Dimpling process in cold roll metal forming by finite element modelling and experimental validation

The dimpling process is a novel cold-roll forming process that involves dimpling of a rolled flat strip prior to the roll forming operation. This is a process undertaken to enhance the material properties and subsequent products’ structural performance while maintaining a minimum strip thickness. In order to understand the complex and interrelated nonlinear changes in contact, geometry and material properties that occur in the process, it is necessary to accurately simulate the process and validate through physical tests. In this paper, 3D non-linear finite element analysis was employed to simulate the dimpling process and mechanical testing of the subsequent dimpled sheets, in which the dimple geometry and material properties data were directly transferred from the dimpling process. Physical measurements, tensile and bending tests on dimpled sheet steel were conducted to evaluate the simulation results. Simulation of the dimpling process identified the amount of non-uniform plastic strain introduced and the manner in which this was distributed through the sheet. The plastic strain resulted in strain hardening which could correlate to the increase in the strength of the dimpled steel when compared to plain steel originating from the same coil material. A parametric study revealed that the amount of plastic strain depends upon on the process parameters such as friction and overlapping gap between the two forming rolls. The results derived from simulations of the tensile and bending tests were in good agreement with the experimental ones. The validation indicates that the finite element analysis was able to successfully simulate the dimpling process and mechanical properties of the subsequent dimpled steel products

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Representaciones y papel de la comunidad residente en la gobernanza turística de Mar del Plata

La estructura productiva de la ciudad de Mar del Plata se ha generado sobre la base del turismo de sol y playa, expandiéndose a través del tiempo, el modelo de prestaciones turísticas masivas,más importante de Argentina. Sin embargo, a partir de la década de los '90 el mismo comienza a manifestar signos de madurez y, si bien desde este momento la ciudad logra desarrollar un turismo fuera de temporada a través de iniciativas de diversificación, se observa que estas acciones no se encuentran incluidas en una política turística estratégica orientada a la reconversión. Dado el importante papel que tiene el turismo en la ciudad, el mismo se presenta como alternativa estratégica para la concreción de un proceso de desarrollo territorial sustentable, a través del compromiso ciudadano, del poder público y del sector productivo. Considerando la idea de que el involucramiento de la comunidad residente en el proceso de desarrollo turístico debe ir más allá de su concientización para ser un buen anfitrión, el objetivo de la ponencia es presentar los principales resultados de un proyecto de investigación orientado a la observación del vínculo comunidad residente-turismo local a partir de la indagación de las representaciones de este grupo específico de actores en torno al turismo y la gobernanza turística. Las representaciones son entendidas como el conjunto de informaciones, opiniones y actitudes referidas a determinados objetos de la realidad turística, que guían los comportamientos y prácticas por parte de los actores,influyendo en la toma de decisiones y la construcción de políticas en torno al turismo; en tanto que la gobernanza es concebida como un sistema de gobierno que implica interacciones entre el gobierno y la sociedad civil, tomándose el concepto de gobernanza turística para referirse al papel de estos sectores dentro del campo turístico. En cuanto al aspecto metodológico, se aplica un enfoque mixto, empleándose como instrumentos de recolección de datos, encuestas y entrevistas aplicadas durante el año 2014 a una muestra intencional y otra representativa de residentes de la ciudad de Mar del Plata, lo que permite la triangulación de datos cualitativos y cuantitativos en pos de un abordaje integrado del objeto de estudio. Los principales resultados indican que, hasta el momento, la comunidad residente de Mar del Plata posee una visión parcializada del fenómeno turístico y sus impactos. En este contexto, el sector público y el privado son percibidos como los actores centrales de la gobernanza turística local. A esta circunstancia se le suma la evidencia de un bajo nivel de involucramiento de los residentes en los aspectos que hacen al turismo y los procesos de toma de decisiones orientados al desarrollo turístico de la ciudad.The productive structure of the city of Mar del Plata has been generated on the basis of sun and beach tourism, expanding over time, the most important model of massive tourism in Argentina. However, from the 90s it began to show signs of maturity and, although the city was able to develop some off-season tourism through diversification initiatives, it is observed that these efforts are not included in an integral strategic policy oriented to re- define the model. Given the important role of tourism in Mar del Plata, it can be considered as a strategic alternative for the realization of a process of sustainable territorial development through civic engagement, public power and production. Considering the idea that the resident community involvement in the tourism development process must go beyond the being just a good host, the aim of the paper is to present the main results of a research project aimed at observing the link between the community and the local tourism. In order to do this, the representations of this specific group of actors around tourism and tourism governance are considered. The representations are understood as the set of information, opinions and attitudes concerning certain objects of the reality that guide the behaviors and practices of the actors influencing decision making and building policies on tourism. Governance is conceived as a system of government that involves interactions between government and civil society. Finally, the concept of tourism governance is referred to the role of these sectors in the field of tourism. As for the methodological aspects, a mixed approach, using as instruments for data collection, surveys and interviews was applied during 2014 to a representative sample of residents of the city of Mar del Plata, allowing a triangulation between qualitative and quantitative strategies towards an integrated approach of the study object. The main results indicate that, so far, the resident community of Mar del Plata has a partial view of tourism and its impacts. In this context, the public and private sectors are perceived as central players in the local tourism governance. Such circumstances evidence a low level of involvement of residents in the aspects related to tourism and in the decision-making processes concerning tourism development of the city.Fil: Barbini, Bernarda. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Castellucci, Daniela I. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Corbo, Yanina A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Cruz, Gonzalo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Roldán, María de los Angeles. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Cacciutto, Mariangel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina

