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Caractéristiques mécaniques et thermiques de l’argile stabilisée par la gomme arabique et renforcée par la paille de riz / Mechanical and thermal characteristics of stabilized clay by gum arabic and reinforced by rice strawAbakar, Ali 28 June 2018 (has links)
Le réchauffement climatique et le coût élevé des matériaux de construction conventionnels (ciment, chaux, acier) nous obligent à recourir aux matériaux locaux, disponibles et sans effet négatif sur l’atmosphère. Il s’agit de blocs de terre comprimée (BTC) stabilisés par de la gomme arabique et renforcés avec de la paille de riz. L’objectif principal de ce travail est la valorisation des matériaux locaux et écologiques pour la construction des habitations durables. L’étude concerne la caractérisation mécanique, thermique et la durabilité des éprouvettes fabriquées avec de l’argile, du sable, de la gomme arabique, de la paille de riz et de l’eau en des différentes proportions. A cet effet, les pourcentages massiques de gomme arabique sont de 5%, 10% et 15%. Ceux de la paille de riz sont de 0,5%, 1%, 1,5% et 30% de sable sont retenus pour ce travail de recherche. Des briques en BTC de 30 x 15 x 8 cm et des éprouvettes de dimension 4 x 4 x 16 cm sont fabriquées pour réaliser les essais mécaniques. Une méthode « fil chaud » adaptée sur les éprouvettes cylindriques de 16 cm de diamètre sur 32 cm de hauteur est utilisée pour la détermination des conductivités thermiques. L’utilisation de la gomme arabique comme liant dans la construction a donné des résultats satisfaisants. A un taux de 15% de gomme arabique associée à une contrainte de compactage beaucoup plus élevée, nous permettent d’obtenir des BTC ayant une résistance mécanique acceptable ainsi qu'une meilleure résistance à l’eau de pluie. Les résultats mécaniques montrent que la gomme arabique améliore la résistance mécanique de même que la contrainte de compactage. Par contre l’utilisation de paille de riz dans le mélange fait chuter sa résistance mécanique et allège le matériau. Les valeurs de conductivité thermique mesurées, montrent que les différents échantillons ne peuvent pas être considérées comme étant des matériaux isolants. Les éprouvettes exposées aux aléas climatiques (pluie et humidité) pendant un mois montrent que les blocs de terre non stabilisés se sont détériorés sous la pluie. Par contre les éprouvettes stabilisées par la gomme arabique ont conservé leurs bonnes tenues. De même, des éprouvettes stabilisées et non stabilisées sont immergées dans l’eau. A partir de 15 min, toutes les éprouvettes sont détériorées. Les matériaux argileux stabilisés par la gomme arabique ne pourront pas servir en fondation dans la construction. Ce travail de recherche sera complété par des essais de vieillissement du matériau sur des différents échantillons pour sa validation comme nouveau matériau de construction durable / Global warming and the high cost of conventional building materials (cement, lime, steel) force us to use local, available materials with no negative effect on the atmosphere. These are compressed earth blocks (BTC) stabilized with arabic gum and reinforced with rice straw. The main objective of this work is the valorization of local and ecological materials for the construction of sustainable homes. The study concerns the mechanical, thermal and durability characterization of specimens made of clay, sand, arabic gum, rice straw and water in different proportions. For this purpose, the percentages of gum Arabic are 5%, 10% and 15%. Those of rice straw are 0.5%, 1%, 1.5% and 30% of sand are retained for this research work. BTC bricks measuring 30 x 15 x 8 cm and specimens measuring 4 x 4 x 16 cm are manufactured to perform the mechanical tests. A "hot wire" method adapted to cylindrical specimens 16 cm in diameter and 32 cm in height is used for the determination of thermal conductivities. The use of arabic gum as a binder in the construction has given satisfactory results. At a rate of 15% gum