Design of a Gecko Adhesive Climbing Robot

Engineering: 1st Place (The Ohio State University Denman Undergraduate Research Forum)I present, ACROBOT, a gecko-adhesive enabled robot that can climb surfaces in any gravitational orientation or operate in full zero gravity. The robot is being developed as a prototype for inspection applications aboard the International Space Station (ISS) where current voids in inspection coverage both inside and outside the station pose risks to the vehicle. A specific area of interest for inspection is a narrow gap, approximately 1.5 inches wide, behind internal equipment racks. The prototype robot uses oppositional pairs of gecko adhesive pads that turn adhesion ON and OFF using an applied shear load. The robot is currently tele-operated and utilizes an inchworm style gait. The robot can turn in a tight circle, fits within a 1.5 inch gap, and can transition between orthogonal surfaces. Gecko adhesives leave no residue, are highly reusable, and create strong adhesion in vacuum and across a wide temperature range. The robot design and initial experimental results are presented including climbing vertical walls in Earth's gravity.NASA Jet Propulsion Laboratory (JPL)NASA JPL Extreme Environment Robotics Group (PI: Dr. Aaron Parness)Academic Major: Mechanical Engineerin

Antisthenes\u27 Theory of Unique Enunciation: Similarities, Differences, and Possible Influences

In this paper I will focus on Antisthenes’ theory of unique enunciation, and will then discuss its similarities and differences with, and/or possible influences on, other theories on language that flourished around the 4th and 3rd centuries BCE. I showed elsewhere that Antisthenes’ theory of language is a practical application or a strategy that has direct implication for his ethical project. My aim here is merely to highlight the originality and relevance of Antisthenes’ theory by presenting it and contextualizing it, before assessing relevant similarities and differences between certain positions of Antisthenes and those of some Skeptics, Sophists, Cyrenaics, and Megarians

Control Moment Gyroscope Stabilization and Maneuverability of Inherently Unstable Vehicles and Mobile Robots

The control problem of stabilizing an inherently unstable body, such as the inverted pendulum, is a classic control theory problem. Traditionally, the solution to this problem has been approached through methods of dynamic stabilization where the inverted pendulum is placed on a wheeled cart that can travel with one translational degree of freedom. This cart essentially accelerates the pivot of the inverted pendulum to accelerate the pendulum to induce a rotation that counteracts the imbalance in the system. A different approach to stabilizing a static or stationary inverted pendulum makes use of the intriguing phenomena known as gyroscopic precession. Precession and the physics of gyros are governed by conservation of angular momentum. By utilizing this technology in a novel way, groundbreaking progress can be made in the field of autonomous stability of inherently unstable mobile robots and vehicles (e.g. two wheeled vehicles). Gyroscopic effects can be found today in simple devices such as a spinning top or a bicycle’s wheel in motion. Gyros are also found in very complex mechanisms such as those used for satellite attitude and large ship anti-roll systems. Recent gyro studies have shown tremendous promise for providing unparalleled capabilities in stabilization and maneuverability for both on and off-road vehicle applications.Air Force Research LabSpecial Ops Transport ChallengeThe Ohio State University's Center for Automotive ResearchThe Ohio State University's Control and Intelligent Transportation LaboratoryNo embargoAcademic Major: Mechanical Engineerin

Is visual estimation of passive range of motion in the pediatric lower limb valid and reliable

<p>Abstract</p> <p>Background</p> <p>Visual estimation (VE) is an essential tool for evaluation of range of motion. Few papers discussed its validity in children orthopedics' practice. The purpose of our study was to assess validity and reliability of VE for passive range of motions (PROMs) of children's lower limbs.</p> <p>Methods</p> <p>Fifty typically developing children (100 lower limbs) were examined. Visual estimations for PROMs of hip (flexion, adduction, abduction, internal and external rotations), knee (flexion and popliteal angle) and ankle (dorsiflexion and plantarflexion) were made by a pediatric orthopaedic surgeon (POS) and a 5^thyear resident in orthopaedics. A last year medical student did goniometric measurements. Three weeks later, same measurements were performed to assess reliability of visual estimation for each examiner.</p> <p>Results</p> <p>Visual estimations of the POS were highly reliable for hip flexion, hip rotations and popliteal angle (ρ_c≥ 0.8). Reliability was good for hip abduction, knee flexion, ankle dorsiflexion and plantarflexion (ρ_c≥ 0.7) but poor for hip adduction (ρ_c= 0.5). Reproducibility for all PROMs was verified. Resident's VE showed high reliability (ρ_c≥ 0.8) for hip flexion and popliteal angle. Good correlation was found for hip rotations and knee flexion (ρ_c≥ 0.7). Poor results were obtained for ankle PROMs (ρ_c< 0.6) as well as hip adduction and abduction, the results of which not being reproducible. Influence of experience was clearly demonstrated for PROMs of hip rotations, adduction and abduction as well as ankle plantarflexion.</p> <p>Conclusion</p> <p>Accuracy of VE of passive hip flexion and knee PROMs is high regardless of the examiner's experience. Same accuracy can be found for hip rotations and abduction whenever VE is performed by an experienced examiner. Goniometric evaluation is recommended for passive hip adduction and for ankle PROMs.</p

