Análise de propriedades térmicas e mecânicas de compósitos de argamassa e resíduo de borracha

Although already to exist alternative technique and economically viable for destination of used tires, quantitative data on properties of constructive elements that use the rubber waste as aggregate still are restricted. In the present work, the waste proceeding from industry of retreading as material for manufacture of composite destined to the production of constructive elements was considered. Mechanical and thermal properties of mortar had been analyzed Portland cement with addition of waste without treatment, in the ratios of 10%, 20% and 30% in mass in relation to the mass of the cement, substituting the aggregate in the trace in mortar 1:5 mass cement and sand. The size of the used residue varied between 0,30mm and 4,8mm (passing in the bolter 4,8mm and being restrained in the one of 0,30mm), being it in the formats fibers and granular. The influences of the size and the percentage of residue added to the mortar (in substitution to the aggregate) in the thermal and mechanical properties had been considered. Assays of body-of-test in thestates had been become fullfilled cool (consistency index) and hardened (absorption of water for capillarity, strength the compression, traction and strength flexural). The work is centralized in the problem of the relation thermal performance /strength mechanics of used constructive systems in regions of low latitudes (Been of the Piauí), characterized for raised indices of solar radiation.

Avaliação do efeito da adição de resíduo de borracha de pneu e brita calcária na formulação de compósitos cimentíceos

Researches have shown that the introduction of rubber in concrete improves the features of its deformability, as well as contributes to environmental disposal of waste generated in the tire retreading process. Furthermore, there is a high availability of limestone within RN and CE country. Ignorance about this stone, does not allow its wide use as aggregate, leaving, this abundant supply idle. A composite of limestone gravel, with proportions of tire rubber waste which could be used as concrete would be an alternative to concrete for low applications. Therefore, this research aims to evaluate the characteristics of concrete containing limestone gravel and proportions of little aggregate replacement (sand) by tire rubber waste. To this goal, the material components of the concrete were characterized, concrete specimens with limestone gravel were made, from the dash 1.0: 2.5: 3.5, varying the water/cement ratio, and inserting a commercial plasticizer, without a proportion of residue, known as reference. From this, concrete with and without the presence of the additive in the same proportions were chosen, as well as these with the use of granite gravel, for being the most used. Selected the references, to these, replacements of little aggregate (sand) were added replaced by rubber waste from the tire retreading process, treated with 1M NaOH in proportions from 5.0 to 20.0 % by mass, cured and exposed to the semiarid environment. The results indicate the possibility of using limestone gravel in the concrete composition with workability correction using plasticizer. There was a decrease in the mechanical properties of the concrete with increments of waste rubber, but there is an improvement in toughness and deformability of the composite, which makes it interesting for the construction of non-structural concrete floors, as well as, the rubber waste delayed the hardening process, continuing to gain resistance after 28 days

Avaliação do desempenho de argamassas à base de cimento Portland para rejuntamento de placas cerâmicas tipo II com adição de pó de borracha de pneus

In this work it is assessed the performance of Portland cement-based mortar to the grouting of type II ceramic plates with the addition of unusable tire rubber powder. It is presented a bibliographical review about the subject in which is done the theoretical and methodological foundation of the whole investigative process. The analyzed universe comprises a sample of mortar to the grouting of conventional ceramic plates type II (reference sample) and five more samples to the grouting of ceramic plates type II, which were made up of the addition of unusable tire rubber powder in the respective proportion (in mass) of 4%, 8%, 12%, 16% and 20%. These mortar samples were subject to the trials of determination of the consistency index (Brazilian Standard NBR 13276:2005), water retention ( Brazilian Standard NBR 14992 Attachment B:2003), permeability in 240 minutes (Brazilian Standard NBR 14992 Attachment G:2003), absorption of water by immersion (Brazilian Standard NBR 9781:2013), resistance to compression (Brazilian Standard NBR14992 Attachment D: 2003), resistance to traction in the flexion (Brazilian Standard NBR 13279:2005), resistance of traction adherence (Brazilian Standard NBR 14081 part 4:2012) and hardened mass density (Brazilian Standard NBR 13280: 2005). It has been found out from the analyzes of the results in the trial the following situation: the reference mortar used met the established requirements in the norms of specifications corresponding to only six from the eight parameters assessed in the research; the mortar with addition of 4,0% of tire rubber powder met the established requirements corresponding to only the resistance to compression and the resistance of adherence to traction. Thus, the other kinds of mortar with addition of 8,0 %, 12,0 %, 16,0 % and 20,0 % of tire rubber powder met the requirements of specifications corresponding to only the resistance to compression and the resistance of adherence to traction. This result concludes that the adding of tire rubber powder does not grant improvement to the mortar of type II grouting to the laying of ceramic plates.

