Virtual Testing of Experimental Continuation

We present a critical advance in experimental testing of nonlinear structures. Traditional quasi-static experimental methods control the displacement or force at one or more load-introduction points on a structure. This approach is unable to traverse limit points in the control parameter, as the immediate equilibrium beyond these points is statically unstable, causing the structure to snap to another equilibrium. As a result, unstable equilibria---observed numerically---are yet to be verified experimentally. Based on previous experimental work, and a virtual testing environment developed herein, we propose a new experimental continuation method that can path-follow along unstable equilibria and traverse limit points. To support these developments, we provide insightful analogies between a fundamental building block of our technique---shape control---and analysis concepts such as the principle of virtual work and Galerkin's method. The proposed testing method will enable the validation of an emerging class of nonlinear structures that exploit instabilities for novel functionality

Development of shape morphing Kirigami honeycombs and actuation methods

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Shape morphing Kirigami mechanical metamaterials

Mechanical metamaterials exhibit unusual properties through the shape and movement of their engineered subunits. This work presents a new investigation of the Poisson’s ratios of a family of cellular metamaterials based on Kirigami design principles. Kirigami is the art of cutting and folding paper to obtain 3D shapes. This technique allows us to create cellular structures with engineered cuts and folds that produce large shape and volume changes, and with extremely directional, tuneable mechanical properties. We demonstrate how to produce these structures from flat sheets of composite materials. By a combination of analytical models and numerical simulations we show how these Kirigami cellular metamaterials can change their deformation characteristics. We also demonstrate the potential of using these classes of mechanical metamaterials for shape change applications like morphing structures

Pseudotumors due to pulmonary infarction

The preferred treatment of pulmonary infarction is nonoperative when the diagnosis can be established. In the present study, five cases are described in which failure of resolution or growth of a radiographic density resulted in eventual thoracotomy and pulmonary resection. Carcinoma was suspected in each case, and in one patient, unremitting hemoptysis was an additional indication for operation. It is thought that the infarction was due to an embolus in four patients and to pulmonary arterial thrombosis in the other. Only one of the patients had evidence of peripheral thrombophlebitis, and none had underlying cardiac disease. The infarcts involved the upper lobes in two patients, the lower lobes in two, and both the upper and lower lobes in one. The benign nature of the process was recognized at operation and conservative resections performed. The typical finding was atelectasis of the involved parenchyma with a central necrotic area. In two patients organizing pulmonary emboli were encountered when transecting the pulmonary arterial supply, and in one of these, pulmonary endarterectomy of the remaining vessel was successfully performed. The apparent ages of the infarcts ranged from two weeks to several months. After the diagnosis had been established at operation, prophylactic anticoagulant therapy was not given in four patients, and no recurrences were observed. In the fifth, bilateral superficial femoral vein ligation was performed, also with a good result. © 1963

Effects of high-intensity progressive resistance training on self-reported health status in older persons with type 2 diabetes

Purpose: To evaluate the influence of high-intensity progressive resistance training (PRT) on self-reported physical and mental health in older persons with type 2 diabetes.Methods: We performed a 12-month RCT with 36 overweight men and women with type 2 diabetes (aged 60-80 years) who were randomly assigned to a moderate weight-loss diet plus PRT (PRT&amp;WL) or a moderate weight-loss diet plus a control (stretching) program (WL). Gymnasium-based training for 6 months was followed by an additional 6 months of home-based training. The SF-36 (v1) questionnaire was used to obtain physical (PCS) and mental (MCS) health component summary scores at baseline, 6 and 12 months.Results: Subject retention was 81% and 72% after 6 and 12 months respectively. Exercise adherence during gymnasium- and home-based training was 88% and 73% for the PRT&amp;WL group, and 85% and 78.1% for the WL group respectively. In a regression model adjusted for age and sex, PCS improved in the PRT&amp;WL group compared to the WL group after 6 months of gymnasium-based training (2.3 versus -2.0, p = 0.05), which persisted after 12 months training (0.7 versus -4.1, p = 0.03). There were no between-group differences at 6 or 12 months for the MCS.Conclusion: High-intensity PRT was effective in improving self-reported physical health, but not mental health. PRT provides an effective exercise alternative in lifestyle management for older adults with type 2 diabetes.<br /