52 research outputs found

    Energy scavenging from insect flight

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    This paper reports the design, fabrication and testing of an energy scavenger that generates power from the wing motion of a Green June Beetle (C otinis nitida ) during its tethered flight. The generator utilizes non-resonant piezoelectric bimorphs operated in the d 31 bending mode to convert mechanical vibrations of a beetle into electrical output. The available deflection, force, and power output from oscillatory movements at different locations on a beetle are measured with a meso-scale piezoelectric beam. This way, the optimum location to scavenge energy is determined, and up to ~115 µW total power is generated from body movements. Two initial generator prototypes were fabricated, mounted on a beetle, and harvested 11.5 and 7.5 µW in device volumes of 11.0 and 5.6 mm 3 , respectively, from 85 to 100 Hz wing strokes during the beetle's tethered flight. A spiral generator was designed to maximize the power output by employing a compliant structure in a limited area. The necessary technology needed to fabricate this prototype was developed, including a process to machine high-aspect ratio devices from bulk piezoelectric substrates with minimum damage to the material using a femto-second laser. The fabricated lightweight spiral generators produced 18.5–22.5 µW on a bench-top test setup mimicking beetles' wing strokes. Placing two generators (one on each wing) can result in more than 45 µW of power per insect. A direct connection between the generator and the flight muscles of the insect is expected to increase the final power output by one order of magnitude.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90804/1/0960-1317_21_9_095016.pd

    Features associated with the development of hallucinations in Parkinson's disease

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    Objective - To identify features related to the development of hallucinations in Parkinson's disease (PD). Materials and methods - Seventy PD patients with hallucinations (group 1) and 60 PD patients without hallucinations (group 2) were evaluated for disease severity, presence of motor complications, rapid eye movement (REM) behavior disorder (RBD), and antiparkinsonian drug profile. The ages at the emergence of hallucinations and duration of disease in group 1 were matched with the ages at the last visit of those in group 2. Results - Disease severity and presence of motor complications were similar in both groups. RBD was more frequently encountered among hallucinators than among non-hallucinators (P = 0.007). The mean duration and daily doses of levodopa and other dopaminergic drugs did not differ in both groups; however, the usage of anticholinergics and amantadine were significantly more frequent in group 2, unexpectedly. Conclusions - The presence of RBD was significantly more common in hallucinators; however, severity of PD, duration and daily doses of dopaminergic drugs were not associated with the emergence of hallucinations

    Association of low cholesterol with primary intracerebral haemorrhage: a case control study

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    Epidemiological studies have shown that the incidence of intracerebral haemorrhage (ICH) is high in patients with low cholesterol levels. The aim of this study was to investigate the correlation between ICH and low cholesterol in cases of primary ICH
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