Abstract This paper presents an exact solution for the boundary-value problem which describes the linear buckling of axially-compressed cylindrical panels with frames attached to the circular edges. The boundary conditions differ from the classical simply supported ones, often assumed for design purposes, in the sense that the torsion resisted by the frames are also taken into account. The quality of the results reported herein may be valuable benchmark data.

Resumo Zeólitas LTA e FAU foram sintetizadas com brometo de cetiltrimetilamônio (CTAB) visando avaliar os efeitos das razões Si/Al, Na/Al e H2O/Al, do tempo e da temperatura no rendimento de cada estrutura. A significância de cada variável foi determinada através de planejamentos experimentais, cujas variáveis resposta foram as áreas de picos de difração de raios X específicos. O CTAB não agiu como direcionador estrutural, mas sim como modificador de crescimento, aumentando a taxa de crescimento dos cristais. Em temperatura baixa, LTA foi obtida em baixas razões Si/Al, enquanto FAU cristalizou-se em razões maiores, indicando uma competição entre as duas estruturas. O aumento da temperatura aumentou a cinética de recristalização das fases LTA e FAU, menos densas e metaestáveis, em fases mais densas e mais estáveis, como sodalita e cancrinita. A diminuição de concentração de Na+ e água reduziu a cristalinidade das estruturas, enquanto que o aumento de Na+ favoreceu a formação de FAU em detrimento de LTA.

Abstract LTA and FAU zeolites were synthesized with the addition of cetyltrimethylammonium bromide (CTAB) to assess the effects of Si/Al, Na/Al and H2O/Al ratios, time and temperature on the yield of each structure. The significance of each variable was determined by means of experimental designs, whose response variables were the areas of specific XRD peaks. CTAB did not act as a structure-directing agent, but rather as a growth modifier, increasing the growth rate of LTA and FAU crystals. At low temperature, LTA was afforded at low Si/Al ratio, while FAU crystallized at higher ratios, indicating a competition between the phases. Increasing temperature accelerated the kinetics of recrystallization of the less dense and metastable LTA and FAU phases in denser and more stable phases, such as sodalite and cancrinite. Decreasing the concentration of Na+ and water reduced the crystallinity of both structures, while increasing the concentration of Na+ favored LTA over FAU.

Emulsifying properties of sodium caseinate -locust bean gum Maillard conjugates produced at different temperatures (54 - 96 ºC), protein/polysaccharide ratios (0.3 - 1.0) and reaction times (1 - 24 hours) were evaluated. Conjugate formation was confirmed by formation of color and high molecular weight fractions and the decrease of the αs- and β-casein bands. The emulsions stabilized by Maillard conjugates showed good stability. The mean droplet diameter (d32) tended to decrease with the increase of incubation time and temperature, except at extreme conditions (24 hours and 90 ºC or 96 ºC) when the partial degradation of the conjugates was probably favored, resulting in phase separation of emulsions. The emulsion viscosity decreased with the increase in the protein/polysaccharide ratio and with the degradation of the conjugates. The conditions used in the experimental design made the optimization of the conjugate production viable, which showed greater emulsifier properties than the pure protein under acid conditions.

This paper reports experimental data of the isobaric vapor-liquid equilibria (VLE) for the mixture methyl acetate + ethanol at 0.3 and 0.7 MPa, determined using a copper still ebulliometer. The activity coefficients obtained from the experimental data were correlated by using different thermodynamic mathematical models. All the binary systems show a positive consistency when subjected to the point-to-point test of Van Ness. The prediction of VLE data obtained with the UNIFAC and ASOG methods has been verified with experimental data.

Falhas em tubos de caldeiras são as maiores causas de paradas forçadas de unidades de geração termelétrica, sendo que a espessura da camada de óxido, que se forma na parede interna destes tubos é a principal causadora de falhas por sobreaquecimento. A partir dos valores medidos da camada interna de óxidos é possível estimar a vida residual do componente através de correlações com parâmetros já estabelecidos na comunidade científica. O Cepel vem desenvolvendo metodologias para estimativa de vida residual de componentes de caldeiras de usinas termelétricas, seguindo as tendências mundiais e as necessidades de seus clientes no Brasil. Com a recente aquisição de equipamento para detecção de defeitos e medições de espessura via ultrassom, tornou-se possível realizar medidas de espessura tanto da parede das tubulações das caldeiras como da camada interna de óxidos presente nas mesmas. O presente artigo apresenta uma comparação entre os resultados de medições de espessura de camada de óxidos em tubos pela técnica não destrutiva de ultrassom e pela técnica destrutiva de metalografia associada à microscopia ótica, em diferentes faixas de espessura da camada e análise do efeito do acabamento superficial na confiabilidade destes resultados por ultrassom. Finalmente, o trabalho analisa de maneira crítica os resultados de vida remanescente, obtidos a partir da medição espessura de camada de óxido. Para esta análise tomou-se como base tubos de uma mesma unidade geradora com diferentes valores de camada de óxido e com o mesmo tempo de operação.