Arabic associated with a much higher compressive stress, allow us to obtain BTCs having an acceptable mechanical strength as well as a better resistance to rainwater. Mechanical results show that gum Arabic improves mechanical strength. As is the compaction constraint. By cons the use of rice straw in the mixture reduces its mechanical strength and lightens the material. The measured thermal conductivity values show that the different formulations cannot be considered as insulating materials. The specimens exposed to the climatic hazards (rain and moisture) for a month show that the unstabilized earth blocks have deteriorated in the rain. On the other hand, samples stabilized by gum Arabic have retained their good habits. Similarly, stabilized and unstabilized specimens are immersed in water. From 15 min, all test pieces are deteriorated. The clay materials stabilized by gum Arabic can not be used as a foundation in construction. This research work will be completed by aging tests on the various formulations for validation as a new sustainable building material
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Developing densified products to reduce transportation costs and improve the quality of rice straw feedstocks for cattle feedingNguyen, Van Hieu, Nguyen, Thanh Nghi, Le, Quang Vinh, Le, Minh Anh, Nguyen, Van Hung, Gummert, Martin 22 February 2019 (has links)
Densification of rice straw such as compacting and pelletizing is an important process to increase the density of rice straw resulting in a reduction of transportation cost. Within this research, we conducted a techno-economic investigation of rice straw densification to produce compressed bales and pellets, which are later used for animal feed. In line with the main deliverable of the performance of rice straw compacting and pelletizing processes, we also looked into the quality of the product in terms of uptake and digestibility of the cattle feed which could be improved by adding amendments such as urea during the compacting process. The compacting technology resulted in a 400% increase of bale density (from 94 to 390 kg.m-3). This could reduce transportation costs by about 60% for a 60 km driving distance using trucks. The net profit that resulted from compacted bales was USD 0.0062 kg-1. Although the pelletizing technology increased the cost of the densified product by 40–50%, its density increases by 700%, from 94 to 666 kg.m-3. The enriched-rice straw pellets contained 12.1% protein, 2.8% lipid, 32.7% raw fibre, and 11.2% ash. In addition, a test of this product for cattle feeding illustrated an increase in its eating desirability for cows. Findings from this study contribute to reducing feedstock cost and developing densified rice straw products. These, therefore, provide more alternative options to increase the benefits from rice production and thus, reduce the unsustainable burning of rice straw in the field. / Nén ép rơm là quá trình quan trọng và cần thiết để tăng khối lượng thể tích với mục đích giảm chi phí vận chuyển. Trong nghiên cứu này, chúng tôi đã thực hiện nghiên cứu đánh giá tính khả thi về kỹ thuật và kinh tế đối với nội dung nén ép rơm cuộn và ép viên rơm. Cùng với mục đích chính là tăng dung trọng của sản phẩm từ rơm, chúng tôi cũng đánh giá chất lượng sản phẩm làm thức ăn cho bò giúp cho tăng kích thích quá trình tiêu hóa. Kết quả nén ép cuộn rơm đã làm tăng dung trọng của kiện rơm đến 400% (từ 94 đến 398.7 kg.m-3). Qua đó, đã giảm được chi phí vận chuyển 60% được ước tính cho 60 km khoảng cách vận chuyển. Đối với ép viên rơm, dung trọng tăng đến 700% (từ 94 đến 666 kg.m-3). Hàm lượng dinh dưỡng của viên nén hỗn hợp rơm gồm protein (12,1%), chất béo (2,8%), chất xơ (32,7%), và lượng tro tổng (11,2%). Ngoài ra, kết quả thử nghiệm cho bò ăn sản phẩm viên nén này cho thấy bò có cảm giác thích và ăn hết toàn bộ viên nén. Kết quả của nghiên cứu đã góp phần giảm chi phí khi sản xuất thức ăn cho bò, tăng thu nhập cho người nông dân và từ đó giảm tác động môi trường do việc đốt rơm trên đồng.
