The objective of this paper is to simulate the human hand when grasping an object, considering the angles of the finger joints and the fingertip deformation. To study the grasp of an object used in activities of daily life (ADL) we focus on the equations given by grasps with force-closure. In this paper we address several topics and study grasping holistically, including power and precision grasping, the position of the finger and joint angles, fingertip deformation and fingertip forces (normal and frictional forces), and assess how all these features combine to perform a complete grasping action.Conclusions: We describe the strategy used to solve the problem of calculating the force when grasping with five fingers; the same strategy is used in both power and precision grasps.
Four different scenarios have been studied in an underground mine, validating the results by actual data. Finding the best ventilation conditions in terms of air velocity and heat load removal. The conditions worsen as the duct is placed further from the face. While the position of the duct regarding cross-section, lower or upper side of the drift, does not give a clear conclusion about the best option, but it depends on the variable used in the analysis, either temperature, air velocity or the specific area in the working face. The findings of this study can be used to implement the most efficient auxiliary ventilation system in the mine considering the potential main issue, whether it is the working face or the place of the equipment. Besides, future scenarios can be also analysed with the model created, providing a good tool to select the auxiliary ventilation layout in each case.
The most reliable prognostic factors associated with Upper Extremity (UE) recovery are localized motor impairments, especially in the musculature of the hand and abduction of the shoulder in the first days after a stroke. Evaluation of the biomechanics of the hand allows an accurate identification of the motion arcs of the digital joints. Objective: Assess the prognostic value of the range of motion of the finger joints using an instrumental glove (CyberGlove II®) one week after stroke for UE functional recovery at 6 months. Methodology: A prospective, longitudinal, observational study with follow-ups at 3-4 days, 1 week, 3 and 6months of patients with UE motor impairment. Variables collected included: demographic data, level of stroke severity (NIHSS), deep sensitivity, sphincter incontinence, Fugl Meyer Assessment of UE (FM-UE), muscle balance with the Medical Research Council (MRC), muscle tone (Modified Ashworth Scale) and pre-and post-stroke functional ability (Barthel Index and Modified Rankin Scale). Active range of motion of the metacarpophalangeal and interphalangeal joints of the index, middle finger, annulary, and little finger was assessed with CyberGlove II® without and against gravity. The dependent variable UE function was evaluated with the Action Research Arm Test (ARAT) categorized as good function (ARAT≥10) and poor function (ARAT<10). Results: 31 patients were included, 18 of which completed the 6-month follow-up. Mean age was 68.2 years (SD = 9.1) and 72.2 % were men. A total of 77.8 % of strokes were ischemic, and 50 % of these were lacunar. Mean NIHSS score was 9.2 (SD = 5.5). Motor NIHSS of UE, FM-UE and MRC of the flexion-extension musculature of the digits and wrist were prognostic factors for the recovery of UE function.
This article evaluates the convective heat transfer coefficient of ventilation air in a potash mine in Catalonia (Spain). Through thermal characterization of ventilation air and rock of a gallery in the selected potash mine, the energy balance is obtained, and the parameters involved in the heat transfer process are calculated. With these parameters as a starting point, different models are analyzed to calculate the convective heat transfer coefficient.The results indicate that the optimal models to apply in this mine include the Pethukov-Kirilov, Gnielinski and modified Dittus-Boelter models. Moreover, the conductivity of the adjacent rock is indirectly studied, and it is deduced that throughout the studied section, the adjacent rock is saturated, and in Section 6-5 of the gallery, there occurs upwelling of liquid water.
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