A Novel Design and Modelling of a Micro Underwater Vehicle With Flapping Fins

2006 ◽  
Author(s):  
Abdorasool Mayahy ◽  
Aghil Yousefi-Koma ◽  
Hesam Maleki ◽  
Donya Mohammadshahi ◽  
Sina Salek
Keyword(s):  
Dynamic Performance ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
The Other ◽  
Software Packages ◽  
Conventional Structure ◽  
Frame Work ◽  
And Performance ◽  
Almost All ◽  
Novel Design

Systems and mechanisms of motion and stability applied in underwater vehicles although various but almost all rely on a conventional structure and frame work. In this paper in pursue of development a new mechanism in term of motion and performance, mainly biomimeticly inspired from fish flapping and their movement principles particularly flatfish, a new Micro Underwater Vehicle (MUV) is designed and fabricated. In modelling phase using ADAMS we simulated the dynamic performance of the mechanism. On the other hand in order to take the flexibility of the fins into account, we used ANSYS as a meshing tool. Linking these two software packages the modelling stages were completed.

scholarly journals Dynamics modeling and performance analysis of underwater vehicles based on the Boltzmann-Hamel equations approach

2018 ◽  
Vol 148 ◽  
pp. 03005
Author(s):  
Elżbieta Jarzębowska ◽  
Michał Cichowski
Keyword(s):  
Performance Analysis ◽  
Dynamical Behavior ◽  
Variable Mass ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Systems Modeling ◽  
Dynamics Modeling ◽  
Configuration Systems ◽  
And Performance ◽  
Boltzmann Hamel Equations

The paper addresses dynamics modeling of underwater vehicles, which are typical examples of variable mass and configuration mechanical systems. Specifically, we address inertia–based propelled vehicles, whose mass changes due to change of water amount in their water tanks and their configuration changes due to movable mass enabling maneuvers. They can be additionally subjected to constraints, which are imposed due to their desired performance, tracking pre-specified motions or are control constraints implying underactuation. The paper presents a new approach to variable mass and configuration systems modeling, which is based upon Boltzmann-Hamel equations derived in quasi-coordinates. The dynamics framework based upon quasi-coordinates results in dynamic models suitable for performance analysis and model-based control applications. It serves free or constrained variable mass and configuration systems modeling. The example researched in the paper is an underwater vehicle, which is purely inertia–based propelled. The theoretical development is illustrated with simulation studies of dynamical behavior and performance of the underwater vehicle model moving a specified trajectory.

Ethnic Voting and Accountability in Africa: A Choice Experiment in Uganda

2015 ◽  
Vol 67 (2) ◽  
pp. 353-385 ◽  
Author(s):  
Elizabeth Carlson
Keyword(s):  
Choice Experiment ◽  
Strong Support ◽  
Vote Share ◽  
Vote Choice ◽  
The Other ◽  
Theoretical Justification ◽  
And Performance ◽  
Almost All ◽  
Dominant Theory ◽  
Empirical Investigations

The strong support that African presidents retain among voters of their own ethnicity, despite clear evidence of shirking and corruption, has prompted numerous empirical investigations into whether an incumbent's ethnicity or performance is more important to African voters. The model of vote choice underlying almost all of these studies is additive and implies that either coethnicity or good performance can increase a candidate's vote share. However, there is little theoretical justification for such a model. In the dominant theory of ethnic voting in Africa, coethnicity is a signal of better outcomes, indicating that ethnicity and performance are not separate considerations. Using an experiment that is designed to determine how Ugandan voters make choices, the author shows that the effects of coethnicity and good performance interact: neither attribute increases support for a candidate in the absence of the other. Though previous analyses indicate that, all else being equal, voters always prefer coethnics, this study demonstrates that coethnics only have an advantage when they are not shirkers. Additionally, though previous studies indicate that voters always prefer good performers, this analysis shows that voters are indifferent to the performance of non-coethnic candidates. The article provides evidence that this pattern is in fact a result of voters' beliefs that they will only receive future goods from coethnics, making a demonstrated ability to provide such goods relevant for the electability of coethnic candidates, but not for non-coethnics. Since a large number of African voters do not share the ethnicity of their incumbent, this finding has troubling implications for accountability of African leaders.

scholarly journals Institucionalno okruženje i FDI u uvjetima pandemije COVID-19 na primjeru Republike Hrvatske

2021 ◽  
Vol 11 (1) ◽  
pp. 51-64
Author(s):  
Vesna Buterin
Keyword(s):  
Economic Growth ◽  
Direct Investment ◽  
Institutional Development ◽  
The Other ◽  
Institutional Changes ◽  
Economic Crises ◽  
Foreign Investments ◽  
And Performance ◽  
Almost All ◽  
National Economies

The COVID-19 virus pandemic caused unprecedented changes in the behaviour of individuals and economic entities, which then led to a slowdown in economic growth in almost all countries and to a real threat of economic crises whose duration and manifestations will depend on the characteristics and performance of individual national economies. The unpredictability and consequent uncertainty of future economic parameters lead to a restraint and reduction of investments, both domestic and foreign, which in turn has the effect of further reducing growth rates. Experience has shown that countries with a higher level of institutional development managed to overcome economic crises faster and more efficiently, while in countries with poor institutions the crises lasted longer and had the characteristics of sustainability. In recent decades, Croatia has been experiencing institutional stagnation, which has reflected an economic lag behind former transition countries in a number of economic areas, including attracting quality foreign direct investment. On the other hand, due to their specificities, times of crisis are suitable for implementing institutional changes and for accelerated institutional development. The author explores the level of institutional development in Croatia and the possibilities of accelerating institutional growth in the context of future attraction of foreign investments and effects on future economic growth.

Starość w nauczaniu św. Bazylego Wielkiego

Vox Patrum ◽  
2011 ◽  
Vol 56 ◽  
pp. 339-348
Author(s):  
Bogdan Czyżewski
Keyword(s):  
Old Age ◽  
Spiritual Maturity ◽  
The Other ◽  
Interesting Aspect ◽  
Other Hand ◽  
Physical Suffering ◽  
Way Of Thinking ◽  
Almost All

Although St. Basil did not live 50 years, the topic of the old age appears in his works quite often. On the other hand, it is clear that Basil does not discuss this issue in one par­ticular work or in the longer argumentation. The fragmentary statements about old age can be found in almost all his works, but most of them can be found in the correspondence of Basil. In this paper we present the most important ad the most interesting aspect of teach­ing of Basil the Great. As these certificates show that the bishop of Caesarea looked at the old age maturely, rationally estimated passage of time, which very often makes a man different. He experienced it, for example as a spiritual and physical suffering, which often were connected with his person. He saw a lot of aspect of the old age, especially its advan­tages – spiritual maturity and wisdom. What is more, he pointed also to passage of time, which leads a man to eternity, which should be prepared to, regardless how old he is. In his opinion fear is not seen opinions of St. Basil present really Christian way of thinking, well-balanced and calm.

Performance of two combine harvester header in soybean crops

2020 ◽  
Vol 13 (2) ◽  
pp. 1
Author(s):  
E. M. Samogim ◽  
T. C. Oliveira ◽  
Z. N. Figueiredo ◽  
J. M. B. Vanini
Keyword(s):  
Experimental Design ◽  
Crop Yield ◽  
Field Performance ◽  
Travel Speed ◽  
The Other ◽  
Combine Data ◽  
Mato Grosso ◽  
Tukey Test ◽  
Combine Harvester ◽  
And Performance

The combine harvest for soybean crops market are currently available two types of combine with header or platform, one of conventional with revolving reel with metal or plastic teeth to cause the cut crop to fall into the auger header and the other called "draper" headers that use a fabric or rubber apron instead of a cross auger, there are few test about performance of this combine header for soybean in Mato Grosso State. The aim of this work was to evaluate the soybean harvesting quantitative losses and performance using two types combine header in four travel speed. The experiment was conducted during soybean crops season 2014/15, the farm Tamboril in the municipality of Pontes e Lacerda, State of Mato Grosso. The was used the experimental design of randomized blocks, evaluating four forward harvesting speeds (4 km h-1, 5 km h-1, 6 km h-1 and 7 km h-1), the natural crops losses were analyzed, loss caused by the combine harvester (combine header, internal mechanisms and total losses) and was also estimated the  field performance of each combine. Data were submitted to analysis of variance by F test and compared of the average by Tukey test at 5% probability. The results show the draper header presents a smaller amount of total loss and in most crop yield when compared with the conventional cross auger.

