Estudo do perfil térmico de fornos do tipo "caipira" utilizados pelo setor de cerâmica vermelha em parelhas na região Seridó-RN

The present study aimed to characterize the thermal profile of wood fired oven used by the red ceramic industry in Parelhas, in the Seridó region/RN, aiming to propose structural interventions that can contribute to increasing productivity and product quality, optimize wood consumption and mitigate existing losses during the burning process. The study was conducted at Cerâmica Esperança in the city of Parelhas -RN, Brazil, during the period from August 2012 to September 2013. Four treatments were performed with three replicates, ie, with, a total of 12 experimental units (burnings). In the first stage 4 treatments were performed with three replicates, totaling 12 experimental units (firings). In the second stage 2 treatments were performed with three replications, totaling 6 experimental units (firings). The physical characteristics of the wood were analyzed using standard NBR 11941 and NBR 7190 for basic density and moisture, respectively. The clay was used as a reference parameter for distinguishing treatments. For both the analysis and characterization was carried out using techniques of fluorescence X (XRF) rays, X-ray diffraction (XRD) analysis, particle size analysis (FA). In the first and second stages were monitored: the time during the firing process, the amount of wood used at each firing, the number of parts enfornadas for subsequent determination of the percentages of losses, but also product quality. To characterize the thermal profile of the oven, we measured the temperature at 15 points scored in the surface charge put into the oven. Measurements were taken every 30 minutes from preheat until the end of burning, using a pyrometer laser sight sighting from preheating until the end of burning. In the second step 12 metal cylinders distributed on the oven walls, and the cylinder end walls 8 of the furnace 2 and rollers on each side walls are installed equidistant to 17 cm from the soil and the surface 30 of the wall are installed. The cylinders distributed on the front were placed 50 cm above the furnace, and the base of the oven 20 cm distant from the ground. 10 also thermocouples were installed, and five thermocouples distributed 1.77 cm above the combustion chambers, and one thermocouple on each side, and three thermocouples in front of the oven. We carried out the measurements of the temperatures every 1 hour during the burning two hours in cooling the cylinders with a pyrometer and thermocouples for dattaloger. These were fixed with depth of 30 cm from the wall. After statistical analysis it was found that: the thermal profile of the furnace surface and at different heights was heterogeneous; and the ranges of density and moisture content of wood are within recommended for use as an energy source standards. We conclude that even at low temperatures reached during firing there was a significant production of good quality products, this is due to high concentrations of iron oxide and potassium oxide found in clay, which lowers the melting point of the piece. The average burn time for each step varied 650-2100 minutes wood consumption was on average 20 m3, product quality was on average 16% of first quality, 70% second, third and 5% to 10% loss . The distance between the wire and the surface of the oven was a significant parameter for all treatments, but with different variations, meaning that the wire should not be so generic and unique form, used as a criterion for completion of the burn process. The central part of the furnace was the area that reached higher temperature, and in a unified manner, with the highest concentration of top quality products. The ideal temperature curve, which provided the highest quality of ceramic products was achieved in the central part of the furnace

Modelo de desdobramento da função qualidade adequado a produção da cerâmica vermelha

A presente dissertação representa uma contribuição na resolução dos problemas que se apresentam no setor das indústrias de cerâmica vermelha, apresentamos um modelo, baseado na estratégia do QFD (Desdobramento da Função Qualidade), na qual associa os requisitos dos consumidores na elaboração dos projetos do produto e dos processos de produção. A qualidade do produto é avaliada tanto no aspecto interno(especificações técnicas) quanto no aspecto externo (qualidades exigidas pelos clientes). A pesquisa mostra, além da realidade que vive o setor das indústrias de cerâmica, a importância e os atributos da qualidade definidos pelos consumidores relativo aos tijolos cerâmicos de vedação. O trabalho também mostra os resultados da aplicação do modelo numa das empresas do setor, através de desdobramentos da qualidade exigida, se estabelece a qualidade planejada, mostra ainda a posição da empresa em relação aos concorrentes em função do desempenho do produto. Procura-se ainda, através de sugestões de melhorias, atacar os problemas das falhas na qual geram o desperdício

