This paper presents a new strategy of embedded energy management between battery and supercapacitors （SC） for hybrid electric vehicles （HEV） applications. This proposal is due to the present trend in the field, kn...This paper presents a new strategy of embedded energy management between battery and supercapacitors （SC） for hybrid electric vehicles （HEV） applications. This proposal is due to the present trend in the field, knowing that the major drawback of the HEV is the autonomy problem. Thus, using supercapacitors and battery with a good energy management improves the HEV performances. The main contribution of this paper is focused on DC-bus voltage and currents control strategies based on polynomial controller. These strategies are implemented in PICI8F4431 microcontroller for DC/DC converters control. Due to reasons of cost and available components （no optimized）, such as the battery and power semiconductors （IGBT）, the experimental tests are carried out in reduced scale （2.7 kW）. Through some simulations and experimental results obtained in reduced scale, the authors present an improved energy management strategy for HEV.展开更多
The sheer amount of disposable bottles being produced nowadays makes it imperative to identify alternative procedures for recycling them since they are non-biodegradable. Experimental investigation on the effects of p...The sheer amount of disposable bottles being produced nowadays makes it imperative to identify alternative procedures for recycling them since they are non-biodegradable. Experimental investigation on the effects of polyethylene terephthalate (PET) polymer, which is a waste material obtained by crushing of used PET bottles, on the mineralogical composition of composites after 28 days of casting are presented in this paper. Various weight fractions of cement 2.5%, 5% and 7.5% were replaced by the same weight of PET plastic;they were then moulded into specimens and cured. The fine powder samples obtained from broken specimens were subjected to X-ray diffraction, FT-IR spectroscopy, differential thermal analysis, thermogravimetric analysis and the composites were also observed by optical microscope. Thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to study the interaction between polymers and cements. Differential thermal analysis (DTA), X-ray diffraction and FT-IR were also used to investigate the cement hydration according to the additions. The results showed that an increase in polymer-cement ratio meets with a decrease in the quantity of Ca(OH)2;in terms of bonding, the rough surface of particle favours greater contact between PET and cement matrix and doesn’t seem to have chemical interaction between the mineral species and the organic molecules which could lead to the formation of new compounds. The present study highlights the capabilities of the different methods for the analysis of composites and opened new way for the recycling of PET in polymer-mortars.展开更多
This investigation contributes to a better understanding of condensation heat transfer in horizontal non-circular microchannels. For this purpose, the conservation equations of mass, momentum and energy have been nume...This investigation contributes to a better understanding of condensation heat transfer in horizontal non-circular microchannels. For this purpose, the conservation equations of mass, momentum and energy have been numerically solved in both phases (liquid and vapor), and all the more, so the film thickness analytical expression has been established. Numerical results relative to variations of the meniscus curvature radius, the condensate film thickness, the condensation length and heat transfer coefficients, are analyzed in terms of the influencing physical and geometrical quantities. The effect of the microchannel shapes on the average Nusselt number is highlighted by studying condensation of steam insquare, rectangular and equilateral triangular microchannels with the same hydraulic diameter of 250 μm.展开更多
Researches into new and innovative uses of waste plastic materials are continuously advancing. These research efforts try to match society’s need for safe and economic disposal of waste materials. The use of recycled...Researches into new and innovative uses of waste plastic materials are continuously advancing. These research efforts try to match society’s need for safe and economic disposal of waste materials. The use of recycled plastic aggregates saves natural resources and dumping spaces, and helps to maintain a clean environment. The present articles deals with the resistance to chemical attack of polymer-mortars, which are often used as low-cost promising materials for preventing or repairing various reinforced concrete structures. To gain more knowledge on the efficiency of polymer-mortar composites, four mortar mixtures: one specimen with Portland cement and three mixtures with 2.5, 5, and 7.5 wt% of the substitution of cement by polyethylene terephthalate (PET) were exposed to the influence of aggressive environment (0.5%, 1% and 1.5% HCl acids, 10% NH4Cl, 5% H2SO4 acid and 10% (NH4)2SO4 solutions). The measurements of several properties were carried out, the results were analyzed and the combination of X-ray diffraction, FT-IR spectroscopy, differential thermal analysis (DTA), thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) analysis and the composites were also observed by SEM led to the positive identification of the deterioration products’ formation. From this study, it was found that the addition of PET to the modified mortars, means reducing the penetration of aggressive agents. So, the PET-modified mortars exposed to aggressive environments showed better resistance to chemical attack. The new composites appear to offer an attractive low-cost material with consistent properties. The present study highlights the capabilities of the different methods for the analysis of composites and opened new way for the recycling of PET in polymer-mortars.展开更多
Ceramic porous MgTiO3 materials have been prepared by classical solid-state route. The sintered pellets of MgTiO3 with different LiF contents were characterized for humidity-sensing application. The sintered disks of ...Ceramic porous MgTiO3 materials have been prepared by classical solid-state route. The sintered pellets of MgTiO3 with different LiF contents were characterized for humidity-sensing application. The sintered disks of these mixtures were subjected to capacitance measurements at 20℃as function of the relative humidity from which revealed that the Mixture MgTiO3 + 2% LiF (w/w) has the better characteristics. The disks were subjected to DC resistance measurements as a function of relative humidity in the range 15% - 95% RH. The selectivity of this material was discussed and compared to commercial sensor results. The response and recovery characteristics were assessed.展开更多
文摘This paper presents a new strategy of embedded energy management between battery and supercapacitors （SC） for hybrid electric vehicles （HEV） applications. This proposal is due to the present trend in the field, knowing that the major drawback of the HEV is the autonomy problem. Thus, using supercapacitors and battery with a good energy management improves the HEV performances. The main contribution of this paper is focused on DC-bus voltage and currents control strategies based on polynomial controller. These strategies are implemented in PICI8F4431 microcontroller for DC/DC converters control. Due to reasons of cost and available components （no optimized）, such as the battery and power semiconductors （IGBT）, the experimental tests are carried out in reduced scale （2.7 kW）. Through some simulations and experimental results obtained in reduced scale, the authors present an improved energy management strategy for HEV.
