Experimental investigations of the effects of cutting angle on chattering of a flexible manipulator

When a machine tool is mounted at the tip of a robotic manipulator, the manipulator becomes more flexible (the natural frequencies are lowered). Moreover, for a given flexible manipulator, its compliance will be different depending on feedback gains, configurations, and direction of interest. Here, the compliance of a manipulator is derived analytically, and its magnitude is represented as a compliance ellipsoid. Then, using a two-link flexible manipulator with an abrasive cut off saw, the experimental investigation shows that the chattering varies with the saw cutting angle due to different compliance. The main work is devoted to finding a desirable cutting angle which reduces the chattering

Checking progress with aAction priority: is it fair?

The liveness characteristics of a system are intimately related to the notion of fairness. However, the task of explicitly modelling fairness constraints is complicated in practice. To address this issue, we propose to check LTS (Labelled Transition System) models under a strong fairness assumption, which can be relaxed with the use of action priority. The combination of the two provides a novel and practical way of dealing with fairness. The approach is presented in the context of a class of liveness properties termed progress, for which it yields a particularly efficient model-checking algorithm. Progress properties cover a wide range of interesting properties of systems, while presenting a clear intuitive meaning to users

Dynamic Mechanical Properties and Fracture Surface Morphologies of Core-Shell Rubber (CSR) Toughened Epoxy at Liquid Nitrogen (Ln2) Temperatures

The dynamic mechanical properties and fracture surface morphologies were evaluated for a commercial epoxy resin toughened with two types of core-shell rubber (CSR) toughening agents (Kane Ace(Registered TradeMark) MX130 and MX960). The impact resistance (R) was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The resulting fracture surface morphologies were examined using Scanning Electron Microscopy (SEM). Fractographic observations of the CSR toughened epoxy tested at ambient temperature, showed a fracture as characterized by slender dendrite textures with large voids. The increasing number of dendrites and decreasing size of scale-like texture with more CSR particles corresponded with increased R. As the temperature decreased to Liquid Nitrogen (LN 2), the fracture surfaces showed a fracture characterized by a rough, torn texture containing many river markings and deep furrows

Multisensory training for postural sway control in non-injured elderly females

Elderly adults demonstrate increased postural sway, which may ultimately lead to falls. The present study used a randomized controlled intervention to investigate whether the three-week multisensory training program lead to a decreased postural sway. A total of 24 non-injured elderly females (60-80 years) volunteered to participate. They were randomly assigned to either a training group (ETG) who received one hour of training twice weekly for three weeks or to a control group (ECG) who received no training. At post-training, the results showed significant improvement in the trained ETG when compared to the untrained ECG for all three postural sway measures for all six training factors. The findings demonstrated that the trained ETG improved in their total Berg Balance Test (BBT) scores indicated that the training program successfully improved postural sway control for non-injured elderly females.Keywords: multisensory training, postural sway control, balance ability, visual input;vestibular input, somatosensory inpu

Coccidioides posadasii infection alters the expression of pulmonary surfactant proteins (SP)-A and SP-D

BACKGROUND: Coccidioidomycosis or Valley Fever is caused by Coccidioides in Southwest US and Central America. Primary pulmonary infection is initiated by inhalation of air-borne arthroconidia. Since, lung is the first organ that encounters arthroconidia, different components of the pulmonary innate immune system may be involved in the regulation of host defense. Pulmonary surfactant proteins (SP)-A and SP-D have been recognized to play an important role in binding and phagocytosis of various microorganisms, but their roles in Coccidioides infection are not known. METHODS: In this study, we studied the changes in amounts of pulmonary SP-A, SP-D and phospholipid in murine model of Coccidioides posadasii infection, and binding of SP-A and SP-D to Coccidioidal antigens. Mice were challenged intranasally with a lethal dose of C. posadasii (n = 30 arthroconidia) and bronchoalveolar lavage fluid (BALF) samples were collected on day 10, post infection. In another group of animals, mice were immunized with protective formalin killed spherule (FKS) vaccine prior to infection. The concentrations of BALF SP-A, SP-D, total phospholipid were measured using enzyme linked immunosorbent assay and biochemical assays. RESULTS: We found that in lavage fluid samples of C. posadasii infected mice, the concentrations of total phospholipid, SP-A and SP-D were 17 % (SEM 3.5, p < 0.001), 38 % (SEM 5.8, p < 0.001) and 4 % (SEM 1.3, p < 0.001) of those in lavage fluid samples of non-infected control mice, respectively. However, the concentrations of SP-A and SP-D remained unchanged in BALF samples of C. posadasii protected mice after immunization with FKS vaccine. Also, we found that both SP-A and SP-D bind to Coccidiodal antigens. CONCLUSION: Our results suggest that the C. posadasii infection perturbs the pulmonary SP-A, SP-D, and phospholipids, potentially enabling the disease progression and promoting fungal dissemination