Influência da adição de rejeitos cerâmicos nas propriedades de cerâmica vermelha da região do Recôncavo Baiano

The study of the physical and mechanic properties is an analysis of unquestioned importance on the production of the ceramic materials. In the region of the Recôncavo Baiano, there are ceramic and small brick factories, that still use rudimentary techniques, where the necessity of characterization of raw materials is denounced by the quality of the final product. The present work has for objective to study the behavior of the clay proceeding from the region of the Recôncavo, between the cities of Candeias and Camaçari/Ba, with addition of 5, 10 and 15% by weight of brick scraps, trying to optimize the physic and mechanical properties of the final product, aiming a better possibility of being manufactured, mechanic resistance, low linear retraction and water absorption. The brick scraps and the clay were characterized by FRX, DRX, TG, ATD and the granulometric analysis. Samples for testing where prepared by uniaxial pressing at 25Mpa, in 60x20x5mm size. The evaluated technological properties were: linear retraction, water absorption, apparent porosity and flexural strength. The samples were burned in electric oven in the temperatures of 850º, 950º and 1050ºC and compared its mechanical properties and the gresification. With addition of 15% by weight of brick scraps and burning at 900º-1000ºC the samples showed properties superior to that clay

Avaliação do processo industrial da cerâmica vermelha na região do Seridó - RN

Particularly in Braziland in Rio Grande do Norte, companies manufacturing red ceramic, play an important role as agents of development to study the region Seridó- RN, specific place for carrying out the research. It is observed in this region a concentration of red ceramic industries of small size, which, despite its importance in the ceramic, they are unable to enjoy or use the new forms of administrative management and technological advances designed and offered by universities, centers of research and projects of governments, remained almost entirely outside the progress and modernization, technological and administrative. These companies still have outdated technology, and management processes, providing quality problems and standardization of end products. Upon these conditions are the companies going through crisis and struggling to survive alone and without assistance. The region of Seridó-RN, lets make a detailed case study of red ceramic companies in the region proposed from the existing theoretical and actual lifting of the condition of the product manufacturing red ceramic, allowing through this overview of the implementation of collect samples of raw materials, allowing the study of each ceramic industry that contributed to the participation of the research, which was determined parameters such as: analysis of the physical, chemical and technological properties of raw materials, characterization of the processes used, raising the technological resources considering equipment, machinery, supplies, raw materials and facilities available and its organization by type of products from companies involved in this study. The methodology consists of the following steps: collection of raw material, crushing and screening, characterization of raw materials (liquid limit, chemical analysis, mineralogical analysis, differential thermal analysis, sieve analysis), mixing, forming, cutting, drying and burning of ceramic bodies and bodies of evidence. The results showed that it was clay with distinct characteristics with respect to plasticity. With respect to the different compositions of mixtures of ceramic masses, we conclude that the ceramic properties showed a direct proportionality with increasing fraction of the clay not plastic. However, the compositions of the masses studied proved to be the most appropriate for the types of simulated clay for use in ceramics. Adopted in the ceramic processing made it possible to obtain products the resulted in consistent properties, and in some cases even exceeding the requirements of technical studies and standard-Brazilian clays to obtain ceramic products such as tiles, bricks and tiles to floor. Based on the discussions from the results obtained in the various processing steps of this work, one can draw conclusions according to the physico-chemical and mineralogical properties of raw materials, the properties of ceramic products burned and analysis. This work may be used by other researchers, private companies and governmental organizations, undergraduate students and graduate, can develop studies and future research to: develop projects to modify the furnaces; mapping projects develop and rationalize the exploitation of raw materials ;promoting reforestation and forest management; develop reduction projects and recovery of waste; develop training projects in manpower sector, and develop security projects, improving the conditions of work in the area pottery