Prosthetic overhang is the most effective way to prevent scapular conflict in a reverse total shoulder prosthesis

Methods An average and a "worst case scenario" shape in A-P view in a 2-D computer model of a scapula was created, using data from 200 "normal" scapulae, so that the position of the glenoid and humeral component could be changed as well as design features such as depth of the polyethylene insert, the size of glenosphere, the position of the center of rotation, and downward glenoid inclination. The model calculated the maximum adduction (notch angle) in the scapular plane when the cup of the humeral component was in conflict with the scapula. Results A change in humeral neck shaft inclination from 155 degrees to 145 degrees gave a 10 degrees gain in notch angle. A change in cup depth from 8 mm to 5 mm gave a gain of 12 degrees. With no inferior prosthetic overhang, a lateralization of the center of rotation from 0 mm to 5 mm gained 16 degrees. With an inferior overhang of only 1 mm, no effect of lateralizing the center of rotation was noted. Downward glenoid inclination of 0 boolean OR to 10 boolean OR gained 10 degrees. A change in glenosphere radius from 18 mm to 21 mm gained 31 degrees due to the inferior overhang created by the increase in glenosphere. A prosthetic overhang to the bone from 0 mm to 5 mm gained 39 degrees. Interpretation Of all 6 solutions tested, the prosthetic overhang created the biggest gain in notch angle and this should be considered when designing the reverse arthroplasty and defining optimal surgical technique

Study of the mechanical properties and behaviour of glenoid cancellous bone for the development of a new glenoid implant with cementless fixation

Les prothèses totales d’épaule ont une survie limitée due essentiellement au descellement de l’implant scapulaire. Le but de ce travail de recherche est la contribution à la mise au point d’un nouvel implant scapulaire à fixation sans ciment.Une première partie a concerné la caractérisation de l’anisotropie et des hétérogénéités de l’os spongieux de la glène par une expérimentation en compression, cette partie a abouti à l’élaboration d’une loi de comportement de l’os spongieux de la glène. La seconde partie de ce travail s’est focalisée sur la modélisation par éléments finis des contraintes aux points d’ancrage de l’implant.Les résultats des tests de simulation montrent l’incapacité du spongieux à assurer un effet press-fit dans le plan transversal, car on observe le dépassement des contraintes maximales pour un déplacement minime. Ce résultat met en question les modes de fixation primaire utilisés ce jour dans les prothèses sans ciment. Nos résultats montrent que la modification de la direction de chargement serait susceptible d’améliorer la fixation primaire ce qui ouvre des perspectives nouvelles pour le dessin d’une prothèse sans ciment.Total shoulder prostheses have a limited survival due mainly to the loosening of the glenoid implant. The purpose of this research is the contribution to the development of a new glenoid implant with cementless fixation.The first part concerned the characterization of the anisotropy and heterogeneity of cancellous bone of the glenoid by a compression experimental tests, this part has led to the drafting of a law of behavior of cancellous bone of the glenoid . The second part of this work has focused on finite element modeling of stress around the anchors of the glenoid implant.Simulation test results show the inability of the transversal plane of the glenoid to ensure effective press-fit fixation with stresses above strength properties of the cancellous bone with a minimal displacement. This calls into question the current modes of primary fixation of cementless implant. However, it appears that a change in the direction of loading would be beneficial for the primary fixation, which opens new perspectives for the design of a cementless prosthesis

Effects of prostaglandin receptors EP2 and FP on the alterations of the trabecular meshwork alterations : implications in glaucoma

