Strong correlation between the peak power density in the time domain and the luminosity of long γ-ray bursts

2005 ◽  
Vol 29 (4) ◽  
pp. 361-369 ◽  
Author(s):  
Zhao-yu Yang ◽  
Li-ming Song ◽  
Rong-feng Shen ◽  
Zhuo Li ◽  
Yu-sheng Lu
Keyword(s):  
Power Density ◽  
Time Domain ◽  
Strong Correlation ◽  
Peak Power ◽  
Peak Power Density ◽  
Γ Ray ◽  
The Time Domain

scholarly journals Characteristic Variability Time Scales of Long Gamma-Ray Bursts

2003 ◽  
Vol 214 ◽  
pp. 339-340
Author(s):  
Rongfeng Shen ◽  
Liming Song
Keyword(s):  
Power Density ◽  
Time Scales ◽  
Time Domain ◽  
Time Scale ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Time Dilation ◽  
Dilation Effect ◽  
The Time Domain ◽  
Intrinsic Characteristic

We determine the characteristic variability time scales for 410 bright long GRBs by locating the maximums of their Power Density Spectra (PDSs) defined and calculated in the time domain. The averaged characteristic variability time scale decreases with peak fluxe. This is consistent with the time dilation effect expected by cosmological origin of GRBs. The occurrence distribution of the characteristic variability time scale shows bimodality, which might be interpreted as that the long GRB sample is composed of two sub-classes with different intrinsic characteristic variability time scales.

Investigation of Transport Phenomena in Micro Flow Channels for Miniature Fuel Cells

2003 ◽  
Author(s):  
S. W. Cha ◽  
S. J. Lee ◽  
Y. I. Park ◽  
F. B. Prinz
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Peak Power ◽  
Gas Flow ◽  
Transport Phenomena ◽  
Cell Performance ◽  
Peak Power Density ◽  
Micro Channels ◽  
Model Predictions ◽  
The Impact

This paper presents a study on the transport phenomena related to gas flow through fuel cell micro-channels, specifically the impact of dimensional scale on the order of 100 microns and below. Especially critical is the ability to experimentally verify model predictions, and this is made efficiently possible by the use of structural photopolymer (SU-8) to directly fabricate functional fuel cell micro-channels. The design and analysis components of this investigation apply 3-D multi-physics modeling to predict cell performance under micro-channel conditions. Interestingly, the model predicts that very small channels (specifically 100 microns and below) result in a significantly higher peak power density than larger counterparts. SU-8 micro-channels with different feature sizes have been integrated into fuel cell prototypes and tested for comparison against model predictions. The results not only demonstrate that the SU-8 channels with metal current collector show quite appreciable performance, but also provide experimental verification of the merits of channel miniaturization. As predicted, the performance in terms of peak power density increases as the feature size of the channel decreases, even though the pressure drop is higher in the more narrow channels. So it has been observed both theoretically and experimentally that cell performance shows an improving trend with micro-channels, and design optimization for miniature fuel cell provides a powerful method for increasing power density.

The Influence of Mediator Concentration on the Performance of Microbial Fuel Cell

2012 ◽  
Vol 512-515 ◽  
pp. 1520-1524 ◽  
Author(s):  
Yu Zhao ◽  
Xiao Bin Wang ◽  
Peng Li ◽  
Yan Ping Sun
Keyword(s):  
Methylene Blue ◽  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Power Density ◽  
Peak Power ◽  
Electrochemical Impedance ◽  
Peak Power Output ◽  
Anode Potential ◽  
High Concentration ◽  
Peak Power Density

Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), power density and anode potential are used to characterize the mediator microbial fuel cell at different methylene blue (MB) concentrations. At lower MB concentration between 9.98×10-3 mmol/L and 1.66×10-1 mmol/L, the increased power density is enabled by using high mediator concentrations. Higher peak power density of 159.6 mw/m2 is observed compared with the peak power density of 36.0 mw/m2. But MB at too high concentration is disadvantageous to the perform of MFC. At the MB concentration of 2.50×10-1 mmol/L, the peak power output is just 128.4 mw/m2, which is lower than 159.6 mw/m2 at MB concentration of 1.66×10-1 mmol/L.

Carbon Nanotube Free-Standing Membrane of Pt/SWNTs as Catalyst Layer in Hydrogen Fuel Cells

2007 ◽  
Vol 60 (7) ◽  
pp. 528 ◽  
Author(s):  
Jason M. Tang ◽  
Kurt Jensen ◽  
Wenzhen Li ◽  
Mahesh Waje ◽  
Paul Larsen ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Fuel Cell ◽  
Power Density ◽  
Peak Power ◽  
Proton Exchange Membrane ◽  
Catalyst Layer ◽  
Proton Exchange ◽  
Free Standing ◽  
Peak Power Density ◽  
Exchange Membrane

A simple and promising fuel-cell architecture is demonstrated using a carbon nanotube free-standing membrane (CNTFSM) made from Pt supported on purified single-walled carbon nanotubes (Pt/SWNT), which act as the catalyst layer in a hydrogen proton exchange membrane fuel cell without the need for Nafion in the catalyst layer. The CNTFSM made from Pt/SWNT at a loading of 0.082 mg Pt cm–2 exhibits higher performance with a peak power density of 0.675 W cm–2 in comparison with a commercially available E-TEK electrocatalyst made of Pt supported on XC-72 carbon black, which had a peak power density of 0.395 W cm–2 at a loading of 0.084 mg Pt cm–2 also without Nafion in the catalyst layer.