Biossorção utilizando alga marinha (sargassum sp.) aplicada em meio orgânico

In this work, biosorption process was used to remove heavy metals from used automotive lubricating oils by a bus fleet from Natal-RN-Brazil. This oil was characterized to determine the physical-chemistry properties. It was also characterized the used oil with the aim of determining and quantifying the heavy metal concentration. Fe and Cu were the metals existent in large concentration and these metals were choused to be studied in solubilization process. For the biosorption process was used the seaweed Sargassum sp for the study of influencing of the metals presents separately and with other metals. It was also studied the effect of the protonation treatment of alga with the objective to know the best efficiency of heavy metals removal. The study of the solubilization showed that the presence of more than a metal favors the solubilization of the metals presents in the oil and consequently, it favors the biosorption process, what becomes interesting the perspective application in the heavy metals removal in lubricating oils used, because the presence of more than a heavy metal favors the solubility of all metals present. It was observed that the iron and copper metals, which are present in large concentration, the protonated biosorbtent was more effective. In this study we used as biomass the marine alga Sargassum sp to study the influence of agitation velocity, temperature and initial biomass concentration on the removal of iron and copper from used lubricant oils. We performed an experimental design and a kinetic study. The experiments were carried out with samples of used lubricant oil and predetermined amounts of algae, allowing sufficient time for the mixture to obtain equilibrium under controlled conditions. The results showed that, under the conditions studied, the larger the amount of biomass present, the lower the adsorption capacity of the iron and of the copper, likely due to a decrease in interface contact area. The experimental design led us to conclude that a function can be obtained that shows the degree of influence of each one of the system variables

Atividade antiinflamatória de uma heterofucana da alga marrom Padina gymnospora

Fucans, sulfated polysaccharides extracted from brown algae and some echinoderms, have been extensively studied for its diverse biological activities and because of its interference with molecular mechanisms of cell to cell recognition, including leukocyte trafficking from blood vessels into sites of inflammation mediated by selectin, a family of adhesion molecules. In the present study, we examined structural features of a heterofucan extracted from brown algae Padina gymnospora and its effect on the leukocyte migration to the peritoneum. The sulfated polysaccharides were extracted from the brown seaweed by proteolysis with the proteolytic enzyme maxatase. The presence of protein and uronic acid contamination was detected in the crude polysaccharide extract. Fractionation of the crude extract with growing concentrations of acetone produced five fractions with different concentrations of fucose, xylose, uronic acid, galactose, glucose and sulfate. The fraction precipitated with 1.5 volumes of acetone was characterized by infrared and nuclear magnetic resonance, through which can be observed the presence of sulfate groups in the C4 of -L-fucose. The anti-inflammatory action of this composite was assessed by a sodium thioglycollate-induced peritonitis assay and through nitric oxide production by the peritoneal macrophages using Griess reagent. Fraction F1.5 was efficient in reducing leukocyte influx into the peritoneal cavity when 10 mg/kg and 25mg/kg were used, resulting in a decrease of 56 and 39%, respectively. A decrease of nitric oxide production occurred when high concentrations of fucana were used. The cytotoxicity of the composite was also assessed using the reduction of 3-(4,5 dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT). Fraction F1.5 had no cytotoxicity when 500 μg/mL of the fraction was used. This study suggests the use of fraction F1.5 (heterofucan) as an anti-inflammatory

Avaliação de uma fração polissacaridica da alga Lobophora variegata (Lamouroux) em modelo de artrite induzida em ratos por Zymosan

