17,286 research outputs found
Soft, comfortable polymer dry electrodes for high quality ECG and EEG recording
Conventional gel electrodes are widely used for biopotential measurements, despite important drawbacks such as skin irritation, long set-up time and uncomfortable removal. Recently introduced dry electrodes with rigid metal pins overcome most of these problems; however, their rigidity causes discomfort and pain. This paper presents dry electrodes offering high user comfort, since they are fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and ease of fabrication. The electrode impedance is measured on phantoms and human skin. After optimization of the polymer composition, the skin-electrode impedance is only similar to 10 times larger than that of gel electrodes. Therefore, these electrodes are directly capable of recording strong biopotential signals such as ECG while for low-amplitude signals such as EEG, the electrodes need to be coupled with an active circuit. EEG recordings using active polymer electrodes connected to a clinical EEG system show very promising results: alpha waves can be clearly observed when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Moreover, all subjects reported that our polymer electrodes did not cause discomfort. Hence, the polymer-based dry electrodes are promising alternatives to either rigid dry electrodes or conventional gel electrodes
Preparation and characterisation of irradiated waste eggshells as oil adsorbent
Adsorption method had been developed by using natural organic adsorbent for the
removal of oil because of its ability to bind the oil molecules into the surface of adsorbent. In
this study, chicken eggshells waste was used and it undergoes irradiation process with four
different amount of dose which was 0.5 kGy, 1.0 kGy, 1.5 kGy, and 2.0 kGy by using Gamma
Cell Irradiator. Three equipment had been used for the characterization process which were the
Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX), and
Fourier-Transform Infrared Spectroscopy (FTIR). The adsorption experiment was conducted
to calculate the sorption efficiency by using different mass of samples. The result showed that
irradiated chicken eggshells powder with 2.0 kGy amount of radiation dose has a best
performance as oil adsorbent
Impedance-matched microwave lens
A microwave lens with highly reduced reflectance, as compared to conventional
dielectric lenses, is proposed. The lens is based on two-dimensional or
three-dimensional transmission-line networks that can be designed to have an
effective refractive index larger than one, while having almost perfect
impedance matching with free space. The design principles are presented and an
example lens is studied using commercial simulation software.Comment: 11 pages, 8 figure
Analysis of drawbacks and constraints of classification algorithms for three-phase voltage dips
Voltage events are one of the most common and harmful disturbances of power electric systems. Voltage dips, swells and interruptions are included under this heading. Given the economic cost that these disturbances represent for electrical power transmission and distribution companies and the industry, it becomes imperative to detect and classify them properly. Several classification criteria and algorithms have been proposed in the literature as analysis tools to differentiate voltage events by their characteristics and, if possible, to determine their causes and consequences. Even though some of these approaches make a correct classification of the voltage events, there are certain operation conditions that are common in real electrical grids, in which the classification criteria, and their corresponding algorithms, make a wrong classification. These particular conditions, together with the lack of a fair comparison in a common scenario, have not been addressed in the specific field literature. This work explores in detail all these aspects by evaluating the symmetrical components criterion and ABC classification criterion, and rigorously analyzes three specific algorithms: the Symmetrical Components Algorithm, the Six Phases Algorithm and the Space Vector Algorithm. Drawbacks arise from both classification criteria and algorithms. The causes of the classification errors are described and discussed in detail in order to better understand the problem, and evidence the constraints of these classification methods.Fil: Strack, Jorge Luis. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica; ArgentinaFil: Carugati, Ignacio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica; ArgentinaFil: Orallo, Carlos Martin. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica; ArgentinaFil: Donato, Patricio Gabriel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica; ArgentinaFil: Maestri, Sebastian Oscar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica; ArgentinaFil: Carrica, Daniel Oscar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones CientĂficas y TecnolĂłgicas en ElectrĂłnica; Argentin
On-Chip Matching Networks for Radio-Frequency Single-Electron-Transistors
In this letter, we describe operation of a radio-frequency superconducting
single electron transistor (RF-SSET) with an on-chip superconducting LC
matching network consisting of a spiral inductor L and its capacitance to
ground. The superconducting network has a lower parasitic capacitance and gives
a better matching for the RF-SSET than does a commercial chip inductor.
Moreover, the superconducting network has negligibly low dissipation, leading
to sensitive response to changes in the RF-SSET impedance. The charge
sensitivity 2.4*10^-6 e/(Hz)^1/2 in the sub-gap region and energy sensitivity
of 1.9 hbar indicate that the RF-SSET is operating in the vicinity of the shot
noise limit.Comment: 3 pages, 3 figures, REVTeX 4. To appear in Appl. Phys. Let
Market-based Investment in Electricity Transmission Networks: Controllable Flow
This paper discusses unregulated market-based electricity transmissio
The status of textile-based dry EEG electrodes
Electroencephalogram (EEG) is the biopotential recording of electrical signals generated by brain activity. It is useful for monitoring sleep quality and alertness, clinical applications, diagnosis, and treatment of patients with epilepsy, disease of Parkinson and other neurological disorders, as well as continuous monitoring of tiredness/ alertness in the field. We provide a review of textile-based EEG. Most of the developed textile-based EEGs remain on shelves only as published research results due to a limitation of flexibility, stickability, and washability, although the respective authors of the works reported that signals were obtained comparable to standard EEG. In addition, nearly all published works were not quantitatively compared and contrasted with conventional wet electrodes to prove feasibility for the actual application. This scenario would probably continue to give a publication credit, but does not add to the growth of the specific field, unless otherwise new integration approaches and new conductive polymer composites are evolved to make the application of textile-based EEG happen for bio-potential monitoring
- âŠ