Boiler tube failures are the major causes of forced shut downs in thermoelectric units. The thickness of the oxide layer formed on the inner wall of these tubes is the main cause of failure due to overheating. From the measured values of the inner oxide layer, it is possible to estimate the residual life of the component via correlations with parameters established in the scientific community. Cepel has been developing methodologies for estimating the residual life of boiler components for power plants, following the world trends and the needs of its customers in Brazil. With the recent acquisition of ultrasonic equipment for detecting defects and to perform thickness measurements it has become possible to perform both operations at the same time. This article presents a comparison between the results of measurements of oxide layer thickness in tubes by the non-destructive ultrasonic technique and the destructive metallographic technique associated with optical microscopy. Oxide layers with different thicknesses were used to perform the analysis. Also, the effect of surface preparation was evaluated for the reliability of results by ultrasonic testing. Finally, the study examines, in a critical way, the remaining life results obtained from the measured oxide layer thickness. To perform this analysis, two tubes with different oxide scale thicknesses were taken from a generation unit, both of them operated for the same amount of time.

Objective. To determine the association between carotid atherosclerotic manifestations and osteoporosis in patients with occlusive cerebrovascular disease (OCVD). Method. From June 2007 to June 2009 115 patients with clinical tomographic diagnosis of ECVO, who underwent carotid artery-Color Doppler Ultrasound exams as well as lumbar spine and hip bone densitometry, were studied. Results. No correlation between the value of bone mineral density (BMD) and the magnitude of carotid atherosclerotic damage was observed. There was a moderate positive correlation between Body Mass Index (BMI) and BMD. Most risk factors were associated with increased intima media thickness, increased atherogenic index, low rates of significant stenosis, and densitometric osteopenia, with aging and hypertension as predominant factors. Conclusions. Despite the presence of shared risk factors, no correlation between osteoporosis and atherosclerotic manifestations in the carotid artery in OCVD was observed.

Objetivo. Determinar la asociación existente entre las manifestaciones ateroescleróticas carotídeas y la osteoporosis, en pacientes con enfermedad cerebrovascular oclusiva (ECVO). Método. Estudiamos 115 pacientes con diagnóstico clínico tomográfico de ECVO desde junio 2007 a junio 2009, a los que se les realizó ultrasonido Doppler color carotídeo y densitometría de columna lumbosacra y caderas. Resultados: No hallamos correlación entre el valor de la densidad mineral ósea (DMO) y la magnitud del daño aterosclerótico carotídeo; encontramos correlación moderada positiva entre el índice de masa corporal y la DMO. La mayoría de los factores de riesgo se asociaron con incremento del grosor íntima media, índice aterogénico aumentado y baja prevalencia de estenosis significativa, así como osteopenia densito-métrica, siendo el envejecimiento y la hipertensión los factores predominantes. Conclusiones: La osteoporosis y las manifestaciones ateroescleróticas carotídeas en la ECVO no guardan relación, más allá de la presencia de factores de riesgo en común.

A estequiometria de poliânions formados pela ação do ácido nítrico sobre a solução de tungstato de sódio (< 0,01M) foi estudada por meio de técnicas eletrométricas envolvendo titulações potenciométricas e condutométricas. As inflexões e degraus bem definidas nas curvas de titulações forneceram evidências convincentes pela existência de poliânions, para-W12O41(10-) e meta-W12O39(6-) nas faixas do pH 5,7-6,0 e 3,6-4,1; correspondendo a razão H+:WO4(2-) como 7:6 e 9:6, respectivamente. A interação entre soluções de nitrato de lantânio e tungstato de sódio a específicos níveis de pH 8,0; 5,9 e 4,0 também foi estudada por titulações potenciométricas e condutométricas, nos meios aquoso e etanólico, com cada reagente usado alternadamente como titulante. Os experimentos eletrométricos forneceram evidências incontestáveis sobre a formação de tungstatos normal-La2O3.3WO3, para-5La2O3.36WO3 e meta-La2O3.12WO3 nas proximidades de valores de pH 6,3; 5,0 e 4,2; respectivamente. Investigações analíticas sobre os precipitados formados confirmam os resultados do estudo eletrométrico.

