Physiological Responses and Thermal Comfort of Subjects in a Tractor Cab

P.O. Fanger of Denmark was the first scientist to generalize the physiological basis for predicting human thermal comfort based on activity level, clothing type, air temperature, air velocity, mean radiant temperature, and air humidity. Thus any activity level and clothing type, it is possible to determine combinations of air temperature, mean radiant temperature, air humidity and relative air velocity which would produce optimum thermal comfort. The Fanger approach has been applied successfully to offices and buildings. It would be quite useful to demonstrate that Fanger’s concepts could be applied to tractor cabs. The objectives of this study were as follows: 1. Determine the effect of cab air temperature an velocity on physiological parameters within a tractor cab for summer conditions. 2. Determine in Fanger’s criteria for thermal comfort is applicable to tractor cabs for summer conditions

System for powered ankle-foot prosthesis with active control of dorsiflexion-plantarflexion and inversion-eversion

A system and method for operating a prosthesis is provided. The system includes a socket configured to engage a residual limb of a subject and a shaft having a first end connected to the socket and an opposing second end. The system also includes a foot piece connected to the second end of the shaft. The foot piece includes an ankle plate and a sole piece configured to contact a surface. The system also includes at least one computer configured to detect a state of the foot piece and to transmit an indication of the state of the foot. The system further includes a motor assembly configured to receive the indication of the state of the foot and to control a position and impedance of the ankle plate based on the state of the foot.https://digitalcommons.mtu.edu/patents/1136/thumbnail.jp

Assessment of stability during gait in patients with spinal deformity-A preliminary analysis using the dynamic stability margin.

Daily living activities are dynamic, requiring spinal motion through space. Current assessment of spinal deformities is based on static measurements from full-spine standing radiographs. Tools to assess dynamic stability during gait might be useful to enhance the standard evaluation. The aim of this study was to evaluate gait dynamic imbalance in patients with spinal deformity using the dynamic stability margin (DSM). Twelve normal subjects and 17 patients with spinal deformity were prospectively recruited. A kinematic 3D gait analysis was performed for the control group (CG) and the spinal deformity group (SDG). The DSM (distance between the extrapolated center of mass and the base of support) and time-distance parameters were calculated for the right and left side during gait. The relationship between DSM and step length was assessed using three variables: gait stability, symmetry, and consistency. Variables’ accuracy was validated by a discriminant analysis. Patients with spinal deformity exhibited gait instability according to the DSM (0.25 m versus 0.31 m) with decreased velocity (1.1 m s−1 versus 1.3 m s−1) and decreased step length (0.32 m versus 0.38 m). According to the discriminant analysis, gait stability was the more accurate variable (area under the curve AUC =0.98) followed by gait symmetry and consistency. However, gait consistency showed 100% of specificity, sensitivity, and accuracy of precision. The DSM showed that patients with spinal malalignment exhibit decreased gait stability, symmetry, and consistency besides gait time-distance parameter changes. Additional work is required to determine how to apply the DSM for preoperative and postoperative spinal deformity management.There is no financial or personal relationship to disclose, nor any other conflicts of interest, that may bias or influence this stud

Instructional Course : Stance Control Orthotics

Lower limb orthosis design has been advanced by the introduction of knee mechanisms that provide stance phase control and swing phase freedom, referred to as a stance control orthosis (SCO). The intent is to allow a more normal, energy efficient gait. This technology is relatively new and many practitioners have only limited experience. This instructional course will make it possible for more practitioners to gain the knowledge needed to introduce this technology into their clinical practice. Attendees will gain knowledge about the technical features of SCO designs along with an understanding of the biomechanical deficits that can be replaced. Clinical examples will be provided to document patient selection and treatment criteria. The effective use of various types of SCOs will be presented. The course will also provide a summary of current research on SCOs and areas that require future development efforts

Stance Control Orthotics

Lower limb orthosis design has been advanced by the introduction of knee mechanisms that provide stance phase control and swing phase freedom, referred to as a stance control orthosis (SCO). The intent is to allow a more normal, energy efficient gait. This technology is relatively new and many practitioners have only limited experience. This instructional course will make it possible for more practitioners to gain the knowledge needed to introduce this technology into their clinical practice. Attendees will gain knowledge about the technical features of SCO designs along with an understanding of the biomechanical deficits that can be replaced. Clinical examples will be provided to document patient selection and treatment criteria. The effective use of various types of SCOs will be presented. The course will also provide a summary of current research on SCOs and areas that require future development efforts

A Highway Test of Gasohol

Tests were conducted using two 1976 Ford Torinos in which the fuel economy using gasohol was compared with that obtained using unleaded gasoline. It was found that gasohoI gave 3% fewer miles per gallon than the unleaded gasoline under typical summer highway driving conditions in North Dakota. This difference was found to be statistically significant at the 99% level of confidence. The reduced fuel economy with gasohol appears to be directly proportional to the lower energy content of gasohol

Ankle mechanics during sidestep cutting implicates need for 2-degrees of freedom powered ankle-foot prostheses

© 2015, Rehabilitation Research and Development Service. All rights reserved. The ankle joint of currently available powered prostheses is capable of controlling one degree of freedom (DOF), focusing on improved mobility in the sagittal plane. To increase agility, the requirements of turning in prosthesis design need to be considered. Ankle kinematics and kinetics were studied during sidestep cutting and straight walking. There were no significant differences between the ankle sagittal plane mechanics when comparing sidestep cutting and straight walking; however, significant differences were observed in ankle frontal plane mechanics. During straight walking, the inversion-eversion (IE) angles were smaller than with sidestep cutting. The ankle that initiated the sidestep cutting showed progressively increasing inversion from 2 to 13 degrees while the following contralateral step showed progressively decreasing inversion from 8 to 4 degrees during normal walking speed. The changes in IE kinematics were the most significant during sidestep cutting compared with straight walking. The IE moments of the step that initiated the sidestep cutting were always in eversion, acting as a braking moment opposing the inverting motion. This suggests that an ankle-foot prosthesis with active DOFs in the sagittal and frontal planes will increase the agility of gait for patients with limb loss

A two-axis cable-driven ankle-foot mechanism

© 2014 Ficanha et al.; licensee Springer. This paper describes a novel cable-driven ankle-foot mechanism with two controllable degrees of freedom (DOF) in dorsiflexion-plantarflexion (DP) and inversion-eversion (IE). The presented mechanism is a proof of concept to demonstrate feasibility. Ankle kinematic measurements demonstrate that ankle IE rotations during a step turn are significantly different from walking on a straight path. This suggests that the ankle-foot mechanisms used in prostheses, exoskeletons, and bipedal robots can be improved by controlling a second degree of freedom in the frontal plane. The proposed prototype mechanism is described in detail, and its design considerations and parameters are presented. The mechanism is capable of producing trajectories similar to the human ankle during a step turn. The device shows passive mechanical impedance close to the human ankle mechanical impedance, allowing its mechanical impedance to be controlled using an impedance controller. The presented mechanism is capable of providing key mechanical characteristics similar to the human ankle, including power, range of motion, and weight, suggesting the feasibility of this design concept