Fucans seaweed Lobophora variegata estructures are known for their chemical and biological properties. In this study, we analyzed, the action of fucans L. variegata and the fractions purified with acetone in Zymosan-induced arthritis. After differential fractionation with acetone, six fractions were obtained and named F0.3, F0.5, F0.8, F1, F1.5 and F2. The results showed that the fraction F1 showed high yield (51.9%) and was chosen for studies of antioxidant activity and induced arthritis. Nuclear magnetic resonance (NMR) of 13C showed signals at 103.3 and 15.78 ppm that are assigned to links β13 galactose and of the C6 methyl fucose, respectively. The infrared (IR) showed absorbance at 1238 and 850 cm-1 which are attributed to sulfate. The fraction F1 showed antioxidant activities in vitro. For analysis of inflammatory parameters chosen the polysaccharide was administered in different doses (25, 50 and 75 mg / kg ip, per body weight) and diclofenac sodium (5 mg / kg ip) and L-NAME (25 mg / kg ip) in groups of animals (n = 6). After 6 h, were analyzed for cellular influx and levels of nitrite. In experiment five days, were made analysis of swelling and serum TNF-α. Histopathological analysis were performed for confirmation of results. The fraction F1 (25, 50 and 75 mg / kg ip) reduced the cellular influx (52.1 to 96.7%) and nitric oxide levels (27.2 - 39%) compared to control group. The reduction of edema (63.4 - 100%) and serum TNF-α (p <0.001) were observed when the polysaccharide F1 administered at a dose (50 mg / kg) These results suggest that these heterofucanas of Lobophora variegata have besides the activity antioxidant and potential anti-inflammatory activity in arthritis induced by zymosan

Purificação e caracterização estrutural de homogalactanas sulfatadas anticoagulantes da alga verde Codium isthmocladum

Conselho Nacional de Desenvolvimento Científico e Tecnológico

O circuito espacial da indústria de cerâmica vermelha no seridó potiguar

This research has as an empirical universe, the productive territory of red ware in the Seridó region of Rio Grande do Norte. In the last years this territory has gone through a process of appropriation that has been substantially changing the environmental and social dynamism of the place. However, the industry of red ware has been focusing in some areas, mainly, in the county of Parelhas and Carnaúba dos Dantas. From this point of view, the aim of this work consists in analyze the use of these areas by the red ware industry and the transformations occurred with the expansion of the number of industries and the productivity raise, that requires bigger amounts of earthenware and wood, resources that are low in referred territory. As the result of this process, the suitable alternative has been to acquire inputs in other Rio Grande do Norte counties, as well as in Paraíba counties. To reach the proposed objective, the methodology of this work was consisted of bibliographic and empirical research, regarding the occupation that this activity covers in the Seridó region. From the information obtained during the research, it can be stated that the inputs to the production execution in the red ware industry are acquired in the geographic nearby lands. The analysis of the stages of the production(acquisition of raw material, production and commercialization) showed that the activity acts in a continuous area, having as principal consumer market other northeastern states and the state of Pará. The present study revealed that the pottery activity is set as untenable, because of non-stopping use of the argil and wood, resources that are vanishing from the area, which consume causes a many problems such as deforestation and erosion. Besides, the sale of productive lands for the red ware industries makes harder its good use by the familiar agriculturists in the development of agriculture and cattle raising activity, which for many times is the main economic activity of the place. The precariousness reveals in the constant accidents at work, that most of them are neglected by the local authorities, without any penalty to the industries. Therefore, the industry of red ware in Seridó uses the territory as a resource, leaving its environmental problems that my compromise the quality of life of the actual and future generations

A biotecnologia na propagação e conservação do umbuzeiro (Spondias tuberosa Arr. Cam.) e percepção sobre sua importância por agricultores da comunidade Malhada Vermelha, Campo Redondo (RN-Brasil)

