from a high Algerian date variety <span style="font-family:Verdana;"><i></i></span><i><i><span style... The objective of this study is the valorization of downgraded dates from a high Algerian date variety <span style="font-family:Verdana;"><i></i></span><i><i><span style="font-family:Verdana;">Deglet Nour</span></i><i><span style="font-family:Verdana;"></span></i></i><span style="font-family:;" "=""><span style="font-family:Verdana;">, locally called “</span><span style="font-family:Verdana;">h’chef</span><span style="font-family:Verdana;">”. The work starts with the implementation of a food formulation of semi-candied dat</span></span><span style="font-family:Verdana;">es in syrup extracted from dates. This formulation was based on dehydration-impregnation by immersion (D.I.I.). The downgraded dates were cleaned, cut, blanched, and then immersed in date syrups with increasing differential</span><span style="font-family:Verdana;"> concentrations in Brix degrees: 65</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">, 70</span><span style="font-family:Verdana;">°</span><span style="font-family:;" "=""> <span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> 75</span></span><span style="font-family:Verdana;">°</span><span style="font-family:;" "=""><span style="font-family:Verdana;">. The chosen date/syrup immersion ratio is 1:2 (w/w). The obtained semi-candied dates were the subject of physicochemical and sensory analyses. The characterization of the downgraded dates before immersion showed high sugar content with a rate </span><span style="font-family:Verdana;">52.67</span><span style="font-family:Verdana;"> g% g of dry matter and low water content (14%) which favors their use in semi-candied products. The </span><span style="font-family:Verdana;">physico-chemical</span> <span style="font-family:Verdana;">analyses</span><span style="font-family:Verdana;"> results of the three semi-candied dates products show an increase in their final sugar content, </span></span><span style="font-family:Verdana;"><i></i></span><i><i><span style="font-family:Verdana;">i.e.</span></i><i><span style="font-family:Verdana;"></span></i></i><span style="font-family:Verdana;"> from 53.55% to 60.78% and in ashes between 1</span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;">76 p.cent and 1</span><span style="font-family:Verdana;">.</span><span style="font-family:Verdana;">94 p.cent. On the other hand, sensory analysis results confirm that the semi-candied dates with a syrup of 75</span><span style="font-family:Verdana;">°</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Brix present the most appreciated and preferable organoleptic characteristics than the other variables. Finally, following appertisation, the stability test </span><span style="font-family:Verdana;">reveal</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> good microbiological quality (100</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C for 20 minutes) of the three (3) semi-candied formulations of dates.</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Thus, the valorization of the “</span><span style="font-family:Verdana;">h’chef</span><span style="font-family:Verdana;">” as sorting gap <i></i></span><i><i><span style="font-family:Verdana;">Deglet Nour</span></i></i></span><span style="font-family:Verdana;"> date allowed its transformation into semi-candied dates, stable, appreciable on the organoleptic side. This new formulation could constitute a value-added product if eventually manufactured on an industrial scale, mainly in southern Algeria.</span> 展开更多
关键词 Phoenix dactylifera L. Downgraded Dates Food Formulation Osmotic Dehydration Stability Test
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Complexity Analysis of an Interior Point Algorithm for the Semidefinite Optimization Based on a Kernel Function with a Double Barrier Term 被引量:1
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作者 Mohamed ACHACHE 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2015年第3期543-556,共14页
In this paper, we establish the polynomial complexity of a primal-dual path-following interior point algorithm for solving semidefinite optimization(SDO) problems. The proposed algorithm is based on a new kernel fun... In this paper, we establish the polynomial complexity of a primal-dual path-following interior point algorithm for solving semidefinite optimization(SDO) problems. The proposed algorithm is based on a new kernel function which differs from the existing kernel functions in which it has a double barrier term. With this function we define a new search direction and also a new proximity function for analyzing its complexity. We show that if q1 〉 q2 〉 1, the algorithm has O((q1 + 1) nq1+1/2(q1-q2)logn/ε)and O((q1 + 1)2(q1-q2)^3q1-2q2+1√n logn/c) complexity results for large- and small-update methods, respectively. 展开更多
关键词 Semidefinite optimization kernel functions primal-dual interior point methods large andsmall-update algorithms complexity of algorithms
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Adolescence’s Anorexia Nervosa:A Behavior to Exist?
