Search results for "Forming"
showing 10 items of 1719 documents
Experimental Investigations and Numerical Analysis for Improving Knowledge of Incremental Sheet Forming Process for Sheet Metal Parts
2009
The paper is related to the analysis of shape distortions and springback effects arising in Single Point Incremental Forming. An experimental set up has been designed and manufactured to carry single point incremental forming on small size sheet metal parts. The experimental set up is mounted on 3-axes CNC milling machine tool and the forming tool is attached and move with the spindle. Experiments have been carried out on sheet metal parts to obtain tronconical shapes. The forming strategy associated to the movement of the forming tool has been also investigated. The experiments indicate that shape distortions arising in the corners of the tronconical shape are clearly related to forming st…
The Geometry of a Domed Architecture: A Stately Example of Kārbandi at Bagh-e Dolat Abad in Yazd
2016
This paper analyses the kārbandi of the Hashti pavilion at Bagh-e-Dolat Abad in Yazd. Kārbandi is a spatial system obtained through the projection of a star-shaped drawing onto a curved surface. It is characterised by a complex use of geometry and repetitive symmetry. The analysis of its geometrical aspects contributes to an understanding of the traditional rules underlying the original design. The kārbandi of the octagonal vestibule of the Hashti pavilion consists of a complex roof system that completes the octagonal volume of the room below; its intrados presents a pattern of interlocking ribbed arches. The paper also looks at the drawings, module and proportions of the Hashti pavilion, w…
“… al estilo de Inglaterra según la última moda”. Figurines ingleses. Edición para España 1824-25 de Rudolph Ackermann
2021
Desde el último tercio del siglo XVIII, las estampas de figurines relacionadas directamente con la apariencia, el gusto y la moda, difundidas desde la prensa, tienen en España una especial significación a la hora de orientar a las élites urbanas e ilustradas. Se trataba, en definitiva, de estar al día de las novedades y adelantos que se producían en todos aquellos objetos y elementos destinados a priorizar el estatus y la elegancia conforme a los dictados que se gestaban en las grandes capitales europeas que marcaban las pautas de la distinción. Londres y lo inglés, junto a los figurines parisinos, comenzó a formar parte de los criterios estéticos de la alta sociedad española, que participó…
Extruded Expanded Polystyrene Sheets Coated by TiO2 as New Photocatalitic Materials for Foodstuffs Packaging
2012
Nanostructured, photoactive anatase TiO2 sol prepared under very mild conditions using titanium tetraisopropoxide as the precursor is used to functionalise extruded expanded polystyrene (XPS) sheets by spray-coating resulting in stable and active materials functionalised by TiO2 nanoparticles. Photocatalytic tests of these sheets performed in a batch reactor in gas-solid system under UV irradiation show their successful activity in degrading probe molecules (2-propanol, trimethylamine and ethene). Raman spectra ensure the deposition of TiO2 as crystalline anatase phase on the polymer surface. The presence of TiO2 with respect to polymer surface can be observed in SEM images coupled to EDAX …
Rheological Behavior Under Shear and Non-Isothermal Elongational Flow of Biodegradable Polymers for Foam Extrusion
2013
The production of many items, in particular for food packaging applications, is based on foam extrusion and thermoforming. These operations require the use of polymers which can grant some specific rheological properties, both under shear and elongational flow. In this work, the behavior of some biodegradable polymers [Mater-Bi® and poly(lactic acid)] under shear and non-isothermal elongational flow was investigated and compared with a traditional, non-biodegradable polymer, in order to assess their suitability for industrial-scale foam extrusion and thermoforming. The rheological characterization evidenced the differences between the different biodegradable polymers and the reference polys…
In situ forming hydrogels of new amino hyaluronic acid/benzoyl-cysteine derivatives as potential scaffolds for cartilage regeneration
2012
A new chemical strategy is described to link ethylenediamino (EDA) groups to primary hydroxyl groups of hyaluronic acid (HA) and the obtained derivatives have been characterized by 1H-NMR and 13C-NMR analyses. Such HA–EDA derivatives have been exploited to control the functionalization degree in benzoyl-cysteine (BC) groups, chosen as moieties able to allow both self-assembling in aqueous media and an oxidative crosslinking. In particular, the kinetics of oxidation of thiol groups in HA–EDA–BC derivatives has been studied in Dulbecco's Phosphate Buffer Solution (DPBS) pH 7.4 by colorimetric assays and rheological measurements. Mechanical properties of chemical hydrogels obtained after oxida…
In situ gel forming graft copolymers of a polyaspartamide and polylactic acid: Preparation and characterization
2008
Abstract In situ gel forming systems have been prepared by linking polylactic acid (PLA) to a water soluble and polyfunctional polymer, such as α,β-poly( N -2-hydroxyethyl)- d , l -aspartamide (PHEA). Three graft copolymers PHEA–PLA with a different derivatization degree in PLA, have been synthesized and characterized. PHEA–PLA graft copolymer with the highest amount in PLA has been used to prepare solutions in organic solvents able to give rise to gel-like matrices when injected into phosphate buffered saline solution. The chemical degradation of these gels has been evaluated and in vitro tests have been performed to evaluate the cell compatibility of the hydrolysis products. The possibili…
The Mössbauer effect and collective motions in glass-forming liquids and polymeric networks
1994
Glass-forming liquids, synthetic polymers and biopolymers share essential properties. Dynamic processes in these complex systems are characterized by cooperative motions with wide distributions of time scales, which manifest themselves in broad quasielastic lines in the Mossbauer spectrum. In this article, the application of the Mossbauer effect to the study of structural dynamics in complex systems is discussed.
Photovoltaic effect in bulk heterojunction system with glass forming indandione derivative DMABI-6Ph
2018
The aim of the work is to evaluate possible use of 2-[[4-(bis(2-trityloxyethyl)amino)phenyl]methylene]indane-1,3-dione (DMABI-6Ph) as light absorbing material for solar cells. DMABI-6Ph is a perspective material due to its good photoelectrical, thermal and chemical properties. The main advantage of DMABI-6Ph is its ability to form amorphous films by wet-casting methods thus allowing using the compound in organic solar cells made from solution. For now most popular materials for solution processable solar cells are polymer P3HT and fullerene derivative PCBM, but lot of investigations are in the field of new low molecular weight materials to replace the polymer. Photoelectrical measurements w…
On the electrochemical reduction of carbon dioxide and ethylene
1973
Die gemeinsame Elektrolyse von Athylen (I) und Kohlendioxid (II) liefert je nach den angewandten Bedingungen Mischungen aus Oxalsaure (III) und Bemsteinsaure (IV).