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Purificação da enzima glicose-6-fosfato desidrogenase por processo de extração líquido-líquido em sistemas aquosos bifásicos integrado ao rompimento celular de Candida guilliermondii / Glucose-6-phosphate dehydrogenase purification by liquid-liquid extraction process using aqueous two-phase systems integrated to cell disruption of Candida guilliermondiiGurpilhares, Daniela de Borba 12 December 2007 (has links)
A utilização de resíduos agrícolas visando à produção de insumos por via biotecnológica tem se mostrado importante uma vez que estes resíduos são fontes renováveis de carbono. A fração hemicelulósica destes resíduos apresenta como componente principal a xilose, que pode ser utilizada como substrato em processos de bioconversão para a obtenção de produtos com valor agregado. Um destes produtos é a enzima glicose-6-fosfato desidrogenase (G6PD), primeira enzima da via das pentoses fosfato que pode ser utilizada como reagente analítico em análises quantitativas, sobretudo em estudos bioquímicos e médicos. O presente trabalho visou estudar o processo de purificação dessa enzima empregando a extração em sistemas de duas fases aquosas convencional (sem integração) e integrado ao rompimento celular, em duas escalas, reduzida e ampliada. A enzima foi produzida por Candida guilliermondii FTI 20037 cultivada em meio constituído de hidrolisado hemicelulósico de palha de arroz, sob condições pré-determinadas. Inicialmente, foram realizados ensaios para avaliar o efeito das variáveis volume de suspensão celular, velocidade de agitação do moinho de esferas de vidro e tempo sobre o rompimento das células. Os valores destas variáveis foram, então, estabelecidos em: 100 mL, 400 rpm e 25 minutos, respectivamente. Posteriormente, a influência da massa molar de PEG e comprimento de linha de amarração sobre a extração da G6PD foram investigados no sistema convencional (homogeneizado obtido a partir do rompimento celular, em presença ou ausência de fragmentos) e integrado (rompimento na presença dos componentes da extração), empregando-se a metodologia do planejamento experimental. Nos ensaios realizados em escala reduzida, sob condições otimizadas, alcançou-se um fator de purificação na fase rica em sal (FPf), ou fase fundo, de 2,8 e em maior escala, ou seja, em moinho de rompimento, de 1,3. Com isso, realizou-se o estudo cinético e termodinâmico empregando a enzima presente no homogeneizado antes da purificação e após purificada no processo integrado em escala reduzida, nas seguintes condições: TLL 40% e PEG 1500 mol/L. Os valores determinados para os parâmetros cinéticos foram Km, 0,07 e 0,05 mM, Vm, 34,8 e 19,1 U/L e dos parâmetros termodinâmicos ΔG, -13,71 e -13,64 KJ/mol; ΔH, -2,49 e -2,50 KJ/mol; ΔS, 37,02 e 36,77 J/mol.K; Ea, 24,18 e 15,02 KJ/mol, da enzima presente no homogeneizado celular antes e após purificação, respectivamente. / The employment of agricultural residues aiming the attainment of biotechnological products has been shown its importance since these residues are renewable and low cost sources of carbon. The hemicellulosic fraction of these residues presents xylose as main component, which can be utilized as substrate for different bioconversion processes for the acquisition of high value products. As an example, glucose-6-phosphate dehydrogenase, the first enzyme of pentose phosphate pathway which can be used as analytical reagent in several quantitative analysis, mainly in biochemical and medical studies. The present work contemplated the study of glucose-6-phosphate (G6PD) purification process by a conventional aqueous two phase systems extraction and integrated with cell disruption, in two scales, reduced and increased. The enzyme was obtained from cells of Candida guilliermondii FTI 20037 grown in hemicellulosic rice straw hydrolysate, using conditions established in previous work. Initially, assays in bead mill were performed to determine the effect of cell suspension volume, agitation speed and time on cell disruption. The determined conditions were: 100 mL, 400 rpm and 25 minutes, respectively. After this, the influence of molar mass of PEG and tie line lenght (TLL) on the G6PD recovery were investigated in the conventional system (with previous disrupted cells, with or without cell fragments) and integrated (disruption in the presence of extraction components), using the experimental design methodology. In the reduced scale assays, in optimized conditions, a purification factor in salt rich phase (FPf), or bottom phase, of 2,8 was reached while in the increased scale, this means in bead mill, a FPf of 1,3 was attained. In addition, kinetic and thermodynamic studies were performed, employing the enzyme present in the homogenate before and after purification in reduced scale, in the following conditions: TLL of 40% and PEG 1500 mol/L. The established values for the kinetics parameters were Km, 0,07 and 0,05 mM, Vm, 34,8 and 19,1 U/L and of thermodynamics ΔG, -13,71 and -13,64 KJ/mol; ΔH, -2,49 and -2,50 KJ/mol; ΔS, 37,02 and 36,77 J/mol.K; Ea, 24,18 and 15,02 KJ/mol, of the enzyme present in the homogenate before and after purification respectively.
