The use of agricultural residues in biocomposite production has gained increasing attention,driven by several benefits.Converting agricultural by-products into bio-based materials within a circular economy represents ...The use of agricultural residues in biocomposite production has gained increasing attention,driven by several benefits.Converting agricultural by-products into bio-based materials within a circular economy represents a sustainable strategy to mitigate lignocellulosic waste,reduce reliance on fossil resources,and lower environmental pollution.This approach also creates economic opportunities for rural African communities by generating diverse income sources for workers in collection,processing,and manufacturing.As a result,the integration of agricultural residues into biocomposites production not only addresses environmental concerns but also fosters economic growth and supports rural development.In this review,five biomasses from West Africa are examined,focusing on their production,chemical composition,physical and mechanical properties,and potential applications in biocomposites.The five biomasses listed are cocoa pod husks,oil palm empty fruit bunches,rice husks,millet stalks,and typha stalks.Key parameters,such as the type of binder,fiber dimensions,fiber-to-binder ratio,and the strength of fiber-binder adhesion,are systematically studied to assess their influence on the overall performance of the resulting composites.Special attention is given to understanding how these factors affect mechanical properties(e.g.,strength and flexibility),thermal behavior(e.g.,insulation capacity and heat resistance),and physico-chemical characteristics(e.g.,moisture absorption,density,and chemical stability).This comprehensive analysis provides insights into optimizing composite formulations for enhanced functionality and sustainability.This study is essential to optimize the use of agricultural residues inWest Africa for biocomposites,tackling waste issues,promoting sustainability,and filling research gaps on their properties.展开更多
The valorization of Amazonian wood residues into active chemical compounds could be an eco-friendly,cost-effective and valuable way to develop wood preservative formulations to enhance the decay and termite resistance...The valorization of Amazonian wood residues into active chemical compounds could be an eco-friendly,cost-effective and valuable way to develop wood preservative formulations to enhance the decay and termite resistance of low-durable wood species.Wacapou(Vouacapoua americana.,Fabaceae)is a well-known Guianese wood spe-cies commonly used in local wood construction due to its outstanding natural durability,which results from the presence of a large panel of extractives compounds.In addition,its industrial processing generates large amounts of residues.Wacapou residues were extracted by maceration using four different solvents(water/ethanol,ethyl acetate,hexane and dichloromethane/methanol),separately and successively.The yield of each extractive fraction was determined,and their chemical compositions were analyzed by Liquid Chromatography-Mass Spectrometry(LC-MS).Ethyl acetate led to the highest extraction yield,and the active compounds were identified in the obtained extractive fraction.In this sense,the fungicidal and termite-repellent properties of these extractives were then tested using a screening laboratory(with temperate and tropical microorganisms),according to the solution concentration(1%,2.5%,5%,8%and 10%).Finally,Virola michelii Heckel wood samples(low durable species)were impregnated with the 8%concentration solution.The impregnated wood samples were then exposed to a soil bed test.The results highlighted that the nature of the solvent used during wood maceration affects the con-tent of the obtained extractive fractions.Ultra-Performance Liquid Chromatography–High-Resolution Mass Spectrometry(UHPLC-HRMS)analyses showed the influence of extraction parameters on the nature of the extracted molecules.Wacapou extracts(from ethyl acetate maceration)showed good anti-fungal and anti-termite activities.Additionally,the concentration in extractives had an impact on the anti-termite activity level for Reti-culitermesflavipes and Cryptotermes sp.Formulations based on Wacapou extractives showed a good potential for valorization in eco-friendly preservatives,aiming to confer better durability to local low-durability wood species.展开更多
