Resumen Se estudió el efecto de la irradiación gamma, a diferentes velocidades y dosis adsorbidas, sobre las propiedades físico-químicas del combustible de petróleo diésel. Las muestras de combustible diesel se expusieron a radiación gamma durante 1,3 h utilizando diferentes dosis absorbidas: 3, 6, 10 y 15 kGy, con tasas de dosis de 2,27, 4,5, 7,4 y 11,15 kGy / h, respectivamente. Las características físico-químicas del combustible diesel se determinaron de acuerdo con los métodos de prueba estándar ASTM, las características son: índice de cetano, puntos de recuperación de la destilación, punto de inflamación, poder calorífico, densidad y viscosidad cinemática. Se estudió el efecto de las dosis de irradiación gamma sobre los compuestos orgánicos del combustible diesel mediante la técnica GC / MS. Los resultados experimentales muestran que la densidad, la destilación, la viscosidad cinemática y el punto de inflamación disminuyeron en las dosis absorbidas de 3, 6 y 15 kGy mientras que aumentaron a 10 kGy. El número de cetanos en el combustible diesel aumentó después de la exposición a 3, 6 y 15 kGy, pero disminuyó a 10 kGy. Estos resultados se se taribuyen a enlaces rotos y formados como resultado de la alta energía aplicada. Los fragmentos formados a (10 kGy; 7,5 kGy / h) produjeron nuevos compuestos que tienen parámetros físicos que afectan negativamente a las propiedades generales del combustible diesel. Los fragmentos formados en el combustible diesel después de la exposición a 3, 6 y 15 kGy (2,27, 4,5 y 11,15 kGy / h) convirtieron algunos de los compuestos orgánicos cíclicos, aromáticos y ramificados en hidrocarburos lineales, lo que contribuyó al aumento del índice de cetano a 54. Todas las características se han mejorado dentro de los límites asignados por ASTM.

Abstract The effect of gamma irradiation on physico-chemical properties of petro-diesel fuel using different rate and absorbed doses has been studied. The diesel fuel samples were exposed to gamma radiation for 1.3 h using different absorbed doses: 3, 6, 10, and 15 kGy, with dose rates 2.27, 4.5, 7.4, and 11.15 kGy/h, respectively. Physico-chemical characteristics of diesel fuel were determined according to the standard test methods assigned by ASTM, characteristics are: cetane number, distillation recovery points, flash point, calorific value, density, and kinematic viscosity. The effect of gamma irradiation doses on organic compounds of diesel fuel was study using GC/MS technique. Experimental results show that the density, distillation, kinematic viscosity and flash point were decreased at absorbed doses 3, 6 and 15 kGy whereas increases at 10 kGy, corresponding with rate doses. Cetane number of diesel fuel increased after exposure to 3, 6, and 15 kGy but decreased at 10 kGy. These results can be attributed to the broken and formed bonds as a result of the high applied energy. The formed fragments at (10 kGy; 7.5 kGy/h) made a new compounds that have physical parameters affected negatively on the overall properties of diesel fuel. The formed fragments in diesel fuel after exposed to 3, 6, and 15 kGy (2.27, 4.5, and 11.15 kGy/h) have converted some of cyclic, aromatic, and branched organic compounds to linear hydrocarbons, which supported increasing of cetane number to 54. All characteristics have been improved within limits assigned by ASTM.

Abstract The seismic behavior of full-scale exterior reinforced concrete (RC) beam-column joints retrofitted with externally bonded Carbon Fiber Polymers (CFRP) is examined in this paper. Casting and testing of two similar reinforced concrete beam column connections in the absence of transverse reinforcement at the joints took place under opposing cyclic loading with regulated displacement so as to examine their fundamental seismic performance. The first joint was examined as the control specimen and the other specimen was then retrofitted with CFRP sheets, with rounded border of the column and beam at and close to the joint region to change them from square to squircle segments. It is demonstrated in the experimental findings that the retrofitted beam column joint shows significantly greater strength, energy dissipation and ductility in comparison to the control specimen. There was a shift in the failure from the joint region to the beam ends in the retrofitted specimens, which would help in preventing the structure from disintegrating progressively. Because of the change in the beam and column from square to squircle segments, the debonding potential of the CFRP decreased and the restrictive impact of the CFRP increased. As a result, the experimental findings were verified using a 3D nonlinear finite element (FE) model. When the finite element and experimental findings are compared, it is determined that the suggested model is quite accurate.

SUMMARY: The critical shoulder angle and acromion index are conventional radiological tools employed as predictors of shoulder degeneration. As they represent the static components of glenohumeral stability, the scapulo-humeral geometry and underlying subacromial tissue appear as the resultant cause-effect factors. Consequently, the purpose of this study was to investigate the critical shoulder angle and acromion index as interrelated parameters within the South African population. The measurement of both biomechanical parameters was conducted on two-hundred and sixty (n = 260) true AP radiographs. This was a cross-sectional study that also incorporated the demographic representation of the population group which was analysed accordingly. The mean values recorded for both the critical shoulder angle (36.31±5.84º) and acromion index (0.74±0.13) suggested rotator cuff arthropathy. The results confirmed the theories of Nyffeler et al. (2006) and Moor et al. (2012) who alluded to glenoid inclination and the acromial coverage over the humeral head. A significant proportionality correlation, verified by a P value of 0.000, was established between the acromion index and critical shoulder angle which may assist to differentiate between normal asymptomatic shoulders and those with cuff disease. Furthermore, these predictors of shoulder degeneration may present as a preventative tool against tear progression.

RESUMEN: El ángulo crítico del hombro y el índice acromial son herramientas radiológicas convencionales empleadas como indicadores de la degeneración del hombro. Debido a que representan los componentes estáticos de la estabilidad glenohumeral, la geometría escápulo-humeral y el tejido subacromial subyacente aparecen como los factores causa-efecto resultantes. En consecuencia, el propósito de este estudio fue investigar el ángulo crítico del hombro y el índice acromial como parámetros interrelacionados dentro de la población sudafricana. La medición de ambos parámetros biomecánicos se realizó en 260 radiografías antero-posteriores (AP). Se realizó un estudio transversal que también incorporó la representación demográfica del grupo de la población que fue analizada. Los valores medios registrados tanto para el ángulo crítico del hombro (36,31 ± 5,84º) como para el índice del acromión (0,74 ± 0,13) sugirieron una artropatía del manguito rotador. Los resultados confirmaron las teorías de Nyffeler et al. (2006) y Moor et al. (2012) que aludían a la inclinación glenoide y a la cobertura acromial sobre la cabeza humeral. Se estableció una correlación de proporcionalidad significativa, verificada por un valor de P de 0,000, entre el índice acromial y el ángulo crítico del hombro, lo que puede ayudar a diferenciar entre los hombros asintomáticos normales y aquellos con enfermedad del manguito rotador. Además, estos predictores de degeneración del hombro pueden ser útiles como una herramienta preventiva contra la progresión del desgarro.