Conception And Parametric Design Workflow For A Timber Large-Spanned Reversible Grid Shell To Shelter The Archaeological Site Of The Roman Shipwrecks In Pisa

Reciprocal structures or nexorade are composed by the assembling of groups of three or more beams mutually connected by mono-lateral T joints in a way that any relative movement is suppressed. This kind of structures can be easily built in relatively unprepared sites, dismantled, transported and re-used even by not specialized handcraft. For these reasons, reciprocal structures have been widely used in the past for military purposes, and nowadays they seem to satisfy very well the different requirements of a quick and temporary shelter of a large archaeological area when they are shaped as grid shells. This paper proposes the design of a reversible, reciprocal framed grid shell to shelter the archaeological site of the Roman Shipwrecks in Pisa. The structure must protect excavations and archaeologists from the weather and provide an easy access to visitors. Additionally, it must allow for easy disassembling and moving to another site. The design choices aim at optimizing both structural efficiency and esthetical qualities. A parametric workflow for both the form finding and the digital fabrication processes has been developed, and a prototype of accommodative steel T-joint for timber reciprocal beams has been realized. Finally, a model using CNC-cutting tested the structural feasibility of such a design approach

Connections : safe spaces for women and youth in Latin America and The Caribbean

RESUMEN: Este libro se puede leer en muchos niveles. Uno de ellos puede no ser muy obvio para aquellos que están acostumbrados a leer sobre violencia e inseguridad en América Latina. Es el nivel que le da a este libro un estatus de originalidad y una contribución que va más allá de la región: el ser una forma de conocimiento destinada no solo a interpretar el mundo, sino a cambiarlo […], visibiliza la importancia de un proceso de investigación ajustado al tipo de conocimiento que produce. Aquí se conectan el proceso y el resultado, lo que debería propiciar un debate más amplio con respecto a cómo y qué sabemos de la naturaleza de la violencia y la agencia social para reducirla […]. Esta visión es particularmente relevante en contextos donde el Estado reproduce la violencia, con terribles impactos, en especial en periferias excluidas. […] El proceso de investigación abordado en este libro transgredió muchas fronteras. Hubo fronteras entre países, barreras lingüísticas, fronteras en torno a la educación, el conocimiento y la experiencia, y entre etnias, géneros y generaciones. […] este proceso reunió a académicos, activistas y líderes comunitarios de cinco países de América Latina y uno del Caribe, incluyendo comunidades indígenas en México y Guatemala […]. La violencia está en el tiempo y en el espacio y se reproduce entre las generaciones en diversos espacios de socialización. Este proceso de investigación que trasciende las fronteras, plantea una discusión que atraviesa los diferentes casos sobre cómo los déficits y las desigualdades materiales, las violencias estatales en nombre de la ‘seguridad’, las especificidades culturales, de género y generacionales de la experiencia y la comprensión de la violencia, así como las diversas formas de criminalidad, se cruzan y se reproducen a través del tiempo y el espacio. Jenny Pearce, investigadora y profesora en el Latin American and Caribbean Centre (LACC) de la London School of Economics and Political ScienceABSTRACT: This book can be read on many levels. One level may not be so obvious to those who are used to reading about violence and insecurity in Latin America. It is the level which gives this book a claim to true originality and a contribution beyond the region. This contribution is to form of scholarship aimed not only to interpret the world but to change it […], this text visibilizes the significance of the research process to the kind of knowledge that is produced. It connects process and outcome, and this should start a wider debate about how as well as what we know about the nature of violence and the social agency to reduce it […]. This is particularly relevant in contexts where the State reproduces violence, with terrible impacts on the margins. The research process discussed in this book transgressed many boundaries. There were intercountry borders, linguistic barriers, boundaries around education, knowledge and experience and between ethnicities, genders and generations. […] the research process brought together scholars and community activists and actors from five Latin American and one Caribbean country. And within Latin America there were indigenous communities in Mexico and Guatemala who participated […]. Violence is located in time and space. It is reproduced inter-generationally through varied socialisation spaces. The boundary crossing research process, raises cross case discussion about how material deficits and inequalities, state violences in the name of ‘security’, cultural, gender and generational specificities of experience and understanding of violence, and varied forms of criminality, intersect and reproduce through time and space. Professor Jenny Pearce. Latin American and Caribbean Centre (LACC), London School of Economics and Political Scienc

An innovative sail-shaped shelter for the Ancient Ships Archaeological Site of Pisa

Reciprocal structures, or nexorade, are composed by the assembling of groups of three or more beams mutually connected by mono-lateral T joints in a way that any relative movement is suppressed. This kind of structures can be easily built in relatively unprepared sites, dismantled, transported and re-used even by not specialized hand-craft. For these reasons, reciprocal structures have been widely used in the past for military purposes, and nowadays they seem to satisfy very well the different requirements of a quick and temporary shelter of a large archaeological area when they are shaped as grid shells. The thesis proposes the design of a reversible, reciprocal framed grid shell to shelter the archaeological site of the Roman Shipwrecks in Pisa. The structure must protect excavations and archaeologists from the weather and provide an easy access to visitors. Additionally, it must allow for easy disassembling and moving to another site. The design choices aim at optimizing both structural efficiency and aesthetic qualities. A parametric workflow for both the form finding and the digital fabrication processes has been developed, and a prototype of accommodative steel T-joint for timber reciprocal beams has been realized. Finally, a model using laser cutting tested the structural feasibility of such a design approach

Bollettino CERIS n. 24 Contributi vari

- Indice #5- Innovazione e venture capital negli strumenti di politica industriale allo studio #7- Valutazione con criteri multipli ed indicatori di bilancio #13- Finanziamento bancario, rischio e tassi d'interesse #101- Struttura ed evoluzione del commercio internazionale di macchine utensili e sistemi di produzione #159- Fluttuazioni dell'attività economica e ordini di macchine utensili. Una analisi econometrica #185- Note a margine sul settore delle macchine elettrobio medicali #25

Study of the influence of PPh3 used as capping ligand or as reaction modifier for hydroformylation reaction involving Rh NPs as precatalyst

International audienceThe presence of capping ligands on the surface of metal nanoparticles (NPs) has been recognized to be a key factor for the control of their size and shape as well as for their stabilization, but their influence on the NP behavior in catalysis is far from being well-understood. Here, we investigated the performance of Rh NPs stabilized by tetraoctylammonium bromide (Rh-TOAB NPs) when applied as precatalyst for hydroformylation reaction. An ehnancement of the catalytic activity was clearly observed after adding monophosphines as a reaction modifier. More interestingly, a much higher effect was observed when a phosphine was directly used as capping ligand for the synthesis of the Rh particles, i.e. in the absence of TOAB. Indeed, triphenylphosphine-stabilized Rh NPs (Rh-PPh3 NPs) were found to be a unique precursor for hydroformylation active catalytic species, leading to higher activity attributed to the existence of a strong phosphine-rhodium interaction in this case. The Rh-PPh3 NPs appeared less affected when adding poisoning ligands in catalytic reaction than the Rh-TOAB NPs PPh3 system which deactivates in the presence of CS2. In addition, a large excess (20 equiv. per Rh atom) of PPh3 was necessary to activate the Rh-TOAB NPs, similarly to the amount typically used in homogeneous catalytic systems. In the contrary, one equiv. of PPh3 (per Rh atom) was enough to prepare Rh-PPh3 NPs, which are more active and more stable against CS2 poisoning. All together our results evidence that a direct interaction of PPh3 ligand at the surface of Rh NPs plays an important role on their behavior in hydroformylation catalysis