Rotating Choke in Cavitating Turbopump Inducer

2004 ◽  
Vol 126 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Yury A. Semenov ◽  
Akira Fujii ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Rotational Speed ◽  
Development Stage ◽  
Liquid Hydrogen ◽  
Cavity Model ◽  
Cavitation Instability ◽  
New Type ◽  
Main Engine ◽  
The Relationship

During the development stage of the liquid hydrogen turbopump for the main engine LE-7A of the H-IIA rocket, a new type of cavitation instability was observed. This instability occurs at lower cavitation numbers where the head of the inducer starts to decrease due to choke. The disturbance rotates around the rotor at about 50% of the inducer rotational speed. So, it is called “rotating choke.” In order to predict the instability, a cavity model with a cavity wake is developed. The region of instability and the frequency predicted by the model are in agreement with experiment. Discussions are made as to the relationship between rotating choke and rotating cavitation.

Tourism awareness as a tourism development strategy: status of the issue

2020 ◽  
Vol 13 (9) ◽  
Author(s):  
M.I. Rosas-Jaco ◽  
S.X. Almeraya-Quintero ◽  
L.G. Guajardo-Hernández
Keyword(s):  
Development Strategy ◽  
Design Methodology ◽  
Local Development ◽  
Local Population ◽  
Host Community ◽  
Government Policies ◽  
Training Manual ◽  
Environmental Development ◽  
Main Engine ◽  
The Relationship

Objective: Tourism has become the main engine of economic, social and environmental development in several countries, so promoting tourism awareness among tourists and the local population should be a priority. The present study aims to suggest a status of the research carried out on the topic of tourism awareness. Design / methodology / approach: The type of analysis is through a retrospective and exploratory bibliometric study. The analysis materials were scientific articles and a training manual published between 2000 and 2020, registered by Scopus, Emerald insight and Dialnet, using “tourism awareness” as the keyword. Results: When considering the three senses in which tourism awareness ought to operate, it is concluded that studies are more focused on the relationship and contact of the host community with the tourist. It is observed that four out of six articles in this sense consider that education, training, and government policies around tourism awareness should be developed in a better way in the destinations, in order to be an element that contributes to the development of communities and reduces poverty in developing countries. Study limitations / implications: It is considered a limitation not to include thesis dissertations. Findings / conclusions: It is necessary to make visible the importance of tourism awareness as a local development strategy for communities, in addition to including tourism awareness on the part of tourists.

scholarly journals Sodium Metasilicate Cemented Analogue Material and Its Mechanical Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Songlin Yue ◽  
Yanyu Qiu ◽  
Pengxian Fan ◽  
Pin Zhang ◽  
Ning Zhang
Keyword(s):  
Complex Geometry ◽  
Sodium Metasilicate ◽  
Raw Material ◽  
Fine Aggregate ◽  
Regression Equations ◽  
Deformation And Failure ◽  
Orthogonal Experiments ◽  
Low Modulus ◽  
New Type ◽  
The Relationship

Analogue material with appropriate properties is of great importance to the reliability of geomechanical model test, which is one of the mostly used approaches in field of geotechnical research. In this paper, a new type of analogue material is developed, which is composed of coarse aggregate (quartz sand and/or barite sand), fine aggregate (barite powder), and cementitious material (anhydrous sodium silicate). The components of each raw material are the key influencing factors, which significantly affect the physical and mechanical parameters of analogue materials. In order to establish the relationship between parameters and factors, the material properties including density, Young’s modulus, uniaxial compressive strength, and tensile strength were investigated by a series of orthogonal experiments with hundreds of samples. By orthogonal regression analysis, the regression equations of each parameter were obtained based on experimental data, which can predict the properties of the developed analogue materials according to proportions. The experiments and applications indicate that sodium metasilicate cemented analogue material is a type of low-strength and low-modulus material with designable density, which is insensitive to humidity and temperature and satisfies mechanical scaling criteria for weak rock or soft geological materials. Moreover, the developed material can be easily cast into structures with complex geometry shapes and simulate the deformation and failure processes of prototype rocks.