Le glaucome est défini par une dégénérescence du nerf optique dont le principal facteur de risque est l’hypertension oculaire due à des altérations du tissu trabéculaire. Les traitements incluent des agonistes du récepteur FP, les agonistes du récepteur EP2 pouvant également avoir des effets bénéfiques.Au cours de cette thèse, un modèle de cellules trabéculaires primaires humaines a été défini et les effets du latanoprost, un agoniste FP, et du butaprost, un agoniste EP2, ont été étudiés, d'une part, sur la survie des cellules trabéculaires, et d’autre part, sur la transition myofibroblastique. Il a été montré que l’activation du récepteur EP2 permet de protéger les cellules trabéculaires d’un stress du réticulum endoplasmique par une diminution de l’accumulation de p53 qui résulte en l’inhibition de l’expression de Puma. Enfin, le butaprost entraîne l’augmentation de l’expression de Bcl-2 et la phosphorylation de Bad qui participent à l’inhibition de l’apoptose.D’autre part, le latanoprost induit une contraction des cellules trabéculaires tandis que le butaprost inhibe la contraction induite par le TGF-B2. En revanche, les deux agonistes inhibent la déposition du collagène.En conclusion, indépendamment de leur effet hypotenseur connu, le latanoprost favoriserait l’acquisition par les cellules trabéculaires d’un phénotype contractile et l’activation du récepteur EP2 pourrait limiter le développement de la dysfonction trabéculaire en protégeant de la mort cellulaire et en favorisant une relaxation. Ces résultats suggèrent que la stimulation du récepteur EP2 pourrait limiter le développement du glaucome et serait plus favorable que les agonistes du récepteur FP.Glaucoma is defined as an optic neuropathy whose main risk factor is ocular hypertension due to alterations of the trabecular meshwork (TM). The first-line therapies for glaucoma are agonists of the FP receptor. Agonists of the EP2 receptor could also present beneficial effects.During the thesis project, a model of primary human TM cells has been defined and the effects of latanoprost, an FP agonist, and butaprost, an EP2 agonist, have been studied on, firstly, the survival of TM cells and, secondly, on the myofibroblast transition.We have shown that activation of the EP2 receptor protects TM cells from an endoplasmic reticulum stress by a decreased accumulation of p53 which results in the inhibition of Puma transcription. Finally, butaprost mediates an increased expression of Bcl-2 and an elevation of Bad phosphorylation which contribute to protection against TM cell death.Moreover, latanoprost induces TM cell contraction while butaprost inhibits TGF-B2-dependent contraction. On the other hand, both agonists inhibit collagen.In conclusion, independently of their hypotensive effects, latanoprost would favor the acquisition by TM cells of a contractile phenotype while stimulation of EP2 receptor could limit TM dysfunction by protecting against TM cell death and relaxing the tissue. These results suggest that activation of EP2 receptor could slow down or inhibit the course of glaucoma progression and would be more favorable than the FP agonists currently used

Etude du comportement mécanique de la glène pour la mise au point d'un nouvel implant scapulaire à fixation sans ciment.

Les prothèses totales d épaule ont une survie limitée due essentiellement au descellement de l implant scapulaire. Le but de ce travail de recherche est la contribution à la mise au point d un nouvel implant scapulaire à fixation sans ciment.Une première partie a concerné la caractérisation de l anisotropie et des hétérogénéités de l os spongieux de la glène par une expérimentation en compression, cette partie a abouti à l élaboration d une loi de comportement de l os spongieux de la glène. La seconde partie de ce travail s est focalisée sur la modélisation par éléments finis des contraintes aux points d ancrage de l implant.Les résultats des tests de simulation montrent l incapacité du spongieux à assurer un effet press-fit dans le plan transversal, car on observe le dépassement des contraintes maximales pour un déplacement minime. Ce résultat met en question les modes de fixation primaire utilisés ce jour dans les prothèses sans ciment. Nos résultats montrent que la modification de la direction de chargement serait susceptible d améliorer la fixation primaire ce qui ouvre des perspectives nouvelles pour le dessin d une prothèse sans ciment.Total shoulder prostheses have a limited survival due mainly to the loosening of the glenoid implant. The purpose of this research is the contribution to the development of a new glenoid implant with cementless fixation.The first part concerned the characterization of the anisotropy and heterogeneity of cancellous bone of the glenoid by a compression experimental tests, this part has led to the drafting of a law of behavior of cancellous bone of the glenoid . The second part of this work has focused on finite element modeling of stress around the anchors of the glenoid implant.Simulation test results show the inability of the transversal plane of the glenoid to ensure effective press-fit fixation with stresses above strength properties of the cancellous bone with a minimal displacement. This calls into question the current modes of primary fixation of cementless implant. However, it appears that a change in the direction of loading would be beneficial for the primary fixation, which opens new perspectives for the design of a cementless prosthesis.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF