Experimental studies on fatigue and behavior to corrosion of high frequency (400 kHz) welded beams and columns

1998 ◽  
Vol 46 (1-3) ◽  
pp. 398
Author(s):  
Arnaldo Gutiérrez
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
And Behavior

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 Do Animals Play a Role in the Transmission of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2)? A Commentary

Animals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 16
Author(s):  
Anna Costagliola ◽  
Giovanna Liguori ◽  
Danila d’Angelo ◽  
Caterina Costa ◽  
Francesca Ciani ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Experimental Studies ◽  
Infectious Agent ◽  
Human Infection ◽  
Farm Animals ◽  
Partial Protection ◽  
Management Measures ◽  
First Case ◽  
And Behavior

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) belongs to the Beta-coronavirus genus. It is 96.2% homologous to bat CoV RaTG13 and 88% homologous to two bat SARS-like coronaviruses. SARS-CoV-2 is the infectious agent responsible for the coronavirus disease (COVID-19), which was first reported in the Hubei province of Wuhan, China, at the beginning of December 2019. Human transmission from COVID-19 patients or incubation carriers occurs via coughing, sneezing, speaking, discharge from the nose, or fecal contamination. Various strains of the virus have been reported around the world, with different virulence and behavior. In addition, SARS-CoV-2 shares certain epitopes with some taxonomically related viruses, with tropism for the most common synanthropic animals. By elucidating the immunological properties of the circulating SARS-CoV-2, a partial protection due to human–animal interactions could be supposed in some situations. In addition, differential epitopes could be used for the differential diagnosis of SARS-CoV-2 infection. There have been cases of transmission from people with COVID-19 to pets such as cats and dogs. In addition, wild felines were infected. All These animals were either asymptomatic or mildly symptomatic and recovered spontaneously. Experimental studies showed cats and ferrets to be more susceptible to COVID-19. COVID-19 positive dogs and felines do not transmit the infection to humans. In contrast, minks at farms were severely infected from people with COVID-19. A SARS-Cov-2 variant in the Danish farmed mink that had been previously infected by COVID-19 positive workers, spread to mink workers causing the first case of animal-to-human infection transmission that causes a moderate decreased sensitivity to neutralizing antibodies. Thus, more investigations are necessary. It remains important to understand the risk that people with COVID-19 pose to their pets, as well as wild or farm animals so effective recommendations and risk management measures against COVID-19 can be made. A One Health unit that facilitates collaboration between public health and veterinary services is recommended.

scholarly journals Mobility And Behavior Influences On Import Malaria In The Kecamatan Watulimo Kabupaten Trenggalek

2019 ◽  
Vol 11 (2) ◽  
pp. 91
Author(s):  
Asep Prastiawan
Keyword(s):  
High Frequency ◽  
Mosquito Net ◽  
Duration Of Stay ◽  
Mobility Factor ◽  
Increased Risk ◽  
Knowledge And Practice ◽  
Endemic Areas ◽  
And Behavior ◽  
The Village ◽  
Control Study

Malaria is becoming the most widely distributed disease in the world. There were 212 million cases of malaria and 429,000 of them died in the year 2015. Enviromental, behavior, knowledge and health care factors play an important role in the incidence of malaria in endemic areas. The purpose of this study was analyze the influence of mobility and behavioral factors on malaria import incidence in the Kecamatan Watulimo, Kabupaten Trenggalek. This research was an observational, used case control study design. The research samples were 42 people. Data were statistics analyzed using logistic regression test. The results of this research were influence between high frequency of mobility (p=0.023; OR=16.670), duration of stay in endemic areas for a bit (p=0.014; OR=35.940), less knowledge (p=0.022; OR=11.946), and less practice (p=0.010; OR=25.534) against malaria import incidence in the Kecamatan Watulimo, Kabupaten Trenggalek. But there was not influence attitude (p=0.470) against malaria import incidence in the Kecamatan Watulimo, Kabupaten Trenggalek. The high frequency of mobility factor ≥ 3 times and duration of stay in endemic areas for a bit 1-2 months, behavior factor less knowledge and practice can lead to increased risk of malaria import incidence in the Kecamatan Watulimo, Kabupaten Trenggalek. We recommended to increased the community knowledge and practice on malaria and its prevention with counseling. Increased JMD empowerment, revitalization of Posmaldes, provision of chemoprophylaxis malaria and insecticide mosquito net at the village level.