CAD AND CAE TECHNOLOGIES OF A NOVEL PLANE SIX-BAR SWAYING MACHINE

2008 ◽  
Vol 07 (01) ◽  
pp. 65-67
Author(s):  
CHANGPING ZOU ◽  
LI DU ◽  
XIANDE HUANG
Keyword(s):  
High Pressure ◽  
Kinetic Analysis ◽  
Rotational Speed ◽  
Preliminary Analysis ◽  
Unit Weight ◽  
The Novel ◽  
Parameterized Modeling ◽  
New Type ◽  
Working Principle ◽  
Key Dimensions

A new type of six-bar swaying machine was put forward, which is an ingenious combination of plane multi-bar mechanism and high pressure oil cylinder. Preliminary analysis shows that this machine has many advantages, such as the torque produced by its unit weight, its small size, its light deadweight, etc. Thus it can be applied to situations that need swaying mechanism with low rotational speed and great torque. Firstly, the mechanism composition and working principle of the swaying machine were introduced. Secondly, parameterized modeling of the mechanism was carried out by utilizing software ADAMS. Then kinematic analysis and kinetic analysis were completed by using ADAMS. Finally, key dimensions were adjusted according to kinetic analysis. These tasks are believed to be beneficial to the development of the novel transmission.

Thermodynamic Performance of an Actual Thermo-Acoustic Refrigeration Micro-Cycle

2012 ◽  
Vol 614-615 ◽  
pp. 64-68
Author(s):  
Tuo Wang ◽  
Feng Wu ◽  
Jin Hua Fei ◽  
Ming Fang Liu
Keyword(s):  
Coefficient Of Performance ◽  
Pressure Amplitude ◽  
Cooling Load ◽  
Acoustic Effect ◽  
Thermodynamic Performance ◽  
Monotonically Increasing Function ◽  
Analytic Expressions ◽  
New Type ◽  
The Relationship ◽  
Increasing Function

Thermo-acoustic refrigerator is a new type of engine, which is based on the thermo-acoustic effect. A new model which expresses as an ellipse in pressure-volume diagram is established to investigate the thermodynamic performance of an actual thermo-acoustic refrigeration micro-cycle. The demarcation points of endothermic processes and exothermic processes in the actual micro-cycle are found. The analytic expressions of the dimensionless cooling load and the coefficient of performance (COP) are deduced. The relationship between the dimensionless cooling load and the COP are investigated by numerical examples. The results show that the dimensionless cooling load is a monotonically increasing function of the COP and the pressure amplitude.

scholarly journals Motives of volunteering and values of work among higher education students

2017 ◽  
Vol 16 (2) ◽  
pp. 117-131 ◽  
Author(s):  
Veronika Bocsi ◽  
Hajnalka Fényes ◽  
Valéria Markos
Keyword(s):  
Higher Education ◽  
Eastern Europe ◽  
Work Values ◽  
Border Region ◽  
Voluntary Work ◽  
Central Eastern Europe ◽  
New Type ◽  
Central Eastern ◽  
Definition Of ◽  
The Relationship

In this article, the motives for voluntary work and work values in higher education contexts are examined in a cross-border region in Central Eastern Europe. Our goal is to find out what kind of relationship exists between different types of volunteering and work values among young people. In the theoretical section, we deal with the definition of volunteering in the education system, the types of and motives for students’ volunteering, and finally, the relationship between the work values and voluntary work of students. In the empirical section, we created cluster groups based on students’ motives for volunteering, and we examined differences among countries. Then we revealed the factor structure of the work values of students and analyzed the relationship between cluster groups and factors with variance analysis. Five cluster groups were identified: “careerists with postmodern features,” “unmotivated,” “highly motivated,” “volunteers in an anti-volunteering climate,” and a “helping new type volunteers” group. There were only slight differences among countries, as most respondents are characterized by mixed motivations. An interesting result is that the most frequent group is “the volunteers in an anti-volunteering climate” in all the countries examined, especially in Ukraine, so the culture of volunteering is not popular enough in this region of Central Eastern Europe. Regarding the relationship between work values and volunteering, we have found that these two fields (work values and volunteering) are closely related.

The Markowitz Wobble

2000 ◽  
Vol 178 ◽  
pp. 351-354 ◽  
Author(s):  
A. Poma
Keyword(s):  
Rotational Speed ◽  
Local Effects ◽  
The Relationship ◽  
Long Term Variations

AbstractSeveral decades ago Markowitz was the first to report the existence of fluctuations in the motion of the Earth’s axis with a period of about twenty-four years. This empirical term was often considered not real but only an artifact due to local effects. In this paper long-term variations and the relationship between the 30-yr Markowitz wobble and changes in the Earth’s rotational speed are briefly discussed.

