31 research outputs found
Development and clinical evaluation of a simple optical method to detect and measure patient external motion
A simple and independent system to detect and measure the position of a number
of points in space was devised and implemented. Its application aimed to detect
patient motion during radiotherapy treatments, alert of out-of-tolerances motion, and
record the trajectories for subsequent studies. The system obtains the 3D position
of points in space, through its projections in 2D images recorded by two cameras.
It tracks black dots on a white sticker placed on the surface of the moving object.
The system was tested with linear displacements of a phantom, circular trajectories
of a rotating disk, oscillations of an in-house phantom, and oscillations of a
4D phantom. It was also used to track 461 trajectories of points on the surface of
patients during their radiotherapy treatments. Trajectories of several points were
reproduced with accuracy better than 0.3 mm in the three spatial directions. The
system was able to follow periodic motion with amplitudes lower than 0.5 mm,
to follow trajectories of rotating points at speeds up to 11.5 cm/s, and to track
accurately the motion of a respiratory phantom. The technique has been used to
track the motion of patients during radiotherapy and to analyze that motion. The
method is flexible. Its installation and calibration are simple and quick. It is easy
to use and can be implemented at a very affordable price. Data collection does
not involve any discomfort to the patient and does not delay the treatment, so the
system can be used routinely in all treatments. It has an accuracy similar to that of
other, more sophisticated, commercially available systems. It is suitable to implement
a gating system or any other application requiring motion detection, such as
4D CT, MRI or PET
Design, development and validation of a new laryngo-pharyngeal endoscopic esthesiometer and range-finder based on the assessment of air-pulse variability determinants
Węzłowy Model Zużywania (NWM) jako alternatywa zrozumienia mechanizmów przepływu i zużycia wyłożenia garu wielkiego pieca
The presence of thermocouples in the lining of crucibles has become a general practice in the new construction of blast furnaces. The Nodal Wear Model (NWM) has also emerged as an instrument that, while using experimental data, obtains nodal variables whose experimental measurement is not possible: global coefficient of pig-iron/refractory heat transfer hpig-iron/liningg-i and nodal temperature Ti. Starting from these nodal properties, the wear of the lining or the growth of scabs may be controlled, independently of the mechanisms responsible for them. In the same way, the properties and influence zone of the dead man in the hearth of the blast furnace may be calculated, along with those regions where the fluid is allowed to move without any other restrictions than the ones of the corresponding viscous flow (raceway hearth region).Obecność termopar w wyłożeniu garu wielkiego pieca, stało się powszechną praktyką w jego nowoczesnych konstrukcjach. Węzłowy Model Zużycia, staje się narzędziem, które korzystając z danych doświadczalnych, uzyskuje zmienne węzłowe, dla których pomiar bezpośredni jest niemożliwy: całkowity współczynnik przenikania ciepła między surówką, a wyłożeniem ogniotrwałym hsurwka/wyoenieg-i oraz temperaturę węzłową Ti. Począwszy od tych własności węzła, zużycie wyłożenia lub powiększanie się narostów, może być kontrolowane, niezależnie od mechanizmów odpowiedzialnych za ich zachodzenie. W ten sam sposób, mogą zostać wyliczone własności i wpływu martwego koksu w garze wielkiego pieca, wzdłuż obszarów, gdzie ciecz może poruszać się bez ograniczeń innych niż te odpowiadające przepływowi lepkiemu (strefa na poziomie dysz w garze pieca)
Nowe rodzaje żużla konwertorowego zawierające sód i mangan
The nature and properties of slag and dust generated during the manufacture of pig iron indicate the two possibilities of their utilization: sintering or cold agglomerating with Portland cement. Both sinter and pellets can be recycled in the LD converter. It was introduced the concept of "preformed synthetic slag" to use the recycling of waste. If the material contains components forming the eutectic properties similar to sinter or pellet (obtained outside the converter) it stimulates the creation of slag in the LD converter.The aim of this research is to address the best way to deal with manganese before the molten metal reaches the final stage of temperature and composition for casting. Ideally, the composition of the slag and dust produced by the BOF-LD can be adjusted so that the molten metal that reaches the secondary metallurgy contains over 1.0% manganese.Charakter i możliwosci żużla i płynów powstających podczas wytwarzania surówki wskazują na dwie możliwości ich utylizacji: spiekanie lub aglomeracja z cementem portlandzkim. Zarówno spiek, jak i brykiety mogą być poddawane recyklingowi w konwertorze LD. Wprowadzono koncepcję "preformed synthetic slag" do zastosowania recyklingu odpadów. Jeśli ten materiał zawiera składniki tworzące eutektykę z własnościami podobnymi do spieku lub pelet (uzyskanych poza konwertorem), to aktywizuje proces tworzenia żużla w konwertorze LD. Celem niniejszych badań jest znalezienie najlepszego sposobu radzenia sobie z manganem, zanim ciekły metal osiągnie końcowe parametry temperatury i składu do odlewania. Najlepiej gdy skład żużla i wytwarzanego przez konwertor pyłu mogą być dostosowane tak, aby ciekły metal, który trafia do obróbki pozapiecowej, zawierał ponad 1,0% manganu
Modelowanie mechanizmów przepływu i zużycia w trzonie wielkiego pieca przy użyciu modelu siatek węzłowych
