Análisis comparativo entre un tutor circular y uno monolateral en elongaciones óseas

El presente trabajo compara la funcionalidad de dos tutores externos utilizados para elongación: el del Dr. Ilizarov y el tutor HG, desarrollado en nuestra institución. De 131 pacientes tratados con elongación ósea en 147 huesos largos se seleccionaron al azar 25 huesos por cada aparato anteriormente mencionado. Para objetivar los resultados se registraron estadísticamente variables independientes y dependientes en sus características subjetivas y objetivas, tales como: edad, sexo, tipo de hueso elongado, tolerancia psíquica, sensación de confort, facilidad de higiene y control, las infecciones, las rigideces articulares por retracción músculo tendinosa, y la deformación ósea residual. El objetivo fue comparar y establecer si el cambio en la elección del sistema fue ventajoso para nuestros pacientes. En el intento comparativo se enfrentaron dos variables, que a nuestro criterio eran las más importantes para establecer diferencias: la calidad del callo del hueso sometido a elongación y la presencia de complicaciones tanto transitorias como definitivas.In this work we compare the results obtained with two different external fixation devices in patients undergoing bone lengthening. The devices studied were the Ilizarov type and the HG, an apparatons developed in our institution. Out of 131 patientes treated by bone lengthening in 147 long bones, 25 bones lengthened with each device were selected at random. Different subjective and objective variables were assessed: age, sex, type of bone, psichological tolerance, patients, confort, nursing, infections, joint stiffness due to musculotendinous retractions, and residual bone deformity. The aim of the study was to analyze if the monolateral frame entailed advantages for our patients. Two main factors were more deeply analysed, namely the quality of the bone callus subjected to lengthening and the presence of both transitory and definitive complications

Weathervaning instabilities of a FPSO in regular waves and consequence on response amplitude operators

A series of model tests in regular seas were performed on a 1:60 scaled model of a generic FPSO. The model was moored by means of four instrumented mooring lines attached to an internal turret. The wavelength to model length ratio was varied from 0.5 to 2.0, while the ratio of the wavelength and the wave amplitude was kept constant as per ITTC seakeeping recommendations. The goal of the tests was to evaluate the response of the hull to swell conditions that may happen in open sea environments and to assess the weathervaning characteristics of the internal turret arrangement. During the tests the six accelerations and six displacements have been measured by means of an inertial and optical system respectively, together with the wave elevation in the basin. From the results, motion response amplitude operators were obtained at different heading conditions. The experimental results for the model displacements were compared with simulations from the well-known diffraction program WAMIT/WADAM. The paper will discuss possible reasons for the yaw instabilities, including the effect of moorings and test duration. The influence of the heading changes on the RAO of the hull with and without constraints will be discussed. Finally, RAO comparison with SESAM will demonstrate similarities and differences with RAOs at different sea headings.Peer reviewed: YesNRC publication: Ye

Weathervaning instabilities of a FPSO in regular waves and consequence on response amplitude operators

A series of model tests in regular seas were performed on a 1:60 scaled model of a generic FPSO. The model was moored by means of four instrumented mooring lines attached to an internal turret. The wavelength to model length ratio was varied from 0.5 to 2.0, while the ratio of the wavelength and the wave amplitude was kept constant as per ITTC seakeeping recommendations. The goal of the tests was to evaluate the response of the hull to swell conditions that may happen in open sea environments and to assess the weathervaning characteristics of the internal turret arrangement. During the tests the six accelerations and six displacements have been measured by means of an inertial and optical system respectively, together with the wave elevation in the basin. From the results, motion response amplitude operators were obtained at different heading conditions. The experimental results for the model displacements were compared with simulations from the well-known diffraction program WAMIT/WADAM. The paper will discuss possible reasons for the yaw instabilities, including the effect of moorings and test duration. The influence of the heading changes on the RAO of the hull with and without constraints will be discussed. Finally, RAO comparison with SESAM will demonstrate similarities and differences with RAOs at different sea headings.Peer reviewed: YesNRC publication: Ye

Some Recent Advances in Liquefied Natural Gas (LNG) Production, Spill, Dispersion, and Safety

The global demand of liquefied natural gas (LNG) has risen rapidly in recent years for the reasons of energy security and sustainable development. This has led to considerable recent research interests and efforts in the LNG production chain and associated risks in handling, storage, and transport of LNG, largely driven by the intrinsic process safety issues of LNG, potential terrorist threats, and public confidence in LNG safety. This review presents an overview on some recent advances in the LNG value chain, covering upstream gas production and gathering, liquefaction, shipping, and regasification processes. Recent developments in the experimentation and modeling of LNG spills associated with the LNG value chain are then summarized, covering the events following a LNG spill, including LNG pool formation, vapor dispersion, and combustion. The consequent hazards and safety issues are also discussed, with a focus on the methods for improving the safety of personnel, facilities, and ships. The key technical gaps in the related research areas have been identified, and future research directions are outlined