European Journal of Engineering Research and Science
It has been argued that cement is the most energy intensive and expensive material in concrete. I... more It has been argued that cement is the most energy intensive and expensive material in concrete. It has also been suggested that energy efficiency could be achieved by using Supplementary Cementitious Materials (SCMs), which require less process heating and emit fewer levels of CO2. This paper reviewed studies from different authors on the possibility of using Corn Cob Ash (CCA) as a SCM. The review targeted studies that had applied the quantitative method, with validity and reliability based on empirical data from laboratory experiments. The review covered workability, density, compressive and tensile strengths, gain in strength over time, water absorption and chemical resistance of CCA-replaced concrete. From the findings, it can be concluded that CCA could be used as an effective SCM to replace cement in concrete, with the benefit of a reduction in CO2 emissions that are associated with the production of cement and a mitigation on environmental nuisance that is attributed to the t...
European Journal of Engineering Research and Science
Durability of concrete is defined as its ability to resist deterioration after it has been expose... more Durability of concrete is defined as its ability to resist deterioration after it has been exposed to the environment of its intended use. This work examined the performance of combined (ternary) Pulverised Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) concrete in sulfate solutions of sodium sulfate (Na2SO4), magnesium sulfate (MgSO4) and mixed Na2SO4 and MgSO4, as well as its performance in water absorption. Investigations were carried out on replacements that were found to have achieved the highest compressive strengths as well as on 30% replacements from a previous study. From the results obtained, it was also found that at highest compressive strengths, the ternary concrete could be used with an advantage over the individual binary concretes in MgSO4 environments, whereas at a higher replacement, the ternary concrete could be used with an advantage over individual binary specimens in Na2SO4 and MgSO4 environments. For visual observations, it was concluded that t...
Comparative biochemistry and physiology. A, Comparative physiology, 1982
1. The extent of cardiovascular adjustments to heat and cold were investigated between ambient te... more 1. The extent of cardiovascular adjustments to heat and cold were investigated between ambient temperatures of 5 and 45 degrees C by measuring conductance and the rates of oxygen consumption and heart beats. 2. Minimum heart rate was observed at 25 degrees C (114 +/- 9 beats/min). In the heat at 45 degrees C heart rate was observed to increase only slightly (127 +/- 12 beats/min) but in the cold -5 degrees C heart rate nearly doubled that at 25 degrees C. 3. Thermal conductance was on average 0.031 mlO2 (g. hr. degrees C)-1 below 25 degrees C but increased by more than 20 times at 40 degrees C. 4. A positive correlation between heart rate and rate of oxygen consumption was demonstrated below 25 degrees C and the relation may be of practical use.
The purpose of this study was to determine whether the maximal rate of oxygen consumption (Vo2max... more The purpose of this study was to determine whether the maximal rate of oxygen consumption (Vo2max) is scaled proportionally to Mb1.0, as the diffusing capacity of the lung, or proportionally to Mb0.75, as the standardized resting rate of oxygen consumption (V02std). We measured Vo2max on a variety of mammalian species (14 wild species and 8 domestic or laboratory species ranging in Mb from 7.2 g to 263 kg) using the same 'treadmill' procedure for all animals. For the wild species we found: Vo2max = 1.94.Mb0.79; r=0.995 where Vo2max has the units ml . sec-1 and mb is in kg. There was a great variability in Vo2max among domestic species of the same size, horse and dog having a Vo2max more than 3 times that of a cow and sheep, respectively. Both the variability in Vo2max with body size and among animals of the same size provide powerful tools for investigating the relationship between structure and function at each step in the respiratory system, from the oxygen in environmental air to the oxygen sink in the mitochondria.
European Journal of Engineering Research and Science
It has been argued that cement is the most energy intensive and expensive material in concrete. I... more It has been argued that cement is the most energy intensive and expensive material in concrete. It has also been suggested that energy efficiency could be achieved by using Supplementary Cementitious Materials (SCMs), which require less process heating and emit fewer levels of CO2. This paper reviewed studies from different authors on the possibility of using Corn Cob Ash (CCA) as a SCM. The review targeted studies that had applied the quantitative method, with validity and reliability based on empirical data from laboratory experiments. The review covered workability, density, compressive and tensile strengths, gain in strength over time, water absorption and chemical resistance of CCA-replaced concrete. From the findings, it can be concluded that CCA could be used as an effective SCM to replace cement in concrete, with the benefit of a reduction in CO2 emissions that are associated with the production of cement and a mitigation on environmental nuisance that is attributed to the t...
European Journal of Engineering Research and Science
Durability of concrete is defined as its ability to resist deterioration after it has been expose... more Durability of concrete is defined as its ability to resist deterioration after it has been exposed to the environment of its intended use. This work examined the performance of combined (ternary) Pulverised Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) concrete in sulfate solutions of sodium sulfate (Na2SO4), magnesium sulfate (MgSO4) and mixed Na2SO4 and MgSO4, as well as its performance in water absorption. Investigations were carried out on replacements that were found to have achieved the highest compressive strengths as well as on 30% replacements from a previous study. From the results obtained, it was also found that at highest compressive strengths, the ternary concrete could be used with an advantage over the individual binary concretes in MgSO4 environments, whereas at a higher replacement, the ternary concrete could be used with an advantage over individual binary specimens in Na2SO4 and MgSO4 environments. For visual observations, it was concluded that t...
Comparative biochemistry and physiology. A, Comparative physiology, 1982
1. The extent of cardiovascular adjustments to heat and cold were investigated between ambient te... more 1. The extent of cardiovascular adjustments to heat and cold were investigated between ambient temperatures of 5 and 45 degrees C by measuring conductance and the rates of oxygen consumption and heart beats. 2. Minimum heart rate was observed at 25 degrees C (114 +/- 9 beats/min). In the heat at 45 degrees C heart rate was observed to increase only slightly (127 +/- 12 beats/min) but in the cold -5 degrees C heart rate nearly doubled that at 25 degrees C. 3. Thermal conductance was on average 0.031 mlO2 (g. hr. degrees C)-1 below 25 degrees C but increased by more than 20 times at 40 degrees C. 4. A positive correlation between heart rate and rate of oxygen consumption was demonstrated below 25 degrees C and the relation may be of practical use.
The purpose of this study was to determine whether the maximal rate of oxygen consumption (Vo2max... more The purpose of this study was to determine whether the maximal rate of oxygen consumption (Vo2max) is scaled proportionally to Mb1.0, as the diffusing capacity of the lung, or proportionally to Mb0.75, as the standardized resting rate of oxygen consumption (V02std). We measured Vo2max on a variety of mammalian species (14 wild species and 8 domestic or laboratory species ranging in Mb from 7.2 g to 263 kg) using the same 'treadmill' procedure for all animals. For the wild species we found: Vo2max = 1.94.Mb0.79; r=0.995 where Vo2max has the units ml . sec-1 and mb is in kg. There was a great variability in Vo2max among domestic species of the same size, horse and dog having a Vo2max more than 3 times that of a cow and sheep, respectively. Both the variability in Vo2max with body size and among animals of the same size provide powerful tools for investigating the relationship between structure and function at each step in the respiratory system, from the oxygen in environmental air to the oxygen sink in the mitochondria.
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