scholarly journals Failure of the tail rotor of the Mi-24 helicopter as a result of a long-term impact of spatial resonance coupling

2021 ◽  
Vol 51 (4) ◽  
pp. 11-24
Author(s):  
Henryk Kowalczyk ◽  
Andrzej Gębura ◽  
Tomasz Tokarski ◽  
Tadeusz Kwiatkowski
Keyword(s):  
Power Plant ◽  
Specific Mechanism ◽  
Transmission Shaft ◽  
Resonance Coupling ◽  
Long Term Impact ◽  
Spatial Resonance

Abstract The most important element that has an impact on the safety of flight includes the helicopter power plant and the transmission shaft assembly. Monitoring with the use of the traditional vibroacoustic techniques does not provide satisfactory results. It is especially difficult to detect spatial resonance couplings, which may result in dangerous and rapid breaking of elements. This article focuses on a specific mechanism for formation and deepening of resonance and effects of resonance couplings of two subassemblies. For their monitoring, the FAM-C method was applied. It uses an on-board generator as a sensor. This is a synchronous method, which enables one to detect the onset of spatial resonance.

Impact Assessment Using the Before-After-Control-Impact (BACI) Model: Concerns and Comments

1993 ◽  
Vol 50 (3) ◽  
pp. 627-637 ◽  
Author(s):  
Eric P. Smith ◽  
David R. Orvos ◽  
John Cairns Jr.
Keyword(s):  
Power Plant ◽  
Statistical Model ◽  
Impact Assessment ◽  
Control Site ◽  
Irregular Sampling ◽  
Relevant Parameter ◽  
Biologically Relevant ◽  
Before And After ◽  
Long Term Impact

The effect of a change in an ecosystem can often be assessed through the use of a statistical model that incorporates the change. A sensible approach for assessing the effects of an industrial or power plant on the aquatic environment is to sample the environment both before and after the plant starts operation and test for a change in some biologically relevant parameter. To improve sensitivity, samples may be taken at a control site as well as at sites receiving the plant effluent. While this provides a powerful means for assessing effects, the implementation of the design is important and subsequent analysis of the collected data depends on proper implementation. Problems such as trends in the measurements, failure to meet the assumptions of the model, irregular sampling, confounding factors, and changes in the habitat can influence results, as we illustrate using a long-term impact assessment of a power plant on fish populations. In long-term studies, it may be difficult to separate effects due to the plant from effects due to other sources. Sound design requires both a good statistical model and an understanding of the underlying biological processes (what to measure) and careful planning (how to measure it well).

Crisis Phones - Suicide Prevention Versus Suggestion/Contagion Effects

Crisis ◽  
2015 ◽  
Vol 36 (3) ◽  
pp. 220-224 ◽  
Author(s):  
Steven Stack
Keyword(s):  
Suicide Prevention ◽  
Contagion Effects ◽  
Long Term Impact

Abstract. Background: There has been no systematic work on the short- or long-term impact of the installation of crisis phones on suicides from bridges. The present study addresses this issue. Method: Data refer to 219 suicides from 1954 through 2013 on the Skyway Bridge in St. Petersburg, Florida. Six crisis phones with signs were installed in July 1999. Results: In the first decade after installation, the phones were used by 27 suicidal persons and credited with preventing 26 or 2.6 suicides a year. However, the net suicide count increased from 48 in the 13 years before installation of phones to 106 the following 13 years or by 4.5 additional suicides/year (t =3.512, p < .001). Conclusion: Although the phones prevented some suicides, there was a net increase after installation. The findings are interpreted with reference to suggestion/contagion effects including the emergence of a controversial bridge suicide blog.

Long-Term Impact of Participation in the Adolescent Diversion Project

2009 ◽  
Author(s):  
Jenna L. Claes ◽  
Sean S. Hankins ◽  
J. K. Ford
Keyword(s):  
Long Term Impact

966-P: The Long-Term Impact of a Flash Glucose Monitoring System on Glycemic Control

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 966-P
Author(s):  
ATSUSHI FUJIYA ◽  
TOSHIKI KIYOSE ◽  
TAIGA SHIBATA ◽  
HIROSHI SOBAJIMA
Keyword(s):  
Glycemic Control ◽  
Monitoring System ◽  
Glucose Monitoring ◽  
Flash Glucose Monitoring ◽  
Long Term Impact ◽  
Flash Glucose Monitoring System

Dual lumen intervention for aortic dissection: long-term impact on aortic remodeling

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Xun Yuan ◽  
Andreas Mitsis ◽  
Thomas Semple ◽  
Michael Rubens ◽  
Christoph A. Nienaber
Keyword(s):  
Aortic Dissection ◽  
Long Term Impact ◽  
Aortic Remodeling

Research on the Economic Vitality of the Northeast China

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Jiayue Jiao
Keyword(s):  
Northeast China ◽  
Practical Significance ◽  
Economic Policies ◽  
Regional Competitiveness ◽  
Regional Economic ◽  
Important Indicator ◽  
Depth Study ◽  
Long Term Impact ◽  
Economic Vitality

 Economic vitality is an important indicator of regional competitiveness. The demand for talents and the vitality of enterprises in different regions are obvious to all and have practical significance. Therefore, it is necessary to establish a survey data model and conduct in-depth study on improving regional economic vitality from the perspective of policy.Based on a variety of forecasting methods, this paper analyzes the short-term and long-term impact of economic policies in Northeast China, and finally puts forward the factors that affect the economic vitality of northeast policies. Finally, the paper puts forward the feasibility and targeted suggestions of strengthening regional economic vitality, obtaining long-term development and building a more competitive city in the new era. 

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