Sugarcane bagasse was pyrolyzed using a laboratory fixed bed reactor to produce char and its by-product(pyrolysis liquid).The pyrolysis experiments were carried out using different temperatures(400℃ and 500℃),heatin...Sugarcane bagasse was pyrolyzed using a laboratory fixed bed reactor to produce char and its by-product(pyrolysis liquid).The pyrolysis experiments were carried out using different temperatures(400℃ and 500℃),heating rate(1℃/min and 10℃/min),and holding time(30 min and 60 min).Char was characterized according to its thermal properties,while the pyrolysis liquid was tested for its anti-fungal and anti-termite activities.Pyrolysis temperature and heating rate had a significant influence on the char properties and the yield of char and pyrolysis liquid,where a high-quality char and high yield of pyrolysis liquid can be obtained at a temperature of 500℃ and a heating rate of 10℃/min.The yield of char and pyrolysis liquid was 28.97%and 55.46%,respectively.The principal compounds of pyrolysis liquid were water,acetic acid,glycolaldehyde,1-hydroxy-2-propanone,methanol,formic acid,levoglucosan,furfural,followed by some phenol compounds and guaiacol derivatives.Pyrolysis liquid at a concentration of 0.20%and 0.25%(v/v)caused a 100%inhibition of Coniophora puteana and Trametes versicolor,respectively,when performing inhibition growth tests in Petri dishes.Filter paper treated with 10%of pyrolysis liquid caused 100%of termite mortality,while only 5.65%–7.03%of the treated filter papers consumed by termites at such concentration.Pyrolysis liquid is potentially effective to be used in the formulation of wood protection against fungi and termites.展开更多
Impregnation of dry wood with pure lactic acid oligomers(OLAs)followed by heat treatment confers promising properties to wood because of OLA’s good diffusion,in-situ polymerization and persistence in cell walls.Treat...Impregnation of dry wood with pure lactic acid oligomers(OLAs)followed by heat treatment confers promising properties to wood because of OLA’s good diffusion,in-situ polymerization and persistence in cell walls.Treatment provides drastic reduction of the equilibrium moisture content,high dimensional stability and good durability.The presence of water during treatment has been evaluated.Curing of OLA impregnated dry wood in humid atmosphere leads to a strong and global degradation of the material.OLA treatment of wet wood only impacts the water leaching rate negatively.Treatment of dry wood with OLA diluted in water additionally decreases the biological resistance and is not efficient for decreasing hygroscopicity.Treatment of dry wood with lactic acid solution leads to a lower polymerization level but confers good properties.展开更多
The past literature on the use of vegetable oils as fuel in diesel engine revealed that utilizing vegetable oil fuels in diesel engines may require property changes in the oil or perhaps, some minor engine modificatio...The past literature on the use of vegetable oils as fuel in diesel engine revealed that utilizing vegetable oil fuels in diesel engines may require property changes in the oil or perhaps, some minor engine modifications or operating changes. This study was conducted to search for the effect of atmospheric oxygen on the puffing and bursting phenomena that occur during vegetable oils droplet vaporization process in their use as fuel in diesel engine. The fiber-suspended droplet technique was used, and the normalized square droplet diameter as well as the temperature evolution vicinity the droplet was analyzed. The results show that puffing and bursting phenomena highly depend on oxygen. In presence of atmospheric oxygen, there is an increase of the puffing and bursting intensity and therefore the evaporation rate of the vegetable oil droplets, but in an inert environment or when the environment is oxygen-depleted puffing and bursting phenomena disappearing and make place of a series of explosions with lower magnitude. The lack of oxygen reduces the thermal degradation, polymerization and oxidation reactions and consequently the vaporization rate of vegetable oils droplets;and could therefore lead to the formation of deposits in the form of polymers. This is unsuitable for their use as a fuel in diesel engines. It can also be concluded that atmospheric oxygen has some positive effects on engine performance and emissions when operating with vegetable oil. These results help to address the challenge for the use of alternative fuels such as non-edible vegetable oils.展开更多
Oil Palm Shell (OPS) concrete can be used in different fields of construction. To determine more accurately the fields of application, it is important to know and understand the behaviour of OPS concrete over<span ...Oil Palm Shell (OPS) concrete can be used in different fields of construction. To determine more accurately the fields of application, it is important to know and understand the behaviour of OPS concrete over<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> long term and when it is in aggressive environments. This paper presents the results of studies conducted on the durability of OPS concrete. Water absorption capacity, electrical resistivity and apparent diffusion of chloride ions have been measured on different concrete samples. In addition, the behaviour of OPS concretes to carbonation was studied in an environment rich in carbon dioxide. Results show that OPS concrete ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> an absorptivity of 0.97 kg/m</span><sup><span style="font-family:Verdana;">2</span></sup></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">h</span><sup><span