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Calderón Arguedas Ólger - One of the best experts on this subject based on the ideXlab platform.
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Determinación del intervalo post mortem mínimo (IPM) basado en un Modelo de acumulación térmica con una cepa de Lucilia eximia (Diptera: Calliphoridae) de Costa Rica
'Autonomous University of Yucatan', 2019Co-Authors: Elizondo Delgado, Julio Iván, Troyo Rodríguez Adriana, Calderón Arguedas ÓlgerAbstract:Introducción. L. eximia es una especie de amplia distribución geográfica en Costa Rica, cuyas poblaciones son estables durante todo el año. Las características biológicas de ésta permiten concebirla como un potencial indicador forense para el cálculo del intervalo post mortem mínimo (IPM). Objetivo. Comparar el IPM calculado mediante un Modelo de acumulación térmica con L. eximia (Diptera: Calliphoridae), con el IPM real en cadáveres de cerdos domésticos (Sus scrofa). Material y Métodos. Dos cadáveres de cerdo fueron expuestos en un bosque premontano húmedo tropical. A partir de dichos cadáveres se colectaron larvas de L. eximia a las 78, 144 y 192 horas posteriores al momento de muerte y se propició su desarrollo en condiciones controladas. Con los datos generados, se realizaron retroproyecciones térmicas para efectuar el cálculo del IPM. Resultados. L. eximia requirió en total 7 236,50 gradoshora acumulados (ADH) para culminar su desarrollo. Los IPM calculados mediante el Modelo de acumulación térmica para los tres momentos de colecta fueron 112,56; 153,60 y 104,64 horas. Únicamente el valor intermedio no presentó diferencias estadísticamente significativas con el tiempo de muerte conocido (p›0.05). Conclusiones. El Modelo de acumulación térmica en que se utilizó L. eximia brindó información precisa sobre el IPM sólo cuando se tomaron las muestras en el campo a las 144 horas, lo que perfila su utilidad para las primeras etapas de la descomposición cadavérica.Introduction.Lucilia eximia is a species that shows a wide geographical distribution in Costa Rica, whose populations are stable throughout the year. The biological characteristics of Lucilia eximia allow it to be considered as a potential forensic indicator for the calculation of the minimum post mortem interval (PMI).Objective. To compare the PMI calculated by a thermal Accumulation Model with Lucilia eximia (Diptera: Calliphoridae), with the PMI in corpses of pigs (Sus scrofa).Methods. Two pig corpses were exposed in a tropical premontane moist forest. Larvae of L. eximia were collected from the pig carcasses at 78, 144 and 192 hours after the moment of death, and their development was promoted under controlled conditions. With the data generated, thermal back-projections were made to calculate the PMI.Results. L. eximia required a total of 7 236.50 accumulated degree hours (ADH) to complete its life cycle. The IPMs calculated by the thermal Accumulation Model were 112.56, 153.60, and 104.64 hours, respectively. Only the intermediate value did not present statistically significant differences with the known time of death (p>0,05).Conclusions. The thermal Accumulation Model using L. eximia as a forensic indicator provided accurate information about the PMI only when samples were collected at 144 hours, which indicates that this method may be accurate and useful during the first stages of cadaveric decomposition.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET)UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí
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Determinación del intervalo post mortem mínimo (IPM) basado en un Modelo de acumulación térmica con una cepa de Lucilia eximia (Diptera: Calliphoridae) de Costa Rica
2019Co-Authors: Elizondo Delgado, Julio Iván, Troyo Adriana, Calderón Arguedas ÓlgerAbstract:Lucilia eximia (Diptera: Calliphoridae) as forensic indicator for the calculation of the post mortem interval in Costa Rica. Introduction. L. eximia is a species that shows a wide geographical distribution in Costa Rica, whose populations are stable throughout the year. The biological characteristics of L. eximia allow it to be considered as a potential forensic indicator for the calculation of the minimum post mortem interval (PMI). Objective. To compare the PMI calculated by a thermal Accumulation Model with L. eximia (Diptera: Calliphoridae), with the PMI in corpses of pigs (Sus scrofa). Methods. Two pig corpses were exposed in a tropical premontane moist forest. Larvae of L. eximia