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作者 Amel Dehane 《Journalism and Mass Communication》 2025年第3期157-169,共13页
Adolescence is the age of all disturbances both physiological and psychological.This internal and external insight conflicts is often hard to be managed.Thus,some teens will be subjected to act more than others.They u... Adolescence is the age of all disturbances both physiological and psychological.This internal and external insight conflicts is often hard to be managed.Thus,some teens will be subjected to act more than others.They use their bodies to show deep suffering as well as confusion.Numerous pathological behaviors can appear due to this significant sensitiveness like escaping difficulties.One of the ways solving this hardness of understanding and resolving these disorders is the disturbance in the nutritional behavior.This paper would allow us to understand the subjective dimensions that incite acting by mental anorexia.We suggest that a lack in the reflexive function might be the main cause of the attitude.Thereby,teen’s mental anorexia would show mistreatment at early care,that would make them feel unable to be good mothers in the future. 展开更多
关键词 ADOLESCENCE anorexia nervosa ACTING drive scopique
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Assessment of Salinity Tolerance and Ecotypic Variability in Vicia narbonensis L.:Morphological,Physiological,and Biochemical Responses
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作者 Hocine Bougrine Salah Hadjout +7 位作者 Mohamed Zouidi Abdeldjalil Belkendil Amer Zeghmar Chaouki Boulekdam Walid Ouaret Walid Soufan Fathi Abdellatif Belhouadjeb Amar Mebarkia 《Phyton-International Journal of Experimental Botany》 2025年第1期251-267,共17页
Salinity stress is a major challenge for global agriculture,particularly in arid and semi-arid regions,limiting plant productivity due to water and soil salinity.These conditions particularly affect countries along th... Salinity stress is a major challenge for global agriculture,particularly in arid and semi-arid regions,limiting plant productivity due to water and soil salinity.These conditions particularly affect countries along the southern Mediterranean rim,including Algeria,which primarily focuses on pastoral and forage practices.This study investigates salinity tolerance and ecotypic variability in Vicia narbonensis L.,a fodder legume species recognized for its potential to reclaim marginal soils.Morphological,physiological,and biochemical responses were assessed in three ecotypes(eco2,eco9,and eco10)exposed to different salinity levels(low,moderate,and severe).The study was conducted using a completely randomized block design with three blocks per ecotype per dose.The results from the two-way analysis of variance demonstrate significant effects across nearly all attributes studied,revealing distinct ecotypic responses.These findings underscore variations in growth parameters,osmotic regulation mechanisms,and biochemical adjustments.The substantial diversity observed among these ecotypes in their response to salinity provides valuable insights for breeders addressing both agronomic and ecological challenges.Multivariate analyses,including Principal Component Analysis(PCA),revealed key variables distinguishing between ecotypes under salinity stress.Moreover,Classification based on Salinity Tolerance Indices(STI)further differentiated ecotypic performance with more precision,and this is because of the combination of the different parameters studied.These results open up new prospects for the development of strategies to improve the salinity tolerance of forage legumes. 展开更多
关键词 Salinity tolerance Vicia narbonensis morphological traits physiological adaptations biochemical changes salinity tolerance index(STI)
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EXISTENCE RESULT FOR FRACTIONAL STATE-DEPENDENT SWEEPING PROCESSES
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作者 Shengda ZENG Abderrahim BOUACH Tahar HADDAD 《Acta Mathematica Scientia》 2025年第4期1471-1481,共11页
This paper addresses the evolution problem governed by the fractional sweeping process with prox-regular nonconvex constraints.The values of the moving set are time and state-dependent.The aim is to illustrate how a f... This paper addresses the evolution problem governed by the fractional sweeping process with prox-regular nonconvex constraints.The values of the moving set are time and state-dependent.The aim is to illustrate how a fixed point method can establish an existence theorem for this fractional nonlinear evolution problem.By combining Schauder’s fixed point theorem with a well-posedness theorem when the set C is independent of the state u(i.e.C:=C(t),as presented in[22,23]),we prove the existence of a solution to our quasi-variational fractional sweeping process in infinite-dimensional Hilbert spaces.Similar to the conventional state-dependent sweeping process,achieving this result requires a condition on the size of the Lipschitz constant of the moving set relative to the state. 展开更多
