Optimization of mix proportions of mineral aggregates using Box Behnken design of experiments

Muthukumar, M.; Mohan, D.; Rajendran, M.

doi:10.1016/s0958-9465(02)00116-6

Cited by 177 publications

(103 citation statements)

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“…An adequate precision of 12.74 for the enzyme activity was recorded. A value greater than 4 is desirable in support of the fitness of the model (Muthukumar et al, 2003). The adjusted R 2 corrects the R 2 value for the sample size and the number of terms used in the selected model.…”

Section: Resultsmentioning

confidence: 99%

Glucoamylase production from food waste by solid state fermentation and its evaluation in the hydrolysis of domestic food waste

2014

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Section: Resultsmentioning

confidence: 99%

Glucoamylase production from food waste by solid state fermentation and its evaluation in the hydrolysis of domestic food waste

2014

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“…Among these methods, response surface methodology (RSM) appears to be the most popular (Abbasi et al 1987, Bayramov et al 2004, Muthukumar et al 2003, Nehdi and Sumner 2004. This method was developed for relatively large and complex experimental matrices, which results in selective examination (production and testing) of considered mixture designs.…”

Section: Introductionmentioning

confidence: 99%

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials

Radlinski¹,

Olek²

2010

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IntroductionConcrete bridge decks are inherently exposed to harsh environment. They are known to undergo degradation due to numerous distresses, of which the most common are corrosion of reinforcement (caused by ingress of chloride through bulk concrete), freeze-thaw damage, shrinkage cracking (aggravating both corrosion and freeze-thaw problems) and surface scaling due to deicing salts.Recently, high performance concrete (HPC) has become widely utilized in the applications where severe environment leads to premature deterioration. The premise behind the development of HPC was to address the durability issues typical of normal concrete. HPC almost always implies incorporation of mineral admixtures, such as fly ash (FA) or silica fume (SF). These materials are added to concrete for variety of reasons, of which the most important is improvement (compared to plain ordinary portland cement (OPC) concrete) of certain durabilityrelated properties. However, there are also some downsides of utilizing them in concrete. For example, fly ash is known to reduce the early age strength and early age resistance to chloride-ion penetration, as well as resistance to salt scaling and carbonation. Furthermore, fly ash concrete has been reported to be fairly sensitive to curing conditions compared to plain cement concrete. The shortcomings of incorporating silica fume, on the other hand, include increased susceptibility to shrinkage cracking and potentially reduced resistance to freezing and thawing.In the view of the aforementioned side effects associated with the use of fly ash or silica fume in binary mixtures, the ternary cementitious systems have been introduced as a potentially viable solution to address those durability issues. Superior properties of this kind of cementitious systems are commonly attributed to so-called synergistic effect taking place when both pozzolanic materials are utilized. The intuitively obvious benefit of the use of OPC/FA/SF mixtures is that the presence of fly ash in concrete compensates for the deficiencies of silica fume, and vice versa. For example, FA offsets the increase in water demand, heat of hydration and alkalinity of pore solution resulting from addition of SF. On the other hand, SF compensates for the low early age strength and sensitivity to curing (with respect to development of both mechanical and durability-related properties of FA concrete). From the economical perspective, a relatively low cost of FA counterbalances higher cost of SF. Although a fairly large amount of research has been conducted to evaluate the properties of ternary cementitious mixtures containing fly ash and silica fume, relatively little was done with the emphasis on the durability-related issues encountered when these binder systems are used in the bridge deck concrete. Up to date, no data exists on the actual performance of ternary concrete containing class C fly ash and silica fume in bridge decks.The purpose of this research was to examine the applicability of ternary binder systems containing ordinary port...

