1,720,984 research outputs found
Dynamical and structural analysis of a Bronze Age war chariot
No full textThe introduction of two-wheel chariots, pulled by horses, was a key technological
innovation in the Bronze Age. Archaeological evidences, found in Northern Africa, Europe and
Asia, allowed identifying various chariot typologies and understanding their main features.
However, many questions about the function of single pieces and the behavior of the vehicles
are still open. In a previous work, a war chariot wheel, found in northern Italy and known as the
“Mercurago wheel”, was studied with an engineering approach. In this paper, the whole vehicle,
to which the wheel was hypothesized to belong, was studied. In particular, two chariot
typologies, differing mainly for the axle position, were analyzed. The stiffness of the various
chariot parts were characterized by means of static finite element analyses. These data were
subsequently used as input parameters in running multibody dynamics simulations. Finite
element dynamical simulations were carried out as well. The analyses results allowed
determining the crucial effect of some parts, particularly the cockpit floor, in favoring the
passenger stability in dangerous conditions, such as bumping. The effect of the axle position on
the passenger and wheel trajectory were evaluated as well
Proof of Concept as a Multidisciplinary Design-Based Approach
No full textThis work deals with the description of the activities developed in the PoC-BS laboratory. In particular, it is proposed first to provide a multidisciplinary definition of Proof of Concept - PoC - and then to illustrate the design-methods-based approach used in the laboratory for the development of different types of PoC. In particular, the presentation of the integrated approach, for the realization of different types of PoC is provided through the description of some examples of activities carried out to support experimental research. In this work we describe: (i) the construction of a cosmic-ray telescope in collaboration with the group of Experimental Physics, (ii) the design and manufacture of devices for qualitative evaluation of the drying process of sludge generated by the inertization of waste incinerator fly-ash, carried out with the group of Chemistry for Technologies. In conclusion, the paper focuses on the future prospects of the Laboratory, whose ambition is to consolidate its activity and to lay the foundations for a new way of service delivery, based on a fair acknowledgement of contributions from this type of laboratories to both educational and scientific research
Techniques for on-board vibrational passenger comfort monitoring in public transport
Full text linkTraffic calming devices on urban streets, such as elevated pedestrian crossings, speed bumps and
roundabouts, are increasingly used, therefore bus passengers on-board comfort assessment is an actual problem.
In order to measure vibrational on-board comfort for public transport standing passengers related to traffic
calming, an acquisition system called ASGCM (Autonomous System for Geo-referenced Comfort
Measurements) has been developed, taking as a reference the European regulations on rail transports. Thanks to
ASGCM, each measurement of vibration, on-ground velocity and acceleration is linked with geographical
information resulting from a GPS, so a map of a comfort index, as well as statistical surveys and correlation
between on-board comfort and traffic calming, can be directly obtained using a Geographic Information System
(GIS), querying a centralized remote database developed ad-hoc. A large number of experimental tests has been
performed in order to define a vibrational comfort index and to collect a large statistics that allows a significant
comparison between different infrastructures and their characterization. The proposed technique can also be
useful for diagnostics purposes, such as vehicles comparison and vehicle and road maintenance state monitorin
Methodology for Online Assessment of Technical Drawing Skills of Industrial Engineering Students
No full textDue to the pandemic, there has been a shift from conducting paper-based in-person exams to conducting online exams. To still be able to evaluate students, a closed-ended test was implemented to verify the skills acquired by the exam candidates. We have developed on Moodle platform an online test called Technical Drawing Test (TDT2) based on graphic questions with closed answers both single and multiple, replacing the open-ended graphic questions of the previous in-person paper exam mode and with the same contents. This article aims to show the method by which the types of exercises were chosen according to the skills to be tested and to present the first results obtained, with the goal of verifying that the new test is equivalent to the old paper-based open-ended test in its ability to test candidates’ skills. The reliability of the TDT2 is quantified through two statistical synthetic indexes calculated by the Moodle platform and comparing the results of the online TDT2 with the results of the paper-based in-person exams
Objective Evaluation of Geometrical Product Specification/Geometrical Dimensioning and Tolerancing Basic Skills
No full textThe aim of this work is to study methods and criteria to objectively evaluate Geometrical Product Specification (GPS) and Geometrical Dimensioning and tolerances (GD&T) basic skills of engineering students. To do so, it is important to define who is the examiner, what is the topic of the exam, how to examine, when and why. In particular, for what concerns the topics, knowledge, competences, skills, concepts and abilities should be assessed. Basic knowledge is the easier topic to evaluate in an objective and reliable way, for example using closed-ended questions, but skills like creativity are difficult to measure. Following the principles of Bloom’s taxonomy, a technical drawing evaluation grid has been developed and used by the authors. The grid has eight learning levels, and target knowledge, competences, and skills have been defined for each learning level, then specific tests to verify the target for each level have been studied and developed. In this paper some examples of application of the grid are described and some preliminary results and considerations are reported. In particular, using an objective closed-ended question test, which rigorously assesses the basic levels of the grid, “residual” students decrease in number, and the students increase in number, the test is cost-effective
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
Prototyping, Testing, and Redesign of a Three-Wheel Trekking Wheelchair for Accessible Tourism Applications
Full text linkThis work is part of the project called “Gölem project”, started in 2017, about special devices developed to enable the so-called Accessible Tourism. This project aims to design and develop a trekking wheelchair for people with impaired mobility. After an initial phase of design and prototyping, the testing phase has now begun. The objective is to validate several aspects of the design, concerning basic kinematics and dynamics, passenger comfort and physical effort of the carriers. This paper describes the development of qualitative tests for drivability and balance validation of this first prototype. At this stage, a list of features to be investigated was made, suitable trekking paths were chosen, and qualitative experimental field tests were performed. Then, the design of the prototype was modified according to these first experimental results, to improve the wheelchair characteristics. The prototype is now undergoing the modification phase, then further testing will be performed with the use of specific instrumental devices to evaluate the wheelchair itself and to perform the kinematic, dynamical, and comfort characterization
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