Role of high-frequency and low-frequency polarization of the medium in the kinetics of electron transfer and thermodynamics of solvation

1992 ◽  
Vol 96 (8) ◽  
pp. 3337-3345 ◽  
Author(s):  
A. M. Kuznetsov
Keyword(s):  
Electron Transfer ◽  
High Frequency ◽  
Low Frequency ◽  
Kinetics Of

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

scholarly journals The Influence ofNrf2on Cardiac Responses to Environmental Stressors

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Reuben Howden ◽  
Eva Gougian ◽  
Marcus Lawrence ◽  
Samantha Cividanes ◽  
Wesley Gladwell ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Low Frequency ◽  
Therapeutic Strategies ◽  
Environmental Stressors ◽  
Total Power ◽  
Airborne Pollutants ◽  
Cardiac Responses

Nrf2protects the lung from adverse responses to oxidants, including 100% oxygen (hyperoxia) and airborne pollutants like particulate matter (PM) exposure, but the role ofNrf2on heart rate (HR) and heart rate variability (HRV) responses is not known. We hypothesized that genetic disruption ofNrf2would exacerbate murine HR and HRV responses to severe hyperoxia or moderate PM exposures.Nrf2-/-andNrf2+/+mice were instrumented for continuous ECG recording to calculate HR and HRV (low frequency (LF), high frequency (HF), and total power (TP)). Mice were then either exposed to hyperoxia for up to 72 hrs or aspirated with ultrafine PM (UF-PM). Compared to respective controls, UF-PM induced significantly greater effects on HR (P<0.001) and HF HRV (P<0.001) inNrf2-/-mice compared toNrf2+/+mice.Nrf2-/-mice tolerated hyperoxia significantly less thanNrf2+/+mice (~22 hrs;P<0.001). Reductions in HR, LF, HF, and TP HRV were also significantly greater inNrf2-/-compared toNrf2+/+mice (P<0.01). Results demonstrate thatNrf2deletion increases susceptibility to change in HR and HRV responses to environmental stressors and suggest potential therapeutic strategies to prevent cardiovascular alterations.

scholarly journals Peranan Lingkungan Sosial terhadap Pembentukan Karakter Peduli Lingkungan Mahasiswa Pendidikan Geografi di Universitas Samudra Langsa

2018 ◽  
Vol 10 (2) ◽  
pp. 235
Author(s):  
Fitria Mustika ◽  
Tengku Muhammad Sahudra
Keyword(s):  
Family Environment ◽  
High Frequency ◽  
Low Frequency ◽  
Measurement Scale ◽  
Education Student ◽  
Achievement Level ◽  
Very High Frequency ◽  
Environmental Care ◽  
The Family

This study aims to determine the role of the family, community, and tertiary environment towards the formation of caring character in the geography education student environment. The output of this study was a four-indexed indexed education journal and a UNIMED google scolar. Samples from the study population were 20 respondents with 30 items about questionnaires. The time of the study starts from May 2018 to October 2018. The measurement scale in this study is the scale of the briquette. Data collection by means of library studies, interviews, questionnaires, and documentation. This research was conducted by distributing questionnaire questionnaires and interviews. Based on the results of questionnaire data processing, the family environment has a very high frequency in the formation of character of the student's environmental care with an achievement level of a total score of 91%. Furthermore, the role of the campus environment also has a high frequency in the formation of the character of the student's environmental care with a total score of 89%. Whereas the family environment has a low frequency in the formation of character of student environmental care with a total score of 57%. It can be concluded that the family environment has the most role in forming the character of the student's environmental care.