style="font-family:Verdana;">1/2</span></sup><span style="font-family:Verdana;">, an electrical resistivity of 64.37 Ω</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">m and an apparent diffusion coefficient of chloride ions of 3.84</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> × </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">10</span><sup><span style="font-family:Verdana;">-12</span></sup><span style="font-family:Verdana;"> m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/s after 90 days. All these results of OPS concrete are very close to those of concrete with normal aggregate and other lightweight concrete</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> which mean OPS concretes have globally good properties with regard to durability</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span>展开更多
Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and th...Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and these engineered products can overcome some solid wood limitations such as heterogeneity and dimension.Bagasse offers an alternative to wood chips for particleboard production but present some disadvantages as well,such as poor physico-mechanical properties.To address these issues,bagassefibers were treated with an innovative natural resin formulated with tannin and furfural.Impregnated particles with different concentrations of resin(5%,10%,and 15%m/m)were exposed to temperatures of 40℃,60℃,80℃,and 100℃ for resin curing.Various types of tannin-based adhesives,including tannin formaldehyde,tannin/formaldehyde-furfural,and tannin hex-amine,were utilized for bonding the treated bagasse particles.The resultant panels were assessed for their physical and mechanical properties and compared to those produced using Melamine-Urea-Formaldehyde(MUF)adhe-sive.The density of the panels varied from 650 to 730 kg/m^(3) depending on the resin concentration.The values for both modulus of elasticity and modulus of rupture increased as the resin concentration increased.The internal bonding values exhibited an increase with resin concentration up to a critical point,after which a decreasing trend was observed.The water absorption and thickness swelling were significantly reduced with an increase in resin concentration.However,the panels produced using MUF adhesive yielded the most favorable physico-mechanical properties.Additionally,the panels made with tannin-based adhesives met the minimum requirements specified in the standard EN 312(specifications for uncoated resin-bonded particleboards)for application in dry condi-tions.The analysis of formaldehyde emissions indicated that panels produced with tannin-based adhesives exhib-ited significantly lower emissions compared to those made with MUF.The tannin/furfural resin showed great potential for improving the quality of bagasse particleboard using tannin-based adhesives.展开更多
Aromatic plant distillation produces residues rich in phenolic compounds known to be bioactive. In this context, residues from the hydrodistillation of Mentha piperita L., Cymbopogon citratus Stapf, and Eucalyptus cam...Aromatic plant distillation produces residues rich in phenolic compounds known to be bioactive. In this context, residues from the hydrodistillation of Mentha piperita L., Cymbopogon citratus Stapf, and Eucalyptus camaldulensis Dehnh were chemically and biologically analyzed. The ethanol percentages (70%, 50%, and 30%) were evaluated by determining antioxidant activity using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, total phenolic content, and total flavonoid content. Antifungal activity was evaluated “in vitro” against Fusarium oxysporum, Alternaria alternata, Trametes versicolor, and Coniophora puteana using the diffusion method in malt-agar medium. Antitermite activity was also assessed against Reticulitermes flavipes using the most active extract with low ethanol concentrations (50% and 30%). The optimum ethanol concentration to extract phenolic compounds is 70% for TFC and 30% for TPC, and the antioxidant activity was 0.45 ± 0.01 mg/mL (IC50). The most active extracts were the ethanolic ones, particularly for Eucalyptus camaldulensis, presenting 100% inhibition against the mycelial growth of Coniophora puteana and Alternaria alternata at 1 mg/mL and 0.5 mg/mL, respectively. For antitermite activity, EE50 was the most effective, with a 24% termite survival rate and a degraded food supply surface of 28%. These data suggest the potential use of hydrodistillation residues for biopesticide development.展开更多