关键词 fractional differential inclusion Moreau's sweeping process prox-regular sets fixed point
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Inflammatory status in chronic renal failure: The role of homocysteinemia and pro-inflammatory cytokines 被引量:34
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作者 Hadja Fatima Tbahriti Djamel Meknassi +5 位作者 Rachid Moussaoui Amar Messaoudi Lakhdar Zemour Abbou Kaddous Malika Bouchenak Khedidja Mekki 《World Journal of Nephrology》 2013年第2期31-37,共7页
AIM: To evaluate determinants of infammatory mark-ers in chronic renal failure patients according to the level of glomerular fltration rate. METHODS: One hundred ffty four patients (Age: 44 ± 06 years; male/f... AIM: To evaluate determinants of infammatory mark-ers in chronic renal failure patients according to the level of glomerular fltration rate. METHODS: One hundred ffty four patients (Age: 44 ± 06 years; male/female: 66/88) with chronic renal fail-ure (CRF) were divided into 6 groups according to the National Kidney Foundation (NKF) classification. They included 28 primary stage renal failure patients (CRF 1), 28 moderate stage renal failure patients (CRF 2),28 severe stage renal failure patients (CRF 3), 18 end-stage renal failure patients (CRF 4), 40 hemodialysis (HD) patients, and 12 peritoneal dialysis (PD) patients. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and C-reactive protein (CRP) were analyzed by immunosorbent assay kit (ELISA) (Cayman Chemical’s ACETM EIA kit). Immunoassay methods were used for total homocysteine (tHcy) (fuorescence polarization immunoanalysis HPLC, PerkinEmer 200 series), transferrin (MININEPHTM human transferin kit: ZK070.R), ferritin (ADVIA Centaur ) and fbrinogen analysis (ACL 200). Differences between groups were performed using SPSS 20.0 and data are expressed as the mean ± SD.RESULTS: Results showed that in comparison with CRF 1 group and other groups, TNF-α and IL-6 levels were respectively more elevated in HD (16.38 ± 5.52 pg/mL vs 0.39 ± 0.03 pg/mL, 11.05 ± 3.59 pg/mL vs 8.20 ± 0.22 pg/mL, P 〈 0.001) and PD (14.04 ± 3.40 pg/mL vs 0.39 ± 0.03 pg/mL, 10.15 ± 1.66 pg/mL vs 8.20 ± 0.22 pg/mL, P 〈 0.001). IL-1β levels were increased in HD (9.63 ± 3.50 pg/mL vs 3.24 ± 0.10 pg/mL, P 〈 0.001) and CRF 4 (7.76 ± 0.66 pg/mL vs 3.24 ± 0.10 pg/mL, P 〈 0.001) patients than in CRF 1 and in the other groups. Plasma tHcy levels were higher in HD (32.27 ± 12.08 μmol/L) and PD (28.37 ± 4.98 μmol/L) patients compared to the other groups of CRF (P 〈 0.001). The serum CRP level was signifcantly increased in HD (18.17 ± 6.38 mg/L) and PD (17.97 ± 4.85 mg/L) patients compared to the other groups of CRF patients (P 〈 0.001). The plasma fbrinogen level was more elevated in HD (6.86 ± 1.06 g/L) and CRF 4 (6.05 ± 0.57 g/L) than in the other groups ( P 〈 0.001). Furthermore; the ferritin level was higher in HD (169.90 ± 62.16 ng/mL) and PD (90.08 ± 22.09 ng/mL) pa-tients compared to the other groups of CRF (P 〈 0.001). The serum transferrin value was signifcantly decreased especially in PD (1.78 ± 0.21 g/L) compared to the oth-er groups (P 〈 0.001). We found a negative correlation between glomerular fltration rate (GFR), TNF-α levels ( r = -0.75, P 〈 0.001), and tHcy levels ( r = -0.68, P 〈 0.001). We observed a positive correlation between GFR and transferrin levels ( r = 0.60, P 〈 0.001). CONCLUSION: CRF was associated with elevated in-flammatory markers. The inflammation was observed at the severe stage of CRF and increases with progres-sion of renal failure. 展开更多
关键词 Chronic renal failure Infammation Pro-infammatory cytokines Total homocysteine Glomerular fltration rate
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Screening of biological activities of Polygonum maritimum L.from A lgerian coast 被引量:2
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作者 Imad Abdelhamid El-Haci Fawzia Atik Bekkara +2 位作者 Wissame Mazari Fay al Hassani Mohamed AmineDidi 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2013年第8期611-616,共6页
Objective:To investigate the antioxidant and the antibacterial activities of crude extract from aerial part of Polygonum maritimumL.(Polygonaceae)(P.maritimum)and to find new actives biomolecules.Methods:The whole pla... Objective:To investigate the antioxidant and the antibacterial activities of crude extract from aerial part of Polygonum maritimumL.(Polygonaceae)(P.maritimum)and to find new actives biomolecules.Methods:The whole plant was collected from the Rechgoune coast(West of Algeria),and methanolic crude extract of aerial parts ofP.maritimum(PMCE)was prepared.The extract was tested against different bacterial strain and tested for his ability to neutralize free radical(DPPH)and to scavenge the H2O2.Results:PMCE had a very high content of total phenol,which was(352.49依18.03)mg/g dry weight,expressed as gallic acid equivalent.PMCE exhibited excellent antioxidant activity,as measured using DPPH and H2O2 scavenging assays.It also showed a high antibacterial activity against gram-positive bacterial strains:Bacillus cereus,Bacillus subtilisandStaphylococcus aureus with an highest MIC of 120μg/mL.Conclusions:The antioxidant and antibacterial activity of the PMCE is probably due to phenolic compounds present in the extract.The contemporary presence of antioxidant and antibacterialactivities in the PMCE suggests that this plant may be a source of bioactive substances with multifaceted activity. 展开更多