were collected from the pig carcasses at 78, 144 and 192 hours after the moment of death, and their development was promoted under controlled conditions. With the data generated, thermal back-projections were made to calculate the PMI. Results. L. eximia required a total of 7 236.50 accumulated degree hours (ADH) to complete its life cycle. The IPMs calculated by the thermal Accumulation Model were 112.56, 153.60, and 104.64 hours, respectively. Only the intermediate value did not present statistically significant differences with the known time of death (p>0.05). Conclusions. The thermal Accumulation Model using L. eximia as a forensic indicator provided accurate information about the PMI only when samples were collected at 144 hours, which indicates that this method may be accurate and useful during the first stages of cadaveric decomposition.Introducción. L. eximia es una especie de amplia distribución geográfica en Costa Rica, cuyas poblaciones son estables durante todo el año. Las características biológicas de ésta permiten concebirla como un potencial indicador forense para el cálculo del intervalo post mortem mínimo (IPM). Objetivo. Comparar el IPM calculado mediante un Modelo de acumulación térmica con L. eximia (Diptera: Calliphoridae), con el IPM real en cadáveres de cerdos domésticos (Sus scrofa). Material y Métodos. Dos cadáveres de cerdo fueron expuestos en un bosque premontano húmedo tropical. A partir de dichos cadáveres se colectaron larvas de L. eximia a las 78, 144 y 192 horas posteriores al momento de muerte y se propició su desarrollo en condiciones controladas. Con los datos generados, se realizaron retroproyecciones térmicas para efectuar el cálculo del IPM. Resultados. L. eximia requirió en total 7 236,50 gradoshora acumulados (ADH) para culminar su desarrollo. Los IPM calculados mediante el Modelo de acumulación térmica para los tres momentos de colecta fueron 112,56; 153,60 y 104,64 horas. Únicamente el valor intermedio no presentó diferencias estadísticamente significativas con el tiempo de muerte conocido (p>0.05). Conclusiones. El Modelo de acumulación térmica en que se utilizó L. eximia brindó información precisa sobre el IPM sólo cuando se tomaron las muestras en el campo a las 144 horas, lo que perfila su utilidad para las primeras etapas de la descomposición cadavéric
Shinobu Ohya - One of the best experts on this subject based on the ideXlab platform.
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quantum size effect in an fe quantum well detected by resonant tunneling carriers injected from a p type ge semiconductor electrode
Applied Physics Letters, 2018Co-Authors: Ryota Suzuki, Yuki K Wakabayashi, Kohei Okamoto, Masaaki Tanaka, Shinobu OhyaAbstract:We report the clear observation of the quantum size effect in an Fe quantum well (QW) detected by resonant tunneling carriers injected from a p-type Ge semiconductor electrode in fully epitaxial double-barrier magnetic tunnel junctions, which are composed of Co/Fe/MgO/Fe QW/MgO/Ge:B grown on a p+-Ge(001) substrate. A large tunnel magnetoresistance (TMR) ratio up to 137% (237%), which is comparable to that in Fe/MgO/Fe, is obtained at 297 K (3.5 K). The quantum oscillations are clearly observed in the dI/dV–V and d2I/dV2–V curves of our devices, and the resonance voltages are in good agreement with the resonant levels calculated by the phase Accumulation Model. Following these oscillations, the TMR is modulated by the quantum size effect. Our results are promising for realizing future quantum spintronics devices based on semiconductor/metal hybrid heterostructures with advanced functionalities.We report the clear observation of the quantum size effect in an Fe quantum well (QW) detected by resonant tunneling carriers injected from a p-type Ge semiconductor electrode in fully epitaxial double-barrier magnetic tunnel junctions, which are composed of Co/Fe/MgO/Fe QW/MgO/Ge:B grown on a p+-Ge(001) substrate. A large tunnel magnetoresistance (TMR) ratio up to 137% (237%), which is comparable to that in Fe/MgO/Fe, is obtained at 297 K (3.5 K). The quantum oscillations are clearly observed in the dI/dV–V and d2I/dV2–V curves of our devices, and the resonance voltages are in good agreement with the resonant levels calculated by the phase Accumulation Model. Following these oscillations, the TMR is modulated by the quantum size effect. Our results are promising for realizing future quantum spintronics devices based on semiconductor/metal hybrid heterostructures with advanced functionalities.
