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W Arnold - One of the best experts on this subject based on the ideXlab platform.

  • finite element simulation of moldboard soil interaction
    Soil & Tillage Research, 2013
    Co-Authors: Hatem Bentaher, Ayadi Ibrahmi, Elyes Hamza, M Hbaieb, G Kantchev, Aref Maalej, W Arnold
    Abstract:

    Abstract The efficiency of the tillage is measured by the power consumption or the tillage force or draught and the quality of the worked soil. The tillage forces are mainly a function of soil mechanical properties, working parameters of the tool (e.g. depth and speed) and tool geometry. In this paper we report on the numerical modeling of soil tillage. The finite element method (FEM) was used to model the cutting process of the soil using a moldboard. The surface geometry of the moldboard was measured with a 3D touch probe bench, also called coordinate measuring machine, and these data were used to construct the shape with SolidWorks design software. An elasto-plastic constitutive model was used for the soil. The generated surface of the plow was imported to Abaqus software as a discrete rigid body with a reference point at the tip of the moldboard. At this tip the reaction force with its three orthogonal components was calculated. The impact of the cutting Angle (Angle between the horizontal generatrix and the tillage direction) and the Lift Angle (Angle between the moldboard surface and the horizontal line in an orthogonal section to the cutting edge) on draught force was investigated. The optimal values of these Angles are in agreement with experimental data from the literature.

  • Finite element simulation of moldboard–soil interaction
    Soil and Tillage Research, 2013
    Co-Authors: Hatem Bentaher, Ayadi Ibrahmi, Elyes Hamza, M Hbaieb, G Kantchev, Aref Maalej, W Arnold
    Abstract:

    Abstract The efficiency of the tillage is measured by the power consumption or the tillage force or draught and the quality of the worked soil. The tillage forces are mainly a function of soil mechanical properties, working parameters of the tool (e.g. depth and speed) and tool geometry. In this paper we report on the numerical modeling of soil tillage. The finite element method (FEM) was used to model the cutting process of the soil using a moldboard. The surface geometry of the moldboard was measured with a 3D touch probe bench, also called coordinate measuring machine, and these data were used to construct the shape with SolidWorks design software. An elasto-plastic constitutive model was used for the soil. The generated surface of the plow was imported to Abaqus software as a discrete rigid body with a reference point at the tip of the moldboard. At this tip the reaction force with its three orthogonal components was calculated. The impact of the cutting Angle (Angle between the horizontal generatrix and the tillage direction) and the Lift Angle (Angle between the moldboard surface and the horizontal line in an orthogonal section to the cutting edge) on draught force was investigated. The optimal values of these Angles are in agreement with experimental data from the literature.

Hatem Bentaher - One of the best experts on this subject based on the ideXlab platform.

  • finite element simulation of moldboard soil interaction
    Soil & Tillage Research, 2013
    Co-Authors: Hatem Bentaher, Ayadi Ibrahmi, Elyes Hamza, M Hbaieb, G Kantchev, Aref Maalej, W Arnold
    Abstract:

    Abstract The efficiency of the tillage is measured by the power consumption or the tillage force or draught and the quality of the worked soil. The tillage forces are mainly a function of soil mechanical properties, working parameters of the tool (e.g. depth and speed) and tool geometry. In this paper we report on the numerical modeling of soil tillage. The finite element method (FEM) was used to model the cutting process of the soil using a moldboard. The surface geometry of the moldboard was measured with a 3D touch probe bench, also called coordinate measuring machine, and these data were used to construct the shape with SolidWorks design software. An elasto-plastic constitutive model was used for the soil. The generated surface of the plow was imported to Abaqus software as a discrete rigid body with a reference point at the tip of the moldboard. At this tip the reaction force with its three orthogonal components was calculated. The impact of the cutting Angle (Angle between the horizontal generatrix and the tillage direction) and the Lift Angle (Angle between the moldboard surface and the horizontal line in an orthogonal section to the cutting edge) on draught force was investigated. The optimal values of these Angles are in agreement with experimental data from the literature.