The stoichiometry of the polyanions formed by the action of nitric acid on sodium tungstate (< 0.01M) has been studied by means of electrometric techniques involving pH-potentiometric and conductometric titrations. The well defined inflections and breaks in the titration curves provide evidence for the existence of the polyanions, para-W12O41(10-) and meta-W12O39(6-) corresponding to the ratio of H+:WO4(2-) as 7:6 and 9:6 in the pH ranges 5.7-6.0 and 3.6-4.1, respectively. The interaction of lanthanum nitrate with sodium tungstate solutions, at specific pH levels 8.0, 5.9 and 4.0 was also studied by pH and conductometric titrations, in aqueous and alcoholic media, with each of the reagents alternatively used as titrant. The electrometric experiments provide definite evidence of the formation of normal-La2O3.3WO3, para-5La2O3.36WO3 and meta-La2O3.12WO3 tungstates in the vicinity of pH 6.3, 5.0 and 4.2, respectively. Analytical investigations on the precipitates formed confirm the results of the electrometric study.

A natureza precisa da reação entre soluções de ácido nítrico e de ortho-vanadato de sódio foi estudada por técnicas electrométricas envolvendo titulações potenciométricas e condutométricas. As inflexões e degraus bem definidas nas curvas de titulações confirmaram a existencia de anions, piro-V2O7(4-), meta-VO3- e poli-H2V10O28(4-) correspondendo as razões de VO4(3-):H+ como 1:1, 1:2 e 1:2,6 na vizinhança do pH 10,5; 7,4 e 3,6, respectivamente. Ainteração entre soluções de nitrato de cério(III) e vanadato de sódio a específicos níveis de pH 12,4; 10,5; 7,4 e 3,6 também foi estudada por titulações potenciométricas e condutométricas entre os reagentes. Os pontos finais obtidos a partir de inflexções nítidas nas curvas de titulações forceram evidências incontestáveis sobre a formação e precipitação de vanadatos orto-Ce2O3.V2O5, piro-2Ce2O3.3V2 O5 e meta-Ce2O3.3V2O5 de cério nas proximidades dos valores de pH 7,4; 6,2 e 4,8, respectivamente. Investigações analíticas sobre os precipitados formados confirmam os resultados do estudo eletrométrico.

The precise nature of the reaction between nitric acid and sodium ortho-vanadate solutions has been studied by means of electrometric techniques involving potentiometric and conductometric titrations. The well defined inflections and breaks in the titration curves confirm the existence of the anions, pyro-V2O7(4-), meta-VO3- and poly-H2V10O28(4-) corresponding to the ratios of VO4(3-):H+ as 1:1, 1:2 and 1:2.6 in the neighborhood of pH 10.5, 7.4 and 3.6, respectively. The interaction of cerium(III) nitrate with sodium vanadate solutions, at specific pH levels 12.4, 10.5, 7.4 and 3.6 was also studied by potentiometric and conductometric titrations between the reactants. The end-points obtained from the sharp inflections in the titration curves provide definite evidence for the formation and precipitation of cerium ortho-Ce2O3.V2O5, pyro-2Ce2O3.3V2O5 and meta-Ce2O3.3V2O5 vanadates in the neighborhood of pH 7.4, 6.2 and 4.8, respectively. Analytical investigations on the precipitates formed confirm the results of the electrometric study.

In previous work, it was observed that the covering of soybean seeds with bacteria and micronutrients enhances vigorous growth of the plant thereby avoiding use of ammoniacal fertilizers. In the spouted bed covering can be done by pulverization of the coater slurry on the soybean seeds using a pneumatic atomizer. The optimum thickness of the cover allows the fundamental gaseous interchanges for germination and provides the ideal conditions for bacterium activity. The objective of this work was to study the influence of the process variables on thickness of the cover. A simulation of the mass distribution of seeds was obtained using a population balance model. Through the results obtained the operational conditions under which the coating layer distribution were determined has the greatest uniformity.