This paper presents an analysis of the effect of two synthetic antioxidants on the vaporization processes of coconut and linseed oils for fuel use. Several studies agree on the effectiveness of synthetic or natural an...This paper presents an analysis of the effect of two synthetic antioxidants on the vaporization processes of coconut and linseed oils for fuel use. Several studies agree on the effectiveness of synthetic or natural antioxidants against the polymerization of vegetable oils. The principle of action of the latter is to increase the rate of vaporization, to the detriment of polymer formation. The droplet suspension technique where a fiber is used to hold a stationary droplet has been used. The vaporization was conducted within a closed chamber under ambient pressure conditions in an inert and oxidizing environment at temperatures of 703 K. The method involves monitoring the projected surface area of vegetable oil droplet blended with antioxidants. The projected area (mm2) of the droplet during the vaporization process as a function of time (s) has been used to determine the vaporization coefficient, or the residue formation rate. The main findings are that the two antioxidants used at 200 ppm and 500 ppm have no influence on the vaporization of saturated oils like coconut, while on unsaturated oils like linseed the two antioxidants appear to reduce slightly the deposition of residues which are identified as polymers and increase slightly vaporization rate. In practice, antioxidants could be used as additives in vegetable oils to facilitate their combustion in diesel engines, representing a potential solution for improving combustion efficiency. To enhance the reliability of the findings, it would be advisable to increase the number of antioxidants and extend the study to encompass a wider range of vegetable oils.展开更多
This work gives tools to overcome the difficulty to determine experimentally physical properties for vegetable oils within the range of temperature typically observed during the injection phase in a diesel engine. Kno...This work gives tools to overcome the difficulty to determine experimentally physical properties for vegetable oils within the range of temperature typically observed during the injection phase in a diesel engine. Knowing vegetable oils’ physical properties to these ranges of temperature is of fundamental importance when modeling their combustion in diesel engine. However, vegetable oils’ experimental physical properties data are rare in the literature for temperature above 523 K. This paper describes experimental measurements and estimation methods for density, dynamic viscosity, thermal conductivity and heat capacity of vegetable oils for this particular range of temperature. The methodology uses several correlative methods using group contribution approach for each property and compares experimental data with predicted one to select the more accurate model. This work has shown the rapeseed and jatropha oils’ physical properties can be satisfactorily predicted as a function of temperature using group contribution approach.展开更多
Furan fatty acids produced by plants and bacteria,and present in some edible resources,have attracted significant scientific attention for their health benefits.They include 10,13-epoxy-11-methyl-octadecan-10,12-dieno...Furan fatty acids produced by plants and bacteria,and present in some edible resources,have attracted significant scientific attention for their health benefits.They include 10,13-epoxy-11-methyl-octadecan-10,12-dienoic acid,which has been identified in the lipid fraction of latex from two Hevea brasiliensis genotypes commonly known as the source of natural rubber.Those two genotypes,namely RRIM501 and PB235,are from Rubber Research Institute of Malaysia(RRIM)and Prang Besar,Malaysia(PB),respectively.This research aimed to undertake the first ever in-vestigation into the existence of this potential high value-added co-product in the lipid fraction of 48 Hevea brasiliensis genotypes,seeking to study the widest possible clonal variability.The results showed furan fatty acid exists in all lipid fractions of their latices.Its content varied significantly,ranging from 0.01%to 0.71%(w/w in latex),the highest concentrations were found in genotypes from the Institut de Recherche sur le Caoutchouc(IRCA)in Côte d’Ivoire,Prang Besar(PB)in Malaysia,and Rubber Research Institute of Vietnam(RRIV)in Vietnam breeding programs.A positive correlation with total fatty acid content was observed when its content exceeded 0.10%,suggesting an additive rather than a substitutive role with the other fatty acids present.Interest-ingly,linoleic and palmitoleic acids strongly correlated with the furan fatty acid concentration,indicating a possible biosynthetic pathway linkage.In terms of yield per tapping PB235,RRIV4,RRIV2,IRCA41,IRCA18,PB324,IRCA814,IRCA323,and IRCA109 genotypes showed the highest production potential,with yields range of 1367-2446 mg furan fatty acid per tree per tapping.Notably,the biochemical markers of natural rubber productivity(sucrose,inorganic phosphorus,thiols,and total solid content)showed no direct involvement in furan fatty acid biosynthesis dur-ing latex regeneration between tappings.Based on knowledge of the parentage of the studied clones,a trait heritability study was conducted and genotype PB5/51 was identified as a very worthwhile genitor for improving furan fatty acid contents in a breeding population.展开更多
基金BIO4Africa Project which is funded by the European Union(Horizon 2020-No.101000762).