The presence of thermocouples in the lining of crucibles has become a general practice in the new construction of blast furnaces. The Nodal Wear Model (NWM) has also emerged as an instrument that, while using experimental data, obtains nodal variables whose experimental measurement is not possible: global coefficient of pig-iron/refractory heat transfer [formula] and nodal temperature Ti. Starting from these nodal properties, the wear of the lining or the growth of scabs may be controlled, independently of the mechanisms responsible for them. In the same way, the properties and influence zone of the dead man in the hearth of the blast furnace may be calculated, along with those regions where the fluid is allowed to move without any other restrictions than the ones of the corresponding viscous flow (raceway hearth region).Istnienie termopar w wyłożeniu ogniotrwałym wielkiego pieca stało się ogólnie przyjętą praktyką w nowoczesnych jego konstrukcjach. Węzłowe modele zużywania wyłożenia (NWM) pojawiły się także jako instrument umożliwiający, przy użyciu danych eksperymentalnych, uzyskanie wartości węzłów dla zmiennych, w przypadku których nie jest możliwy pomiar praktyczny: globalny współczynnik wymiany ciepła surówka-wyłożenie ogniotrwałe [wzór] oraz węzłowa temperatura Ti. Przy wykorzystaniu właściwości siatek węzłowych zużycie wyłożenia wielkiego pieca lub narostów na niej może być kontrolowane niezależnie od mechanizmów odpowiedzialnych za nie. W ten sam sposób mogą być obliczone własności i wpływ strefy martwej koksu w trzonie wielkiego pieca. Podobną metodykę można stosować w tych strefach, gdzie możliwy jest przepływ ciekły bez żadnych ograniczeń z wyjątkiem tych, które wynikają z przepływu lepkiego (strefa na poziomie dysz wielkiego pieca)
MECHANISMS KNOWLEDGE OF THE FLOW AND WEAR IN THE BLAST FURNACE CRUCIBLE WITH THE NODAL WEAR MODEL
The presence of thermocouples in the lining of crucibles has become a general practice in the new construction of blast furnaces. The Nodal Wear Model (NWM) has also emerged as an instrument that, while using experimental data, obtains nodal variables whose experimental measurement is not possible: global coefficient of pig-iron/refractory heat transfer [formula] and nodal temperature Ti. Starting from these nodal properties, the wear of the lining or the growth of scabs may be controlled, independently of the mechanisms responsible for them. In the same way, the properties and influence zone of the dead man in the hearth of the blast furnace may be calculated, along with those regions where the fluid is allowed to move without any other restrictions than the ones of the corresponding viscous flow (raceway hearth region)
La restauración del conjunto monumental de Valdediós
Sensibilizar al alumno ante nuestro patrimonio histórico-artístico, su importancia dentro de nuestra cultura, su estado actual y recuperación. Proporcionar un estudio multidisciplinar a los profesores que motive a utilizar los recursos cercanos, en torno a un centro de interés: Valdediós. Promover el trabajo activo y lúdico de los alumnos que incentive su afán de búsqueda del conocimiento. Proporcionar ayuda pedagógica para estudiar el concepto de tiempo historico, adecuándolo a los diferentes niveles de aprendizaje. El proyecto de visitas escolares de la Escuela Taller de Valdediós trata de sensibilizar a la población del progresivo deterioro que muestra nuestro patrimonio y ante el que no se puede quedar impasible. Consta de 2 libretos: 1.'Una visita, un aprendizaje' en el que se incluyen los objetivos generales del proyecto, la metodología que organiza el trabajo didáctico a desarrollar con las guías en sus tres fases consecutivas antes, durante y después de la visita. Los objetivos a perseguir en cada nivel de enseñanza (ciclo medio, superior y Enseñanzas Medias) orientadores del proceso y por último las guías de trabajo en el que se descubre el eje de la investigación que llevaron a cabo los alumnos y el itinerario a desarrollar. 2. El libreto 'Los datos, el análisis' está destinado a completar la información que los alumnos registran durante la visita. En él se incluyen datos del medio físico donde se asienta el conjunto monumental, su historia, los estilos arquitectónicos de los edificios, los materiales utilizados, los oficios y las disciplinas que intervienen en la recuperación del patrimonio. Bibliografía. Se propone un método de trabajo activo y lúdico, es el alumno quien a través de la observación, recogida de datos y posterior consulta y ampliación de los mismos, construye su aprendizaje, al mismo tiempo que desarrolla la capacidad de relación social. Las guías de trabajo se centran en el estudio del recinto de Valdediós, enfocado de distinto modo para cada nivel de aprendizaje: Ciclo medio: observación y estudio de San Salvador. Ciclo superior: se propone la comparación de ambos edificios para deducir hipótesis que se comprobarán en el aula. Enseñanzas Medias: verificar hipótesis y conocimientos que poseen sobre distintos periodos históricos y su producción artística; se intenta desarrollar la autonomía en su proceso investigador. Se presentan los objetivos para cada nivel, así como las actividades apoyadas en dibujos, fotografías, esquemas, planos, documentos, prácticas de laboratorio, así como un material complementario en el que se dan datos sobre su historia, arquitectura, recuperación y vocabulario utilizado.AsturiasES
A novel concept to include uncertainties in the evaluation of stereotactic body radiation therapy after 4D dose accumulation using deformable image registration
Purpose: To use four-dimensional (4D) dose accumulation based on deformable image registration (DIR) to assess dosimetric uncertainty in lung stereotactic body radiation therapy (SBRT) treatment planning. A novel concept, the Evaluation Target Volume (ETV), was introduced to achieve this goal.