Avaliação do desempenho de argamassas à base de cimento Portland para rejuntamento de placas cerâmicas tipo II com adição de pó de borracha de pneus

In this work it is assessed the performance of Portland cement-based mortar to the grouting of type II ceramic plates with the addition of unusable tire rubber powder. It is presented a bibliographical review about the subject in which is done the theoretical and methodological foundation of the whole investigative process. The analyzed universe comprises a sample of mortar to the grouting of conventional ceramic plates type II (reference sample) and five more samples to the grouting of ceramic plates type II, which were made up of the addition of unusable tire rubber powder in the respective proportion (in mass) of 4%, 8%, 12%, 16% and 20%. These mortar samples were subject to the trials of determination of the consistency index (Brazilian Standard NBR 13276:2005), water retention ( Brazilian Standard NBR 14992 Attachment B:2003), permeability in 240 minutes (Brazilian Standard NBR 14992 Attachment G:2003), absorption of water by immersion (Brazilian Standard NBR 9781:2013), resistance to compression (Brazilian Standard NBR14992 Attachment D: 2003), resistance to traction in the flexion (Brazilian Standard NBR 13279:2005), resistance of traction adherence (Brazilian Standard NBR 14081 part 4:2012) and hardened mass density (Brazilian Standard NBR 13280: 2005). It has been found out from the analyzes of the results in the trial the following situation: the reference mortar used met the established requirements in the norms of specifications corresponding to only six from the eight parameters assessed in the research; the mortar with addition of 4,0% of tire rubber powder met the established requirements corresponding to only the resistance to compression and the resistance of adherence to traction. Thus, the other kinds of mortar with addition of 8,0 %, 12,0 %, 16,0 % and 20,0 % of tire rubber powder met the requirements of specifications corresponding to only the resistance to compression and the resistance of adherence to traction. This result concludes that the adding of tire rubber powder does not grant improvement to the mortar of type II grouting to the laying of ceramic plates.

Desenvolvimento e caracterização de biocompósito de látex (borracha natural) e fibra de carnaúba

The development of composite materials encompasses many different application areas. Among the composites, it is had, especially, the materials of organic origin, which have the greatest potential for biodegradability and so, have been bringing relevance and prominence in the contemporary setting of environmental preservation and sustainable development. Following this perspective of ecological appeal, it was developed a biocomposite material with natural inputs typically brazilian. This composite was made from latex (natural rubber) and carnauba fiber in different mass proportions. Formulations had varied by 5%, 10%, 15% and 20% of fiber in relation the matrix. This material has been designed aiming at application in thermal insulation systems, which requirethermal protection surfaces and/or reduction of thermal energy loss. Therefore, the composite was characterized by thermal conductivity testing, specific heat, thermal diffusivity and thermogravimetry. As has also been characterized for their physical-mechanical, by testing density, moisture content, tensile strength, hardness and scanning electron microscopy (SEM). The characterization of the material revealed that the composite presents a potential of thermal insulation higher than the natural rubber, that was used as reference. And the formulation at 15% fiber in relation the matrix showed the best performance. Thus, the composite material in question presents itself as a viable and effective alternative for new thermal insulation material design.

Desenvolvimento e caracterização de biocompósito de látex (borracha natural) e fibra de carnaúba

The development of composite materials encompasses many different application areas. Among the composites, it is had, especially, the materials of organic origin, which have the greatest potential for biodegradability and so, have been bringing relevance and prominence in the contemporary setting of environmental preservation and sustainable development. Following this perspective of ecological appeal, it was developed a biocomposite material with natural inputs typically brazilian. This composite was made from latex (natural rubber) and carnauba fiber in different mass proportions. Formulations had varied by 5%, 10%, 15% and 20% of fiber in relation the matrix. This material has been designed aiming at application in thermal insulation systems, which requirethermal protection surfaces and/or reduction of thermal energy loss. Therefore, the composite was characterized by thermal conductivity testing, specific heat, thermal diffusivity and thermogravimetry. As has also been characterized for their physical-mechanical, by testing density, moisture content, tensile strength, hardness and scanning electron microscopy (SEM). The characterization of the material revealed that the composite presents a potential of thermal insulation higher than the natural rubber, that was used as reference. And the formulation at 15% fiber in relation the matrix showed the best performance. Thus, the composite material in question presents itself as a viable and effective alternative for new thermal insulation material design.

