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Strengthening of Sewerage Systems with Composites Plates:Numerical Optimization

Materials Sciences and Applications 2011年第3期2卷 151-162页

作者： Stephan Kesteloot Chafika Djelal Idriss Benslimane said baraka Laboratoire Genie Civil et Geo-Environnement Lille Nord de France Universite d’Artois BethuneLilleFrance Structure&Rehabilitation Bagnolet BagnoletFrance

Sewerage systems are subject to many types of degradation. In France, an estimated 10% of the total systems length requires work due to structural degradation. At present, there is no method to localised rehabilitation of man-entry sewers. Laboratory tests have validated localised methods that involve bonding composite plates to the sewer. Those tests were performed on pre-damaged (multi-cracked) ovoid test pieces. The degradation observed was a longitudinal crack opened at the crown. The tests were performed under vertical loading. Our Study concerns the application of partial lining of sewer with composites plates. The composite strengtheners used were 1.2 mm thick pultruded carbon plates. A series of experiments were carried out on reinforced-concrete ovoids (T180) strengthened and unstrengthened by carbon plates in the keystone. After this test, a vertically-loaded ovoid was subjected to three-dimensional modelling in order to determinate its structural behavior and collapse mechanism. Knowledge of the latter make it possible to limit the areas in need of strengthening. An ovoid strengthened by composite plates adhered to the damaged areas was also modelled. Using real case data, modelling was carried out using a finite-element computational software program. This program allows cracking to be monitored until the structure collapses. Many conventional approaches using intensity factors k and contour integrals J have already been reported in the literature. We used methods for restituting energy G. Because nonlinear elasticity was being calculated, the constitutive laws of the various materials had to be taken into account. These constitutive laws describe the evolution of the materials. Moreover, those laws are subject to deformation limits. The simulated models were homogeneously meshed with physically nonlinear, triangular elements. The test results were then compared to those of the digital models. Partial lining of a sewer with composite plates, compared to

关键词： Sewerage Systems Carbon Plates Concrete Repair Reinforcement Finites Elements

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Prediction of Residential Building’s Solar Installation Energy Demand in Morocco Using Multiple Linear Regression Analysis

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Energy Engineering 2022年第5期119卷 2135-2148页

作者： Nada Yamoul Latifa Dlimi baraka Achraf Chakir Department of Physics Faculty of SciencesIbn Tofail UniversityKenitra City14000Morocco Department of Mathematics Faculty of SciencesIbn Tofail UniversityKenitra City14000Morocco

The building sector is one of the main energy-consuming sectors in *** fact,it accounts for 33%of the final consumption of energy and records a high increase in the annual consumption of energy caused by further planned large-scale ***,the energy consumption of the building sector is experiencing a significant acceleration justified by the rapid need for the development of housing stock,wich is estimated at an average increase of 1,5%per year;furthermore,tant is an estimated increase of about 6,4%.In this sense,building constitutes an important potential source for rationalizing both energy consumption and energy savings through the adoption of energy efficiency *** consumption control efforts in the residential building sector involve socio-economic,technological,and environmental concerns that require sophisticated ***,different types of quantitative models have been developed and examined so as to find a solution for the optimizing energy *** this work,we have highlighted the importance of using solar heaters to reduce energy demand in terms of the use of domestic hot *** do this,we have defined the needs and characteristics of a solar installation of a residential building located in Casablanca through a calculating tool“SOLO 2000”in addition to the use of multiple linear regression analysis to deduct the impact of irradiation and solar contributions on the energy demand of the solar installation.

关键词： Residential sector energy simulation prediction models black box solar energy

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WELL-POSEDNESS AND STABILITY FOR THE GENERALIZED INCOMPRESSIBLE MAGNETO-HYDRODYNAMIC EQUATIONS IN CRITICAL FOURIER-BESOV-MORREY SPACES

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Acta Mathematica Scientia 2019年第6期39卷 1551-1567页

作者： Azzeddine EL baraka Mohamed TOUMLILIN FST FES Laboratory AAFA Department of Mathematics University Sidi Mohamed Ben Abdellah

This paper concerns the Cauchy problem of the 3D generalized incompressible magneto-hydrodynamic(GMHD) equations. By using the Fourier localization argument and the Littlewood-Paley theory, we get local well-posedness results of the GMHD equations with large initial data(u0, b0) belonging to the critical Fourier-Besov-Morrey spaces FN^1-2α+3/p'+λ/pp,λ,q(R^3) Moreover, stability of global solutions is also discussed.