Medios de comunicación y gobernanza turística en Mar del Plata

Se propone el desarrollo de un proyecto de investigación a través del cual observar el vínculo medios de comunicación local - turismo local, a partir de la indagación del contenido de la información relacionada con el turismo presente en medios de prensa gráfica local, a fin de determinar el papel específico que los mismos juegan en los procesos de gobernanza turística local, como así también, realizar una evaluación integral de la gobernanza turística en Mar del Plata.Fil: Cacciutto, Mariangel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Roldán, Nadia G. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Castellucci, Daniela I. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Corbo, Yanina A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Cruz, Gonzalo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Barbini, Bernarda. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina

Comunidad residente y gobernanza turística en Mar del Plata

La estructura productiva de Mar del Plata se ha concebido históricamente sobre la modalidad turística de sol y playa. Sin embargo, a partir de la década de los '90, dicho modelo ha comenzado a manifestar signos de madurez. Para que el turismo constituya una auténtica alternativa estratégica que permita un proceso de desarrollo territorial sustentable, se requiere no sólo el involucramiento del poder público y del sector productivo, sino también el compromiso ciudadano. El objetivo de este artículo es presentar los principales resultados de un proyecto de investigación orientado a la observación del vínculo comunidad residente-turismo local, a partir de la indagación de las representaciones de este grupo específico de actores en torno al turismo y la gobernanza turística.The production structure of Mar del Plata has been conceived historically on sun and beach tourism. However, from the early '90s, this model has begun to show signs of maturity. In order for tourism to constitute a genuine strategic alternative that allows a process of sustainable territorial development, it is necessary the involvement of government and the productive sector, but also the engagement of the citizenship. The aim of this paper is to present the main results of a research project aimed at observing the linkage between the local community and tourism, considering the representations of this specific group of actors around tourism and tourism governance.Fil: Barbini, Bernarda. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Castellucci, Daniela I. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Corbo, Yanina A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Cruz, Gonzalo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Roldán, Nadia G. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Cacciutto, Mariangel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina

Current LISA Spacecraft Design

The Laser Interferometer Space Antenna (LISA) mission. a space based gravitational wave detector. uses laser metrology to measure distance fluctuations between proof masses aboard three spacecraft. LISA is unique from a mission design perspective in that the three spacecraft and their associated operations form one distributed science instrument. unlike more conventional missions where an instrument is a component of an individual spacecraft. The design of the LISA spacecraft is also tightly coupled to the design and requirements of the scientific payload; for this reason it is often referred to as a "sciencecraft." Here we describe some of the unique features of the LISA spacecraft design that help create the quiet environment necessary for gravitational wave observations

Exploring mitogenome evolution in Branchiopoda (Crustacea) lineages reveals gene order rearrangements in Cladocera

The class Branchiopoda, whose origin dates back to Cambrian, includes ~ 1200 species which mainly occupy freshwater habitats. The phylogeny and systematics of the class have been debated for long time, until recent phylogenomic analyses allowed to better clarify the relationships among major clades. Based on these data, the clade Anostraca (fairy and brine shrimps) is sister to all other branchiopods, and the Notostraca (tadpole shrimps) results as sister group to Diplostraca, which includes Laevicaudata + Spinicaudata (clam shrimps) and Cladoceromorpha (water fleas + Cyclestherida). In the present analysis, thanks to an increased taxon sampling, a complex picture emerges. Most of the analyzed mitogenomes show the Pancrustacea gene order while in several other taxa they are found rearranged. These rearrangements, though, occur unevenly among taxa, most of them being found in Cladocera, and their taxonomic distribution does not agree with the phylogeny. Our data also seems to suggest the possibility of potentially homoplastic, alternative gene order within Daphniidae

Molecular systematics and phylogenetics of the spider genus Mastigusa Menge, 1854 (Araneae, Cybaeidae)

The palearctic spider genus Mastigusa Menge, 1854 is characterized by a remarkable morphology and wide ecological variability, with free-living, cave dwelling and myrmecophile populations known. This genus has a long and tangled taxonomic history and was placed in different families in the past, all belonging to the “marronoid clade”, an informal grouping of families characterized by the lack of strong synapomorphies. Three species are currently recognized, but their identity and circumscription has been long debated. A molecular approach was never applied for trying to solve these uncertainties, and doubts still remain both about its phylogenetic placement and about the taxonomic status of the described species. For the first time the genus Mastigusa is included in a molecular phylogenetic analysis and strong support is found for its placement within the family Cybaeidae, in sister relationship with the genus Cryphoeca Thorell, 1870. An analysis of Mastigusa populations spanning across the distribution range of the genus identifies a high and previously overlooked genetic diversity, with six distinct genetic lineages showing a strong geographic pattern. Divergence times between Mastigusa and its sister genus and between the distinct Mastigusa lineages are estimated, and the groundwork is laid for a taxonomic revision of the species belonging to the genus

Finite Element Analysis of Cold-Formed Dimpled Steel Columns

Dimpled steel products are produced from the combination of an innovative dimpling process and a traditional forming process such as cold-roll forming or press-braking. The wider use of cold-formed dimpled steel members has promoted considerable interest in the local instability and strength of these members. Of particular interest is their buckling behaviour and ultimate strength capacity. However, the dimpling process produces cold-formed sections with a complex ‘dimpled’ surface topography and the ‘dimpled’ material is nonuniformly work hardened through the entire thickness. Owing to these complex issues, there are no existing methods to calculate the buckling strength of the dimpled products and validate against physical measurements. This paper presents a Finite Element analysis of the compressive behaviour of cold-formed dimpled steel columns. True stress-strain data obtained from physical tests were incorporated into nonlinear simulations of dimpled steel columns. The simulation results were compared with compression test results on dimpled channel and lipped channel columns and good agreements in both buckling and ultimate strength were obtained. It is demonstrated that the Finite Element analysis can therefore be used to analyse and design cold-formed dimpled steel columns