Hydration and interactions between C3S and C3A polymorphs in the presence of different calcium sulfates

Calcium sulfate is an important constituent in Portland cement nowadays. It is used to control the setting time of Portland cement. However, many questions about the role of calcium sulfate on the cement phases (C3A and C3S) hydration and its mechanisms persist. A critical overview of the effect of sulfates on Portland cement hydration and properties is presented here in a review manuscript form. In this sense, several knowledge gaps, such as the influence of C3S and C3A polymorphs and the calcium sulfate composition on the sulfate balance in Portland cement, were identified. To address some of the questions identified in the review three different experimental studies were executed. The first one was focused to understand how gypsum accelerates the C3S hydration and whether aluminum incorporated in its structure plays an essential role or not. The effects of gypsum on the hydration of C3S and aluminum-doped C3S (Al-C3S) hydration were assessed. Calorimetry, XRD, TGA, and 27Al and 29Si MAS-NMR were performed to analyze gypsum’s influence on the hydration of C3S and Al-C3S. The results showed that the inclusion of gypsum retarded the initial hydration (first 3 h) for both C3S and Al-C3S, due to the interaction between the sulfate ions and C3S. In contrast, gypsum enhanced the hydration of both C3S and Al-C3S afterward. This acceleration effect occurred earlier for the Al-C3S due to the removal of aluminum from the solution. However, this is not the main mechanism behind the acceleration of C3S by gypsum, which mainly results from changes in C-S-H morphology and increases in the ionic strength. Secondly, the mechanism responsible for the higher reactivity of orthorhombic C3A (ort-C3A) in sulfate-containing solutions, compared with cubic C3A (cb-C3A), which was previously related to either the difference in crystal structure or the sodium in ort-C3A pore solution were investigated. The hydration of cbC3A (in water and NaOH solution) and Na-doped ort-C3A in the presence of gypsum and hemihydrate were analyzed using isothermal calorimetry, in-situ XRD, TGA, SEM, and rheological tests. The results showed that NaOH accelerated the hydration of cb-C3A, but ortC3A still presented a higher hydration rate. Ort-C3A pastes revealed more and larger ettringite crystals at 30-120 minutes, resulting in higher viscosities and yield stresses than cb-C3A pastes. The replacement of gypsum with hemihydrate accelerated ort-C3A hydration but retarded cbC3A hydration. Overall, the higher reactivity of ort-C3A is related to differences in crystal structure rather than the sodium in pore solution. Finally, the hydration of three-phase systems (C3S-C3A-calcium sulfate) was analyzed. Two C3S (T1 pure C3S and M1 aluminum-doped C3S), two C3A polymorphs (cubic and orthorhombic), and two calcium sulfates (gypsum and hemihydrate) were evaluated. For each system, the hydration of four different SO3 contents was evaluated by calorimetry. From the calorimetry results, a 1.5 wt.% SO3 content was fixed, and the mixtures were evaluated by in-situ XRD and TGA. The C3S type was the factor that most affected the sulfate balance of the systems. The mixes with Al-C3S presented higher ettringite formation in the first hours, resulting in much earlier sulfate depletions when compared to the mixes with C3S. The mixes with ort-C3A also presented faster sulfate depletions, due to its higher reactivity compared with cb-C3A. Finally, the replacement of gypsum by hemihydrate, also resulted in faster sulfate depletions, which is the consequence of the higher solubility of hemihydrate

Corrosion Inhibitors for Reinforced Concrete

Reinforced concrete has been widely used in the last century, however, due to aggressive agents such as carbonic gas and chloride ions, it suffers premature deterioration. The concrete is a physical barrier that protects steel from corrosion, and the alkalinity of concrete leads to the formation of a passive layer around the reinforcement, which increases protection against corrosive processes. However, concrete is a porous material and has cracks that allow the entrance of aggressive agents, destabilizing the passive layer and corroding steel. The corrosion is the major cause of deterioration of concrete structures and several methods of protection and repair have been developed to increase the durability of such structures. Corrosion inhibitors, chemical substances that reduce the corrosion rate, have been widely used, both for prevention and correction. Inhibitors are classified according to their method of application, their mechanism of protection and chemical composition. In this chapter, through a literature review the main inhibitors used in reinforced concrete structures and their acting mechanisms are presented, as well as their efficiency and some side effects on concrete. It is very important to know the different types of inhibitors for correct use, thus increasing the life span of reinforced concrete structures