文摘The use of agricultural residues in biocomposite production has gained increasing attention,driven by several benefits.Converting agricultural by-products into bio-based materials within a circular economy represents a sustainable strategy to mitigate lignocellulosic waste,reduce reliance on fossil resources,and lower environmental pollution.This approach also creates economic opportunities for rural African communities by generating diverse income sources for workers in collection,processing,and manufacturing.As a result,the integration of agricultural residues into biocomposites production not only addresses environmental concerns but also fosters economic growth and supports rural development.In this review,five biomasses from West Africa are examined,focusing on their production,chemical composition,physical and mechanical properties,and potential applications in biocomposites.The five biomasses listed are cocoa pod husks,oil palm empty fruit bunches,rice husks,millet stalks,and typha stalks.Key parameters,such as the type of binder,fiber dimensions,fiber-to-binder ratio,and the strength of fiber-binder adhesion,are systematically studied to assess their influence on the overall performance of the resulting composites.Special attention is given to understanding how these factors affect mechanical properties(e.g.,strength and flexibility),thermal behavior(e.g.,insulation capacity and heat resistance),and physico-chemical characteristics(e.g.,moisture absorption,density,and chemical stability).This comprehensive analysis provides insights into optimizing composite formulations for enhanced functionality and sustainability.This study is essential to optimize the use of agricultural residues inWest Africa for biocomposites,tackling waste issues,promoting sustainability,and filling research gaps on their properties.
基金PROTEXTWOOD (ID 2202-102) funded through LabEx AGRO ANR-10-LABX-0001-01 (under ISiteUniversité de Montpellier framework)the project PANTHER2-Guyane funded through AgenceNationale de la Recherche (ANR-22-CE43-0019)+2 种基金“Investissement d’Avenir” grant managed by Agence Nationale de la Recherche (CEBA, ref. ANR-10-LABX-25-01)supported by the FEDER (European Regional Development Fund)research project “EcovaloBois” (Project number: GY0015430)by the CNRS peps INSIS2018 research project “GuyavaloFibres”.
文摘The valorization of Amazonian wood residues into active chemical compounds could be an eco-friendly,cost-effective and valuable way to develop wood preservative formulations to enhance the decay and termite resistance of low-durable wood species.Wacapou(Vouacapoua americana.,Fabaceae)is a well-known Guianese wood spe-cies commonly used in local wood construction due to its outstanding natural durability,which results from the presence of a large panel of extractives compounds.In addition,its industrial processing generates large amounts of residues.Wacapou residues were extracted by maceration using four different solvents(water/ethanol,ethyl acetate,hexane and dichloromethane/methanol),separately and successively.The yield of each extractive fraction was determined,and their chemical compositions were analyzed by Liquid Chromatography-Mass Spectrometry(LC-MS).Ethyl acetate led to the highest extraction yield,and the active compounds were identified in the obtained extractive fraction.In this sense,the fungicidal and termite-repellent properties of these extractives were then tested using a screening laboratory(with temperate and tropical microorganisms),according to the solution concentration(1%,2.5%,5%,8%and 10%).Finally,Virola michelii Heckel wood samples(low durable species)were impregnated with the 8%concentration solution.The impregnated wood samples were then exposed to a soil bed test.The results highlighted that the nature of the solvent used during wood maceration affects the con-tent of the obtained extractive fractions.Ultra-Performance Liquid Chromatography–High-Resolution Mass Spectrometry(UHPLC-HRMS)analyses showed the influence of extraction parameters on the nature of the extracted molecules.Wacapou extracts(from ethyl acetate maceration)showed good anti-fungal and anti-termite activities.Additionally,the concentration in extractives had an impact on the anti-termite activity level for Reti-culitermesflavipes and Cryptotermes sp.Formulations based on Wacapou extractives showed a good potential for valorization in eco-friendly preservatives,aiming to confer better durability to local low-durability wood species.