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quantum size effect in an fe quantum well detected by resonant tunneling carriers injected from a p type ge semiconductor electrode
Applied Physics Letters, 2018Co-Authors: Ryota Suzuki, Yuki K Wakabayashi, Kohei Okamoto, Masaaki Tanaka, Shinobu OhyaAbstract:We report the clear observation of the quantum size effect in an Fe quantum well (QW) detected by resonant tunneling carriers injected from a p-type Ge semiconductor electrode in fully epitaxial double-barrier magnetic tunnel junctions, which are composed of Co/Fe/MgO/Fe QW/MgO/Ge:B grown on a p+-Ge(001) substrate. A large tunnel magnetoresistance (TMR) ratio up to 137% (237%), which is comparable to that in Fe/MgO/Fe, is obtained at 297 K (3.5 K). The quantum oscillations are clearly observed in the dI/dV–V and d2I/dV2–V curves of our devices, and the resonance voltages are in good agreement with the resonant levels calculated by the phase Accumulation Model. Following these oscillations, the TMR is modulated by the quantum size effect. Our results are promising for realizing future quantum spintronics devices based on semiconductor/metal hybrid heterostructures with advanced functionalities.
Elizondo Delgado, Julio Iván - One of the best experts on this subject based on the ideXlab platform.
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Determinación del intervalo post mortem mínimo (IPM) basado en un Modelo de acumulación térmica con una cepa de Lucilia eximia (Diptera: Calliphoridae) de Costa Rica
'Autonomous University of Yucatan', 2019Co-Authors: Elizondo Delgado, Julio Iván, Troyo Rodríguez Adriana, Calderón Arguedas ÓlgerAbstract:Introducción. L. eximia es una especie de amplia distribución geográfica en Costa Rica, cuyas poblaciones son estables durante todo el año. Las características biológicas de ésta permiten concebirla como un potencial indicador forense para el cálculo del intervalo post mortem mínimo (IPM). Objetivo. Comparar el IPM calculado mediante un Modelo de acumulación térmica con L. eximia (Diptera: Calliphoridae), con el IPM real en cadáveres de cerdos domésticos (Sus scrofa). Material y Métodos. Dos cadáveres de cerdo fueron expuestos en un bosque premontano húmedo tropical. A partir de dichos cadáveres se colectaron larvas de L. eximia a las 78, 144 y 192 horas posteriores al momento de muerte y se propició su desarrollo en condiciones controladas. Con los datos generados, se realizaron retroproyecciones térmicas para efectuar el cálculo del IPM. Resultados. L. eximia requirió en total 7 236,50 gradoshora acumulados (ADH) para culminar su desarrollo. Los IPM calculados mediante el Modelo de acumulación térmica para los tres momentos de colecta fueron 112,56; 153,60 y 104,64 horas. Únicamente el valor intermedio no presentó diferencias estadísticamente significativas con el tiempo de muerte conocido (p›0.05). Conclusiones. El Modelo de acumulación térmica en que se utilizó L. eximia brindó información precisa sobre el IPM sólo cuando se tomaron las muestras en el campo a las 144 horas, lo que perfila su utilidad para las primeras etapas de la descomposición cadavérica.Introduction.Lucilia eximia is a species that shows a wide geographical distribution in Costa Rica, whose populations are stable throughout the year. The biological characteristics of Lucilia eximia allow it to be considered as a potential forensic indicator for the calculation of the minimum post mortem interval (PMI).Objective. To compare the PMI calculated by a thermal Accumulation Model with Lucilia eximia (Diptera: Calliphoridae), with the PMI in corpses of pigs (Sus scrofa).Methods. Two pig corpses were exposed in a tropical premontane moist forest. Larvae of L. eximia were collected from the pig carcasses at 78, 144 and 192 hours after the moment of death, and their development was promoted under controlled conditions. With the data generated, thermal back-projections were made to calculate the PMI.Results. L. eximia required a total of 7 236.50 accumulated degree hours (ADH) to complete its life cycle. The IPMs calculated by the thermal Accumulation Model were 112.56, 153.60, and 104.64 hours, respectively. Only the intermediate value did not present statistically significant differences with the known time of death (p>0,05).Conclusions. The thermal Accumulation Model using L. eximia as a forensic indicator provided accurate information about the PMI only when samples were collected at 144 hours, which indicates that this method may be accurate and useful during the first stages of cadaveric decomposition.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET)UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí
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Determinación del intervalo post mortem mínimo (IPM) basado en un Modelo de acumulación térmica con una cepa de Lucilia eximia (Diptera: Calliphoridae) de Costa Rica