Role of fascia in maintenance of muscle tension and pressure

1981 ◽  
Vol 51 (2) ◽  
pp. 317-320 ◽  
Author(s):  
S. R. Garfin ◽  
C. M. Tipton ◽  
S. J. Mubarak ◽  
S. L. Woo ◽  
A. R. Hargens ◽  
...  
Keyword(s):  
High Frequency ◽  
Muscle Tension ◽  
Fluid Pressure ◽  
Low Frequency ◽  
Testing Procedure ◽  
Force Transducer ◽  
High Frequency Stimulation ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation

The effect of fasciotomy on muscle tension (measured by a force transducer attached to the tendon) and interstitial fluid pressure (measured by Wick catheters in the muscle belly) was studied in the anterolateral compartments of 13 dog hindlimbs. Muscle tension and pressure were monitored in the tibialis cranialis muscle after low- and high-frequency stimulation of the peroneal nerve to produce twitch- and tetanic-type contractions. Fasciotomy decreased muscle force during the low-frequency stimulation by 16% (35.3 +/- 4.9 to 28.4 +/- 3.9 N) and during the high-frequency stimulation by 10% (60.8 %/- 4.9 to 54.8 +/- 3.9 N). Muscle pressure decreased 50% after fasciotomy under both conditions, 15 +/- 2 to 6 +/- 1 mmHg and 84 +/- 17 to 41 +/- 8 mmHg), respectively. Repeated functional evaluations during the testing procedure indicated that muscle fatigue was not a major factor in these results. It was concluded that fascia is important in the development of muscle tension and changes in interstitial pressure. Furthermore, the results raised questions concerning the merits of performing a fasciotomy for athletes with a compartment syndrome.

Role of Dominance Status in Shock-Stimulated Agonistic Behavior

1971 ◽  
Vol 29 (3) ◽  
pp. 768-770 ◽  
Author(s):  
G. McA. Kimbrell ◽  
D. Chesler
Keyword(s):  
High Frequency ◽  
Agonistic Behavior ◽  
Defensive Behavior ◽  
Low Frequency ◽  
Behavior Patterns ◽  
Dominance Status ◽  
Very Low Frequency ◽  
The Relationship ◽  
Shock Situation

To clarify the relationship between dominance status and frequency of specific sub-classes of agonistic behavior in response to foot shock, 30 mice were selected on the basis of high- or low-dominance status and paired in a foot-shock situation. Dominant pairs exhibit a high frequency of defensive behavior patterns whereas submissive pairs exhibit a very low frequency of defensive patterns.

Voltammetric investigation of the kinetics of alkali metal cation reduction in N,N-dimethylformamide

1975 ◽  
Vol 28 (2) ◽  
pp. 237 ◽  
Author(s):  
JW Diggle ◽  
AJ Parker ◽  
DA Owensby
Keyword(s):  
Electron Transfer ◽  
Alkali Metal ◽  
Propylene Carbonate ◽  
Rate Constant ◽  
Alkali Metal Cation ◽  
Electrode Reaction ◽  
Amalgam Electrode ◽  
Kinetics Of ◽  
Dipolar Aprotic Solvents

The standard electron-transfer heterogeneous rate constant of lithium, potassium, sodium and caesium amalgams in N,N-dimethylformamide was ascertained employing cyclic voltammetry in an effort to relate the presence of a non-equilibrium electrode reaction at the dropping lithium amalgam electrode to the variation of the lithium amalgam electrode potential with amalgam electrode con- figuration, i.e. whether streaming, dropping or stationary. Such variations are not observed at other alkali metal amalgam electrodes. ��� In the dipolar aprotic solvents the standard electron-transfer heterogeneous rate constant for the Li(Hg) electrode increases as the solvating power for Li+ decreases, i.e. dimethyl sulphoxide < di- methylformamide < propylene carbonate. Water is a much stronger solvator of Li+ than is propylene carbonate, but the electron transfer is faster in water than in propylene carbonate; the important role of entropic contributions in ion solvation is discussed as an explanation.

scholarly journals Timbre and Affect Dimensions: Evidence from Affect and Similarity Ratings and Acoustic Correlates of Isolated Instrument Sounds

