The global warming which preoccupies humanity,is still considered to be linked to a single cause which is the emission of greenhouse gases,CO2 in particular.In this article,we try to show that,on the one hand,the gree...The global warming which preoccupies humanity,is still considered to be linked to a single cause which is the emission of greenhouse gases,CO2 in particular.In this article,we try to show that,on the one hand,the greenhouse effect(the radiative imprisonment to use the scientific term)took place in conjunction with the infrared radiation emitted by the earth.The surplus of CO2 due to the combustion of fossil fuels,but also the surplus of infrared emissions from artificialized soils contribute together or each separately,to the imbalance of the natural greenhouse effect and the trend of global warming.In addition,another actor acting directly and instantaneously on the warming of the ambient air is the heat released by fossil fuels estimated at 17415.1010 kWh/year inducing a rise in temperature of 0.122°C,or 12.2°C/century.展开更多
Britholites are considered as potential matrices for storage of nuclear wastes such as minor actinides and long-lived fission byproducts. This investigation is concerned with the study of simultaneous substitution in ...Britholites are considered as potential matrices for storage of nuclear wastes such as minor actinides and long-lived fission byproducts. This investigation is concerned with the study of simultaneous substitution in calcium fluor-britholite framework of two lanthanide ions assimilated to radionuclides. A series of calcium fluorbritholites doped with lanthanum and neodymium Ca8La2-xNdx(PO4)4(SiO4)2F2 with 0 ≤ x ≤ 2 were prepared via a solid state reaction in the temperature range 1450℃- 1250℃. The obtained products were characterized by several techniques such as Chemical analysis via Inductively coupled plasma Atomic emission spectrometry ICP-AES, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy FTIR and Nuclear magnetic resonance 31P NMR (MAS). Obtained solid solutions containing lanthanum and neodymium in variable proportions were typically apatite of hexagonal structure P63/m spatial group. The stoichiometry of the powders was verified via the metal/(phosphate + silicate) molar ratios found at about 1.67. The lattice parameters a and c calculated by the Rietveld method decreased as neodymium level increased. Despite, the close respective sizes of lanthanum and neodymium ions (VIrLa3+= 1.032A, VIrNd3+= 0.983A), their mutual substitutions led to solid solutions in whole range of composition with preferential occupation of Me (2) sites.展开更多
The environment suffers more and more from the accumulation of plastics made by petrochemical rows,which are non-biodegradable.That is why this study aims to develop bio-based films by incorporating fibers concentrate...The environment suffers more and more from the accumulation of plastics made by petrochemical rows,which are non-biodegradable.That is why this study aims to develop bio-based films by incorporating fibers concentrate of parthenocarpic date(FCPD)as easily available ingredients.The FCPD based film showed enhanced thickness,water solubility,phenol content and antioxidant capacity.However,the transparency was reduced which enhanced the film opacity by the addition of FCPD.Scanning electronic microscopy(SEM)showed homogeneity between fibers and the constituents of the film.The addition of FCPD did not change the FTIR peaks in comparison with starch-based film.The hydroxyl index value and water contact angle showed that the hydrophilicity increases with the film FCPD percentage.In addition,the FCPDs have enhanced the microbial biodegradation of the developed films as showed by SEM.Quantitative PCR using specific primers for nine target microbial groups showed that fungi were the predominant agent of the biodegradation.Among bacteria,realtime PCR showed thatβ-Proteobacteria,Acidobacteria,Bacteriodetes andα-Proteobacteria groups were involved in film biodegradation.展开更多
文摘The global warming which preoccupies humanity,is still considered to be linked to a single cause which is the emission of greenhouse gases,CO2 in particular.In this article,we try to show that,on the one hand,the greenhouse effect(the radiative imprisonment to use the scientific term)took place in conjunction with the infrared radiation emitted by the earth.The surplus of CO2 due to the combustion of fossil fuels,but also the surplus of infrared emissions from artificialized soils contribute together or each separately,to the imbalance of the natural greenhouse effect and the trend of global warming.In addition,another actor acting directly and instantaneously on the warming of the ambient air is the heat released by fossil fuels estimated at 17415.1010 kWh/year inducing a rise in temperature of 0.122°C,or 12.2°C/century.
文摘Britholites are considered as potential matrices for storage of nuclear wastes such as minor actinides and long-lived fission byproducts. This investigation is concerned with the study of simultaneous substitution in calcium fluor-britholite framework of two lanthanide ions assimilated to radionuclides. A series of calcium fluorbritholites doped with lanthanum and neodymium Ca8La2-xNdx(PO4)4(SiO4)2F2 with 0 ≤ x ≤ 2 were prepared via a solid state reaction in the temperature range 1450℃- 1250℃. The obtained products were characterized by several techniques such as Chemical analysis via Inductively coupled plasma Atomic emission spectrometry ICP-AES, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy FTIR and Nuclear magnetic resonance 31P NMR (MAS). Obtained solid solutions containing lanthanum and neodymium in variable proportions were typically apatite of hexagonal structure P63/m spatial group. The stoichiometry of the powders was verified via the metal/(phosphate + silicate) molar ratios found at about 1.67. The lattice parameters a and c calculated by the Rietveld method decreased as neodymium level increased. Despite, the close respective sizes of lanthanum and neodymium ions (VIrLa3+= 1.032A, VIrNd3+= 0.983A), their mutual substitutions led to solid solutions in whole range of composition with preferential occupation of Me (2) sites.
基金supported by the project GreenPalm of the PRIMA European Action,Project 25/Section II-2019,PCI2020-112088 MINECOsupported by the project"Joint Tunisian Moroccan laboratory:Laboratory of Plant Physiology and Biotechnology and Climate Change(LR11ES09).
文摘The environment suffers more and more from the accumulation of plastics made by petrochemical rows,which are non-biodegradable.That is why this study aims to develop bio-based films by incorporating fibers concentrate of parthenocarpic date(FCPD)as easily available ingredients.The FCPD based film showed enhanced thickness,water solubility,phenol content and antioxidant capacity.However,the transparency was reduced which enhanced the film opacity by the addition of FCPD.Scanning electronic microscopy(SEM)showed homogeneity between fibers and the constituents of the film.The addition of FCPD did not change the FTIR peaks in comparison with starch-based film.The hydroxyl index value and water contact angle showed that the hydrophilicity increases with the film FCPD percentage.In addition,the FCPDs have enhanced the microbial biodegradation of the developed films as showed by SEM.Quantitative PCR using specific primers for nine target microbial groups showed that fungi were the predominant agent of the biodegradation.Among bacteria,realtime PCR showed thatβ-Proteobacteria,Acidobacteria,Bacteriodetes andα-Proteobacteria groups were involved in film biodegradation.
