scholarly journals Zinc Coating Obtained in the Result of the Mechanochemical Effects in Vibrodynamic the Setups of Various Types

2019 ◽  
Vol 297 ◽  
pp. 01003
Author(s):  
Vladimir Ivanov ◽  
Sergey Popov ◽  
Nikolay Dontsov ◽  
Dieudonné Essola
Keyword(s):  
Surface Layer ◽  
Mechanochemical Synthesis ◽  
Zinc Coating ◽  
Low Frequency ◽  
Technological Systems ◽  
Coating Structure ◽  
Traditional Methods ◽  
Low Frequency Oscillations ◽  
Zinc Coatings

The results of investigations of zinc coatings obtained on the surface of metals in the process of mechanochemical synthesis realized in conditions of vibro-wave technological systems (VTS) are presented. The features of the morphology of the coating structure are revealed, which activates the role of indents in the formation of free-moving vibrations under the influence of low-frequency oscillations, and its influence on increasing the operational properties of the surface layer of the parts. The advantages of this method of applying zinc coatings in comparison with traditional methods are shown.

scholarly journals Zinc Coating Obtained in the Result of the Mechanochemical Effects in Vibrodynamic the Setups of Various Types

2019 ◽  
Vol 297 ◽  
pp. 01012
Author(s):  
Vladimir Ivanov ◽  
Sergey Popov ◽  
Nikolay Dontsov ◽  
Dieudonné Essola
Keyword(s):  
Surface Layer ◽  
Mechanochemical Synthesis ◽  
Zinc Coating ◽  
Low Frequency ◽  
Technological Systems ◽  
Coating Structure ◽  
Traditional Methods ◽  
Low Frequency Oscillations ◽  
Zinc Coatings

The results of investigations of zinc coatings obtained on the surface of metals in the process of mechanochemical synthesis realized in conditions of vibro-wave technological systems (VTS) are presented. The features of the morphology of the coating structure are revealed, which activates the role of indents in the formation of free-moving vibrations under the influence of low-frequency oscillations, and its influence on increasing the operational properties of the surface layer of the parts. The advantages of this method of applying zinc coatings in comparison with traditional methods are shown.

scholarly journals Research of micro and nano profile surface morphology of vibrational mechanical and chemical zinc coating

2018 ◽  
Vol 226 ◽  
pp. 01018 ◽  
Author(s):  
Vladimir V. Ivanov ◽  
Nikolay P. Pogorelov ◽  
Mikhail F. Selemenev ◽  
Artem A. Sakunov
Keyword(s):  
Surface Morphology ◽  
Processing Time ◽  
Coating Layer ◽  
Zinc Coating ◽  
Low Frequency ◽  
Reliable Data ◽  
Technological Systems ◽  
Low Frequency Oscillations ◽  
The Given

There are some results of zinc coating research acquired on the metals’ surface as a result of mechanical and chemical synthesis, realized in conditions of vibro wave technological systems. The peculiarities of the surface morphology at the micro / nano level of the zinc coating are shown which are formed under the influence of low-frequency oscillations. The growth interconnection of the micro / nano profile of the applied zinc coating is shown. The determination of changes occurring on the coating layer surface at the micro / nano level. The absence of reliable data of the surface layer of the coating at the nano level has significantly limited its modification background. All of the mentioned above brings up to the following task, the given article is devoted to its solution: establishment of particlesdimension, the way of their distribution on the metal surface, besidestheir maximal and minimal roughness data cause by the alteration of the processing time.

scholarly journals Mechanical coating formed under conditions of vibration exposure

2020 ◽  
Vol 175 ◽  
pp. 05023 ◽  
Author(s):  
Vladimir Ivanov ◽  
Sergey Popov ◽  
Nikolai Dontsov ◽  
Galina Ekinil ◽  
Julia Oleynikova ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Mechanochemical Synthesis ◽  
Zinc Coating ◽  
Low Frequency ◽  
Vibration Exposure ◽  
Study Results ◽  
Coating Formation ◽  
Zinc Coatings ◽  
Coating Formation Mechanism ◽  
Mechanical Coating

The study results of the zinc coating obtained on the surface of metals in the process of mechanochemical synthesis, implemented in the conditions of vibrowave systems, are presented. The features of coating formation mechanism, an activating role in its formation of free-moving, under the influence of low-frequency vibrations, indenters, are disclosed. The advantages of applying zinc coatings method in comparison with traditional methods are shown.

The Role of Low-frequency Neural Oscillations in Speech Processing: Revisiting Delta Entrainment

2019 ◽  
Vol 31 (8) ◽  
pp. 1205-1215 ◽  
Author(s):  
Victor J. Boucher ◽  
Annie C. Gilbert ◽  
Boutheina Jemel
Keyword(s):  
Speech Processing ◽  
Low Frequency ◽  
Phase Coherence ◽  
Theta Oscillations ◽  
Neural Oscillations ◽  
Acoustic Cues ◽  
Low Frequency Oscillations ◽  
Temporal Grouping ◽  
Delta Oscillations