关键词： magneto-hydrodynamic Fourier-Besov-Morrey space stability

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VISCOMETRIC INVESTIGATIONS OF POLYVINYLPYRROLIDONE IN MIXED SOLVENTS AND WITH VARYING TEMPERATURE

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Chinese Journal of Polymer Science 2005年第4期23卷 367-371页

作者： Omar Melad Omar Abu-Tiem Rajai baraka Chemistry Department

The viscosity behavior of polyvinylpyrrolidone(PVP)has been determined at 25℃ in mixed solvents comprising water/dimethylformamide(DMF)and water/methanol(MeOH).Analysis of the data has considered the PVP as being both host and guest polymer in *** intrinsic viscosity of PVP in DMF is higher than in water and in MeOH,but also increases in a mixed solvent with high water content because of the effect of polymer-solvent *** was also found that the intrinsic viscosity of PVP at finite concentration,[η_(pvp)]_c decreases with an increase in the concentration of PVP in *** viscosity behavior of PVP in a mixed solvent is affected by the concentration-dependent intermolecular excluded volume effect,which can be quantitatively expressed by the parameter,b_Y,which reflects the shrinkage of PVP chain coils,resulting in a decrease of[η_(pvp)]_*** effect of temperature on the viscosity behavior of PVP in MeOH shows that the interaction parameter increases up to a maximum value,and then decreases after a certain temperature.

关键词： Polyvinylpyrrolidone Intermolecular excluded volume effect Intrinsic viscosity

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Targeting efficient biomass gasification

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Chinese Journal of Chemical Engineering 2021年第5期34卷 268-278页

作者： Saneliswa Magagula Jiangze Han Xinying Liu baraka C.Sempuga Institute for the Development of Energy for African Sustainability(IDEAS) University of South AfricaScience CampusFloridaJohannesburg 1710South Africa Department of Chemistry University of Puerto RicoRio Piedras CampusSan JuanPR 00931USA College of Chemical and Pharmaceutical Engineering Hebei University of Science and TechnologyShijiazhuang 050018China International Joint Laboratory of New Energy Hebei University of Science and TechnologyShijiazhuang 050018China

The sustainability of biomass use as a primary energy source depends on the efficiency of its conversion *** key contributing factors are well understood,owing to extensive experimental and theoretical modeling efforts in *** this manuscript,we present a systematic study of the thermochemical conversion route that allows us to target desirable outcomes when converting biomass to other fuels and *** process synthesis techniques that include material,energy and work balances,we identify the best targets to consider for highly efficient processes given specific *** analysis shows that by supplying the right amount of oxygen,a 100%carbon conversion efficiency can be achieved for certain applications that require gas as *** the objective is to obtain a cleaner fuel from biomass,converting it to char is most efficient in terms of carbon and energy *** to our analysis,an energy neutral biomass gasification process is theoretically possible over a wide range of H_(2) and CO production *** demonstrate its feasibility by simulating the process on Aspen Plus®.The simulation reveals that with heat integration,we can achieve the energy neutral target at a hydrogen production rate of 0.9 mol/mol *** further show that even at zero energy requirement,biomass gasification processes can have excess chemical potential,which can be recovered as useful work or conserved by producing more *** low temperature heat in the form of steam at 102℃ gives an 8% gain in chemical potential conservation and increases the hydrogen production rate by 60%.The insights revealed in this work allow for better decision making in early stages of process design,and consequently,more efficient biomass gasification processes.

关键词： Biomass Gasification Gasification thermodynamics Biomass conversion efficiency Process targeting

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Electrodeposited Ni and Ni-Co alloys using cysteine and conventional ultrasound waves

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Science China Chemistry 2013年第10期56卷 1446-1454页

作者： EL-FEKY Hesham NEGEM Mosaad ROY Sudipta HELAL Nadia baraka A. Chemistry Department Faculty of Science Fayoum UniversityFayoum 63514 Egypt School of Chemical Engineering and Advanced Materials Newcastle University Newcastle upon TyneNE1 7RU United Kingdom Chemistry Department Faculty of Science Cairo UniversityGiza 12613 Egypt

Ni-Co alloys were electroplated from sulphate electrolyte using addition agents including sodium gluconate,boric acid and cysteine on copper foil by the galvanostatic technique and ultrasound *** chemical composition,surface morphologies,crystalline structure and hardness of the Ni-Co alloys were studied using energy dispersive spectroscopy,scanning electron microscope,X-ray diffraction and Vickers testing method,*** effect of current density and addition agents on the microstructure and morphology of Ni-Co alloys were *** appropriate concentration of additives and ultrasound waves were found to produce fine and smooth crystals leading to higher hardness of Ni-Co *** microhardness of the Ni-Co alloys was varied between 4860–7530 *** surface morphology of coatings was changed from granular to fine due to using of gluconate,boric acid,cysteine and ultrasound *** mechanical properties of nanocrystalline Ni-Co alloys showed an increase of the hardness with the growing of Ni content in the *** X-ray diffraction studies indicated that nanocrystalline structure was face-centred cubic for pure Ni and Ni-Co alloys with Co content in the range of 1–75 wt.%.A hexagonal closed-package structure was obtained for pure Co and Ni-Co alloys with the cobalt content with range of 75–99wt.%.