The umbu tree (Spondias tuberosa Arruda) is a fruit native to the northeast of Brazil with great economic, social and ecological importance for the northeastern semi-arid region. Despite its role, the umbu tree has suffered negative pressure thanks to cluttered extractivism and to negative selection of its fruits, which as the deforestation and the dormancy of seeds contribute to the decrease of its production year after year, making necessary studies that contribute to the improvement of this specie and its conservation. Given the risks to the conservation of the specie and its usefulness to the population, the association between plant biotechnology, for being a tool that can be used to increase its production. and the perception of gathering communities, by valuing the point of view and the knowledge of the population, can facilitate its conservation. This work aimed to develop methods of propagation for umbu tree as well as contribute to its conservation by using biotechnology, with specific objectives to contribute to the conservation of this species; determine concentrations of BAP and ANA in the formation of buds; testing the efficiency of different substrates and concentrations of gibberellic acid on germination in vitro and ex vitro, as well as capture the perception of families in communities that engage in the gathering of umbu. To study the germination, the seeds were inoculated in different substrates (vermiculite, vermiculite + clay, clay, clay + manure and manure + vermiculite) and in different concentrations of gibberellic acid (0 mg, 250 g and 500 mg). For the formation of buds BAP to 0.1 mg-1 was associated with different concentrations of ANA (0.2; 0.4; 0.8mg.L-1). The study of perception was conducted by applying semi-structured questionnaire with Malhada Vermelha community. The experiments resulted in vermiculite and concentration of 500 mg gibberellic acid as the best for germination. The association of 0.1 mg.L-1 of BAP to 0.2 mg.L-1 of ANA provided better formation of buds. As to the application of questionnaires, they revealed that the population understands the decreased amount of umbu plants and umbu fruit in the region, as well as shows concern for its conservation.

Estudo da incorporação de cinza e chamote gerado pela cerâmica vermelha ao próprio processo industrial

The ceramics industry generates waste at various stages of that process, defective products, waste from burning solid fuels, among others. This waste is dumped in landfills, garbage dumps or directly on roads, which has a negative environmental impact. This paper presents a study to incorporate the waste of algaroba wood and chamote (scrap pieces of ceramic already sintered), in to the ceramic material for making sealing blocks. The methodological procedures consist in the characterization of chemical and mineralogical residues, raw materials, and physical-mechanical of the formulations of mixes with clay, silt and waste. By pressing test pieces were produced using a pressure of 200 kgf/cm², varying compositions in the range of 0%, 5%, 10% and 15% by weight of residue. The sintering was performed in a muffle furnace, with the temperature levels of 850 ° C, 900 ° C, 950 ° C, 1000 ° C and 1050 ° C. The evaluated physical and mechanical properties were: Water Absorption, Linear Shrinkage Burning, Apparent Porosity, Apparent Density and Mechanical Resistance to Flexion. Analysis was carried out by Scanning Electron Microscopy on fracture surfaces of the specimens. Evaluation of linear shrinkage property drying and firing , water absorption and mechanical resistance to compression of the sealing blocks 5% wood ash residue, sintered at 900 °C hold temperature in the laboratory the products manufactured on an industrial scale. The main results, it was found on the viability of using the residues of algaroba wood and to confer refractory properties of the ceramic product. The main results, it was concluded feasibility of using the ash residues algaroba wood to impart refractory properties to the ceramic product and the residue of chamote, being derived from the own ceramic product not interfere with the properties, when used in a percentage of up to 5%.Since the residue of chamote being derived from the ceramic product itself had no effect on the properties. Studies in the laboratory have shown that the incorporation of up to 5% of these residues may be adopted as an alternative technology to reduce the environmental impact caused by the industrial sector, without compromising the final properties of the material, since the results on an industrial scale showed absorption values 11.66 and 11.74 of water and waste products respectively, within the parameters of NBR - 15,270, since the mechanical strength was 1.25 MPa and 0.94 MPa respectively for products with and without residue, lower than the minimum required by the technical standard that is 1.5 MPa.