Studies that use measures of cerebro-acoustic coherence have shown that theta oscillations (3–10 Hz) entrain to syllable-size modulations in the energy envelope of speech. This entrainment creates sensory windows in processing acoustic cues. Recent reports submit that delta oscillations (<3 Hz) can be entrained by nonsensory content units like phrases and serve to process meaning—though such views face fundamental problems. Other studies suggest that delta underlies a sensory chunking linked to the processing of sequential attributes of speech sounds. This chunking associated with the “focus of attention” is commonly manifested by the temporal grouping of items in sequence recall. Similar grouping in speech may entrain delta. We investigate this view by examining how low-frequency oscillations entrain to three types of stimuli (tones, nonsense syllables, and utterances) having similar timing, pitch, and energy contours. Entrainment was indexed by “intertrial phase coherence” in the EEGs of 18 listeners. The results show that theta oscillations at central sites entrain to syllable-size elements in speech and tones. However, delta oscillations at frontotemporal sites specifically entrain to temporal groups in both meaningful utterances and meaningless syllables, which indicates that delta may support but does not directly bear on a processing of content. The findings overall suggest that, although theta entrainment relates to a processing of acoustic attributes, delta entrainment links to a sensory chunking that relates to a processing of properties of articulated sounds. The results also show that measures of intertrial phase coherence can be better suited than cerebro-acoustic coherence in revealing delta entrainment.

scholarly journals Contribution of low-frequency climatic–oceanic oscillations to streamflow variability in small, coastal rivers of the Sierra Nevada de Santa Marta (Colombia)

2019 ◽  
Vol 23 (5) ◽  
pp. 2379-2400 ◽  
Author(s):  
Juan Camilo Restrepo ◽  
Aldemar Higgins ◽  
Jaime Escobar ◽  
Silvio Ospino ◽  
Natalia Hoyos
Keyword(s):  
Energy Spectrum ◽  
Sierra Nevada ◽  
Large Scale ◽  
Low Frequency ◽  
Maximum Power ◽  
Simultaneous Occurrence ◽  
Atmospheric Processes ◽  
Low Frequency Oscillations ◽  
Streamflow Variability

Abstract. This study evaluated the influence of low-frequency oscillations, that are linked to large-scale oceanographic–atmospheric processes, on streamflow variability in small tropical coastal mountain rivers of the Sierra Nevada de Santa Marta, Colombia. We used data from six rivers that had > 32 years of complete, continuous monthly streamflow records. This investigation employed spectral analyses to (1) explore temporal characteristics of streamflow variability, (2) estimate the net contribution to the energy spectrum of low-frequency oscillations to streamflow anomalies, and (3) analyze the linkages between streamflow anomalies and large-scale, low-frequency oceanographic–atmospheric processes. Wavelet analyses indicate that the 8–12-year component exhibited a quasi-stationary state, with a peak of maximum power between 1985 and 2005. These oscillations were nearly in phase in all rivers. Maximum power peaks occurred for the Palomino and Rancheria rivers in 1985 and 1995, respectively. The wavelet spectrum highlights a change in river variability patterns between 1995 and 2015, characterized by a shift towards the low-frequency oscillations' domain (8–12 years). The net contribution of these oscillations to the energy spectrum was as high as 51 %, a value much larger than previously thought for rivers in northwestern South America. The simultaneous occurrence of hydrologic oscillations, as well as the increase in the amplitude of the 8–12-year band, defined periods of extremely anomalous wet seasons during 1989–1990, 1998–2002 and 2010–2011, reflecting the role of low-frequency oscillations in modulating streamflow variability in these rivers. Cross-wavelet transform and wavelet coherence revealed high common powers and significant coherences in low-frequency bands (>96 months) between streamflow anomalies and Atlantic Meridional Oscillation (AMO), Pacific Decadal Oscillation (PDO) and the Tropical North Atlantic Index (TNA). These results show the role of large-scale, low-frequency oceanographic–climate processes in modulating the long-term hydrological variability of these rivers.

Very-low-frequency oscillations in heart rate and blood pressure in periodic breathing: role of the cardiovascular limb of the hypoxic chemoreflex

2000 ◽  
Vol 99 (2) ◽  
pp. 125 ◽  
Author(s):  
Darrel P. FRANCIS ◽  
L. Ceri DAVIES ◽  
Keith WILLSON ◽  
Piotr PONIKOWSKI ◽  
Andrew J.S. COATS ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Low Frequency ◽  
Periodic Breathing ◽  
Very Low Frequency ◽  
Low Frequency Oscillations

Role of cardiac output in mediating arterial blood pressure oscillations

1996 ◽  
Vol 271 (3) ◽  
pp. R641-R646 ◽  
Author(s):  
D. S. O'Leary ◽  
D. J. Woodbury
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Low Frequency ◽  
Left Ventricular ◽  
Right Atrial ◽  
Total Power ◽  
Av Block ◽  
Arterial Blood ◽  
Low Frequency Oscillations

The objective of this study was to determine the role of cardiac output in mediating spontaneous fluctuations in mean arterial pressure (MAP) conscious dogs. Dogs were chronically instrumented to monitor MAP and cardiac output. Atrioventricular (AV) block was induced, and left ventricular and right atrial electrodes were implanted. After recovery, MAP was observed for 5 min under two conditions: 1) normal variation in heart rate and cardiac output via triggering the ventricular stimulator with each atrial depolarization (effectively reversing the AV block, AV-linked stimulation) and 2) computer control of ventricular rate to maintain cardiac output constant on a by-beat basis at the same level as observed during normal variations in heart rate and cardiac output. When cardiac output was held constant, large-amplitude, low-frequency oscillations in MAP were readily apparent. Spectral analysis by fast Fourier transform revealed that during constant cardiac output the power observed at low frequencies in the MAP spectrum represented 95.0 +/- 2.7% of the total power compared with 75.5 +/- 4.6% during normal variations in heart rate and cardiac output (P < 0.05). In addition, when cardiac output was held constant, the power observed at higher frequencies markedly decreased from 24.5 +/- 4.6% of total power during AV-linked stimulation to only 5.0 +/- 2.7% of total power during constant cardiac output (P < 0.05). We conclude that low-frequency oscillations in MAP are due to changes in peripheral resistance, whereas a significant amount of high-frequency changes in MAP stems from spontaneous changes in cardiac output.

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