Análise de propriedades térmicas e mecânicas de compósitos de argamassa e resíduo de borracha

Although already to exist alternative technique and economically viable for destination of used tires, quantitative data on properties of constructive elements that use the rubber waste as aggregate still are restricted. In the present work, the waste proceeding from industry of retreading as material for manufacture of composite destined to the production of constructive elements was considered. Mechanical and thermal properties of mortar had been analyzed Portland cement with addition of waste without treatment, in the ratios of 10%, 20% and 30% in mass in relation to the mass of the cement, substituting the aggregate in the trace in mortar 1:5 mass cement and sand. The size of the used residue varied between 0,30mm and 4,8mm (passing in the bolter 4,8mm and being restrained in the one of 0,30mm), being it in the formats fibers and granular. The influences of the size and the percentage of residue added to the mortar (in substitution to the aggregate) in the thermal and mechanical properties had been considered. Assays of body-of-test in thestates had been become fullfilled cool (consistency index) and hardened (absorption of water for capillarity, strength the compression, traction and strength flexural). The work is centralized in the problem of the relation thermal performance /strength mechanics of used constructive systems in regions of low latitudes (Been of the Piauí), characterized for raised indices of solar radiation.

Avaliação do efeito da adição de resíduo de borracha de pneu e brita calcária na formulação de compósitos cimentíceos

Researches have shown that the introduction of rubber in concrete improves the features of its deformability, as well as contributes to environmental disposal of waste generated in the tire retreading process. Furthermore, there is a high availability of limestone within RN and CE country. Ignorance about this stone, does not allow its wide use as aggregate, leaving, this abundant supply idle. A composite of limestone gravel, with proportions of tire rubber waste which could be used as concrete would be an alternative to concrete for low applications. Therefore, this research aims to evaluate the characteristics of concrete containing limestone gravel and proportions of little aggregate replacement (sand) by tire rubber waste. To this goal, the material components of the concrete were characterized, concrete specimens with limestone gravel were made, from the dash 1.0: 2.5: 3.5, varying the water/cement ratio, and inserting a commercial plasticizer, without a proportion of residue, known as reference. From this, concrete with and without the presence of the additive in the same proportions were chosen, as well as these with the use of granite gravel, for being the most used. Selected the references, to these, replacements of little aggregate (sand) were added replaced by rubber waste from the tire retreading process, treated with 1M NaOH in proportions from 5.0 to 20.0 % by mass, cured and exposed to the semiarid environment. The results indicate the possibility of using limestone gravel in the concrete composition with workability correction using plasticizer. There was a decrease in the mechanical properties of the concrete with increments of waste rubber, but there is an improvement in toughness and deformability of the composite, which makes it interesting for the construction of non-structural concrete floors, as well as, the rubber waste delayed the hardening process, continuing to gain resistance after 28 days

Acidentes por quedas em um grupo específico de idosos

Este estudo objetivou conhecer a incidência do evento queda e identificar a presença de seus principais fatores de risco. Estudo exploratório, realizado de março a novembro/2009, com aplicação de um formulário sobre quedas em um grupo de idosos. Os dados foram analisados por cálculo de frequências, média e desvio-padrão. Participaram 62 idosos, 41,9% relataram queda nos últimos seis meses, a maioria mulheres. Identificou-se ocorrência de agravos concomitantes: visão regular, audição boa, polifarmácia, IMC normal, forte força de preensão palmar e condições dos pés adequadas. Na maioria dos que caiu, o desequilíbrio foi apontado como principal motivo. A queda ocorreu mais no período da manhã, em local de piso áspero e seco, sem degraus, rampas ou tapetes, iluminação adequada e o tipo de calçado mais utilizado foi chinelo de borracha. Percebe-se a alta ocorrência das quedas na população idosa, fato que fundamenta a necessidade de avaliação das condições de risco envolvidas

Análise de falhas em martelos oscilantes dos desfibradores da indústria sucroalcooleira da Região Norte-Nordeste

The failure of materials is always an unwelcome event for several reasons: human lives are put in danger, economic losses, and interference in the availability of products and services. Although the causes of failures and behaviour of materials can be known, the prevention of such a condition is difficult to be guaranteed. Among the failures, wear abrasion by the low voltage is the kind of failure that occurs in more equipment and parts industry. The Plants Sucroalcooleiras suffer significant losses because of such attrition, this fact that motivated their choice for the development of this work. For both, were considered failures in the swing hammers desfibradores stopped soon after the exchange provided in accordance with tonnage of cane processed, then were analyzed by the level of wear testing of rubber wheel defined by the standard ASTM G65-91.The failures were classified as to the origin of the cause and mechanism, moreover, were prepared with samples of welding procedures according to ASME code, sec. IX as well, using the technique of thermal spraying to analyze the performance of these materials produced in laboratories, and compares them with the solder used in the plant. It was observed that the bodies-of-proof prepared by the procedure described as welding, and the thermal spraying the results of losing weight have been minimized significantly compared to the preparations in the plant. This is because the use of techniques more appropriate and more controlled conditions of the parameters of welding. As for the thermal spraying, this technique has presented a satisfactory result, but requires the use of these coatings in the best condition for real affirmation of the results