scholarly journals Watching television in a home environment: effect on children’s attention, comprehension and behavior

2019 ◽  
Author(s):  
Sarah E Rose ◽  
Alexandra Lamont ◽  
Nicholas Reyland
Keyword(s):  
Problem Solving ◽  
Ecological Validity ◽  
Experimental Studies ◽  
Tv Viewing ◽  
Facilitation Effect ◽  
Environment Effect ◽  
And Performance ◽  
And Behavior ◽  
Harmful Effects ◽  
Problem Solving Task

Correlational studies have suggested some harmful effects of television (TV) viewing in early childhood, especially for the viewing of fast-paced entertainment programs. However, this has not been consistently supported by experimental studies, many of which have lacked ecological validity. The current study explores the effects of pace of program on the attention, problem solving and comprehension of 41 3- and 4-year-olds using an ecologically valid experimental design. Children were visited twice at home; on each visit they were shown an episode of a popular animated entertainment program which differed in pace: one faster paced, one slower paced. Children’s behavior was coded for attention and arousal during viewing, attention, effort and performance after viewing during a problem-solving task, and comprehension of the program. The faster paced program was attended to more, but this had no impact on comprehension. Although 3-year-olds showed more attention and effort on the problem-solving task after watching the slower program, both 3- and 4-year-olds completed more problems successfully after watching the faster program. The results provide evidence to counter the ‘harm’ perceived in young children watching fast-paced entertainment programs as where differences were found it was the fast-paced program which appeared to have a cognitive facilitation effect.

Population Numbers and Reproductive Health

Endocrinology ◽  
2021 ◽  
Vol 162 (11) ◽  
Author(s):  
Alexander Suvorov
Keyword(s):  
Reproductive Behavior ◽  
Alternative Hypothesis ◽  
Experimental Studies ◽  
Causal Chain ◽  
Reproductive Physiology ◽  
Global Changes ◽  
Population Densities ◽  
Related Factors ◽  
And Behavior ◽  
Population Numbers

Abstract A recent study published in The Lancet predicts a remarkable drop in population numbers following a peak that will be reached by 2064. A unique feature of the upcoming population drop is that it will be almost exclusively caused by decreased reproduction, rather than factors that increase rates of mortality. The reasons for decreased reproduction are also unique, as, unlike previous centuries, limited reproduction today is hardly due to a shortage in resources. In other words, the predicted population drop is almost exclusively due to changes in reproductive behavior and reproductive physiology. Today, global changes in reproductive behavior are mostly explained by social sciences in a framework of demographic transition hypotheses, while changes in reproductive physiology are usually attributed to effects of endocrine-disrupting pollutants. This review outlines a complementary/alternative hypothesis, which connects reproductive trends with population densities. Numerous wildlife and experimental studies of a broad range of animal species have demonstrated that reproductive behavior and reproductive physiology are negatively controlled via endocrine and neural signaling in response to increasing population densities. The causal chain of this control system, although not fully understood, includes suppression of every level of hypothalamic-pituitary-gonadal cascade by hypothalamic-pituitary-adrenal axis, activated in response to increasing stress of social interactions. This paper discusses evidence in support of a hypothesis that current trends in reproductive physiology and behavior may be partly explained by increasing population densities. Better understanding of the causal chain involved in reproduction suppression by population density–related factors may help in developing interventions to treat infertility and other reproductive conditions.

Information-Measuring Complex for Registration High Frequency Gravitational Waves

2020 ◽  
pp. 42-51
Author(s):  
I. S. Golyak ◽  
A. N. Morozov ◽  
A. L. Nazolin ◽  
S. E. Tabalin
Keyword(s):  
Solid State ◽  
Active Region ◽  
Gravitational Waves ◽  
Spectral Range ◽  
High Frequency ◽  
Experimental Studies ◽  
Yag Laser ◽  
Information Measuring ◽  
Measuring Complex ◽  
Fabry Perot

The information-measuring complex designed to register high-frequency fluctuations of the space-time metric and its main elements are described in paper. The complex is based on a Fabry-Perot interferometer with highly reflective mirrors and a two-meter resonator. A solid-state Nd: YAG laser with a wavelength λ = 1064 nm is used for pumping. To read the signal, an InGaAs receiver DET10N2, with a working spectral range of 500-1700 nm and an active region of 0.8 mm2, is applied. Using the developed complex, experimental studies of signal registration at readout frequencies of 1 MHz and 20 MHz were carried out. The graphs of signal fluctuations in time and the spectra constructed from them are given.