Growth and Performance of Agriculture Sector in India

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Naresh Singla ◽  
Mamandeep Kaur
Keyword(s):  
Growth Rate ◽  
Capital Formation ◽  
The Other ◽  
Agricultural Credit ◽  
Agricultural Growth ◽  
Indian Economy ◽  
Agriculture Sector ◽  
Food Grain ◽  
And Performance ◽  
Agricultural Labourers

The growth of agriculture and allied sectors is critical for the Indian economy as about 49 percent of the population is directly or indirectly dependent on agriculture. During the last decade and so, the agriculture sector has undergone profound changes resulting in sharp deceleration in its growth. The study has attempted to analyze growth and performance of the agriculture sector in India since 1980-81 and tries to comprehend some of the factors responsible for the deceleration in growth. The study has shown that agriculture sector has been able to show tremendous improvement in expansion of area and production of food grain and non-food grain crops. However, there are so many underlying factors responsible for slowdown of the agricultural growth. Some of the factors identified include: Increase in area under non-agriculture uses, excessive dependence on rain fed farming, increase in number of agricultural labourers, reducing size of the operation holdings, over use of agri-inputs, inequity in the distribution of agriculture credit along with sharp deceleration in public gross capital formation in agriculture etc. The study pointed in order to achieve higher growth rate, there is a need to enhance the gross capital formation in agriculture sector particularly on irrigation so that more area can be brought under assured irrigation. Bringing equity in distribution of agricultural credit coupled with judicious and need-based agricultural inputs are some of the other recommendations drawn based upon the study.

Musical training improves memory for instrumental music, but not vocal music or words

2018 ◽  
Vol 48 (1) ◽  
pp. 150-159
Author(s):  
Jonathan M. P. Wilbiks ◽  
Sean Hutchins
Keyword(s):  
Instrumental Music ◽  
Musical Training ◽  
Vocal Music ◽  
Verbal Material ◽  
The Other ◽  
Musical Experience ◽  
Facilitative Effect ◽  
Musical Excerpts ◽  
And Performance ◽  
The Brain

In previous research, there exists some debate about the effects of musical training on memory for verbal material. The current research examines this relationship, while also considering musical training effects on memory for musical excerpts. Twenty individuals with musical training were tested and their results were compared to 20 age-matched individuals with no musical experience. Musically trained individuals demonstrated a higher level of memory for classical musical excerpts, with no significant differences for popular musical excerpts or for words. These findings are in support of previous research showing that while music and words overlap in terms of their processing in the brain, there is not necessarily a facilitative effect between training in one domain and performance in the other.

Descriptions of the larvae of four species of Procladius from Great Slave Lake (Chironomidae:Diptera)

1978 ◽  
Vol 56 (9) ◽  
pp. 2055-2057 ◽  
Author(s):  
J. W. Moore ◽  
I. A. Moore
Keyword(s):  
Antennal Segment ◽  
The Other ◽  
Large Size ◽  
Great Slave Lake ◽  
Palpal Segment ◽  
Almost All

Descriptions of larvae of Procladius denticulatus, Procladius culiciformis, Procladius freemani, and Procladius bellus collected from Yellowknife Bay (lat., 62°25′; long., 114°20′) are given. Procladius denticulatus was separated from the other species by its large size, a character which always proved distinctive. Procladius culiciformis and P. freemani were separated from one another through several measurements including those of the basal antennal segment and the basal palpal segment. Almost all characters of the head were useful in distinguishing the much smaller P. bellus from the other species.

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