scholarly journals Groźba popełnienia przestępstwa o charakterze terrorystycznym w ujęciu art. 115 § 20 k.k. – wybrane problemy wykładni

2019 ◽  
Vol 28 (3) ◽  
pp. 41
Author(s):  
Aneta Michalska-Warias
Keyword(s):  
Criminal Law ◽  
Criminal Code ◽  
Eu Law ◽  
Terrorist Threat ◽  
Special Part ◽  
New Type ◽  
The Relationship

<p>The paper discusses the concept of a terrorist threat in the light of Article 115 § 20 of the Polish Criminal Code. The author stresses the relationship between this term and the punishable threat described in the special part of the Criminal Code. The conducted analysis leads to the conclusion that the terrorist threat must be treated as a special type of the punishable threat and, as a result, many real terrorist threats may not meet the criteria of a forbidden act, e.g. because of the lack of an individualised victim. As a result, there appear serious doubts as to whether Polish criminal law meets the requirements of EU law referring to the criminalisation of terrorist threats and, therefore, the introduction of a new type of offence of a terrorist threat and some changes in Article 115 § 20 and Article 115 § 12 of the Criminal Code have been proposed.</p>

scholarly journals On t-Neighbourhoods in Trigonometric Topological Spaces

2021 ◽  
Vol 12 (1S) ◽  
pp. 655-658
Author(s):  
S. Malathi, Et. al.
Keyword(s):  
Necessary Condition ◽  
Topological Spaces ◽  
Basic Properties ◽  
New Type ◽  
The Relationship

In this paper we introduce a new type of neighbourhoods, namely, t-neighbourhoods in trigonometric topological spaces and study their basic properties. Also, we discuss the relationship between neighbourhoods and t-neighbourhoods. Further, we give the necessary condition for t-neighbourhoods in trigonometric topological spaces.  .

scholarly journals Language in social reproduction: Sociolinguistics and sociosemiotics

2009 ◽  
Vol 37 (1/2) ◽  
pp. 43-81
Author(s):  
Patrizia Calefato
Keyword(s):  
Social Reproduction ◽  
Social Dimension ◽  
The Social ◽  
The Sixties ◽  
Roman Jakobson ◽  
New Type ◽  
General Linguistics ◽  
Definition Of ◽  
The Relationship

This paper focuses on the semiotic foundations of sociolinguistics. Starting from the definition of “sociolinguistics” given by the philosopher Adam Schaff, the paper examines in particular the notion of “critical sociolinguistics” as theorized by the Italian semiotician Ferruccio Rossi-Landi. The basis of the social dimension of language are to be found in what Rossi-Landi calls “social reproduction” which regards both verbal and non-verbal signs. Saussure’s notion of langue can be considered in this way, with reference not only to his Course of General Linguistics, but also to his Harvard Manuscripts.The paper goes on trying also to understand Roland Barthes’s provocative definition of semiology as a part of linguistics (and not vice-versa) as well as developing the notion of communication-production in this perspective. Some articles of Roman Jakobson of the sixties allow us to reflect in a manner which we now call “socio-semiotic” on the processes of transformation of the “organic” signs into signs of a new type, which articulate the relationship between organic and instrumental. In this sense, socio-linguistics is intended as being sociosemiotics, without prejudice to the fact that the reference area must be human, since semiotics also has the prerogative of referring to the world of non-human vital signs.Socio-linguistics as socio-semiotics assumes the role of a “frontier” science, in the dual sense that it is not only on the border between science of language and the anthropological and social sciences, but also that it can be constructed in a movement of continual “crossing frontiers” and of “contamination” between languages and disciplinary environments.

scholarly journals Waste Management in Bronze Age Europe

2017 ◽  
Vol 10 (1) ◽  
pp. 35-43
Author(s):  
Filip Havlíček ◽  
Martin Kuča
Keyword(s):  
Waste Management ◽  
Bronze Age ◽  
Management Strategies ◽  
Waste Material ◽  
Social Activities ◽  
Stone Age ◽  
New Type ◽  
The Relationship ◽  
The Bronze Age

AbstractThis article deals with the relationship between humans and waste in the Bronze Age. Based on selected examples of waste management strategies from the European Bronze Age, it presents an overview of different strategies. In comparison with the preceding Stone Age, a new type of material began to appear: metal. The process involved in producing metal objects, however, brought with it the appearance of a specific type of waste material that is indelibly linked to the production of metal. This article also deals with the significance of ritualized social activities in the Bronze Age, which materialized in waste and waste management strategies.

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