  • Finite element simulation of moldboard–soil interaction
    Soil and Tillage Research, 2013
    Co-Authors: Hatem Bentaher, Ayadi Ibrahmi, Elyes Hamza, M Hbaieb, G Kantchev, Aref Maalej, W Arnold
    Abstract:

    Abstract The efficiency of the tillage is measured by the power consumption or the tillage force or draught and the quality of the worked soil. The tillage forces are mainly a function of soil mechanical properties, working parameters of the tool (e.g. depth and speed) and tool geometry. In this paper we report on the numerical modeling of soil tillage. The finite element method (FEM) was used to model the cutting process of the soil using a moldboard. The surface geometry of the moldboard was measured with a 3D touch probe bench, also called coordinate measuring machine, and these data were used to construct the shape with SolidWorks design software. An elasto-plastic constitutive model was used for the soil. The generated surface of the plow was imported to Abaqus software as a discrete rigid body with a reference point at the tip of the moldboard. At this tip the reaction force with its three orthogonal components was calculated. The impact of the cutting Angle (Angle between the horizontal generatrix and the tillage direction) and the Lift Angle (Angle between the moldboard surface and the horizontal line in an orthogonal section to the cutting edge) on draught force was investigated. The optimal values of these Angles are in agreement with experimental data from the literature.

Jordi Llorens - One of the best experts on this subject based on the ideXlab platform.

  • Differential role of type I and type II vestibular hair cells in two anti-gravity reflexes in the rat.
    2020
    Co-Authors: Alberto F. Maroto, Alejandro Barrallo-gimeno, Jordi Llorens
    Abstract:

    The tail-Lift reflex and the air-righting reflex in rats are anti-gravity reflexes that depend on vestibular function. We assessed reflex loss in relationship to the graded lesions caused in the vestibular sensory epithelia by varying doses of an ototoxic compound. Using high-speed video recording, we obtained nose-back of the neck-tail Angles from the tail-Lift reflex and time to right in the air-righting test. We then correlated these measures with type I (HCI), type II (HCII) and all hair cell (HC) counts in central and peripheral zones of the crista, utricle, and saccule. Correlations varied with the cell type, zone and end-organ considered, and those of tail-Lift Angles were strikingly greater with HCI counts that HCII counts. A similar HCI vs HCII difference was not recorded for air-righting times. We conclude that these two reflexes depend differently on HCI and HCII function and that the tail-Lift Angle measures HCI function.

  • Quantitative Assessment of Anti-Gravity Reflexes to Evaluate Vestibular Dysfunction in Rats
    Journal of the Association for Research in Otolaryngology, 2019
    Co-Authors: Vanessa Martins-lopes, Alberto F. Maroto, Anna Bellmunt, Erin A. Greguske, Pere Boadas-vaello, Jordi Llorens
    Abstract:

    The tail-Lift reflex and the air-righting reflex are anti-gravity reflexes in rats that depend on vestibular function. To obtain objective and quantitative measures of performance, we recorded these reflexes with slow-motion video in two experiments. In the first experiment, vestibular dysfunction was elicited by acute exposure to 0 (control), 400, 600, or 1000 mg/kg of 3,3′-iminodipropionitrile (IDPN), which causes dose-dependent hair cell degeneration. In the second, rats were exposed to sub-chronic IDPN in the drinking water for 0 (control), 4, or 8 weeks; this causes reversible or irreversible loss of vestibular function depending on exposure time. In the tail-Lift test, we obtained the minimum Angle defined during the Lift and descent maneuver by the nose, the back of the neck, and the base of the tail. In the air-righting test, we obtained the time to right the head. We also obtained vestibular dysfunction ratings (VDRs) using a previously validated behavioral test battery. Each measure, VDR, tail-Lift Angle, and air-righting time demonstrated dose-dependent loss of vestibular function after acute IDPN and time-dependent loss of vestibular function after sub-chronic IDPN. All measures showed high correlations between each other, and maximal correlation coefficients were found between VDRs and tail-Lift Angles. In scanning electron microscopy evaluation of the vestibular sensory epithelia, the utricle and the saccule showed diverse pathological outcomes, suggesting that they have a different role in these reflexes. We conclude that these anti-gravity reflexes provide useful objective and quantitative measures of vestibular function in rats that are open to further development.

Llorens Baucells I Jordi - One of the best experts on this subject based on the ideXlab platform.

