Space exploration: The interstellar goal and Titan demonstration

Automated interstellar space exploration is reviewed. The Titan demonstration mission is discussed. Remote sensing and automated modeling are considered. Nuclear electric propulsion, main orbiting spacecraft, lander/rover, subsatellites, atmospheric probes, powered air vehicles, and a surface science network comprise mission component concepts. Machine, intelligence in space exploration is discussed

Musculoskeletal modelling of an ostrich (Struthio camelus) pelvic limb: influence of limb orientation on muscular capacity during locomotion

We developed a three-dimensional, biomechanical computer model of the 36 major pelvic limb muscle groups in an ostrich (Struthio camelus) to investigate muscle function in this, the largest of extant birds and model organism for many studies of locomotor mechanics, body size, anatomy and evolution. Combined with experimental data, we use this model to test two main hypotheses. We first query whether ostriches use limb orientations (joint angles) that optimize the moment-generating capacities of their muscles during walking or running. Next, we test whether ostriches use limb orientations at mid-stance that keep their extensor muscles near maximal, and flexor muscles near minimal, moment arms. Our two hypotheses relate to the control priorities that a large bipedal animal might evolve under biomechanical constraints to achieve more effective static weight support. We find that ostriches do not use limb orientations to optimize the moment-generating capacities or moment arms of their muscles. We infer that dynamic properties of muscles or tendons might be better candidates for locomotor optimization. Regardless, general principles explaining why species choose particular joint orientations during locomotion are lacking, raising the question of whether such general principles exist or if clades evolve different patterns (e.g., weighting of muscle force–length or force–velocity properties in selecting postures). This leaves theoretical studies of muscle moment arms estimated for extinct animals at an impasse until studies of extant taxa answer these questions. Finally, we compare our model’s results against those of two prior studies of ostrich limb muscle moment arms, finding general agreement for many muscles. Some flexor and extensor muscles exhibit self-stabilization patterns (posture-dependent switches between flexor/extensor action) that ostriches may use to coordinate their locomotion. However, some conspicuous areas of disagreement in our results illustrate some cautionary principles. Importantly, tendon-travel empirical measurements of muscle moment arms must be carefully designed to preserve 3D muscle geometry lest their accuracy suffer relative to that of anatomically realistic models. The dearth of accurate experimental measurements of 3D moment arms of muscles in birds leaves uncertainty regarding the relative accuracy of different modelling or experimental datasets such as in ostriches. Our model, however, provides a comprehensive set of 3D estimates of muscle actions in ostriches for the first time, emphasizing that avian limb mechanics are highly three-dimensional and complex, and how no muscles act purely in the sagittal plane. A comparative synthesis of experiments and models such as ours could provide powerful synthesis into how anatomy, mechanics and control interact during locomotion and how these interactions evolve. Such a framework could remove obstacles impeding the analysis of muscle function in extinct taxa

Functional Design and Analysis of a Linked Shoulder Prosthesis

Persistent shoulder instability following joint arthroplasty remains a concern with mixed outcomes following clinical and surgical intervention. Thus, a linked universal joint implant was developed and functionally analyzed. A virtual model of the linked implant was developed and implanted in a 3D bony specimen to measure the available circumduction range of motion. Stresses in the implant were estimated using finite element analysis based on joint loads during activities of daily life. The glenoid fixation stress was evaluated using finite element analysis. The implant was capable of restoring normal range of motion, and withstanding expected joint loads without yield or fatigue failure. Bone fixation stress remains a concern, depending on the implant configuration and aggressive joint loading

Range of motion measurements based on depth camera for clinical rehabilitation

Dissertação para obtenção do Grau de Mestre em Engenharia BiomédicaIn clinical rehabilitation, biofeedback increases the patient’s motivation which makes it one of the most effective motor rehabilitation mechanisms. In this field it is very helpful for the patient and even for the therapist to know the level of success and performance of the training process. The human motion tracking study can provide relevant information for this purpose. Existing lab-based Three-Dimensional (3D) motion capture systems are capable to provide this information in real-time. However, these systems still present some limitations when used in rehabilitation processes involving biofeedback. A new depth camera - the Microsoft KinectTM - was recently developed overcoming the limitations associated with the lab-based movement analysis systems. This depth camera is easy to use, inexpensive and portable. The aim of this work is to introduce a system in clinical practice to do Range of Motion(ROM) measurements, using the KinectTM sensor and providing real-time biofeedback. For this purpose, the ROM measurements were computed using the joints spatial coordinates provided by the official Microsoft KinectTM Software Development Kit (SDK)and also using our own developed algorithm. The obtained results were compared with a triaxial accelerometer data, used as reference. The upper movements studied were abduction, flexion/extension and internal/external rotation with the arm at 90 degrees of elevation. With our algorithm the Mean Error (ME) was less than 1.5 degrees for all movements. Only in abduction the KinectTM Sketelon Tracking obtained comparable data. In other movements the ME increased an order of magnitude. Given the potential benefits, our method can be a useful tool for ROM measurements in clinics