Methods: The internal target volume (ITV) approach was used for treatment planning for 11 patients receiving lung SBRT. Retrospectively, 4D dose calculation was done in Pinnacle v9.10. Total dose was accumulated in the reference phase using DIR with MIM. DIR was validated using landmarks introduced by an expert radiation oncologist. The 4D and three-dimensional (3D) dose distributions were compared within the gross tumor volume (GTV) and the planning target volume (PTV) using the D95 and Dmin (calculated as Dmin,0.035cc ) metrics. For lung involvement, the mean dose and V20 , V10 , and V5 were used in the 3D to 4D dose comparison, and Dmax (D0.1cc ) was used for all other organs at risk (OAR). The new evaluation target volume (ETV) was calculated by expanding the GTV in the reference phase in order to include geometrical uncertainties of the DIR, interobserver variability in the definition of the tumor, and uncertainties of imaging and delivery systems. D95 and Dmin,0.035cc metrics were then calculated on the basis of the ETV for 4D accumulated dose distributions, and these metrics were compared with those calculated from the PTV for 3D planned dose distributions.
Results: The target registration error (TRE) per spatial component was below 0.5 ± 2.1mm for all our patients. For five patients, dose degradation above 2% (>4% in 2 patients) was found in the PTV after 4D accumulation and attributed to anatomical variations due to breathing. Comparison of D95 and Dmin,0.035cc metrics showed that the ETV (4D accumulated dose) estimated substantially lower coverage than the PTV (3D planning dose): in six out of the 11 cases, and for at least for one of the two metrics, coverage estimated by ETV was at least 5% lower than that estimated by PTV. Furthermore, the ETV approach revealed hot and cold spots within its boundaries.
Conclusions: A workflow for 4D dose accumulation based on DIR has been devised. Dose degradation was attributed to respiratory motion. To overcome limitations in the PTV for the purposes of evaluating DIR-based 4D accumulated dose distributions, a new concept, the ETV, was proposed. This concept appears to facilitate more reliable dose evaluation and a better understanding of dosimetric uncertainties due to motion and deformation
Development and clinical evaluation of a simple optical method to detect and measure patient external motion
A simple and independent system to detect and measure the position of a number
of points in space was devised and implemented. Its application aimed to detect
patient motion during radiotherapy treatments, alert of out-of-tolerances motion, and
record the trajectories for subsequent studies. The system obtains the 3D position
of points in space, through its projections in 2D images recorded by two cameras.
It tracks black dots on a white sticker placed on the surface of the moving object.
The system was tested with linear displacements of a phantom, circular trajectories
of a rotating disk, oscillations of an in-house phantom, and oscillations of a
4D phantom. It was also used to track 461 trajectories of points on the surface of
patients during their radiotherapy treatments. Trajectories of several points were
reproduced with accuracy better than 0.3 mm in the three spatial directions. The
system was able to follow periodic motion with amplitudes lower than 0.5 mm,
to follow trajectories of rotating points at speeds up to 11.5 cm/s, and to track
accurately the motion of a respiratory phantom. The technique has been used to
track the motion of patients during radiotherapy and to analyze that motion. The
method is flexible. Its installation and calibration are simple and quick. It is easy
to use and can be implemented at a very affordable price. Data collection does
not involve any discomfort to the patient and does not delay the treatment, so the
system can be used routinely in all treatments. It has an accuracy similar to that of
other, more sophisticated, commercially available systems. It is suitable to implement
a gating system or any other application requiring motion detection, such as
4D CT, MRI or PET