RESUMEN. En el músculo de especies marinas existen compuestos nitrogenados no proteicos que se usan como índices de calidad, estos corresponden a contenido de bases volátiles totales (BVT), óxido de trimetilamina (OTMA) y trimetilamina (TMA). El pH también se usa como índice de calidad. En el presente estudio se determinaron estos valores en un producto marino al estado fresco y después de que fue sometido a tratamientos térmicos. El recurso escogido corresponde al crustáceo jaiba mora (Homalaspis plana) que se obtuvo desde las costas de la V región de Chile. Se extrajo carne de las pinzas y se mantuvo en hielo hasta su análisis y tratamientos térmicos. Se aplicó un diseño estadístico 3² en el que se consideraron dos variables y tres niveles, la variable tiempo tiene los niveles 15, 30 y 45 minutos y la variable temperatura tiene los niveles 80 , 100 y 121ºC, obteniéndose 9 combinaciones tiempo-temperatura. El pH, BVT y TMA de las muestras tratadas térmicamente aumentaron respecto a la carne fresca, mientras que el contenido de OTMA disminuyó

SUMMARY. Marine species muscles present non-proteics nitrogenated compounds, used as quality index. They are total volatile basis (NBVT), trimethylamine oxide (TMAO) and trimethylamine (TMA). pH is considered too as a quality index .The aim of this work was to evaluate these parameters in a fresh and canned marine product from the V region, corresponding to mora crab (Homalaspis plana). Fresh pincer meat from mora crab was extracted and kept in ice until theits analysis and thermal process of the canned product. A 3² statistical design was applied, considering two variables with 3 levels; 15, 30 y 45 minutes time levels; 80º, 100º y 121ºC temperature levels. Nine conditions of time-temperature were obtained. The thermal treatment caused an increase in pH and BVT. The TMA was increased since reduction of OTMA.

Estudou-se o processo de eletrodeposição de uma camada amorfa de liga Ni-W-B sobre um cátodo, utilizando um banho contendo sulfato de níquel 0,0185 M, tungstato de sódio 0,0155 M, fosfato de boro 0,0364 M, citrato de sódio 0,0161 M, 1-docecilsulfato de sódio 0,017 g/L e hidróxido de amônio para pH 8,5. Estudos detalhados sobre a influência da temperatura do banho, agitação mecânica e densidade de corrente catódica conduziram as condições ótimas para obtenção de depósitos de ligas satisfatórias. Observou-se que esta liga apresentou, elevada resistência à corrosão e ao desgaste quando comparadas com o cromo duro, além de se comprovar, através da difratometria de raios X, sua característica amorfa. Estas ligas podem ter grande utilidade em várias aplicações nas indústrias químicas, petrolíferas, petroquímicas, navais, de construções civis e automobilísticas em decorrência de algumas características especiais, como alta resistência à corrosão e desgaste e à capacidade de manter suas propriedades mecânicas em altas temperaturas.

The process of electrodeposition of amorphous layer of Ni-W-B alloy on a cathode, using a bath containing 0.0185 M nickel sulfate, 0.0155 M sodium tungstate, 0.0364 M sodium citrate, 0.017 g/L 1-dodecylsulfate-Na and ammonia for pH adjustment to 8.5, has been studied. Detailed studies on bath temperature, bath agitation and cathode current density led to the optimum conditions for obtaining satisfactory alloy deposit. The alloy presented higher corrosion and wear resistance in comparison to the hard chromium, besides its amorphous characteristic verified by X-ray diffraction. These alloys should have great importance in various applications in chemical, petroleum, petrochemical, naval, automobile and civil construction industries due to their special characteristics such as high wear and corrosion resistance and the capacity to maintain their mechanical properties at high temperatures.

We demonstrate here that acute third ventricle injections of GR 113808, a highly selective 5-HT4 antagonist, decrease water intake induced by a previous salt load while potentiating drinking elicited by hypovolemia induced by previous subcutaneous administration of polyethylene glycol in male Wistar rats (200 ± 20 g). At the dose of 160 nmol/rat, third ventricle injections of GR 113808 induced a significant reduction of water intake in salt-loaded animals after 120 min as compared to salt-loaded animals receiving third ventricle injections of saline (salt load + GR = 3.44 ± 0.41 ml, N = 12; salt load + saline = 5.74 ± 0.40 ml, N = 9). At the dose of 80 nmol/rat, GR 113808 significantly enhanced water intake in hypovolemic animals after 120 min as compared to hypovolemic animals receiving third ventricle injections of saline (hypovol + GR = 4.01 ± 0.27 ml, N = 8; hypovol + saline = 2.41 ± 0.23 ml, N = 12). We suggest that central 5-HT4 receptors may exert a positive drive on water intake due to hyperosmolarity and a negative input on drinking provoked by hypovolemia.