COMPORTAMENTO ADAPTATIVO DO COFFEA CANEPHORA L. NA ZONA DA MATA PERNAMBUCANA

A agricultura no Brasil é atividade com grande impacto na balança comercial. A cafeicultura constitui-se em uma das atividades que mais contribuem para o equilíbrio das exportações brasileiras. Os produtores de café buscam adequar-se a nova realidade do mercado, o qual vem exigindo atenção a aspectos relacionados à responsabilidade ambiental dos empreendimentos. Neste sentido há grande preocupação para obter a eficiência do uso da água e manutenção dos altos níveis de produtividade das lavouras. Dessa forma, objetivou-se com o presente trabalho: Realizar a caracterização da estrutura e funcionalidade hidráulica em amostras coletadas no campo experimental e realizar a avaliação adaptativa da variedade à região, visando uma utilização mais adequada da espécie em estudo. A técnica mostrou-se eficiente para ser usada na estimativa acurada desses parâmetros em plantas de café conilon.  De modo geral, concluiu-se que o clone do cafeeiro conilon (Variedade Vitória 2 Precoce) não apresentou grandes variações fenotípicas, indicando que as plantas estão apresentando o mesmo comportamento adaptativo no ambiente estudado

Modelagem da interação rio-oceano no sudeste do brasil: abordagem inicial na foz do rio Macaé, Rio de Janeiro

The effects of climate change in environments influenced by watercourses have been causing collective problems that need to be monitored through simulations, in order to adopt prevention and containment measures by city managers. The objective of this work was to carry out a modeling that represents the behavior of the interaction of the Atlantic Ocean with the Macaé River, located in the Macaé and Ostras Hydrographic Region (RH-VIII), state of Rio de Janeiro, Brazil. The computational modeling was performed using the OpenFlows FLOOD software through a built three-dimensional model, and FES (Finite Element Solution), with the FES2014 tidal database. The construction of the model was carried out in a scenario of constant flow of the Macaé River of approximately 200 m³/s, during a period of 24 hours. The computational model initially elaborated still needs adjustments and calibrations. The modeling presented is in its initial phase, and the data used in the simulation can be refined in order to better serve the development of this and other related scenarios.Os efeitos das mudanças climáticas em ambientes influenciados por cursos d’água vêm causando problemas de ordem coletiva que precisam ser monitorados por meio de simulações, a fim de se adotar medidas de prevenção e contenção pelos gestores das cidades. O objetivo deste trabalho foi realizar uma modelagem que representasse o comportamento da interação do oceano atlântico com o Rio Macaé, localizado na Região Hidrográfica Macaé e das Ostras (RH-VIII), estado do Rio de Janeiro, Brasil. A modelagem computacional foi realizada utilizando o software OpenFlows FLOOD por meio de um modelo tridimensional construído, e FES (Solução de Elementos Finitos), com o banco de dados de marés FES2014. A construção do modelo foi feita em um cenário de vazão constante do rio Macaé de aproximadamente 200 m³/s, durante um período de 24 horas. O modelo computacional inicialmente elaborado ainda necessita de ajustes e calibrações. A modelagem apresentada está em fase inicial, e os dados utilizados na simulação podem ser refinados a fim de atender melhor o desenvolvimento deste e de outros cenários relacionados

TRANSPIRAÇÃO EM COFFEA CANEPHORA L. VIA BALANÇO DE CALOR NO CAULE E LISÍMETRO DE PESAGEM ELETRÔNICA

O consumo de água em uma planta de café conilon cultivado em lisímetro foi avaliado. O experimento objetivou estudar a transpiração diária do café e foi realizado no Departamento de Energia Nuclear da UFPE, em Recife – PE, em 2011, por meio de dois métodos: a) lisimetria, por análise de variação de massa; b) fluxo de seiva via método térmico do balanço de calor no caule. A área foliar variou de 1,39 a 1,87 m2 durante o experimento. O consumo de água medido através do lisímetro variou entre 2,61 L a 5,16 L com média de 3,86 L por dia. A demanda atmosférica foi determinada com dados obtidos em duas estações meteorológicas, uma situada próximo ao lisímetro, e a outra, distante cerca de um quilômetro, situada no pátio externo do CRCN. A transpiração medida pelo fluxo de seiva via método térmico subestimou em 10% as medidas realizadas no lisímetro. Os resultados do estudo indicaram grande precisão na estimativa da transpiração do café conilon.