2012 ◽  
Vol 30 (1) ◽  
pp. 49-70 ◽  
Author(s):  
Tuomas Eerola ◽  
Rafael Ferrer ◽  
Vinoo Alluri
Keyword(s):  
High Frequency ◽  
Sound Production ◽  
Three Dimensional ◽  
Low Frequency ◽  
Structural Features ◽  
Two Dimensions ◽  
Acoustic Features ◽  
Behavioral Experiments ◽  
Acoustic Correlates

considerable effort has been made towards understanding how acoustic and structural features contribute to emotional expression in music, but relatively little attention has been paid to the role of timbre in this process. Our aim was to investigate the role of timbre in the perception of affect dimensions in isolated musical sounds, by way of three behavioral experiments. In Experiment 1, participants evaluated perceived affects of 110 instrument sounds that were equal in duration, pitch, and dynamics using a three-dimensional affect model (valence, energy arousal, and tension arousal) and preference and emotional intensity. In Experiment 2, an emotional dissimilarity task was applied to a subset of the instrument sounds used in Experiment 1 to better reveal the underlying affect structure. In Experiment 3, the perceived affect dimensions as well as preference and intensity of a new set of 105 instrument sounds were rated by participants. These sounds were also uniform in pitch, duration, and playback dynamics but contained systematic manipulations in the dynamics of sound production, articulation, and ratio of high-frequency to low-frequency energy. The affect dimensions for all the experiments were then explained in terms of the three kinds of acoustic features extracted: spectral (e.g., ratio of high-frequency to low-frequency energy), temporal (e.g., attack slope), and spectro-temporal (e.g., spectral flux). High agreement among the participants' ratings across the experiments suggested that even isolated instrument sounds contain cues that indicate affective expression, and these are recognized as such by the listeners. A dominant portion (50-57%) of the two dimensions of affect (valence and energy arousal) could be predicted by linear combinations of few acoustic features such as ratio of high-frequency to low-frequency energy, attack slope, and spectral regularity. Links between these features and those observed in the vocal expression of affects and other sound phenomena are discussed.

Modeling of Perforated Screens or Membrane Using Rigid Frame Porous Models Combined with Thin Membrane Resonance Sound Absorbing Theory

2013 ◽  
Vol 357-360 ◽  
pp. 1206-1211
Author(s):  
Xiao Ling Gai ◽  
Xian Hui Li ◽  
Bin Zhang ◽  
Peng Xie ◽  
Zhi Hui Ma
Keyword(s):  
High Frequency ◽  
Sound Absorption ◽  
Mass Density ◽  
Low Frequency ◽  
Frequency Region ◽  
Thin Membrane ◽  
High Frequency Region ◽  
Rigid Frame ◽  
Membrane Resonance

The sound absorption ability of screen or perforated membrane is studied based on rigid frame porous models combined with thin membrane resonance sound absorbing theory in this paper. Results show that the sound absorption of screen or perforated membrane is better considering the role of membrane than using the rigid frame porous models when the mass density of screen or perforated membrane is smaller. The rigid frame porous model is very accuracy to model the sound absorption ability of screen or perforated membrane when the mass density of membrane is greater. The parameter studies present that the sound absorption peaks move toward low frequency region with the increasing of the depth of air-back cavity, mass density and thickness of screens or perforated membrane and moves toward high frequency region with the increasing of the perforation and perforated radius of screens or perforated membrane when other parameters keep invariant.

Temperature dependence of the inverted regime electron transfer kinetics of betaine‐30 and the role of molecular modes

1992 ◽  
Vol 96 (10) ◽  
pp. 7859-7862 ◽  
Author(s):  
Eva Åkesson ◽  
Alan E. Johnson ◽  
Nancy E. Levinger ◽  
Gilbert C. Walker ◽  
Thomas P. DuBruil ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Temperature Dependence ◽  
Electron Transfer Kinetics ◽  
Kinetics Of
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