关键词： Ni-Co合金半胱氨酸超声波电沉积扫描电子显微镜纳米晶结构显微硬度镍钴合金

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VISCOMETRIC STUDY OF POLY(METHYL METHACRYLATE) AND POLYSTYRENE BLENDS IN DIFFERENT SOLVENTS

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Chinese Journal of Polymer Science 2003年第1期21卷 15-19页

作者： Omar Melad Rajai baraka Jamil K.J.Salem Hani Hilles Awni El-Khazandar Department of Chemistry AL-Azhar University P.O. Box 1277 GAZA PalestineDepartment of Chemistry AL-Azhar University P.O. Box 1277 GAZA PalestineDepartment of Chemistry AL-Azhar University P.O. Box 1277 GAZA PalestineDepartment of Chemistry AL-Azhar University P.O. Box 1277 GAZA PalestineDepartment of Chemistry AL-Azhar University P.O. Box 1277 GAZA Palestine

The intermolecular interaction between poly(methyl methacrylate) (PMMA) and polystyrene (PS) intetrahydrofuran (THF) and N,N'-dimethyl formamide (DMF) solvents was studied at 28℃ using a dilute solution viscometrymethod. Solvent is believed to play a key role in characterizing the viscosity behavior of the polymer solution. The intrinsicviscosity and viscosity interaction parameter were experimentally measured for the binary (solvent/polymer) and for theternary systems in two solvents. The compatibility of the polymer mixture was discussed in terms of the sign of △b_m. Theresults show that the compatibility of PMMA/PS blend in DMF is larger than that in THF.

关键词： Viscometry Compatibility PMMA/PS blend

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Trends and Factors Associated with Changes in Early Initiation of Breastfeeding: Analysis of the Tanzania Demographic and Health Surveys 2004-2016

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Open Journal of Epidemiology 2022年第4期12卷 505-520页

作者： Hans P. Maro Tara Mtuy Levina J. Msuya baraka Moshi Michael J. Mahande Department of Epidemiology and Biostatistics Institute of Public Health Kilimanjaro Christian Medical University College Moshi Tanzania Faculty of Public Health and Policy London School of Hygiene and Tropical Medicine London UK Department of Pediatrics and Child Health Kilimanjaro Christian Medical University College Moshi Tanzania Department of Pediatrics and Child Health Kilimanjaro Christian Medical Centre Moshi Tanzania

Background: Despite WHO recommendations on the benefits of early initiation of breastfeeding for both the mother and child, only 53.5% of newborns in Tanzania are breastfed within the first hour of life. The trend for early initiation of breastfeeding shows little progress and Tanzania is still far behind reaching the global recommended rate of 70% of early initiation of breastfeeding. This study aims to determine trends and factors associated with changes in the early initiation of breastfeeding in Tanzania from 2004-2016. Methodology: This was an analytical cross-sectional study utilizing secondary data from the Tanzania Demographic and Health Surveys (TDHS) for the years 2004-2005, 2010, and 2015-2016. Data analysis was performed using Stata 15. Frequencies and proportions were used to summarize categorical variables. A Modified Poisson regression model was used to determine factors associated with the early initiation of breastfeeding. Multivariable Poisson decomposition analysis was used to assess factors associated with changes in the early initiation of breastfeeding across surveys. Results: Trends in early initiation of breastfeeding decreased from 59.53% in 2004/2005 to 46.72% in 2010, and then increased to 51.94% in 2015/2016. Only 5.9% of the overall change in early initiation of breastfeeding was contributed by the difference in characteristics such as mode of delivery and working status. The difference in coefficients contributed to a 94% decrease in early initiation of breastfeeding mostly due to a decrease in early initiation of breastfeeding among caesarean section delivery patients. Conclusion: The prevalence of early initiation of breastfeeding in Tanzania decreased between 2004 and 2016, then increased from 2010-2016. Interventions and health policies need to target factors that had significant effects on the early initiation of breastfeeding such as increasing health facility delivery and promoting the initiation of breastfeeding soon after caesa

关键词： Early Initiation of Breastfeeding Trends Factors Associated with Changes Tanzania

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Enhancing the explosive characteristics of a Semtex explosive by involving admixtures of BCHMX and HMX

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Defence Technology（防务技术） 2020年第2期16卷 487-492页

