SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Alternator

26

Pacemaker generators are routinely implanted in the anterior chest. However, where to place the generator may need to be considered from the mental, functional, and cosmetic standpoints.

Concepts: Electricity, Alternating current, Axillary vein, Alternator

0

The present double-blind crossover study examines the effects of cerebellar transcranial direct current stimulation (tDCS) in controls and in an analogue population to psychosis: individuals reporting elevated symptoms of nonclinical psychosis (NCP). A total of 18 controls and 24 NCP individuals were randomized into conditions consisting of 25 minutes of anodal (active) or sham cerebellar tDCS. Following this, both groups completed a pursuit rotor task designed to measure procedural learning performance. Participants then returned 1-week later and received the corresponding condition (either active or sham) and repeated the pursuit rotor task. Results indicate that in the sham condition, control participants showed significantly greater rates of motor learning when compared with the NCP group. In the active condition, the NCP group exhibited significant improvements in the rate of motor learning and performed at a level that was comparable to controls; these data support the link between cerebellar dysfunction and motor learning. Taken together, tDCS may be a promising treatment mechanism for patient populations and a useful experimental approach in elucidating our understanding of psychosis.

Concepts: Improve, Population, Crossover study, Cerebellum, Direct current, Transcranial magnetic stimulation, Transcranial direct current stimulation, Alternator

0

This paper presents an image reconstruction method to monitor the temperature distribution of electric generator stators. The main objective is to identify insulation failures that may arise as hotspots in the structure. The method is based on temperature readings of fiber optic distributed sensors (DTS) and a sparse reconstruction algorithm. Thermal images of the structure are formed by appropriately combining atoms of a dictionary of hotspots, which was constructed by finite element simulation with a multi-physical model. Due to difficulties for reproducing insulation faults in real stator structure, experimental tests were performed using a prototype similar to the real structure. The results demonstrate the ability of the proposed method to reconstruct images of hotspots with dimensions down to 15 cm, representing a resolution gain of up to six times when compared to the DTS spatial resolution. In addition, satisfactory results were also obtained to detect hotspots with only 5 cm. The application of the proposed algorithm for thermal imaging of generator stators can contribute to the identification of insulation faults in early stages, thereby avoiding catastrophic damage to the structure.

Concepts: Electricity, Optics, Thermography, Electric motor, Stator, Electrical generator, Alternator, Armature

0

This study used bilateral transcranial direct current stimulation (tDCS) to target neural generators of auditory Mismatch Negativity (MMN) and oddball P300 in schizophrenia patients. tDCS was applied to the pre-frontal cortex in a parallel between-group design. There was a significant main effect of stimulation resulting in modulation of MMN amplitude. This effect was mainly driven by a non-significant, but large, effect-size decrease in MMN amplitude with anodal stimulation. This is the first study to demonstrate that tDCS is able to engage and modulate an EEG-based auditory processing measure in schizophrenia.

Concepts: Brain, Electricity, Electrochemistry, Direct current, Alternating current, Frontal lobe, Transcranial direct current stimulation, Alternator

0

A simple but practical method to convert the hydroenergy of microfluids into continuous electrical output is reported. Based on the principle of streaming potential/current, a microfluidic generator (MFG) is demonstrated using patterned micropillar arrays as a quasi-porous flow channel. The continuous electrical output makes this MFG particularly suitable as a power source in self-powered systems. Using the proposed MFG to power a single nanowire-based pH sensor, a self-powered fluid sensor system is demonstrated.

Concepts: Electricity, Fluid dynamics, Direct current, Alternating current, Microfluidics, Electrical engineering, Electrical generator, Alternator

0

In this paper, PZT actuators are used to study the dynamic behavior of a rotating disk structure due to rotor-stator interaction excitation. The disk is studied with two different surrounding fluids-air and water. The study has been performed analytically and validated experimentally. For the theoretical analysis, the natural frequencies and the associated mode shapes of the rotating disk in air and water are obtained with the Kirchhoff-Love thin plate theory coupled with the interaction with the surrounding fluid. A model for the Rotor Stator Interaction that occurs in many rotating disk-like parts of turbomachinery such as compressors, hydraulic runners or alternators is presented. The dynamic behavior of the rotating disk due to this excitation is deduced. For the experimental analysis a test rig has been developed. It consists of a stainless steel disk (r = 198 mm and h = 8 mm) connected to a variable speed motor. Excitation and response are measured from the rotating system. For the rotating excitation four piezoelectric patches have been used. Calibrating the piezoelectric patches in amplitude and phase, different rotating excitation patterns are applied on the rotating disk in air and in water. Results show the feasibility of using PZT to control the response of the disk due to a rotor-stator interaction.

Concepts: Scientific method, Science, Experiment, Phase, Test method, Theory, Electric motor, Alternator

0

In the growing regions across the globe, products are being differentiated not only by their performance but also on characteristics like noise, aesthetics, ergonomics, etc. Noise norms are getting more and more stringent and customers are looking for quieter products. Engineers and technicians now face the challenge of developing effective products for lower noise emissions in addition to enhanced performance. As generators are a major noise source in a power plant, it is essential to contain generator noise well within the limit to meet statutory requirements. The major contributors to generator noise include cooling fan, rotor jet, electromagnetic excitation, and vibrations. These sources should be configured properly for reducing the overall noise. Therefore, it is essential to establish a robust process to predict the generator noise accurately. This paper describes the process for predicting generator noise by using Statistical Energy Analysis methodology. Correlation of the predictions with test data is also discussed.

Concepts: Scientific method, Prediction, Futurology, Prophecy, Electricity generation, Electric motor, Wind turbine, Alternator