Análise do comportamento reológico de pastas de cimento contendo resíduos de pneu para poços de petróleo

The low tenacity presented by the Portland cement pastes used in the oil wells cementation has been motivating several researches with attention focused on alternative materials. Additives have been developed to generate flexible pastes with mechanical resistance capable to support the expansions and retractions of the metallic covering of the wells that submit to the steam injection, technique very used to increase the recovery factor in oil reservoirs with high viscosity. A fresh paste with inadequate rheological behavior may commit the cementation process seriously, involving flaws that affect the performance of the paste substantially in the hardened state. This work proposes the elaboration and the rheological analysis of Portland cement pastes with addition of residues of rubber tire in several proportions, with the aim of minimizing the damages provoked in the hem cementing of these wells. By thermogravimetric analysis, the particles of eraser that go by the sieve of 0,5mm (35 mesh) opening and treated superficially with NaOH solution of 1 mol/L presented appropriate thermal resistance for wells that submit to thermal cyclic. The evaluation of the study based on the results of the rheological analysis of the pastes, complemented by the mechanical analysis, thickening, stability, tenor of free water and filtrate loss, being used as parameter a paste reference, without rubber addition. The results showed satisfactory rheology, passive of few corrections; considerable loss of mechanical resistance (traction and compression), compensated by earnings of tenacity, however with established limits for its application in oil wells; satisfactory stability, free water and thickening time

Estudos de Durabilidade Frente ao Ataque Ácido de Compósitos Portland-Polímero para Cimentação de Poços de Petróleo

Portland-polymers composites are promising candidates to be used as cementing material in Northeastern oil wells of Brazil containing heavy oils submitted to steam injection. In this way, it is necessary to evaluate its degradation in the commonly acidizind agents. In addition, to identify how aggressive are the different hostile environments it is an important contribution on the decision of the acidic systems to be used in. It was investigated the performance of the Portland-polymer composites using powdered polyurethane, aqueous polyurethane, rubber tire residues and a biopolymer, those were reinforced with polished carbon steel SAE 1045 to make the electrochemical measurements. HCl 15,0 %, HCl 6,0 % + HF 1,5 % (soft mud acid), HCl 12,0 % + HF 3,0 % (regular mud acid) and HAc 10 % + HF 1,5 % were used as degrading environment and electrolytes. The more aggressive acid solution to the plain Portland hardened cement paste was the regular mud acid, that showed loss of weight around 23.0 %, followed by the soft mud acid, the showed 11.0 %, 15.0 % HCl with 7,0 % and, at last the 10.0 % HAc plus HF 1.5 % with just 1.0 %. The powdered polyurethane-composite and the aqueous polyurethane one showed larger durability, with reduction around 87.0 % on the loss of weight in regular mud acid. The acid attack is superficial and it occurs as an action layer, where the degraded layer is responsible for the decrease on the kinetic of the degrading process. This behavior can be seen mainly on the Portland- aqueous polyurethane composite, because the degraded layer is impregnated with chemically modified polymer. The fact of the acid attack does not have influence on the compressive strength or fratography of the samples, in a general way, confirms that theory. The mechanism of the efficiency of the Portland-polymers composites subjected to acid attack is due to decreased porosity and permeability related with the plain Portland paste, minor quantity of Ca+2, element preferentially leached to the acidic solution, wave effect and to substitute part of the degrading bulk for the polymeric one. The electrolyte HAc 10 % + HF 1,5 % was the least aggressive one to the external corrosion of the casing, showing open circuit potentials around +250 mV compared to -130 mV to the simulated pore solution to the first 24 hours immersion. This behavior has been performed for two months at least. Similar corrosion rates were showed between both of the electrolytes, around 0.01 μA.cm-2. Total impedance values, insipient arcs and big polarization resistance capacitive arcs on the Nyquist plots, indicating passivity process, confirm its efficiency. In this way, Portlandpolymers composites are possible solutions to be succeed applied to oilwell cementing concomitant submitted to steam injection and acidizing operation and the HAc 10,0 % + HF 1,5 % is the less aggressive solution to the external corrosion of the casing