Quality of minimally processed table cassava cultivated in southeastern Pará, brazilian Amazonian / Qualidade da mandioca de mesa minimamente processada cultivada no sudeste do Pará, Amazônia brasileira

This paper aimed to assess the quality of the cassava roots of the variety Cacau minimally processed. Physical characterization of 100 root samples was carried out by measuring the weight of roots, weight of roots without bark, weight of bark, root yield, length and diameter. The following treatments were performed: T1: roots was washed in running water; T2: sanitized roots (150 mg. L-1); T3: sanitized roots (150 mg. L-1) and acidified roots (1% citric acid) and T4: sanitized roots (150 mg. L-1) and bleached (55ºC/10 min). The physicochemical characterization of leaves, stems and roots were performed through the analysis of pH, total titratable acidity (TTA), moisture, ashes, protein content, lipids, carbohydrates and total energy value (TEV). For the variables of plant growth, the number of roots (9.10 units) and dry matter of the roots (1312.15 g), in addition the yield of the unshelled root (80.95 kg or 61.80 %) was close to the values reported in the literature. As for the physicochemical parameters of minimally processed cassava roots, they were in accordance with those established by the Brazilian Table Food Composition. These parameters are considered the most important for the industry, so they explain the reasons for the agroindustrial potential this feedstoock. 

Protocols for management of oral complications of chemotherapy and/or radiotherapy for oral cancer : systematic review and meta-analysis current

Considering the high possibility of dentist consult a patient with oral complications of chemotherapy and/or radiotherapy for oral cancer because of the advances in this area, this study aims to systematically review the literature to identify and suggest effective and safe protocols for the managements of oral complications in oncology patients. TThe systematic review was designed by PICO and PRISMA including eligibility and exclusion criteria; the source of information and search strategy in PubMed according MeSH: ?Mouth Neoplasms and Radiotherapy? and ?Mouth Neoplasms and Drug Therapy? the period from 2010 to 2015; selection and data collection of study was carried form blind and independently by two researchers; risk of bias and methodological quality: ensured by the PEDro scale; synthesis of data: of oral complications were evaluated by adapted version of associative direction classification proposed by Costigan and collaborators; and data analysis was performed by the meta-analysis of BioEstat program (5.0) in the included studies. 2,700 articles found, 2,371 were selected after removal of duplicate and elected 40 full-text articles. Of these, only 06 articles were included in the systematic review with exclusion of others, per obtain punctuation ? 7 with high methodological quality for synthesis of the managements of oral complications. Since 05 articles were associated with low risk of bias composing the protocols suggestive for managements and the meta-analysis in odds ratio (0.916) to cure and relative risk (1.049) for the development of oral mucositis and pain. The protocols suggestive for managements of oral mucositis and pain with MuGard - mucoadhesive hydrogel; PerioAid Tratamiento® antiseptic mouthrinse with chlorhexidine and cetylpyridinium chloride; Episil® plus benzydamine - bioadhesive oromucosal gel; 0,03% of Triclosan mouthwash Colgate Plax; and Diode Laser Therapy of low-level are safe for oncology patients applied according to adopted clinical parameters