文摘Sugarcane bagasse was pyrolyzed using a laboratory fixed bed reactor to produce char and its by-product(pyrolysis liquid).The pyrolysis experiments were carried out using different temperatures(400℃ and 500℃),heating rate(1℃/min and 10℃/min),and holding time(30 min and 60 min).Char was characterized according to its thermal properties,while the pyrolysis liquid was tested for its anti-fungal and anti-termite activities.Pyrolysis temperature and heating rate had a significant influence on the char properties and the yield of char and pyrolysis liquid,where a high-quality char and high yield of pyrolysis liquid can be obtained at a temperature of 500℃ and a heating rate of 10℃/min.The yield of char and pyrolysis liquid was 28.97%and 55.46%,respectively.The principal compounds of pyrolysis liquid were water,acetic acid,glycolaldehyde,1-hydroxy-2-propanone,methanol,formic acid,levoglucosan,furfural,followed by some phenol compounds and guaiacol derivatives.Pyrolysis liquid at a concentration of 0.20%and 0.25%(v/v)caused a 100%inhibition of Coniophora puteana and Trametes versicolor,respectively,when performing inhibition growth tests in Petri dishes.Filter paper treated with 10%of pyrolysis liquid caused 100%of termite mortality,while only 5.65%–7.03%of the treated filter papers consumed by termites at such concentration.Pyrolysis liquid is potentially effective to be used in the formulation of wood protection against fungi and termites.
文摘Impregnation of dry wood with pure lactic acid oligomers(OLAs)followed by heat treatment confers promising properties to wood because of OLA’s good diffusion,in-situ polymerization and persistence in cell walls.Treatment provides drastic reduction of the equilibrium moisture content,high dimensional stability and good durability.The presence of water during treatment has been evaluated.Curing of OLA impregnated dry wood in humid atmosphere leads to a strong and global degradation of the material.OLA treatment of wet wood only impacts the water leaching rate negatively.Treatment of dry wood with OLA diluted in water additionally decreases the biological resistance and is not efficient for decreasing hygroscopicity.Treatment of dry wood with lactic acid solution leads to a lower polymerization level but confers good properties.
文摘The past literature on the use of vegetable oils as fuel in diesel engine revealed that utilizing vegetable oil fuels in diesel engines may require property changes in the oil or perhaps, some minor engine modifications or operating changes. This study was conducted to search for the effect of atmospheric oxygen on the puffing and bursting phenomena that occur during vegetable oils droplet vaporization process in their use as fuel in diesel engine. The fiber-suspended droplet technique was used, and the normalized square droplet diameter as well as the temperature evolution vicinity the droplet was analyzed. The results show that puffing and bursting phenomena highly depend on oxygen. In presence of atmospheric oxygen, there is an increase of the puffing and bursting intensity and therefore the evaporation rate of the vegetable oil droplets, but in an inert environment or when the environment is oxygen-depleted puffing and bursting phenomena disappearing and make place of a series of explosions with lower magnitude. The lack of oxygen reduces the thermal degradation, polymerization and oxidation reactions and consequently the vaporization rate of vegetable oils droplets;and could therefore lead to the formation of deposits in the form of polymers. This is unsuitable for their use as a fuel in diesel engines. It can also be concluded that atmospheric oxygen has some positive effects on engine performance and emissions when operating with vegetable oil. These results help to address the challenge for the use of alternative fuels such as non-edible vegetable oils.