2019Co-Authors: Elizondo Delgado, Julio Iván, Troyo Adriana, Calderón Arguedas ÓlgerAbstract:Lucilia eximia (Diptera: Calliphoridae) as forensic indicator for the calculation of the post mortem interval in Costa Rica. Introduction. L. eximia is a species that shows a wide geographical distribution in Costa Rica, whose populations are stable throughout the year. The biological characteristics of L. eximia allow it to be considered as a potential forensic indicator for the calculation of the minimum post mortem interval (PMI). Objective. To compare the PMI calculated by a thermal Accumulation Model with L. eximia (Diptera: Calliphoridae), with the PMI in corpses of pigs (Sus scrofa). Methods. Two pig corpses were exposed in a tropical premontane moist forest. Larvae of L. eximia were collected from the pig carcasses at 78, 144 and 192 hours after the moment of death, and their development was promoted under controlled conditions. With the data generated, thermal back-projections were made to calculate the PMI. Results. L. eximia required a total of 7 236.50 accumulated degree hours (ADH) to complete its life cycle. The IPMs calculated by the thermal Accumulation Model were 112.56, 153.60, and 104.64 hours, respectively. Only the intermediate value did not present statistically significant differences with the known time of death (p>0.05). Conclusions. The thermal Accumulation Model using L. eximia as a forensic indicator provided accurate information about the PMI only when samples were collected at 144 hours, which indicates that this method may be accurate and useful during the first stages of cadaveric decomposition.Introducción. L. eximia es una especie de amplia distribución geográfica en Costa Rica, cuyas poblaciones son estables durante todo el año. Las características biológicas de ésta permiten concebirla como un potencial indicador forense para el cálculo del intervalo post mortem mínimo (IPM). Objetivo. Comparar el IPM calculado mediante un Modelo de acumulación térmica con L. eximia (Diptera: Calliphoridae), con el IPM real en cadáveres de cerdos domésticos (Sus scrofa). Material y Métodos. Dos cadáveres de cerdo fueron expuestos en un bosque premontano húmedo tropical. A partir de dichos cadáveres se colectaron larvas de L. eximia a las 78, 144 y 192 horas posteriores al momento de muerte y se propició su desarrollo en condiciones controladas. Con los datos generados, se realizaron retroproyecciones térmicas para efectuar el cálculo del IPM. Resultados. L. eximia requirió en total 7 236,50 gradoshora acumulados (ADH) para culminar su desarrollo. Los IPM calculados mediante el Modelo de acumulación térmica para los tres momentos de colecta fueron 112,56; 153,60 y 104,64 horas. Únicamente el valor intermedio no presentó diferencias estadísticamente significativas con el tiempo de muerte conocido (p>0.05). Conclusiones. El Modelo de acumulación térmica en que se utilizó L. eximia brindó información precisa sobre el IPM sólo cuando se tomaron las muestras en el campo a las 144 horas, lo que perfila su utilidad para las primeras etapas de la descomposición cadavéric
Shun-peng Zhu - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear fatigue damage Accumulation: Isodamage curve-based Model and life prediction aspects
International Journal of Fatigue, 2019Co-Authors: Shun-peng Zhu, Ding Liao, José A.f.o. Correia, Qiang Liu, Abílio M.p. De JesusAbstract:Abstract Cumulative fatigue damage analysis and life prediction of engineering structures/components is vital for ensuring their structural integrity and operational reliability under variable amplitude loadings. In this regard, a new nonlinear fatigue damage Accumulation Model is proposed by introducing a damage function related to the isodamage curves and remaining life aspects. Specifically, its damage exponent is refined by considering effects of loading history. Experimental data from tests available in literature are utilized for Model validation and comparison. Compared with four existing Models, the proposed Model shows higher precision for cumulative damage Modelling and fatigue life prediction than others. Moreover, it improves the deficiencies inherent in other rules under the promise of maintaining its simplicity in practice.
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strain energy based fatigue life prediction under variable amplitude loadings
Structural Engineering and Mechanics, 2018Co-Authors: Shun-peng Zhu, José A.f.o. Correia, Peng Yue, S Blason, Abilio De Jesus, Qingyuan WangAbstract:With the aim to evaluate the fatigue damage Accumulation and predict the residual life of engineering components under variable amplitude loadings, this paper proposed a new strain energy-based damage Accumulation Model by considering both effects of mean stress and load interaction on fatigue life in a low cycle fatigue (LCF) regime. Moreover, an integrated procedure is elaborated for facilitating its application based on S-N curve and loading conditions. Eight experimental datasets of aluminum alloys and steels are utilized for Model validation and comparison. Through comparing experimental results with Model predictions by the proposed, Miner\'s rule, damaged stress Model (DSM) and damaged energy Model (DEM), results show that the proposed one provides more accurate predictions than others, which can be extended for further application under multi-level stress loadings.
