1,721,017 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Static and dynamic characteristics of direct operated pressure relief valve, part 2
No full textThis paper is
dealing with static and dynamic performances of direct operated pressure relief valves. The subject of
research was Rexroth pressure relief valve type DBD6 A6G 200. A mathematical model of the valve was
obtained and an algorithm was developed in MATLAB. Experimental test stand was built for experimental
verification of the theoretical mathematical model. Theoretically end experimentally obtained static and
dynamic characteristics of the valve are presented in few diagrams
Some geometric parameters impact to the static characteristics of a pilot operated pressure relief valves
Full text linkSome geometric parameters impact to the static characteristics of pilot operated pressure
relief valves were investigated in this paper. It has been shown that with introducing a compensating control
piston in the pilot line of the conventional design of pressure relief valve improves the static characteristic at
the beginning of the opening of the valve i.e. decrease the pressure difference between opening of the pilot
valve and the main valve. Also, better static characteristic is achieved if the area of the main valve seat is
equal with the main valve poppet area, i.e. when the factor is decreasing
Static characteristics of pilot operated pressure relief valves with compensating control piston
Full text linkIn this paper a mathematical model of the static characteristics for a pilot operated
pressure relief valve with compensating piston has been developed. The static characteristic has
been presented in few diagrams. The influence of the compensating piston to the static
characteristic has been emphasized as a manner for reducing the difference between pressure of
opening of the pilot valve and the main valve
Numerical and experimental determination of the static characteristics of pilot operated pressure relief valves
No full textIn this article a mathematical model of pressure drop vs. flow depending for pilot operated
pressure relief valve type 1502-PPT is developed. An experimental test stand is created for practical
determination of the pressure drop vs. flow depending which confirm the mathematical model. The results of
solving the mathematical model and experimental investigation are presented in two diagrams. A few directions
for improving the static characteristics at the moment of opening of the main valve are given
Transient response of a pilot operated pressure relief valve with compensating control piston
No full textA subject of investigation was pilot operated pressure relief valve with compensating control
piston. Non linear mathematical model of the valve was developed. Theoretically and experimentally the
transient response of the valve has been investigated. Using advance measurement equipment
experimentally has been shown the opening of the main valve before the pilot valve, i.e. opposite of the
static characteristic
Synthesis of dynamic characteristics of a pilot operated pressure relief valve with compensating control piston
Full text linkIn this paper analyzes of the linear mathematical model of the pilot operated
pressure relief valve with compensating control piston through the matrix method in the state space
has been done. The transfer function of the system contained of the valve, inlet volume of oil and
outlet pipeline has been numerically obtained. Synthesis of the key parameters of the valve to the
dynamic characteristics has been done
Investigation of static characteristics of pilot operated pressure relief valves
No full textTheoretical and experimental investigation of the static characteristics of the pilot operated pressure relief valve is presented in this article. A mathematical model of pressure drop vs. flow depending for pilot operated pressure relief valve is developed. An experimental test stand was created for experimental determination of the static characteristics and compared with each other which confirm the mathematical model. The results of solving the mathematical model and experimental investigation are presented in few diagrams. A few directions for improving the static characteristics are given, especially at the moment of opening of the main valve. Advantages and disadvantages of the static characteristics are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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