Ruptura Bilateral do Músculo Fibular Terceiro em Bovino

Background: The peroneus tertius muscle is responsible for tarsal flexion and coordinate extension of the stifle joint. The most common causes of rupture are excessive effort when trying to rise on a slippery surface, mounting, or being mounted. Rupture of the peroneus tertius muscle is characterized by an inability to flex the hock. Most cases are not curable, presenting an unfavorable to poor prognosis, and the animal has to be euthanized. This study aimed to report the clinical picture and treatment of a bilateral rupture of the peroneus tertius muscle in a cow from the municipality of Castanhal, state of Pará (Amazonian biome). Case: We report the clinical picture and treatment of a bilateral rupture of the peroneus tertius muscle in a 4-year-old cow, mixed breed, weighing approximately 400 kg, calved 3 months ago, belonging to a batch of 40 cattle kept on extensive breeding system in a pasture of Urochloa (Brachiaria) brizantha. The clinical signs appeared after the cow was mounted by a 1,100 kg bull and consisted of lameness, falling into sternal decubitus with hind limbs extended backward, hyperextension of the hocks with flexed stifle, with the tibia and metatarsus in a straight line, which lead to a 90-degree position of the femur and knee. Abrasions in the dorsal region of the fetlocks reinforce evidence of dragging hooves. Diagnosis of bilateral rupture of the peroneus tertius muscle was performed by a clinical examination and semiological test. Non-steroidal anti-inflammatory drugs (flunixin meglumine, 2,2 mg/kg, every 24 h for 4 days) were prescribed for treatment, in addition to resting in a paddock with good availability of pasture, water, and mineral salt. After 3 months, we observed an improvement of the clinical signs, and after 6 months, an almost complete recovery. Only a slight difficulty in flexing the hock when moving remained. Discussion: In the present report, bull mounting was the probable cause of the hyperextension of both hocks and the bilateral rupture of the peroneus tertius muscle. According to the handler, these clinical signs were only evidenced after the animal was mounted. As stated in the literature, accidents such as falls, slips, mounting or being mounted, as well as excessive traction and over-elevation of the limb are considered predisposing factors for the onset of the disease. Rupture of the peroneus tertius muscle is unusual in production animals; therefore, the low occurrence of reports on this kind of rupture in the literature makes this case even more unique. The bilateral injury differs from cases described in the literature, in which the reported injuries were always unilateral. Our findings reinforce the hypothesis that the act of mounting was the triggering factor for the bilateral rupture of the animal peroneus tertius muscle. The breeding system also differs from the cases diagnosed by the same authors, since they describe the disease in bovines kept on intensive or semi-intensive breeding. In the present case, the cattle were kept on an extensive breeding system. The extension and flexion tests used in the clinical examination allowed for the diagnosis of rupture of the peroneus tertius muscle in both limbs, similarly to what has been reported by other authors. Anamnesis, clinical findings, and exclusion of different diagnoses were decisive for establishing the diagnosis. The treatment chosen was efficient, even though the case was severe, as the injury occurred in both hind limbs. Keywords: cattle disease, muscle injury, lameness, rupture. Título: Ruptura bilateral do músculo fibular terceiro em bovino Descritores: doença do gado, lesão muscular, claudicação, ruptura.Background: O músculo fibular terceiro é responsável pela flexão do tarso e extensão coordenada da articulação fêmuro-tíbio-patelar. As causas mais comuns da ruptura são o esforço excessivo ao se levantar em piso escorregadio, montar ou ser montado por outros animais, entre outras causas. A ruptura do músculo fibular terceiro é caracterizada pela incapacidade de flexão do jarrete e, na maioria dos casos, não há recuperação, o prognóstico geralmente é desfavorável a ruim e o animal é destinado à eutanásia. O objetivo deste estudo foi relatar o quadro clínico e o tratamento empregado na ruptura bilateral do músculo fibular terceiro em uma vaca do município de Castanhal, estado do Pará (bioma amazônico). Case: Descreve-se o quadro clínico e o tratamento empregado na ruptura bilateral do músculo fibular terceiro em uma vaca, com quatro anos de idade, sem raça definida, com aproximadamente 400kg, parida há três meses, pertencente a um lote de 40 bovinos mantidos em sistema de criação extensiva em pastagem de Urochloa (Brachiaria) brizantha. Os sinais clínicos surgiram após ser coberta por um touro de 1.100Kg e consistiram em claudicação, queda em decúbito esternal com os membros posteriores estendidos para trás, hiperextensão dos jarretes com a soldra flexionada, ficando a tíbia e o metatarso em linha reta, levando a formação de um ângulo de 90º entre o fêmur e o joelho. As escoriações na região dorsal dos boletos pélvicos reforçam a evidência do arrastar das pinças. O diagnóstico da ruptura bilateral do músculo fibular terceiro foi realizado por meio do exame clínico semiológico. No tratamento foi prescrito anti-inflamatório não-esteroidal (flunixin meglumine, 2,2 mg/kg, a cada 24h, durante quatro dias) e repouso em um piquete com boa disponibilidade de pastagem, água e sal mineral. Após três meses observou-se a melhora dos sinais clínicos e após seis meses uma recuperação quase completa, permanecendo apenas uma leve dificuldade de flexionar o jarrete no momento da locomoção. Discussion: No presente relato, a monta do touro foi a provável causa da hiperextensão de ambos os jarretes e a ruptura bilateral dos músculos fibulares terceiros. A lesão bilateral difere de casos descritos em livros e artigos em que as lesões relatadas foram sempre unilaterais, reforçando a hipótese de o ato da monta ter sido o fator desencadeante da ruptura bilateral do músculo fibular terceiro do animal. Conclui-se que a anamnese, achados clínicos e exclusão de diagnósticos direfencias foram decisivos para instituição do diagnóstico. O tratamento instituído foi eficiente, mesmo se tratando de um caso grave, no qual a lesão ocorreu em ambos os membros posteriores

Infantile hypothyroidism and its relationship with delayed tooth eruption : a case report

Hypothyroidism is characterized as a systemic endocrine disorder that is caused by a dysfunction of the thyroid gland. This produces the thyroid hormones T3 and T4 that are responsible for carrying out the normal functions of the physical body, that is,