EFFECT OF STEEL FIBERS ON REFRACTORY CASTABLES

Reinforcement of refractory castables with steel fibers improves their strength for cracking and spalling and expands the service life. The results show that raising the temperature from 700°C to 900°C causes an increase in porosityand decrease in bulk density for refractory castables. This happens because of decomposition of the hydraulic bond of alumina cement. When the temperature is raised higher than 900°C, ceramic bond is formed as a result of sol dreaction between alumina cement and bauxite aggregate. This leads to reduction of the porosity ar d aincrease in the bulk density. Steel fibers are affected positively in reducing the porosity ardaincreasing the bulk density for refractory castables. This positive effect increases with increasethe fibers contentup to 1.5%. All castable samples have good spalling resistances at all temperatures for different percentage of steel fibers.Improvement of reinforced refractory castables increases with rising temperature of firing, but itwas not possible to raise the temperature above 1000°C because of the oxidation of the steel fibers

ESTIMATION THE 7 AND 28- DAY NORMAL COMPRESSIVE STRENGTH BY ACCELERATED TEST METHODS IN CONCRETE

Curing of concrete is the maintenance of a satisfactory moisture content and temperature for a period of time immediately following placing so the desired properties are developed. Accelerated curing is advantages where early strength gain in concrete is important. The expose of concrete specimens to the accelerated curing conditions which permit the specimens to develop a significant portion of their ultimate strength within a period of time (1-2 days), depends on the method of the curing cycle.Three accelerated curing test methods are adopted in this study. These are warm water, autogenous and proposed test methods. The results of this study has shown good correlation between the accelerated strength especially for the proposal curing test method and normal strength using normal curing method at ages 7 and 28 day for the five different chemical composition of cement with different water to cement ratios equal to 0.45, 0.55, 0.65 and 0.75. Linear and nonlinear regression analysis show high correlation for the different types of the accelerated curing methods with coefficient of correlation (R2) more than 0.9

The Toronto Concussion Study: a prospective investigation of characteristics in a cohort of adults from the general population seeking care following acute concussion, 2016–2020

PurposeThere is limited research regarding the characteristics of those from the general population who seek care following acute concussion.MethodsTo address this gap, a large cohort of 473 adults diagnosed with an acute concussion (female participants = 287; male participants = 186) was followed using objective measures prospectively over 16 weeks beginning at a mean of 5.1 days post-injury.ResultsFalls were the most common mechanism of injury (MOI) (n = 137, 29.0%), followed by sports-related recreation (n = 119, 25.2%). Male participants were more likely to be injured playing recreational sports or in a violence-related incident; female participants were more likely to be injured by falling. Post-traumatic amnesia (PTA) was reported by 80 participants (16.9 %), and loss of consciousness (LOC) was reported by 110 (23.3%). In total, 54 participants (11.4%) reported both PTA and LOC. Male participants had significantly higher rates of PTA and LOC after their injury compared to their female counterparts. Higher initial symptom burden was associated with a longer duration of recovery for both male and female participants. Female participants had more symptoms and higher severity of symptoms at presentation compared to male participants. Female participants were identified to have a longer recovery duration, with a mean survival time of 6.50 weeks compared to 5.45 weeks in male participants (p < 0.0001). A relatively high proportion of female and male participants in this study reported premorbid diagnoses of depression and anxiety compared to general population characteristics.ConclusionAlthough premorbid diagnoses of depression and/or anxiety were associated with higher symptom burden at the initial visit, the duration of symptoms was not directly associated with a pre-injury history of psychological/psychiatric disturbance. This cohort of adults, from the general population, seeking care for their acute concussion attained clinical and functional recovery over a period of 4–12 weeks

Optimal Controller Design for a Turbogenerator Automatic Voltage Regulator and Governor using Two Degree of Freedom Linear Quadratic Gaussian (2DOFLQG)

This paper introduces a computational methodology that adopted a method of Linear Quadratic Gaussian (LQG) controller as Automatic Voltage Regulator (AVR) and Governor to control the generator terminal voltage and the turbine speed. In this method the models were assumed to be Linear, depending on this method the controller power consumption was minimized depending on some performance index, which is assumed to be Quadratic. This method was taken into account the noise and the disturbance in view, considered its distribution as Gaussian. The two degree of freedom (2DOF) structure was adopted, in which two controllers are used. The effectiveness of the proposed control action is demonstrated through some computer simulations on a Single-Machine Infinite- Bus (SMIB) power system. To accommodate stability requirements, a mathematical model for the generator and the turbine was derived based on the twoaxis theorem and starting from the swing equation. Results obtained show that adopting such a controller enhanced the steady state and transient stability

Complex Synthesis of Cis-[Pt(Asc) (NH₃)₂] and its Effect on Human Breast Cancer MCF-7 Cell <i>in vitro</i>

Bosom malignancy is the most regularly analyzed disease and the imperative reason for growth-related passing among ladies, accounting for 23% of all new tumor cases and 14% of tumor passing's. L-Ascorbic acid, commonly known as vitamin C is well-known in chemistry since long back. It has tremendous medical applications in several diseases. Therefore, in this paper five concentrations of complex cis-[Pt(Asc)(NH3)2] where Asc=L-ascorbic acid derivative on MCF-7 cell line to detect the changes in five cellular parameters (nuclear intensity, mitochondrial membrane potential, valid cell count, cytochrome C, and membrane permeability) after exposure with 24 h are investigated. The results showed that 400 μg/mL has the highest significant effect on the five parameters (nuclear intensity, mitochondrial membrane potential, valid cell count, cytochrome C, and membrane permeability) when compared with Doxorubicin 20 μM (substance used as anti-cancer) which represent the positive control. Also, the 200 μg/mL showed results close to those of the untreated cells which represent the negative control (-ve) with a very few significant differences

Image_1_The Toronto Concussion Study: a prospective investigation of characteristics in a cohort of adults from the general population seeking care following acute concussion, 2016–2020.JPEG

PurposeThere is limited research regarding the characteristics of those from the general population who seek care following acute concussion.MethodsTo address this gap, a large cohort of 473 adults diagnosed with an acute concussion (female participants = 287; male participants = 186) was followed using objective measures prospectively over 16 weeks beginning at a mean of 5.1 days post-injury.ResultsFalls were the most common mechanism of injury (MOI) (n = 137, 29.0%), followed by sports-related recreation (n = 119, 25.2%). Male participants were more likely to be injured playing recreational sports or in a violence-related incident; female participants were more likely to be injured by falling. Post-traumatic amnesia (PTA) was reported by 80 participants (16.9 %), and loss of consciousness (LOC) was reported by 110 (23.3%). In total, 54 participants (11.4%) reported both PTA and LOC. Male participants had significantly higher rates of PTA and LOC after their injury compared to their female counterparts. Higher initial symptom burden was associated with a longer duration of recovery for both male and female participants. Female participants had more symptoms and higher severity of symptoms at presentation compared to male participants. Female participants were identified to have a longer recovery duration, with a mean survival time of 6.50 weeks compared to 5.45 weeks in male participants (p ConclusionAlthough premorbid diagnoses of depression and/or anxiety were associated with higher symptom burden at the initial visit, the duration of symptoms was not directly associated with a pre-injury history of psychological/psychiatric disturbance. This cohort of adults, from the general population, seeking care for their acute concussion attained clinical and functional recovery over a period of 4–12 weeks.</p