关键词 POLYGONUM maritimumL. PHENOLIC compounds ANTIOXIDANT ACTIVITY ANTIBACTERIAL ACTIVITY
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Numerical Simulation of Double Diffusive Mixed Convection in a Horizontal Annulus with Finned Inner Cylinder 被引量:3
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作者 Cherfi Ryad Sadaoui Djamel +1 位作者 Sahi Adel Mouloud Smail 《Fluid Dynamics & Materials Processing》 EI 2019年第2期153-169,共17页
The present work relates to a numerical investigation of double diffusive mixed convection around a horizontal annulus with a finned inner cylinder.The solutal and thermal buoyancy forces are sustained by maintaining ... The present work relates to a numerical investigation of double diffusive mixed convection around a horizontal annulus with a finned inner cylinder.The solutal and thermal buoyancy forces are sustained by maintaining the inner and outer cylinders at uniform temperatures and concentrations.Buoyancy effects are also considered,with the Boussinesq approximation.The forced convection effect is induced by the outer cylinder rotating with an angular velocity(ω)in an anti-clockwise direction.The studies are made for various combinations of dimensionless numbers;buoyancy ratio number(N),Lewis number(Le),Richardson number(Ri)and Grashof number(Gr).The isotherms,isoconcentrations and streamlines as well as both average and local Nusselt and Sherwood numbers were studied.A finite volume scheme is adopted to solve the transport equations for continuity,momentum,energy and mass transfer.The results indicate that the use of fins on the inner cylinder with outer cylinder rotation,significantly improves the heat and mass transfer in the annulus. 展开更多
关键词 Finned INNER CYLINDER double diffusive flow heat and mass TRANSFER ROTATING ANNULUS mixed CONVECTION numerical simulation
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Conceptual design of irradiation device for silicon neutron transmutation doping around Es-Salam research reactor 被引量:3
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作者 M.Salhi B.Mohammedi +4 位作者 S.Laouar M.Dougdag M.Touiza M.Abbaci M.Moughari 《Nuclear Science and Techniques》 SCIE CAS CSCD 2020年第4期69-78,共10页
Silicon neutron transmutation doping remains one of the most viable nuclear applications for research reactors.Providing this kind of product involves an irradiation method capable of fulfilling the quality requiremen... Silicon neutron transmutation doping remains one of the most viable nuclear applications for research reactors.Providing this kind of product involves an irradiation method capable of fulfilling the quality requirements of doping and alleviating the challenges related to the design and safety of the irradiation device.In this paper,we propose an irradiation device prototype for neutron transmutation doping of silicon ingots with diameters of 2 to 3 in.based on the Es-Salam research reactor.The thermal hydraulic analysis of the proposed irradiation device was performed to determine the optimum conditions for cooling.The effect of the mechanical vibrations induced by the circulation of coolant in the device was quantified via experimental measurements under different flow rates.The results show that the maximum temperature reached by the silicon ingots is below the temperature limit,effectively validating the design of the irradiation device.Other investigations are prospected to further optimize the design and the irradiation conditions.The irradiation of silicon ingots with a large diameter will be considered. 展开更多
关键词 IRRADIATION DEVICE PROTOTYPE Es-Salam research REACTOR NTD-Si IRRADIATION temperature CFD method
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ANALYTICAL ANALYSIS OF INTERFACIAL STRESSES IN FRP-RC HYBRID BEAMS WITH TIME-DEPENDENT DEFORMATIONS OF RC BEAM 被引量:3
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作者 Bouazza Fahsi Kouider Halim Benrahou +3 位作者 Baghdad Krour Abdeloauhed Tounsi Samir Benyoucef1 E Abbas Adda Bedia 《Acta Mechanica Solida Sinica》 SCIE EI 2011年第6期519-526,共8页