scholarly journals Acoustic Signatures of the Phases and Phase Transitions in the Blume Capel Model with Random Crystal Field

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Gul Gulpinar
Keyword(s):  
High Frequency ◽  
Sound Propagation ◽  
Ultrasonic Attenuation ◽  
Experimental Studies ◽  
Power Laws ◽  
Sound Attenuation ◽  
Irreversible Processes ◽  
Acoustic Signatures ◽  
Sound Dispersion ◽  
Good Agreement

Sound propagation in the Blume Capel model with quenched diluted single-ion anisotropy is investigated. The sound dispersion relation and an expression for the ultrasonic attenuation are derived with the aid of the method of thermodynamics of irreversible processes. A frequency-dependent dispersion minimum that is shifted to lower temperatures with rising frequency is observed in the ordered region. The thermal and sound frequency (ω) dependencies of the sound attenuation and effect of the Onsager rate coefficient are studied in low- and high-frequency regimes. The results showed that ωτ≪1 and ωτ≫1 are the conditions that describe low- and high-frequency regimes, where τ is the single relaxation time diverging in the vicinity of the critical temperature. In addition, assuming a linear coupling of sound wave with the order parameter fluctuations in the system and ε as the temperature distance from the critical point, we found that the sound attenuation follows the power laws α(ω,ε)~ω2ε-1 and α(ω,ε)~ω0ε1 in the low- and high-frequency regions, while ε→0. Finally, a comparison of the findings of this study with previous theoretical and experimental studies is presented and it is shown that a good agreement is found with our results.

Gender and Political Cognition: Integrating Evolutionary Biology and Political Science

1989 ◽  
Vol 8 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Roger D. Masters
Keyword(s):  
Political Science ◽  
Evolutionary Biology ◽  
Scientific Explanation ◽  
Cultural Anthropology ◽  
Experimental Studies ◽  
Political Leaders ◽  
Cognitive Reactions ◽  
And Behavior ◽  
Attitudes And Behavior ◽  
Political Cognition

Although men and women often differ in political attitudes and behavior, there is no widely accepted scientific explanation of such phenomena. After surveying evidence concerning gender differences in the fields of social psychology, ethology, neurology, cultural anthropology, and political science, five hypotheses concerning the way males and females respond to social cues are derived from the neo-Darwinian theory of natural selection. The predicted differences in the mode of political cognition are then shown to be consistent with findings from experimental studies of emotional and cognitive reactions to televised facial displays of political leaders.

Efficient and reliable surge prevention algorithm for centrifugal compressor

2020 ◽  
Vol 92 (1) ◽  
pp. 47-59
Author(s):  
Grzegorz Liśkiewicz
Keyword(s):  
Working Conditions ◽  
High Frequency ◽  
Experimental Studies ◽  
Phase Portraits ◽  
Centrifugal Blower ◽  
Local Flow ◽  
Content Type ◽  
Operating Range ◽  
Surge Margin ◽  
External Conditions

Purpose The paper aims to present an outline of the technology of the active anti-surge algorithm based on high-frequency pressure measurement. The presented system is fast, inexpensive and reliable and does not limit the machine-operating range. Many contemporary anti-surge systems are based on theoretical surge margin. This solution limits machine operating range by about 10-15 per cent in the region of the highest pressure ratios. It is also often sensitive to change in external conditions such as temperature or density, as the system reacts to limits calculated theoretically. Design/methodology/approach This paper presents results of pressure measurements obtained on the low-speed centrifugal blower DP1.12. The pressure signals were presented in the form of phase diagrams, and conclusions were drawn from their phase portraits to develop the surge indication parameter. Findings The presented safety system uses the signal to develop the so-called (rate of derivative fluctuation) RDF parameter. In nominal working conditions, this parameter keeps the value close to 1. When RDF reaches values over 3, the anti-surge procedure should be implemented. Experimental studies have shown that this algorithm assures enough time to incur actions suppressing unstable phenomena. Originality/value The system reacts to real machine working conditions and is hence reliable. The RDF algorithm could also be used to identify local flow instabilities, as well as off-design operation.

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