Juan López Martínez

PIRÓLISIS DE RESIDUOS DE BIOPLÁSTICOS: PRODUCTOS OBTENIDOS DEL ÁCIDO POLILÁCTICO ( PLA)

ABSTRACT Pyrolysis of bioplastics waste may offer an alternative waste treatment option, allowing the recovery of resources. Bioplastics have taken special interest in the industry. They could be an alternative to conventional petroleum based plastics. Polylactic acid (PLA) is a bioplastic that has gained big interest during the last two decades. Pyrolysis of bioplastics waste may be economically and environmentally attractive. In order to obtain optimal energy recovery with an appropriate composition of emitted products, pyrolysis treatment has to ensure the adequate conditions. In this work, the thermal degradation of PLA was studied by pyrolysis coupled with gas chromatography and mass spectrometry detection. The test conditions allowed to identify and quantify the major compounds produced during thermal degradation of PLA.

Efficacy and safety of the pars plana clip in the Ahmed valve device in patients with refractory glaucoma

Purpose To evaluate the efficacy and safety of the pars plana clip (PPC) in the Ahmed valve tube PC7 inserted via the pars plana in patients with secondary refractory glaucoma. Methods Prospective and interventional case series that included 8 patients with secondary refractory glaucoma. The pars plana vitrectomy and the implant of the modified tube were performed during the same surgery. Control of intraocular pressure (IOP) and the development of intra- and postoperative complications were evaluated during the follow-up. Results Follow-up time was twelve months in all the patients. Control of IOP was achieved in 85% of patients, and 75% needed no antiglaucoma treatment. The complications that occurred were transient hypotony in two cases, choroidal detachment in two cases, and one case of intraocular hemorrhage and one case of hyphema. No case of tube extrusion was observed. Conclusions Our clinical experince suggests that implantation of the Ahmed tube modified with the PPC via the pars plana is safe and effective in patients with secondary refractory glaucomas.

Reconstrucción tridimensional de superficies en el cuerpo humano

A study on the alignment process of data of human morphology obtained by laser acquisition devices is presented in this paper. A three-dimensional latest generation digitizer is used and a methodology of alignment for the human morphology data is established. Also, guides on how to solve problems of this alignment are discussed and a comparative study of point clouds processing programs is carried out. RapidFormTM, the standard software used for editing data acquired by the scanner 3D is compared with PolyworksTM, the alternative to RapidFormTM software used due to its good characteristics for the alignment mechanical parts. Results of the comparison of some software applications are showed.Resumen Se presenta un estudio del proceso de alineacion de datos obtenidos de morfologias humanas mediante un dispositivo de adquisicion por laser. Se utiliza un dispositivo digitalizador tridimensional de ultima generacion y se establece una metodologia de trabajo para el proceso de alineacion de los datos obtenidos de morfologias humanas. Ademas, se indican las directrices para resolver los problemas derivados de esta alineacion y se realiza el estudio comparativo de programas de tratamiento de nubes de puntos. RapidForm™, el software estandar utilizado para la edicion de los datos adquiridos por el escaner 3D es comparado con Polyworks™, el software alternativo a RapidForm™, debido a su calidad de alineamiento de piezas mecanicas. Resultados de la comparacion de algunas aplicaciones de los programas son presentados y discutidos. Palabras clave: reconstruccion 3D, morfologias humanas, alineacion de datos, RapidForm, Polyworks Three-dimensional reconstruction of surfaces in human body

The Application of Horizontal Rotational Forming Process in Fabrication of Thermoplastic Sliding Bearings

The paper is presented an application of horizontal rotational-forming in fabrication of thermoplastic sliding bearings for machine tools. In addition, general aspects regarding the flow process of thermoplastics by used rotational-forming of revolution parts are described. The heat of plastic material at melt-temperature point is realized by High Frequency Current Induction (HFCI) on a centrifugal molding installation of bimetallic bushes. From the experiment tests has observed that between melt-temperature point of thermoplastic material, revolution speed and size molding a synchronism is required, which depends of material density and whirl form of melting. The predictable revolution speed of metallic mold has achievement by technological attempts, in function of workpiece size and type of material. The charge weight is experimental determined in dependence of part’s thickness walls. This process leads to obtain the workpieces at high quality level and constant thickness walls. The new bearings have been made from polyamide-PA.6, which changed with success the bronze bearings used at drilling machine tools.© 2010 ASME

Theoretical and Practical Estimations Regarding of Borderline Conditions Imposed for Qualitative Achievement of Sliding Bimetallic Bearings From Steel-Bronze

The paper has presented the reduced structure of horizontal centrifugal casting mechanism by high frequency current of bimetallic bushes from steel-bronze, with a chemical stability treatment of borderline alloy layer. This stabilizer borderline layer at interference of inner cylindrical surfaces from steel and external surfaces from bronze, has achieved by adding into filler metal of Cu-Sn a supplier non-ferrous metal added, with great specific weight and low melting point as Cu-Sn alloy, for example Sn with contents of 1% from Cu-Sn alloy. At high temperature and pressure, Sn is forming with Fe from steel mass of bimetallic bearing an inter-metallic compound FeSn2 , which reactions with Cu-Sn alloy due to a stable metallic connection. The experimental tests have realized at Machine Tools ‘Infratirea’ Co from Oradea, achieved bimetallic bearings of steel-bronze, with a good physical and thermal stability and well adhesion between antifriction steel with bronze.Copyright