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Purificação da enzima glicose-6-fosfato desidrogenase por processo de extração líquido-líquido em sistemas aquosos bifásicos integrado ao rompimento celular de Candida guilliermondii / Glucose-6-phosphate dehydrogenase purification by liquid-liquid extraction process using aqueous two-phase systems integrated to cell disruption of Candida guilliermondiiDaniela de Borba Gurpilhares 12 December 2007 (has links)
A utilização de resíduos agrícolas visando à produção de insumos por via biotecnológica tem se mostrado importante uma vez que estes resíduos são fontes renováveis de carbono. A fração hemicelulósica destes resíduos apresenta como componente principal a xilose, que pode ser utilizada como substrato em processos de bioconversão para a obtenção de produtos com valor agregado. Um destes produtos é a enzima glicose-6-fosfato desidrogenase (G6PD), primeira enzima da via das pentoses fosfato que pode ser utilizada como reagente analítico em análises quantitativas, sobretudo em estudos bioquímicos e médicos. O presente trabalho visou estudar o processo de purificação dessa enzima empregando a extração em sistemas de duas fases aquosas convencional (sem integração) e integrado ao rompimento celular, em duas escalas, reduzida e ampliada. A enzima foi produzida por Candida guilliermondii FTI 20037 cultivada em meio constituído de hidrolisado hemicelulósico de palha de arroz, sob condições pré-determinadas. Inicialmente, foram realizados ensaios para avaliar o efeito das variáveis volume de suspensão celular, velocidade de agitação do moinho de esferas de vidro e tempo sobre o rompimento das células. Os valores destas variáveis foram, então, estabelecidos em: 100 mL, 400 rpm e 25 minutos, respectivamente. Posteriormente, a influência da massa molar de PEG e comprimento de linha de amarração sobre a extração da G6PD foram investigados no sistema convencional (homogeneizado obtido a partir do rompimento celular, em presença ou ausência de fragmentos) e integrado (rompimento na presença dos componentes da extração), empregando-se a metodologia do planejamento experimental. Nos ensaios realizados em escala reduzida, sob condições otimizadas, alcançou-se um fator de purificação na fase rica em sal (FPf), ou fase fundo, de 2,8 e em maior escala, ou seja, em moinho de rompimento, de 1,3. Com isso, realizou-se o estudo cinético e termodinâmico empregando a enzima presente no homogeneizado antes da purificação e após purificada no processo integrado em escala reduzida, nas seguintes condições: TLL 40% e PEG 1500 mol/L. Os valores determinados para os parâmetros cinéticos foram Km, 0,07 e 0,05 mM, Vm, 34,8 e 19,1 U/L e dos parâmetros termodinâmicos ΔG, -13,71 e -13,64 KJ/mol; ΔH, -2,49 e -2,50 KJ/mol; ΔS, 37,02 e 36,77 J/mol.K; Ea, 24,18 e 15,02 KJ/mol, da enzima presente no homogeneizado celular antes e após purificação, respectivamente. / The employment of agricultural residues aiming the attainment of biotechnological products has been shown its importance since these residues are renewable and low cost sources of carbon. The hemicellulosic fraction of these residues presents xylose as main component, which can be utilized as substrate for different bioconversion processes for the acquisition of high value products. As an example, glucose-6-phosphate dehydrogenase, the first enzyme of pentose phosphate pathway which can be used as analytical reagent in several quantitative analysis, mainly in biochemical and medical studies. The present work contemplated the study of glucose-6-phosphate (G6PD) purification process by a conventional aqueous two phase systems extraction and integrated with cell disruption, in two scales, reduced and increased. The enzyme was obtained from cells of Candida guilliermondii FTI 20037 grown in hemicellulosic rice straw hydrolysate, using