In this paper, the effect of time-dependent deformations (such as shrinkage and creep) on the interracial stresses between an RC beam and FRP plate is presented. For this end, a closed-form solution for such stresse... In this paper, the effect of time-dependent deformations (such as shrinkage and creep) on the interracial stresses between an RC beam and FRP plate is presented. For this end, a closed-form solution for such stresses in externally FRP plated RC beams including creep and shrinkage effects is presented. The developed model is formulated to predict the interfacial stresses at time 't', in which the RC beams have been already subjected to creep and shrinkage effects. The adherend shear deformations have been included in the present theoretical analysis by assuming a parabolic shear stress through the thickness of the RC beam and the FRP panel. Contrary to some existing studies, the assumption that both RC beam and FRP panel have the same curvature is not used in the present investigation. This research is helpful for the understanding on mechanical behavior of the interface and design of the FRP-RC hybrid structures. 展开更多
关键词 hybrid structure RC beams FRP composites interfacial stresses CREEP SHRINKAGE
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Effects of nano-voids and nano-cracks on the elastic properties of a host medium: xfem modeling with level-set function and free surface energy 被引量:2
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作者 B.E. Hachi D. Hachi M. Haboussi 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2019年第4期799-811,共13页
This work deals with the influences of nano-heterogeneities in the form of voids/cavities or cracks on the elastic (please confirm which word is correct. effective or elastic? According to the title of paper, I choose... This work deals with the influences of nano-heterogeneities in the form of voids/cavities or cracks on the elastic (please confirm which word is correct. effective or elastic? According to the title of paper, I choose elastic.) properties of a host medium. With a relatively large ratio of apparent-surface to volume and particularly strong physical interactions with the surrounding medium at nano-scale, nano-heterogeneities can potentially affect the elastic(effective or elastic?) properties of the parent medium (matrix) containing them in a significant manner. This has been reported by various theoretical and experimental studies, some of them are discussed in the present paper. To describe the positive (reinforcement) or negative (degradation) effect of the nano-heterogeneities from the modeling perspective, it is necessary to take into account the energy of interfaces/surfaces between nano-heterogeneities and the matrix which, by the fact of the relatively large extent of their apparent surface and their strong physical interaction with their neighborhood, can no longer be neglected compared to those of the volume energy. Thus, to account for the effects of interfaces/surfaces in a nanostructured heterogeneous medium, the coherent interface model is considered in the present investigation within a periodic homogenization procedure. In this interface/surface model, the displacement vector is assumed to be continuous across the interface while the stress vector is considered to be discontinuous and satisfying the Laplace-Young equations. To solve these equations coupled to the classical mechanical equilibrium problem, a numerical simulation tool is developed in a two-dimensional (2D) context using the eXtended Finite Element Method (XFEM) and the Level-Set functions. The developed numerical tool is then used to carry out a detailed analysis about the effect of nano-heterogeneities on the overall mechanical properties of a medium. The nano-heterogeneities are present in the medium initially as cylindrical cavities (circular in 2D) before being reduced to plane cracks (line in 2D) by successive flattenings. 展开更多
关键词 Interface/Surface ENERGY XFEM LEVEL-SET FUNCTION Periodic homogenization Nano-voids/Nano-cavities Nano-cracks Nano-inclusions/Nano-heterogeneities
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SVM Model Selection Using PSO for Learning Handwritten Arabic Characters 被引量:2
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作者 Mamouni El Mamoun Zennaki Mahmoud Sadouni Kaddour 《Computers, Materials & Continua》 SCIE EI 2019年第9期995-1008,共14页
Using Support Vector Machine(SVM)requires the selection of several parameters such as multi-class strategy type(one-against-all or one-against-one),the regularization parameter C,kernel function and their parameters.T... Using Support Vector Machine(SVM)requires the selection of several parameters such as multi-class strategy type(one-against-all or one-against-one),the regularization parameter C,kernel function and their parameters.The choice of these parameters has a great influence on the performance of the final classifier.This paper considers the grid search method and the particle swarm optimization(PSO)technique that have allowed to quickly select and scan a large space of SVM parameters.A comparative study of the SVM models is also presented to examine the convergence speed and the results of each model.SVM is applied to handwritten Arabic characters learning,with a database containing 4840 Arabic characters in their different positions(isolated,beginning,middle and end).Some very promising results have been achieved. 展开更多