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“…Con el fin de establecer un comportamiento a lo largo de un rango de valores, el programa introduce un valor medio, que es la mitad del valor entre el menor y el valor más alto, los cuales son representados en la tabla 1. Para lograr finalmente la optimización de la respuesta ( % degradación de cianuro) [29]. En la tabla 1 se muestran los niveles de las variables del diseño de experimentos usando T iO 2 degussa P-25 y N b 2 O 5 · 3H 2 O como catalizador, pH y concen-tración de H 2 O 2 , fue colocado dentro de paréntesis los números -1, 0 y +1 a la derecha del valor tomado para cada variable, los cuales son las convenciones que utiliza un modelo factorial tipo Box Becken.…”

Section: Diseño Estadístico De Experimentosunclassified

“…Con el fin de minimizar el número de ensayos experimentales, para la degradación de cianuro y a su vez optimizar el porcentaje (variable de respuesta), se realizaron 15 ensayos para cada catalizador mediante el diseño experimental Box-Behnken, debido a su eficiencia en termino de ensayos requeridos para optimizar la variable de respuesta a analizar [29]. En las tablas 3 y 4 se revelan las características experimentales para cada uno de los ensayos, usando como catalizador N b 2 O 5 o3H 2 O y T iO 2 Degussa P-25 respectivamente.…”

Section: Diseño De Experimentosunclassified

“…Para ambos diseños experimentales podemos observar que a menores valores de pH la variable de respuesta experimental mostró mejor eficiencia en la degradación de cianuro, sin embargo debido a la formación de HCN a pH bajos [29], no podemos analizar el comportamiento de la variable de respuesta experimental a valores de pH inferiores a 9.5. Cuando se estudió la influencia de la concentración de H 2 O 2 , se apreció que este, al ser una fuente de radicales oOH, incrementó el carácter oxidante de la reacción fotocatalítica, lo cual se vió expresado en una mayor degradación del contaminante.…”

Section: Diseño De Experimentosunclassified

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Estudio catalítico comparativo de los sistemas TiO2 y Nb2O5 en la degradación de cianuro en función del tipo de oxidante

López

Sierra

2012

ing.cienc.

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La viabilidad del uso de otros agentes fotocatalizadores como el niobio, radicaen disminuir las energías altas de la banda prohibida para hacerlo competitivo frente al TiO2, sin embargo la presencia de coayudantes de oxidación, talescomo H2O2 y O3 podrían presentar resultados sorprendentes en el desempeño catalítico, debido a una mayor generación del radicales OH. La obtención de óxidos de mayor área y propiedades texturales diferentes al oxido de niobio comercial, mejoran su actividad catalítica en la remoción de cianuro libre. El trabajo presenta resultados experimentales de fotodegradación de cianuro 100mg=l sobre TiO2 Degussa P- 25 y Nb2O5 · 3H2O, usando un fotorreactor CPC con una capacidad de 4L de solución, usando como fuente de radiación la luz solar, tomando una inclinación igual a la latitud de Cartagena 10.45°, los resultados indicaron un claro efecto del pH, el tipo de catalizador y el coayudante de oxidación. La reducción de ion cianuro del efluente contaminado aumento por la adición del agente oxidante (O3 y H2O2). Sugiriendo una mayor susceptibilidad del cianuro libre, para oxidarse a cianato de forma indirecta, por una mayor generación de radicales hidroxilos, inducidos por la presencia de H2O2 o del O3 bajo radiación solar. Se obtuvo porcentajes de oxidación fotocatalítica de cianuro libre, entre el 64% y 72% usando Nb2O5 · 3H2O y un rango entre 67% y 71% usando TiO2 Degussa P - 25. Los catalizadores fueron caracterizados estructuralmente usando DRX, BET,Raman e FT-IR, con la finalidad de correlacionar los cambios morfológicos con el desempeño catalítico.

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Optimization of mix proportions of mineral aggregates using Box Behnken design of experiments

Cited by 177 publications

References 1 publication

Glucoamylase production from food waste by solid state fermentation and its evaluation in the hydrolysis of domestic food waste

Glucoamylase production from food waste by solid state fermentation and its evaluation in the hydrolysis of domestic food waste

High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study Volume 2: Materials

Estudio catalítico comparativo de los sistemas TiO2 y Nb2O5 en la degradación de cianuro en función del tipo de oxidante

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