conditions established in previous work. Initially, assays in bead mill were performed to determine the effect of cell suspension volume, agitation speed and time on cell disruption. The determined conditions were: 100 mL, 400 rpm and 25 minutes, respectively. After this, the influence of molar mass of PEG and tie line lenght (TLL) on the G6PD recovery were investigated in the conventional system (with previous disrupted cells, with or without cell fragments) and integrated (disruption in the presence of extraction components), using the experimental design methodology. In the reduced scale assays, in optimized conditions, a purification factor in salt rich phase (FPf), or bottom phase, of 2,8 was reached while in the increased scale, this means in bead mill, a FPf of 1,3 was attained. In addition, kinetic and thermodynamic studies were performed, employing the enzyme present in the homogenate before and after purification in reduced scale, in the following conditions: TLL of 40% and PEG 1500 mol/L. The established values for the kinetics parameters were Km, 0,07 and 0,05 mM, Vm, 34,8 and 19,1 U/L and of thermodynamics ΔG, -13,71 and -13,64 KJ/mol; ΔH, -2,49 and -2,50 KJ/mol; ΔS, 37,02 and 36,77 J/mol.K; Ea, 24,18 and 15,02 KJ/mol, of the enzyme present in the homogenate before and after purification respectively.
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The potential of electricity generation from the major agricultural wastes in the Mekong Delta of VietnamNguyen, Vo Chau Ngan, Nguyen, Thi Thuy, Nguyen, Le Phuong 22 February 2019 (has links)
Agricultural activities produce a large quantity of waste each year in the Mekong Delta. For example, appropriately 26.86 million tons of rice straw, 5.37 million tons of rice husks, 1.33 million tons of bagasse and 0.59 million tons of corn straw were produced in 2016. Despite such a huge quantity of agricultural waste, the waste has been rarely used effectively. Around 54.1 - 98.0% of rice straw is normally burnt on the field; only 20 - 50% of rice husk is used for pellet or energy purposes; a few sugar-cane factories apply bagasse feeding to steam cookers, and a small quantity of corn straw is used as livestock feeding. If this biomass source is used for electricity generation, in theory, for the period of 2006 - 2020, it is estimated that this source can potentially generate 1203 million MWh/year from rice straw, 236 million MWh/year from rice husk, 45 million MWh/year from bagasse, and 40 million MWh/year from corn straw. Electricity generation of biomass source will not only solve the problem of environmental pollution caused by agricultural waste but also meet increasing energy demands for socio-economic development in this region. / Hàng năm lượng chất thải phát sinh từ một số loại hình canh tác nông nghiệp chính ở ĐBSCL rất lớn. Chỉ tính riêng năm 2016 ghi nhận thải ra khoảng 26,86 triệu tấn rơm rạ; 5,37 triệu tấn vỏ trấu; 1,33 triệu tấn bã mía và 0,59 triệu tấn thân cây bắp. Lượng chất thải phát sinh lớn nhưng các biện pháp sử dụng những nguồn sinh khối này chưa đa dạng, rơm rạ phần lớn được người dân đốt trực tiếp ngay trên đồng ruộng chiếm 54,1 - 98,0% lượng rơm rạ thải ra; chỉ có khoảng 20 - 50% lượng vỏ trấu được sử dụng; bã mía chỉ được một số nhà máy sử dụng để đốt cho lò hơi; một lượng nhỏ thân cây bắp được người dân sử dụng cho chăn nuôi. Nếu có thể tận dụng các nguồn sinh khối này để sản xuất điện thì tiềm năng lý thuyết ước tính từ năm 2005 đến 2020 của rơm rạ là 1203 triệu MWh/năm; vỏ trấu là 236 triệu MWh/năm; bã mía là 45 triệu MWh/năm; và thân cây bắp là 40 triệu MWh/năm. Sản xuất điện từ các nguồn sinh khối này không chỉ giải quyết lượng phế phẩm nông nghiệp phát sinh, giảm thiểu ô nhiễm môi trường mà còn có thể tạo ra nguồn điện cung cấp cho nhu cầu phát triển của vùng.
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