文摘The sheer amount of disposable bottles being produced nowadays makes it imperative to identify alternative procedures for recycling them since they are non-biodegradable. Experimental investigation on the effects of polyethylene terephthalate (PET) polymer, which is a waste material obtained by crushing of used PET bottles, on the mineralogical composition of composites after 28 days of casting are presented in this paper. Various weight fractions of cement 2.5%, 5% and 7.5% were replaced by the same weight of PET plastic;they were then moulded into specimens and cured. The fine powder samples obtained from broken specimens were subjected to X-ray diffraction, FT-IR spectroscopy, differential thermal analysis, thermogravimetric analysis and the composites were also observed by optical microscope. Thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to study the interaction between polymers and cements. Differential thermal analysis (DTA), X-ray diffraction and FT-IR were also used to investigate the cement hydration according to the additions. The results showed that an increase in polymer-cement ratio meets with a decrease in the quantity of Ca(OH)2;in terms of bonding, the rough surface of particle favours greater contact between PET and cement matrix and doesn’t seem to have chemical interaction between the mineral species and the organic molecules which could lead to the formation of new compounds. The present study highlights the capabilities of the different methods for the analysis of composites and opened new way for the recycling of PET in polymer-mortars.
文摘This investigation contributes to a better understanding of condensation heat transfer in horizontal non-circular microchannels. For this purpose, the conservation equations of mass, momentum and energy have been numerically solved in both phases (liquid and vapor), and all the more, so the film thickness analytical expression has been established. Numerical results relative to variations of the meniscus curvature radius, the condensate film thickness, the condensation length and heat transfer coefficients, are analyzed in terms of the influencing physical and geometrical quantities. The effect of the microchannel shapes on the average Nusselt number is highlighted by studying condensation of steam insquare, rectangular and equilateral triangular microchannels with the same hydraulic diameter of 250 μm.
文摘Researches into new and innovative uses of waste plastic materials are continuously advancing. These research efforts try to match society’s need for safe and economic disposal of waste materials. The use of recycled plastic aggregates saves natural resources and dumping spaces, and helps to maintain a clean environment. The present articles deals with the resistance to chemical attack of polymer-mortars, which are often used as low-cost promising materials for preventing or repairing various reinforced concrete structures. To gain more knowledge on the efficiency of polymer-mortar composites, four mortar mixtures: one specimen with Portland cement and three mixtures with 2.5, 5, and 7.5 wt% of the substitution of cement by polyethylene terephthalate (PET) were exposed to the influence of aggressive environment (0.5%, 1% and 1.5% HCl acids, 10% NH4Cl, 5% H2SO4 acid and 10% (NH4)2SO4 solutions). The measurements of several properties were carried out, the results were analyzed and the combination of X-ray diffraction, FT-IR spectroscopy, differential thermal analysis (DTA), thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) analysis and the composites were also observed by SEM led to the positive identification of the deterioration products’ formation. From this study, it was found that the addition of PET to the modified mortars, means reducing the penetration of aggressive agents. So, the PET-modified mortars exposed to aggressive environments showed better resistance to chemical attack. The new composites appear to offer an attractive low-cost material with consistent properties. The present study highlights the capabilities of the different methods for the analysis of composites and opened new way for the recycling of PET in polymer-mortars.
文摘Ceramic porous MgTiO3 materials have been prepared by classical solid-state route. The sintered pellets of MgTiO3 with different LiF contents were characterized for humidity-sensing application. The sintered disks of these mixtures were subjected to capacitance measurements at 20℃as function of the relative humidity from which revealed that the Mixture MgTiO3 + 2% LiF (w/w) has the better characteristics. The disks were subjected to DC resistance measurements as a function of relative humidity in the range 15% - 95% RH. The selectivity of this material was discussed and compared to commercial sensor results. The response and recovery characteristics were assessed.