scholarly journals Application of platinum-cobalt-boron as the anode material for sodium borohydride-hydrogen peroxide fuel cells

Chemija ◽  
2018 ◽  
Vol 29 (4) ◽  
Author(s):  
Aldona Balčiūnaitė ◽  
Zita Sukackienė ◽  
Loreta Tamašauskaitė-Tamašiūnaitė ◽  
Rimantas Vaitkus ◽  
Eugenijus Norkus
Keyword(s):  
Hydrogen Peroxide ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Power Density ◽  
Anode Materials ◽  
Peak Power ◽  
Anode Catalysts ◽  
Fuel Cell Performance ◽  
Peak Power Density ◽  
Density Values

The electroless deposition and galvanic displacement methods were used for the fabrication of cobalt–boron (CoB) catalysts modified with small amounts of platinum crystallites in the range of 9.8 to 14.4 μgPt cm–2. The prepared catalysts were studied as the anode materials for direct borohydride–hydrogen peroxide (NaBH4/H2O2) fuel cells at temperatures of 25–55°C. Polarization curves have been recorded with the aim to evaluate the fuel cell performance using the prepared CoB and that modified with Pt crystallites as the anode catalysts. For all catalysts (pure CoB and PtCoB) investigated, the peak power density values increase consecutively with the increment in temperature from 25°C up to 55°C. The values from 86–146 mV cm–2 and 146–234 mV cm–2 were determined for pure CoB and PtCoB catalysts, respectively. The highest specific peak power density of 21.5 kWgPt–1 was achieved at 55°C temperature when the PtCoB catalyst with the Pt loading of 9.8 μgPtcm–2 was employed as the anode catalyst in the NaBH4/H2O2 single fuel cell.

Human auditory system response to modulated electromagnetic energy

1962 ◽  
Vol 17 (4) ◽  
pp. 689-692 ◽  
Author(s):  
Allan H. Frey
Keyword(s):  
Power Density ◽  
Peak Power ◽  
Acoustic Noise ◽  
Average Power ◽  
Critical Factor ◽  
Electromagnetic Energy ◽  
Acoustic Energy ◽  
System Response ◽  
Peak Power Density ◽  
Energy Sensor

The intent of this paper is to bring a new phenomenon to the attention of physiologists. Using extremely low average power densities of electromagnetic energy, the perception of sounds was induced in normal and deaf humans. The effect was induced several hundred feet from the antenna the instant the transmitter was turned on, and is a function of carrier frequency and modulation. Attempts were made to match the sounds induced by electromagnetic energy and acoustic energy. The closest match occurred when the acoustic amplifier was driven by the rf transmitter's modulator. Peak power density is a critical factor and, with acoustic noise of approximately 80 db, a peak power density of approximately 275 mw/ cm2 is needed to induce the perception at carrier frequencies of 425 mc and 1,310 mc. The average power density can be at least as low as 400 μw/cm2. The evidence for the various possible sites of the electromagnetic energy sensor are discussed and locations peripheral to the cochlea are ruled out.

scholarly journals Plasma membrane temperature gradients and multiple cell permeabilization induced by low peak power density femtosecond lasers

2016 ◽  
Vol 5 ◽  
pp. 168-174 ◽  
Author(s):  
Allen L. Garner ◽  
V. Bogdan Neculaes ◽  
Maxim Deminsky ◽  
Dmitry V. Dylov ◽  
Chulmin Joo ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Power Density ◽  
Peak Power ◽  
Femtosecond Lasers ◽  
Temperature Gradients ◽  
Cell Permeabilization ◽  
Peak Power Density ◽  
Multiple Cell

A high-performance supportless silver nanowire catalyst for anion exchange membrane fuel cells

2015 ◽  
Vol 3 (4) ◽  
pp. 1410-1416 ◽  
Author(s):  
L. Zeng ◽  
T. S. Zhao ◽  
L. An
Keyword(s):  
Fuel Cells ◽  
Anion Exchange ◽  
Power Density ◽  
Peak Power ◽  
High Performance ◽  
Anion Exchange Membrane ◽  
Silver Nanowire ◽  
Peak Power Density ◽  
Exchange Membrane

The use of supportless Ag NWs enabled the H2/O2 AEMFC to yield a peak power density of 164 mW cm−2.

scholarly journals Ternary coded melody as blind audio watermark

2020 ◽  
Vol 12 (1) ◽  
pp. 28-33
Author(s):  
Rustam Latypov ◽  
Evgeni Stolov
Keyword(s):  
Time Domain ◽  
Amplitude Modulation ◽  
Strong Correlation ◽  
Extended Version ◽  
Conference Paper ◽  
Audio File ◽  
B Splines ◽  
A New Technique ◽  
Audio Files ◽  
The Time Domain

In this paper, we developed a new technique for blind embedding of ternary coded watermarks into audio files. Usage of ternary coding increases payload of the method that can be considered as an advantage against binary-coded watermarks. A well-known melody is presented as a sequence of ternary digits (trits) and is used as a watermark. This sequence is embedded into the time domain of a host audio file through amplitude modulation and B-splines. There is a version of that procedure where the clean copy of the container is necessary for extraction watermark [1]. In our approach, we exclude that container and convert the method into a blind one. The strong correlation between neighbor samples in the container is used to this end. A procedure based on neuron net is suggested for enhancement perception of ternary coded music. In this case, we exploit the correlation between samples in the watermark melody. It is supposed that a person checks the mark's existence, and he/she can recognize the melody even after significant distortions. The resistance of the technique to the most successful attacks is investigated. The paper is an extended version of the conference paper [1].

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