Estudo da incorporação de cinza e chamote gerado pela cerâmica vermelha ao próprio processo industrial

The ceramics industry generates waste at various stages of that process, defective products, waste from burning solid fuels, among others. This waste is dumped in landfills, garbage dumps or directly on roads, which has a negative environmental impact. This paper presents a study to incorporate the waste of algaroba wood and chamote (scrap pieces of ceramic already sintered), in to the ceramic material for making sealing blocks. The methodological procedures consist in the characterization of chemical and mineralogical residues, raw materials, and physical-mechanical of the formulations of mixes with clay, silt and waste. By pressing test pieces were produced using a pressure of 200 kgf/cm², varying compositions in the range of 0%, 5%, 10% and 15% by weight of residue. The sintering was performed in a muffle furnace, with the temperature levels of 850 ° C, 900 ° C, 950 ° C, 1000 ° C and 1050 ° C. The evaluated physical and mechanical properties were: Water Absorption, Linear Shrinkage Burning, Apparent Porosity, Apparent Density and Mechanical Resistance to Flexion. Analysis was carried out by Scanning Electron Microscopy on fracture surfaces of the specimens. Evaluation of linear shrinkage property drying and firing , water absorption and mechanical resistance to compression of the sealing blocks 5% wood ash residue, sintered at 900 °C hold temperature in the laboratory the products manufactured on an industrial scale. The main results, it was found on the viability of using the residues of algaroba wood and to confer refractory properties of the ceramic product. The main results, it was concluded feasibility of using the ash residues algaroba wood to impart refractory properties to the ceramic product and the residue of chamote, being derived from the own ceramic product not interfere with the properties, when used in a percentage of up to 5%.Since the residue of chamote being derived from the ceramic product itself had no effect on the properties. Studies in the laboratory have shown that the incorporation of up to 5% of these residues may be adopted as an alternative technology to reduce the environmental impact caused by the industrial sector, without compromising the final properties of the material, since the results on an industrial scale showed absorption values 11.66 and 11.74 of water and waste products respectively, within the parameters of NBR - 15,270, since the mechanical strength was 1.25 MPa and 0.94 MPa respectively for products with and without residue, lower than the minimum required by the technical standard that is 1.5 MPa.

Caracterização estrutural e atividades farmacológicas do alginato obtido da alga Dictyopteris delicatula (J.V. Lamouroux., 1809) e seu derivado sulfatado

Marine algae are rich sources of various structural compounds which recently has been increasingly studied as a new source of bioactive substances. The alginate, as come as fucans, are considered the main acidic polysaccharides found in brown seaweed. This molecule consists a linear natural polysaccharide, non-sulfated, and presents monosaccharides: acid β-D-mannuronic (M) and α-L-guluronic acid (G); in a vast amount compositions and threads. Alginate has been widely applied in food and pharmaceutical industries because of its ability to retain water, forming films and gels as well as thickening, stabilizing and form emulsions. In this work we aimed to extract, structurally characterize, compare and analyze the possible pharmacological activities of native alginate molecule obtained from brown seaweed Dyctiopteris delicatula (DYN), and its chemically sulfated derivative (DYS). The alginate structure and composition molecule can be proven through chemical dosing, that showed low protein contamination and high sugar level, existence and separation of M and G blocks in the descending paper chromatography, infrared spectroscopy and nuclear magnetic resonance. Molecule sulfation was proven with sulphate dosage, resulting in 28.56% sulphate in molecule; electrophoresis, verify metachromasia with toluidine blue; and infrared spectroscopy, that showed a characteristic band at 1221cm-1 corresponding a sulfate group vibration. For the pharmacological activities the tests was: antioxidant activity, changes in cell function (MTT test) and anticoagulant test. In the antioxidant activity we observed that DYN showed better results in the kidnapping of hydroxyl radicals and ferric chelation compared to DYS, this had the best result in the total antioxidant capacity. Both showed similar activity in reducing power and the kidnapping radicals DPPH. In MTT test DYN and DYS had not proliferative and cytotoxic activity in fibroblast cells (3T3) and showed antiproliferative and cytotoxic activity in cancer cell lines HeLa and B16 melanoma. In anticoagulant assay DYN showed good activity in the intrinsic pathway of blood coagulation, and a small activity in the extrinsic pathway, in the other hand DYS showed only a very small activity in the extrinsic pathway, but cannot come to be regarded as an anticoagulant agent. From these results it can be concluded that the alginate was extracted and sulfated, revealing a potential compound to be used in the pharmaceutical industry as an anticoagulant agent, antioxidant and antitumor and the sulfation has not been conclusively important to performance in the tested pharmacological activities