  • Quantitative Assessment of Anti-Gravity Reflexes to Evaluate Vestibular Dysfunction in Rats
    Journal of the Association for Research in Otolaryngology, 2019
    Co-Authors: Martins Lopes, Vanessa P., Bellmunt Tarragó I Anna, Greguske, Erin A., Maroto, Alberto F., Boadas Vaello I Pere, Llorens Baucells I Jordi
    Abstract:

    The tail-Lift reflex and the air-righting reflex are anti-gravity reflexes in rats that depend on vestibular function. To obtain objective and quantitative measures of performance, we recorded these reflexes with slow-motion video in two experiments. In the first experiment, vestibular dysfunction was elicited by acute exposure to 0 (control), 400, 600, or 1000 mg/kg of 3,3′-iminodipropionitrile (IDPN), which causes dose-dependent hair cell degeneration. In the second, rats were exposed to sub-chronic IDPN in the drinking water for 0 (control), 4, or 8 weeks; this causes reversible or irreversible loss of vestibular function depending on exposure time. In the tail-Lift test, we obtained the minimum Angle defined during the Lift and descent maneuver by the nose, the back of the neck, and the base of the tail. In the air-righting test, we obtained the time to right the head. We also obtained vestibular dysfunction ratings (VDRs) using a previously validated behavioral test battery. Each measure, VDR, tail-Lift Angle, and air-righting time demonstrated dose-dependent loss of vestibular function after acute IDPN and time-dependent loss of vestibular function after sub-chronic IDPN. All measures showed high correlations between each other, and maximal correlation coefficients were found between VDRs and tail-Lift Angles. In scanning electron microscopy evaluation of the vestibular sensory epithelia, the utricle and the saccule showed diverse pathological outcomes, suggesting that they have a different role in these reflexes. We conclude that these anti-gravity reflexes provide useful objective and quantitative measures of vestibular function in rats that are open to further development.

Elyes Hamza - One of the best experts on this subject based on the ideXlab platform.

  • finite element simulation of moldboard soil interaction
    Soil & Tillage Research, 2013
    Co-Authors: Hatem Bentaher, Ayadi Ibrahmi, Elyes Hamza, M Hbaieb, G Kantchev, Aref Maalej, W Arnold
    Abstract:

    Abstract The efficiency of the tillage is measured by the power consumption or the tillage force or draught and the quality of the worked soil. The tillage forces are mainly a function of soil mechanical properties, working parameters of the tool (e.g. depth and speed) and tool geometry. In this paper we report on the numerical modeling of soil tillage. The finite element method (FEM) was used to model the cutting process of the soil using a moldboard. The surface geometry of the moldboard was measured with a 3D touch probe bench, also called coordinate measuring machine, and these data were used to construct the shape with SolidWorks design software. An elasto-plastic constitutive model was used for the soil. The generated surface of the plow was imported to Abaqus software as a discrete rigid body with a reference point at the tip of the moldboard. At this tip the reaction force with its three orthogonal components was calculated. The impact of the cutting Angle (Angle between the horizontal generatrix and the tillage direction) and the Lift Angle (Angle between the moldboard surface and the horizontal line in an orthogonal section to the cutting edge) on draught force was investigated. The optimal values of these Angles are in agreement with experimental data from the literature.

  • Finite element simulation of moldboard–soil interaction
    Soil and Tillage Research, 2013
    Co-Authors: Hatem Bentaher, Ayadi Ibrahmi, Elyes Hamza, M Hbaieb, G Kantchev, Aref Maalej, W Arnold
    Abstract:

    Abstract The efficiency of the tillage is measured by the power consumption or the tillage force or draught and the quality of the worked soil. The tillage forces are mainly a function of soil mechanical properties, working parameters of the tool (e.g. depth and speed) and tool geometry. In this paper we report on the numerical modeling of soil tillage. The finite element method (FEM) was used to model the cutting process of the soil using a moldboard. The surface geometry of the moldboard was measured with a 3D touch probe bench, also called coordinate measuring machine, and these data were used to construct the shape with SolidWorks design software. An elasto-plastic constitutive model was used for the soil. The generated surface of the plow was imported to Abaqus software as a discrete rigid body with a reference point at the tip of the moldboard. At this tip the reaction force with its three orthogonal components was calculated. The impact of the cutting Angle (Angle between the horizontal generatrix and the tillage direction) and the Lift Angle (Angle between the moldboard surface and the horizontal line in an orthogonal section to the cutting edge) on draught force was investigated. The optimal values of these Angles are in agreement with experimental data from the literature.