Determinação de parâmetros de qualidade para formas farmacêuticas homeopáticas

All medicine, whether allopathic or homeopathic, must go through strict quality control, which must ratify their characteristics throughout the period of validity. During the time of preparation and storage, solutions of the drugs are in permanent contact with packaging materials that can release undesirable substances to the solution. Several factors may influence the release of packing materials, and factorial design (FD) is a useful tool for analyzing the phenomenon. The aim of this study was the determination of quality parameters for Homeopathic solid (globules) and liquid (drops) dosage forms. It was carried out analysis in homeopathic globules for weight variation, mechanical strength, and moisture content uniformity. For liquid preparations, standard solutions were prepared from natural rubber bulbs, which were subjected to exhaustive extraction with two ethanol solutions (30 and 70%) in the ultrasonic bath for 20 minutes at 25°C and 50°C in three successive cycles. Studies of transfer have been made within five days, by spectrophotometric analysis in the UV region at 312 nm with λmáx and 323 nm for samples in 70% ethanol and 30% respectively. PH values were analyzed. We also conducted two FD studies, where the first, the three-level variables were solvent (chloroform, ethanol and nhexane), sample mass (30, 60 and 90mg), particle size (large disk, small disk and powder sample). In the second study, the solvent level variables were different ethanolic degrees (EtOH 30%, 70% and pure). The percentage of lending in the solutions was 5.5%, 12.4%, 24.2% and 41% of the total estimated in the reference solution. The values of rate constants of transfer were determined in the order of 0.0134 days-1 and 0.0232 days-1 in absorbance values, the solutions in ethanol at 30% and 70% respectively. These results suggest that the speed of transfer of materials from rubber is affected both by the nature of the vehicle as by the temperature

O Cariri cearense: da ocupação do território à institucionalização da região metropolitana do Cariri

Urbanization in their mearing simpler, the agglomeration of people, occurred from the time that the productive activities have to be based on trade. The first cities arose when the evolution of agriculture allowed the production and storage of surpluses. However, with industrialization was that urbanization becomes intense, according to Singer (1987), the industrial revolution was to stage, from the beginning, the urban area. It requires, in its proximity, the presence of a large number of workers. With respect to the Cariri cearense, the occupation of its territory is associated with the movement of agricultural surpluses produced and reproduced under the hegemony of merchant capital and due to the development of extensive cattle that promoted the territorial occupation of Ceará. From the 1960s, the region has undergone changes in its productive structure due to industrial planning policies of the government of Ceará. However it was in the 1990s that the region itself as economic and urban polo because policies to attract investments from the state government of Ceará. This policy led to boosting trade and services marking the predominance of tertiary activities in the region, especially the retail, wholesale , medical services and education. Investments also consolidated the industrial park area making it diverse, especially the footwear industries, mining, non-metallic minerals, transport equipment, pharmaceutical chemical, food and beverages, rubber and leather and construction. Thus, the aim of this study was to review the region of Cariri cearense occupation of its territory institutionalizing its metropolitan region, to understand what factors influenced the Cariri cearense become an important area in urban and economic terms in the interior of Ceará. In order to develop this research in that refers to the methodological perspective, research is guided by bibliographic studies and also makes use of secondary data analysis (population, GDP, urbanization rate, employment) of the main databases the country, as IBGE, IPEADATA and RAIS - MTE

Avaliação do concreto de cimento portland com resíduo da produção de scheelita em substituição ao agregado miúdo

From the 70`s, with the publication of the Manifesto for Environment UN Conference, held in Stockholm, in Sweden (1972), defend and improve the environment became part of our daily lives. Thus, several studies have emerged in several segments in order to reuse the waste. Some examples of waste incorporated in portland cement concrete are: rice husk ash, bagasse ash of cane sugar, powder-stone, microsilica, tire rubber, among others. This research used the residue of the mining industry Scheelite, to evaluate the incorporation of the residue composition of Portland cement concrete, replacing the natural sand. The percentage of residue were incorporated from 0% to 100%, with a variation of 10%, 11 being produced concrete mix in the ratio 1:2:3:0.60, by mass. We evaluated the following characteristics of concrete: slump test, compressive strength, tensile strength by diametral compression, water absorption, porosity and density, based on the ABNT, through tests performed in the Laboratory of Civil Construction, UFRN. The trace with the addition of 60% scheelite residue was obtained which better performance. Therefore, the use of the waste from the production of Scheelite is feasible due to the durability parameters (water absorption and porosity), sustainability, and the good results of the resistance of the concrete