Variação no conteúdo protéico e pigmentar em variantes cromáticas de Gracilaria domingensis nas populações naturais de Rio do Fogo-RN, BRASIL

The seaweed Gracilaria domingensis is a common species in the coast of Rio Grande do Norte. This species lives in the intertidal zone, where colour strains (red, green and brown) co-occur during the whole year. Seaweeds that live in this region are exposed to daily changes and to the rhythm of the tide. During the low tide they are exposed to dissection, hiper-or hipo-osmotic shock, high temperatures and high irradiance. The aim of this study was to analyze whether the pigment and protein content of the colour strains of G. domingensis is affected by some environmental parameters in a temporal scale. The seaweeds were collected during 10 months in the seashore of Rio do Fogo (RN). The total soluble proteins and the phycobiliprotein were extracted in phosphate buffer and the carotenoids were analyzed by a standardized method through HPLC-UV. The pigments analysis showed that phycoerithrin is the most abundant pigment in the three strains. This pigment was strongly correlated with nitrogen and the photosynthetically active radiation. Chlorophyll presented higher concentrations than carotenoids during the whole, but the ratio carotenoid/chlorophyll-a was modified by incident radiation. The most abundant carotenoid was ß-carotene and zeaxanthin, which had higher concentrations in the higher radiation months. The concentration increase of zeaxanthin in this period indicated a photoprotective response of the seaweed. The three strains presented a pigment profile that indicates different radiation tolerance profile. Our results pointed that the green strain is better adapted to high irradiance levels than the red and brown strains

Homogalactanas sulfatadas da alga Codium isthmocladum com atividade anticoagulante

Since the first description of sulfated polysaccharides from seaweeds, the biological activities of these compounds have been evaluated under different aspects and experimental procedures. Among the broad biological activities presented by seaweed polysaccharides, anticoagulant action appears as a promising function. In this present study we have obtained sulfated polysaccharides from the green seaweed Codium isthmocladium by proteolytic digestion, followed by separation into five fractions (0.3, 0.5, 0.7, 0.9 and 1.2) by sequential acetone precipitation. The chemical analyses have demonstrated that all fractions are composed mainly by sulfated polysaccharides. The anticoagulant activity of these fractions was determined by activated partial thromboplastin time (aPTT) and prothrombin time test (PT) using citrate normal human plasma. None fraction has shown anticoagulant activity by PT test. Furthermore, all of them have shown anticoagulant activity by aPTT test. These results indicated that the molecular targets of these sulfated polysaccharides are mainly in the intrinsic via of the coagulation cascade. Agarose gel electrophoresis in 1,3-diaminopropane acetate buffer, pH 9.0, stained with 0.1% toluidine blue showed the presence of two or three bands in several fractions while the fraction 0.9 showed a single spot. By anion exchange chromatography, the acid polysaccharides from the 0.9 acetone fraction were separated into two new fractions eluted respectively with 2.0 and 3.0 M NaCl. These compounds showed a molecular weight of 6.4 and 7.4 kDa respectively. Chemical analyses and infrared spectroscopy showed that Gal 1 and Gal 2 are sulfated homogalactans and differ one from the other in degree and localization of sulfate groups. aPPT test demonstrated that fractions 2,0 and 3,0M (Gal1 and Gal 2, respectively) have anticoagulant activity. This is the first time that anticoagulant sulfated homogalatans have been isolated from green algae. To prolong the coagulation time to double the baseline value in the aPTT, the required amount of sulfated galactan 1 (6,3mg) was similar to low molecular heparin Clexane®, whereas only 0,7mg of sulfated galactan 2 was needed to obtain the same effect. Sulfated galactan 2 in high doses (250mg) induces platelet aggregation. These results suggest that these galactans from C. isthmocladum have a potential application as an anticoagulant drug