作者： Ahmed Elbeih Ahmed K.Hussein Tamer Elshenawy Svatopluk Zeman Sara M.Hammad Ahmad baraka Mohamed A.Elsayed Mohamed Gobara Hesham Tantawy Military Technical College Kobry ElkobbahCairoEgypt Technical Research Center CairoEgypt Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of PardubiceCzech Republic Faculty of Pharmacy University of CairoGizaEgypt

A well-known ternary plastic explosive,Czech Semtex 1H,contains a mixture of PETN and RDX softened by *** this work,BCHMX was used to replace PETN in Semtex 1H to form Sem-BC+*** addition,another mixture based on BCHMX and HMX as energetic fillers bonded by the polymeric matrix of Semtex 1H(Sem-BC+HMX)was *** particle size distribution of each individual explosive was determined to obtain the optimum mixing *** and impact sensitivities were *** velocity of detonation was reported practically and the detonation properties were calculated by EXPLO5 *** explosive strength of each sample was measured by the ballistic mortar *** conclusion confirms that the velocity of detonation of Sem-BC+HMX was the highest in comparison with the prepared ***-BC+RDX has the least impact and frictions ***-BC+RDX has higher detonation velocity,detonation properties and explosive strength than Semtex *** of BCHMX in Semtex 1H as a replacement for PETN is the candidate to produce a high performance advanced Czech plastic explosive.

关键词： Semtex Explosives Combustion Sensitivity Detonation Explosive strength

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Habitat productivity and pyrethroid susceptibility status of Aedes aegypti mosquitoes in Dar es Salaam,Tanzania

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Infectious Diseases of Poverty 2017年第1期6卷 921-930页

作者： Leah Mathias Vito baraka Anitha Philbert Ester Innocent Filbert Francis Gamba N.kwengulila Eliningaya J.Kweka Department of Zoology and Wildlife Conservation College of Natural and Applied SciencesUniversity of Dar es SalaamP.O.Box 35165Dar es SalaamTanzania National Institute for Medical Research Tanga Medical Research CentreP.O.Box 5004Tanga UrbanTangaTanzania Global Health Institute University of AntwerpGouverneur KinsbergencentrumDoornstraat 331B-2610WilrijkBelgium Mkwawa University College of Education Private BagIringaTanzania Institute of Traditional Medicine Muhimbili University of Health and Allied SciencesP.O.Box 65001Dar es SalaamTanzania Department of Medical Parasitology and Entomology Catholic University of Health and Allied SciencesP.O.Box 1464MwanzaTanzania Division of Livestock and Human Diseases Vector Control Tropical Pesticides Research InstituteNgaramtoniOff Nairobi RoadP.O.Box 3024ArushaTanzania

Background:Aedes aegypti(Diptera:Culicidae)is the main vector of the dengue virus *** vector control is mainly based on reducing the vector population through interventions,which target potential breeding ***,in Tanzania,little is known about this vector’s habitat productivity and insecticide susceptibility status to support evidence-based implementation of control *** present study aimed at assessing the productivity and susceptibility status of *** mosquitoes to pyrethroid-based insecticides in Dar es Salaam,***:An entomological assessment was conducted between January and July 2015 in six randomly selected wards in Dar es Salaam,*** productivity was determined by the number of female adult *** mosquitoes emerged per square *** susceptibility status of adult *** females after exposure to 0.05%deltamethrin,0.75%permethrin and 0.05%lambda-cyhalothrin was evaluated using the standard WHO *** rates were recorded after 24 h exposure and the knockdown effect was recorded at the time points of 10,15,20,30,40,50 and 60 min to calculate the median knockdown times(KDT50 and KDT95).Results:The results suggest that disposed tyres had the highest productivity,while water storage tanks had the lowest productivity among the breeding habitats Of *** *** sites demonstrated reduced susceptibility to deltamethrin(0.05%)within 24 h post exposure,with mortalities ranging from 86.3±1.9(mean±SD)to 96.8±0.9(mean±SD).The lowest and highest susceptibilities were recorded in Mikocheni and Sinza wards,***,all sites demonstrated reduced susceptibility permethrin(0.75%)ranging from 83.1±2.1%(mean±SD)to 96.2±0.9%(mean±SD),in Kipawa and Sinza,*** low mortality rates were observed in relation to lambda-cyhalothrin(0.05%)at all sites,ranging from 83.1±0.7(mean±SD)to 86.3±1.4(mean±SD).The median KDT_(50)for deltamethrin,permethrin and lambda-cyhalo

关键词： Culicidae Aedes aegypti Abundance Productivity Pyrethroid Knockdown effect Dar es Salaam Tanzania

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