1,720,995 research outputs found
Performance evaluation of electrically driven agricultural implements powered by an external generator
Full text linkIn the last decade, many studies have been conducted on tractor and agricultural machinery electrification. In particular, the electrification of power take-off (PTO)-powered implements could support many benefits, such as improved comfort and safety during implement connection, less noisiness, accurate control of the implement rotational speed, and fuel consumption reduction. However, commercially available tractors do not generate sufficient electric power to run electrified implements. A solution to this issue is powering eventual electrified implements with an external electric generator powered by the PTO and mounted with the front three-point linkage. This study aimed to evaluate the potential benefits of using this combination with respect to PTO powered implements. The types of implements analyzed in detail in this study were a sprayer and a mulcher. Field tests were performed acquiring performance, operational, and environmental parameters. Results show that on the electrified implements, the absence of the cardan shaft and hydraulic remotes shortened the time required for the hitching phase and reduced the in-work noisiness. Field tests demonstrated that the electrified implements permitted an improvement of the fuel consumption per hectare, up to 33.3% and 29.8% lower than their PTO-powered homologue for the sprayer and the mulcher, respectively
Influence of Ploughshare Wear on Plough Efficiency
No full textRegarding agricultural machines, one of the main durability requirements are the wear resistance of the soil engaging tools. Wear of soil engaging tools should be minimized, since it impairs the tool specifications and affects tractor performances, tillage quality and machine maintenance costs. The purpose of this work was to investigate the impact of a worn ploughshare on tractor performances. Wear leads to a geometrical change of the soil engaging tools and previous studies investigated the relationship between the tool cutting edge geometry and the developed drought by means of trials and Finite Elements Modelling. However, no study has reported the influence of worn ploughshares on the power requirements of soil engaging tools. The methodology adopted in this study consists in a comparison of the tractor performances between its configuration with a plough equipped with a worn ploughshare and the configuration with the same plough with a new ploughshare. The tractor speed was measured with a GPS receiver and important tractor parameters such as engine torque and fuel consumption were acquired through a CAN logger
Preliminary Study On Traction Efficiency Of An Agricultural Tractor Equipped With An Extendable Ballast Holder
No full textTractive and soil compaction performances of an agricultural tractor fitted with rubber tracks
No full textThe objective of this study was to compare the tractive and the soil compaction performances of a conventional wheeled tractor with the fully tracked version of the same model.
The tested tractors were connected each other through a steel chain equipped with a load cell. The performances of the towing tractor were evaluated using the towed tractor as a brake, then the tractors were inverted in order to test both. The traction efficiency and the maximum draft force of the tractor were measured through the load cell and the tractor parameters acquired with a CAN logger. The soil compaction was evaluated through the analysis of soil bulk density and cone penetration test.
The results show a reduced soil compaction for the tracked tractor with respect to the wheeled version despite of the increase of the tractor mass due to the four rubber tracks weight. Furthermore, the tractor equipped with rubber tracks showed an improvement of the traction efficiency, especially on low grip surfaces
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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Radiolabelled nanoparticles for cancer diagnosis
No full textRecently, nanomedicine emerged as one of the most promising branches in biomedical field with the development of new tools for diagnostic and therapeutic purposes such as functionalized nanoparticles for the detection and prevention of cancer. Here, we systematically reviewed different types of radiolabelled nanoparticles for tumor imaging focusing on nuclear medicine applications.A systematic analysis of literature was performed using the following string: "[ALL (label* AND diagnosis AND tumor AND nanoparticle* AND radio*) AND PUBYEAR > 2006]" on PubMed and Scopus, limiting the analysis to English articles and original papers from 2007 to 2018. Seventy-one original papers were included in the analysis, second divided between radiolabelled NPs for SPECT (n = 34) and PET imaging (n = 37).Among 34 original articles that analysed radiolabelled NPs for tumor SPECT imaging, 12 were radiolabelled with indium-111, 6 with iodine (3 with iodine-125; 3 with iodine-131), 14 with Technetium-99m, 1 with lutetium-177, and 1 with rhenium-188. Among 37 original papers regarding radiolabelled NPs for tumor PET imaging, 16 were radiolabelled with copper-64, 5 with fluorine-18, 5 with gallium (4 with gallium-68, 1 with gallium-66), 4 with iodine-124, 1 with titanium 45, 6 with zirconium-89.Several NPs can be engineered to achieve suitable chemistry, physical properties, and morphology, overcoming many limitations of other conventional approaches. By modifying their size, it is possible to increase or decrease their biological half-life and maximize uptake in tumors due to the enhanced permeability and retention effect. It is also possible to bind to their surface different ligands like monoclonal antibodies or peptides to increase their specificity for tumor antigens
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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