11 research outputs found
Mass-manufacturable scintillation-based optical fiber dosimeters for brachytherapy
No full textScintillation-based fiber dosimeters are a powerful tool for minimally invasive localized real-time monitoring of the dose rate during Low Dose Rate (LDR) and High Dose Rate (HDR) brachytherapy (BT). This paper presents the design, fabrication, and characterization of such dosimeters, consisting of scintillating sensor tips attached to polymer optical fiber (POF). The sensor tips consist of inorganic scintillators, i.e. Gd2O2S:Tb for LDR-BT, and Y2O3:Eu+4YVO4:Eu for HDR-BT, dispersed in a polymer host. The shape and size of the tips are optimized using non-sequential ray tracing simulations towards maximizing the collection and coupling of the scintillation signal into the POF. They are then manufactured by means of a custom moulding process implemented on a commercial hot embossing machine, paving the way towards series production. Dosimetry experiments in water phantoms show that both the HDR-BT and LDR-BT sensors feature good consistency in the magnitude of the average photon count rate and that the photon count rate signal is not significantly affected by variations in sensor tip composition and geometry. Whilst individual calibration remains necessary, the proposed dosimeters show great potential for in-vivo dosimetry for brachytherapy.</p
Investigation of crack propagation in single optical fiber composite with thermal influence by finite element method
No full textTwo parallel comparative ‘Conventional Method and Computer Simulation using ANSYS software’ for prediction of crack growth and its behavior in optical fiber are studied and presented in this work. Corresponding finite element analysis was performed to determine the evolution of stress and strain states. The method is developed and combined with the modified J-integral theory to deal with this problem. The effects of crack length, temperature and mechanical forces are investigated by Finite Element Method in the cracked body. The conditions where the Mode I stress intensity factor motivate fracture occurrence is investigated and variations of the different cases are discussed. The most deleterious situation is found to be that wherein the entire model reaches rupture at some stage. The accuracy of the method is investigated through comparison of numerical results with computerized simulation using commercial ANSYS softwar
Investigation of crack propagation in single optical fiber composite with thermal influence by finite element method
Get PDFTwo parallel comparative ‘Conventional Method and Computer Simulation using ANSYS software’for prediction of crack growth and its behavior in optical fiber are studied and presented in this work.Corresponding finite element analysis was performed to determine the evolution of stress and strain states. Themethod is developed and combined with the modified J-integral theory to deal with this problem. The effects ofcrack length, temperature and mechanical forces are investigated by Finite Element Method in the crackedbody. The conditions where the Mode I stress intensity factor motivate fracture occurrence is investigated andvariations of the different cases are discussed. The most deleterious situation is found to be that wherein theentire model reaches rupture at some stage. The accuracy of the method is investigated through comparison ofnumerical results with computerized simulation using commercial ANSYS software
Investigation of crack propagation in single optical fiber composite with thermal influence by finite element method
No full textTwo parallel comparative ‘Conventional Method and Computer Simulation using ANSYS software’ for prediction of crack growth and its behavior in optical fiber are studied and presented in this work. Corresponding finite element analysis was performed to determine the evolution of stress and strain states. The method is developed and combined with the modified J-integral theory to deal with this problem. The effects of crack length, temperature and mechanical forces are investigated by Finite Element Method in the cracked body. The conditions where the Mode I stress intensity factor motivate fracture occurrence is investigated and variations of the different cases are discussed. The most deleterious situation is found to be that wherein the entire model reaches rupture at some stage. The accuracy of the method is investigated through comparison of numerical results with computerized simulation using commercial ANSYS software
Wear and Contact Temperature Evolution in Pin-on-Disc Tribotesting of Low-Metallic Friction Material Sliding Against Pearlitic Cast Iron
No full textThin film lithium-ionbatteries crack initiation due to thermal and electric effects
No full textThe transient and thermo-electric finite element analysis (FEA) of a 2D lithium-on (Li-ion) battery is presented. The process of recharging and discharging of thin film lithium-ion (LiFePO4) battery in the presence of a transversal crack is numerically investigated. During this process significant temperature load influences the behavior of the battery and thermal fields can affect the way crack propagates into the thin film media. The simulations infer about relationship between temperature and electric field and their effect on crack propagation. A Li-ion battery model suitable for this investigation is implemented in the multi-physics software package by COMSOL Inc., and it is extended to include the thermal and electrical effects. Results and discussion are accompanied with pertinent conclusions
Experimental investigation to evaluate LiFePO4 batteries anode and cathode elastic properties under cyclic temperature loading conditions
No full textExperimental investigations and associated methods are provided to characterize the mechanical properties of a lithium-ion battery accounting for operating temperature variation and thermal effects. Material properties for LiFePO4 cathode and anode samples taken from an off-the-shelf battery are evaluated in new and fatigued (subjected to charging and discharging cycles) conditions
Investigation of crack propagation in single optical fiber composite with thermal influence by finite element method
No full textTwo parallel comparative ‘Conventional Method and Computer Simulation using ANSYS software’for prediction of crack growth and its behavior in optical fiber are studied and presented in this work.Corresponding finite element analysis was performed to determine the evolution of stress and strain states. Themethod is developed and combined with the modified J-integral theory to deal with this problem. The effects ofcrack length, temperature and mechanical forces are investigated by Finite Element Method in the crackedbody. The conditions where the Mode I stress intensity factor motivate fracture occurrence is investigated andvariations of the different cases are discussed. The most deleterious situation is found to be that wherein theentire model reaches rupture at some stage. The accuracy of the method is investigated through comparison ofnumerical results with computerized simulation using commercial ANSYS software
Mass manufacturable scintillation-based optical fiber dosimeters for brachytherapy
No full textScintillation-based fiber dosimeters are a powerful tool for minimally invasive localized real-time monitoring of the dose rate during brachytherapy (BT). We present a fabrication method for mass manufacturing of scintillating sensor tips which are to be attached to polymer optical fiber (POF) to enable fiber-optic dosimetry. The scintillating sensor tips consist of inorganic scintillators, dispersed in a polymer host. The manufacturing is done by means of a custom compression and transfer moulding process implemented on a commercially available hot embossing machine. We show the manufacturing of 237 sensor tips, which are subsequently attached to the end of the POF using UV-curable adhesive. Finally, we perform dosimetry experiments in water phantoms which show a great potential for in-vivo dosimetry for brachytherapy, both for Low Dose Rate (LDR) and High Dose Rate (HDR) BT.<br/
Scintillation-based optical fiber dosimeters for high dose rate and low dose rate brachytherapy
No full textScintillation-based fiber dosimeters are a powerful tool for minimally invasive localized real-time monitoring of the dose rate during Low Dose Rate (LDR) and High Dose Rate (HDR) brachytherapy (BT). This paper shows the design, fabrication and characterization of such dosimeters, consisting of scintillating sensor tips attached to polymer optical fiber (POF). The scintillating sensor tips consist of inorganic scintillators, dispersed in a polymer host. We present the design, fabrication and characterization of those sensor tips. The manufacturing is done by means of a custom compression and transfer moulding process implemented on a commercially available hot embossing machine. We show the manufacturing of 237 sensor tips, which are subsequently attached to the end of the POF using UV-curable adhesive. Finally, we perform dosimetry experiments in water phantoms which show a great potential for in-vivo dosimetry for brachytherapy.<br/