文摘Oil Palm Shell (OPS) concrete can be used in different fields of construction. To determine more accurately the fields of application, it is important to know and understand the behaviour of OPS concrete over<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> long term and when it is in aggressive environments. This paper presents the results of studies conducted on the durability of OPS concrete. Water absorption capacity, electrical resistivity and apparent diffusion of chloride ions have been measured on different concrete samples. In addition, the behaviour of OPS concretes to carbonation was studied in an environment rich in carbon dioxide. Results show that OPS concrete ha</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> an absorptivity of 0.97 kg/m</span><sup><span style="font-family:Verdana;">2</span></sup></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">h</span><sup><span style="font-family:Verdana;">1/2</span></sup><span style="font-family:Verdana;">, an electrical resistivity of 64.37 Ω</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">·</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">m and an apparent diffusion coefficient of chloride ions of 3.84</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> × </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">10</span><sup><span style="font-family:Verdana;">-12</span></sup><span style="font-family:Verdana;"> m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/s after 90 days. All these results of OPS concrete are very close to those of concrete with normal aggregate and other lightweight concrete</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> which mean OPS concretes have globally good properties with regard to durability</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span>
基金This work was supported by the office of vice-president for research and technology,University of Tehran,Gundishapur project 1584/45227SG,and Campus France.
文摘Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and these engineered products can overcome some solid wood limitations such as heterogeneity and dimension.Bagasse offers an alternative to wood chips for particleboard production but present some disadvantages as well,such as poor physico-mechanical properties.To address these issues,bagassefibers were treated with an innovative natural resin formulated with tannin and furfural.Impregnated particles with different concentrations of resin(5%,10%,and 15%m/m)were exposed to temperatures of 40℃,60℃,80℃,and 100℃ for resin curing.Various types of tannin-based adhesives,including tannin formaldehyde,tannin/formaldehyde-furfural,and tannin hex-amine,were utilized for bonding the treated bagasse particles.The resultant panels were assessed for their physical and mechanical properties and compared to those produced using Melamine-Urea-Formaldehyde(MUF)adhe-sive.The density of the panels varied from 650 to 730 kg/m^(3) depending on the resin concentration.The values for both modulus of elasticity and modulus of rupture increased as the resin concentration increased.The internal bonding values exhibited an increase with resin concentration up to a critical point,after which a decreasing trend was observed.The water absorption and thickness swelling were significantly reduced with an increase in resin concentration.However,the panels produced using MUF adhesive yielded the most favorable physico-mechanical properties.Additionally,the panels made with tannin-based adhesives met the minimum requirements specified in the standard EN 312(specifications for uncoated resin-bonded particleboards)for application in dry condi-tions.The analysis of formaldehyde emissions indicated that panels produced with tannin-based adhesives exhib-ited significantly lower emissions compared to those made with MUF.The tannin/furfural resin showed great potential for improving the quality of bagasse particleboard using tannin-based adhesives.
文摘Aromatic plant distillation produces residues rich in phenolic compounds known to be bioactive. In this context, residues from the hydrodistillation of Mentha piperita L., Cymbopogon citratus Stapf, and Eucalyptus camaldulensis Dehnh were chemically and biologically analyzed. The ethanol percentages (70%, 50%, and 30%) were evaluated by determining antioxidant activity using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, total phenolic content, and total flavonoid content. Antifungal activity was evaluated “in vitro” against Fusarium oxysporum, Alternaria alternata, Trametes versicolor, and Coniophora puteana using the diffusion method in malt-agar medium. Antitermite activity was also assessed against Reticulitermes flavipes using the most active extract with low ethanol concentrations (50% and 30%). The optimum ethanol concentration to extract phenolic compounds is 70% for TFC and 30% for TPC, and the antioxidant activity was 0.45 ± 0.01 mg/mL (IC50). The most active extracts were the ethanolic ones, particularly for Eucalyptus camaldulensis, presenting 100% inhibition against the mycelial growth of Coniophora puteana and Alternaria alternata at 1 mg/mL and 0.5 mg/mL, respectively. For antitermite activity, EE50 was the most effective, with a 24% termite survival rate and a degraded food supply surface of 28%. These data suggest the potential use of hydrodistillation residues for biopesticide development.