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fatigue life prediction under variable amplitude loading using a non linear damage Accumulation Model
International Journal of Damage Mechanics, 2015Co-Authors: Fang-jun Zuo, Hongzhong Huang, Shun-peng Zhu, Huiying GaoAbstract:Most of engineering components in service are usually subjected to variable cyclic loading. It is important to predict fatigue life and deal with the issue about fatigue damage Accumulation for the...
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Fatigue life prediction under variable amplitude loading using a non-linear damage Accumulation Model:
International Journal of Damage Mechanics, 2014Co-Authors: Fang-jun Zuo, Hongzhong Huang, Shun-peng Zhu, Huiying GaoAbstract:Most of engineering components in service are usually subjected to variable cyclic loading. It is important to predict fatigue life and deal with the issue about fatigue damage Accumulation for these components. One of the largest difficulties in fatigue failure analysis is to find a representative ‘damage criterion’ which can be easily connected with the Wohler curve taken as the known material data. The most commonly used Model is the Miner’s rule which ignores the loading history effect, under the same loading conditions the experimental results are higher than the Miner expectations for low-to-high load sequence and are lower than the Miner expectations for high-to-low load sequence. The fatigue driving stress that causes fatigue damage is presented to predict residual fatigue life under variable amplitude loading. It increases with loading cycles until equals the fatigue strength when fracture occurs. By determining the equivalent number of cycles that yields the same fatigue driving stress as the pr...
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a new non linear continuum damage mechanics Model for the fatigue life prediction under variable loading
Mechanics, 2013Co-Authors: Rong Yuan, Hongzhong Huang, Shun-peng ZhuAbstract:Fatigue is a damage Accumulation process in which material property deteriorates continuously. For the usual failure mode of mechanical components under vari-able loading, fatigue life prediction issues are very impor-tant for selection, design, and safety assessments of these components. Based on continuum damage mechanics theory, this paper presents a new non-linear fatigue dam-age Accumulation Model for fatigue life prediction under variable loading. The proposed Model has been formulated to take the damage evolution of material and the effects of loading sequence on fatigue life under dif-ferent loading conditions into account. Moreover, it con-siders the mean stress effects through characterizing the damage evolution of materials with fewer parameters. Experimental data of 30NiCrMoV12 and 30CrMnSiA under two-stress level loading from literature were used to verify the proposed Model. Predicted fatigue lives using the proposed Model show a good agreement with the reported experimental data. DOI: http://dx.doi.org/10.5755/j01.mech.19.5.5541
Xin Sun - One of the best experts on this subject based on the ideXlab platform.
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scaling limits for the critical fortuin kastelyn Model on a random planar map ii local estimates and empty reduced word exponent
Electronic Journal of Probability, 2017Co-Authors: Ewain Gwynne, Xin SunAbstract:We continue our study of the inventory Accumulation introduced by Sheffield (2011), which encodes a random planar map decorated by a collection of loops sampled from the critical Fortuin-Kasteleyn (FK) Model. We prove various local estimates for the inventory Accumulation Model, i.e., estimates for the precise number of symbols of a given type in a reduced word sampled from the Model. Using our estimates, we obtain the scaling limit of the associated two-dimensional random walk conditioned on the event that it stays in the first quadrant for one unit of time and ends up at a particular position in the interior of the first quadrant. We also obtain the exponent for the probability that a word of length $2n$ sampled from the inventory Accumulation Model corresponds to an empty reduced word, which is equivalent to an asymptotic formula for the partition function of the critical FK planar map Model. The estimates of this paper will be used in a subsequent paper to obtain the scaling limit of the lattice walk associated with a finite-volume FK planar map.
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scaling limits for the critical fortuin kastelyn Model on a random planar map ii local estimates and empty reduced word exponent
arXiv: Probability, 2015Co-Authors: Ewain Gwynne, Xin SunAbstract:We continue our study of the inventory Accumulation introduced by Sheffield (2011), which encodes a random planar map decorated by a collection of loops sampled from the critical Fortuin-Kasteleyn (FK) Model. We prove various \emph{local estimates} for the inventory Accumulation Model, i.e., estimates for the precise number of symbols of a given type in a reduced word sampled from the Model. Using our estimates, we obtain the scaling limit of the associated two-dimensional random walk conditioned on the event that it stays in the first quadrant for one unit of time and ends up at a particular position in the interior of the first quadrant. We also obtain the exponent for the probability that a word of length $2n$ sampled from the inventory Accumulation Model corresponds to an empty reduced word, which is equivalent to an asymptotic formula for the partition function of the critical FK planar map Model. The estimates of this paper will be used in a subsequent paper to obtain the scaling limit of the lattice walk associated with a finite-volume FK planar map.
