An Investigation on the Grasping Position Optimization-Based Control for Industrial Soft Robot Manipulator

Mitigating fatigue damage and improving grasping performance are the two main challenging tasks of applying the soft manipulator into industrial production. In this paper, the grasping position optimization-based control strategy is proposed for the soft manipulator and the corresponding characteristics are studied theoretically and experimentally. Specifically, based on the simulation, the resultant stress of step-function-type channels at the same pressure condition that was smallest compared with those of sine-function- and ramp-function-type channels, hence, a pneumatic network with step-function-type channels was selected for the proposed soft manipulator. Furthermore, in order to improve the grasping performance, the kinematics, mechanical, and grasping modeling for the soft manipulator were established, and a control strategy considering the genetic algorithm is introduced to detect the optimal position of the soft manipulator. The corresponding fabrication process and experiments were conducted to cross verify the results of the modeling and the control strategy. It is demonstrated that the internal pressure of the soft manipulator was reduced by 13.05% at the optimal position, which effectively helped mitigate the fatigue damage of the soft manipulator and prolonged the lifespan.

Haemophagocytic lymphohistiocytosis (HLH)-associated stress cardiomyopathy secondary to autoimmune conditions successfully treated with anakinra

We describe two young cases of reactive haemophagocytic lymphohistiocytosis (HLH) with the resultant stress cardiomyopathy in the setting of underlying autoimmune diseases, systemic lupus erythematosus (SLE) and Still’s disease. The initial presentation was similar in both cases with fever, hyperinflammatory response, hypotension (vasoplegia), bicytopenia and hyperferritinemia. Despite standard of care and multiple broad-spectrum antibiotics, both cases remained pyrexic and were ultimately admitted to the intensive therapy unit to treat cardiogenic shock. Echocardiogram of both cases showed low ejection fraction, the cause for which was not found until the final diagnosis of HLH was made. Both cases made a complete clinical and cardiac recovery following the initiation of high-dose glucocorticoids and anakinra.

Reliability Analysis of Resultant Stress for Unsymmetrical Columns for Stress Follow Exponential Distribution

When a body is subjected to eccentric loads, the direct stress as well as bending stress is produced. Resultant stress is obtained by adding these two stresses. In this paper, probabilistic approach has been made for designing the structure of unsymmetrical column by finding suitable parameters length of outer square and length of a hole and eccentric load of the column to get the specified reliability of the structure of a body or component. Reliability analysis has been done at the point of maximum compressive stress occurred and at the point of minimum tensile stress occurred. Reliability computations have been obtained for changing the various parameter values. It is observed from the computations that Reliability of the component when compressive stress occurs at the edge AB increases with increasing of length of outer square, decrease of load, decrease of length of hole and increasing of eccentricity. Reliability of the component when tensile stress occurs at the edge CD increases with decrease of length of outer square increasing the length of a hole, decreases the load and decrease of eccentricity

The effect of tooth morphology and vertical bracket positioning on resultant stress in periodontal ligament- a three dimensional finite element study

Introduction. The purpose of this study is to evaluate the effect of change in vertical placement of bracket and effect of tooth morphology on stress developed on periodontal ligament with the help of three dimensional finite element modeling. Methods. A three-dimensional model of the maxillary bone, maxillary right central incisor, lateral incisor and canine was designed based on the average dimensions of the anatomy and morphology given by Wheeler’s and standard edgewise bracket with Slot of 0.022″ X 0.028″ inch was designed using the finite element method. Brackets were placed on each tooth, on the mentioned labial surface at variable distances from the cusp tip, and a full size archwire was virtually engaged into the bracket, then optimum orthodontic load of 2N is applied and PDL stress were calculated. Results. The lowest stress values were measured as bracket position changes from crest of teeth to the apical direction. By displacing the bracket gingivally from 1.5 to 6 mm, a 16.2% decrease in stress level for central incisor, for lateral incisor the stress level decrease by 25.8% and for canine the stress level decrease by 21.6% thus our study confirms that variation in vertical bracket position results in change in resultant stress in PDL. Conclusion.It can be concluded that the variation in the vertical position of the bracket on different tooth can have an important effect on the stresses developed in the PDL.

Fitting in with the team: Facilitative mentors in physiotherapy student placements’

Clinical placements are central to physiotherapy students’ education, providing an environment in which students can apply learning they have been introduced to in academic settings. However placement learning has been identified as fraught with problems and resultant stress, and there is limited evidence available on what exactly makes a good placement for physiotherapy students. This paper reports on selected findings from a study exploring narratives of physiotherapy students over three years, relating to their overall experiences of being a student. A narrative prompt provided an opportunity for the students to speak about ‘episodes’ of their learning experiences. A number of these ‘episodes’ related to the students’ experiences of clinical placements; thus it was decided to extract these from the narratives and undertake a separate qualitative analysis of these placement experiences. The majority of the students reported positive experiences of placements overall; however, it was clear that some placement teams and mentors did not support students appropriately. A welcoming team and a mentor who facilitated learning from an individual student perspective were considered to be key to a good placement experience, whilst an unwelcoming team and a mentor who objectified the student resulted in bad placement experiences.

Analysis of Thermal Residual Stress on Large Thickness Polypropylene Joints as in a Reel-Lay System

The purpose of this document is to be an initial study into the affects that increased insulation thickness requirements have on a typical field joint. An observed increase in joint failures has begun to occur with larger insulation thickness requirements which requires justification as to a possible and probable cause. The method of failure that is looked into in this document is the increase in comparative stress at the bonding joints caused by the increased stress of the comparatively increased thermal shrinkage and resultant residual thermal stress. This is analyzed through an ABAQUS simulation for current stress of the common 3in insulation thickness and the resultant stress of increasing the insulation to a 4 in thickness. The increase in stress upwards of 30% can be a cause of concern when paired with bending due to the requirements of reel lay installation methods.

Screen-Printed Ceramic Based MEMS Piezoelectric Cantilever for Harvesting Energy

Screen-printing technology provides a convenient method in fabricating thick-film conductive circuits and devices in the past few decades. Conventionally, piezoelectric thick-film is printed on alumina substrate with high mechanical Q-factor and resonates at higher frequency outside the range of ambient vibration. As the piezoelectric charge generation is proportional to the mechanical stress on the material, therefore the substrate can be removed in order to lower the natural frequency of the structure. In this paper, a series of piezoelectric ceramic cantilevers were fabricated in the form of free-standing cantilever. An additional layer of ceramic was also introduced to the upper and lower electrode to prevent delamination. The issue of zero resultant stress for the sandwiched piezoelectric cantilever was solved by repeating the electrode-PZT-electrode layer to form a multilayer structure. It was found from the experiment that an electrical output power of 32 μW was generated when it operates at its resonant frequency at 403 Hz.