关键词 SVM PSO handwritten Arabic grid search character recognition
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Nickel ferrite spinel as catalyst precursor in the dry reforming of methane:Synthesis,characterization and catalytic properties 被引量:5
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作者 Rafik Benrabaa Hamza Boukhlouf +4 位作者 Axel Lfberg Annick Rubbens Rose-Nelle Vannier Elisabeth Bordes-Richard Akila Barama 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第5期595-604,共10页
Dry reforming of methane by CO2 using nickel ferrite as precursor of catalysts was investigated.Nickel ferrite crystalline particles were prepared by coprecipitation of nitrates with NaOH or ammonia followed by calcin... Dry reforming of methane by CO2 using nickel ferrite as precursor of catalysts was investigated.Nickel ferrite crystalline particles were prepared by coprecipitation of nitrates with NaOH or ammonia followed by calcination,or by hydrothermal synthesis without calcination step.The textural and structural properties were determined by a number of analysis methods,including X-ray diffraction (XRD),Raman spectroscopy and X-ray photoelectron spectroscopy (XPS),among which X-ray diffraction (XRD) was at room and variable temperatures.All synthesized oxides showed the presence of micro or nanoparticles of NiFe2O4 inverse spinel,but Fe2O3 (hematite) was also present when ammonia was used for coprecipitation.The reducibility by hydrogen was studied by temperature-programmed reduction (TPR) and in situ XRD,which showed the influence of the preparation method.The surface area (BET),particle size (Rietveld refinement),as well as surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied according to the synthesis method.The catalytic reactivity was investigated using isopropanol decomposition to determine the acid/base properties.The catalytic performance of methane reforming with CO2 was measured with and without the pre-treatment of catalysts under H2 in 650-800 C range.The catalytic conversions of methane and CO2 were quite low but they increased when the catalysts were pre-reduced.A significant contribution of reverse water gas shift reaction accounted for the low values of H2 /CO ratio.No coking was observed as shown by the reoxidation step performed after the catalytic reactions.The possible formation of nickel-iron alloy observed during the study of reducibility by hydrogen was invoked to account for the catalytic behavior. 展开更多
关键词 dry reforming of methane NiFe2O4 spinel hydrothermal synthesis coprecipitation isopropanol decomposition
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Free vibration of functionally graded sandwich plates using four-variable refined plate theory 被引量:1
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作者 L.HADJI H.A.ATMANE +2 位作者 A.TOUNSI I.MECHAB E.A.ADDA BEDIA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第7期925-942,共18页
This paper uses the four-variable refined plate theory (RPT) for the free vibration analysis of functionally graded material (FGM) sandwich rectangular plates. Unlike other theories, there are only four unknown fu... This paper uses the four-variable refined plate theory (RPT) for the free vibration analysis of functionally graded material (FGM) sandwich rectangular plates. Unlike other theories, there are only four unknown functions involved, as compared to five in other shear deformation theories. The theory presented is variationally consistent and strongly similar to the classical plate theory in many aspects. It does not require the shear correction factor, and gives rise to the transverse shear stress variation so that the transverse shear stresses vary parabolically across the thickness to satisfy free surface conditions for the shear stress. Two common types of FGM sandwich plates are considered, namely, the sandwich with the FGM facesheet and the homogeneous core and the sandwich with the homogeneous facesheet and the FGM core. The equation of motion for the FGM sandwich plates is obtained based on Hamilton's principle. The closed form solutions are obtained by using the Navier technique. The fundamental frequencies are found by solving the eigenvalue problems. The validity of the theory is shown by comparing the present results with those of the classical, the first-order, and the other higher-order theories. The proposed theory is accurate and simple in solving the free vibration behavior of the FGM sandwich plates. 展开更多
关键词 functionally graded material (FGM) free vibration sandwich plate refinedplate theory (RPT) Navier solution
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Location and Characterization of Breeding Sites of Solitary Desert Locust Using Satellite Images Landsat 7 ETM+ and Terra MODIS 被引量:2
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作者 Lazar Mohammed Aliou Diongue +2 位作者 Jeng-Tze Yang Doumandji-Mitiche Bahia Lecoq Michel 《Advances in Entomology》 2015年第1期6-15,共10页
In the southern Algerian Sahara, populations of the desert locust have been monitored during the past 43 years. On a limited study area, the use of remote sensing data from Landsat 7 ETM+ and Terra MODIS, coupled with... In the southern Algerian Sahara, populations of the desert locust have been monitored during the past 43 years. On a limited study area, the use of remote sensing data from Landsat 7 ETM+ and Terra MODIS, coupled with the locust population database, allowed the identification and mapping of solitary desert locust breeding areas during remission periods. These sites are mainly located in wadis and in areas of accumulation/spreading of rainwater. The use of this methodology to all the Algerian Sahara is surely possible in order to improve the preventive management of this pest. 展开更多
关键词 Desert LOCUST SCHISTOCERCA gregaria Remote Sensing MODIS LANDSAT Early Warning
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Unveiling the Residual Stresses,Local Micromechanical Properties and Crystallographic Texture in a Ti-6Al-4V Weld Joint 被引量:3
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作者 B.Mehdi R.Badji +5 位作者 V.Ji B.Alili D.Bradai W.Bedjaoui F.Deschaux-Beaume F.Brisset 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2021年第7期997-1006,共10页
In this work,the micromechanical properties,crystallographic texture,welding residual stresses and their evolution after plastic strain were investigated in a Ti-6Al-4V alloy tungsten inert gas weld joint.It was found... In this work,the micromechanical properties,crystallographic texture,welding residual stresses and their evolution after plastic strain were investigated in a Ti-6Al-4V alloy tungsten inert gas weld joint.It was found that the welding process affected the Young modulus and microhardness values in bothαandβphases in the different regions of the weld joint.The highest microhardness and Young modulus values of a phase were recorded in the heat-affected zone,whereas the highest values of these characteristics for theβphase were found in the fusion zone(FZ).The change in the micro mechanical properties was accompanied by a change in the crystallographic texture components of the dominant a phase from(0001)<10-10>and(11-20)<10-10>components in the base material to(10-10)<11-20>and(11-20)<3-302>components in the FZ.The introduction of tensile testing resulted in a continuous stress relaxation and improved the weld joint performances. 展开更多
关键词 Ti-6Al-4 V Tungsten inert gas(TIG)weld Residual stress Local mechanical properties Crystallographic texture
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Delineation of groundwater potential zones in Wadi Saida Watershed of NW-Algeria using remote sensing,geographic information system-based AHP techniques and geostatistical analysis 被引量:1
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作者 Cherif Kessar Yamina Benkesmia +1 位作者 Bilal Blissag Lahsen Wahib Kébir 《Journal of Groundwater Science and Engineering》 2021年第1期45-64,共20页
Sustainable management of groundwater resources has now become an obligation,especially in arid and semi-arid regions given the socio-economic importance of this resource.The optimization in zoning for groundwater exp... Sustainable management of groundwater resources has now become an obligation,especially in arid and semi-arid regions given the socio-economic importance of this resource.The optimization in zoning for groundwater exploitation helps in planning and managing groundwater supply works such as boreholes and wells in the catchment.The objective of this study is to use remote sensing and GIS-based Analytical Hierarchy Process(AHP)techniques to evaluate the groundwater potential of Wadi Saida Watershed.Spatial analysis such as geostatistics was also used to validate results and ensure more accuracy.Through the GIS tools and remote sensing technique,earth observation data were converted into thematic layers such as lineament density,geology,drainage density,slope,land use and rainfall,which were combined to delineate groundwater potential zones.Based on their respective impact on groundwater potential,the AHP approach was adopted to assign weights on multi-influencing factors.These results will enable decision-makers to optimize hydrogeological exploration in large-scale catchment areas and map areas.According to the results,the southern part of the Wadi Saida Watershed is characterized as a higher groundwater potential area,where 32%of the total surface area falls in the excellent and good class of groundwater potential.The validation process revealed a 71%agreement between the estimated and actual yield of the existing boreholes in the study area. 展开更多
关键词 Wadi Saida Watershed Groundwater potential mapping Remote Sensing GIS Analytical Hierarchical Process Geostatistic
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