文摘This paper presents an analysis of the effect of two synthetic antioxidants on the vaporization processes of coconut and linseed oils for fuel use. Several studies agree on the effectiveness of synthetic or natural antioxidants against the polymerization of vegetable oils. The principle of action of the latter is to increase the rate of vaporization, to the detriment of polymer formation. The droplet suspension technique where a fiber is used to hold a stationary droplet has been used. The vaporization was conducted within a closed chamber under ambient pressure conditions in an inert and oxidizing environment at temperatures of 703 K. The method involves monitoring the projected surface area of vegetable oil droplet blended with antioxidants. The projected area (mm2) of the droplet during the vaporization process as a function of time (s) has been used to determine the vaporization coefficient, or the residue formation rate. The main findings are that the two antioxidants used at 200 ppm and 500 ppm have no influence on the vaporization of saturated oils like coconut, while on unsaturated oils like linseed the two antioxidants appear to reduce slightly the deposition of residues which are identified as polymers and increase slightly vaporization rate. In practice, antioxidants could be used as additives in vegetable oils to facilitate their combustion in diesel engines, representing a potential solution for improving combustion efficiency. To enhance the reliability of the findings, it would be advisable to increase the number of antioxidants and extend the study to encompass a wider range of vegetable oils.
基金A.S.Zongo expresses his gratitude to French Cooperation in Burkina Faso who,through the Service for Cooperation and Cultural Action(SCAC),financed this study by awarding an internship fellowship in 2017 at CIRAD Montpellier.
文摘This work gives tools to overcome the difficulty to determine experimentally physical properties for vegetable oils within the range of temperature typically observed during the injection phase in a diesel engine. Knowing vegetable oils’ physical properties to these ranges of temperature is of fundamental importance when modeling their combustion in diesel engine. However, vegetable oils’ experimental physical properties data are rare in the literature for temperature above 523 K. This paper describes experimental measurements and estimation methods for density, dynamic viscosity, thermal conductivity and heat capacity of vegetable oils for this particular range of temperature. The methodology uses several correlative methods using group contribution approach for each property and compares experimental data with predicted one to select the more accurate model. This work has shown the rapeseed and jatropha oils’ physical properties can be satisfactorily predicted as a function of temperature using group contribution approach.
基金financial support from SEAMEO SEARCA and Agropolis Fondation(No.2002-227)was undertaken in connection with the Hevea Research Platform in Partnership(HRPP).
文摘Furan fatty acids produced by plants and bacteria,and present in some edible resources,have attracted significant scientific attention for their health benefits.They include 10,13-epoxy-11-methyl-octadecan-10,12-dienoic acid,which has been identified in the lipid fraction of latex from two Hevea brasiliensis genotypes commonly known as the source of natural rubber.Those two genotypes,namely RRIM501 and PB235,are from Rubber Research Institute of Malaysia(RRIM)and Prang Besar,Malaysia(PB),respectively.This research aimed to undertake the first ever in-vestigation into the existence of this potential high value-added co-product in the lipid fraction of 48 Hevea brasiliensis genotypes,seeking to study the widest possible clonal variability.The results showed furan fatty acid exists in all lipid fractions of their latices.Its content varied significantly,ranging from 0.01%to 0.71%(w/w in latex),the highest concentrations were found in genotypes from the Institut de Recherche sur le Caoutchouc(IRCA)in Côte d’Ivoire,Prang Besar(PB)in Malaysia,and Rubber Research Institute of Vietnam(RRIV)in Vietnam breeding programs.A positive correlation with total fatty acid content was observed when its content exceeded 0.10%,suggesting an additive rather than a substitutive role with the other fatty acids present.Interest-ingly,linoleic and palmitoleic acids strongly correlated with the furan fatty acid concentration,indicating a possible biosynthetic pathway linkage.In terms of yield per tapping PB235,RRIV4,RRIV2,IRCA41,IRCA18,PB324,IRCA814,IRCA323,and IRCA109 genotypes showed the highest production potential,with yields range of 1367-2446 mg furan fatty acid per tree per tapping.Notably,the biochemical markers of natural rubber productivity(sucrose,inorganic phosphorus,thiols,and total solid content)showed no direct involvement in furan fatty acid biosynthesis dur-ing latex regeneration between tappings.Based on knowledge of the parentage of the studied clones,a trait heritability study was conducted and genotype PB5/51 was identified as a very worthwhile genitor for improving furan fatty acid contents in a breeding population.
