Results 1 - 10 of 960
Results 1 - 10 of 960. Search took: 0.027 seconds
|Sort by: date | relevance|
[en] The implant Osseointegration rate depends, among other factors, on the surface´s topography and chemical composition, as in the interactions between the implant surface and cells. In this work the surface free energy for three surface treatments was calculated through contact angle measurements. For the anodic oxidized samples, a heat treatment was carried out to evaluate the influence of this process on the reduction of fluorine content. The aim of this work was study the influence of surface morphology and chemical composition on the alloy´s wettability behavior. The contact angle measurement was analyzed by the sessile drop method. The nanotubes morphology was evaluated by Field Emission Scanning Electron Microscopy (FESEM). The surface composition was analyzed by Energy Dispersive Spectroscopy (EDS). The non-photoinduced nanotubes surface free energy was higher than the polished or acid etched samples. The heat treatment lowered the F/Ti ratio in the nanotube and decreased the contact angle, increasing the interaction with the surface.
[es]La tasa de osteointegración de los implantes, entre otros factores, depende de la topografía y de la composición química de la superficie, así como de las interacciones entre la superficie del implante y las células. Con el objetivo de evaluar esta interacción, el presente trabajo evalúa la energía superficial de tres acabados superficiales a partir de la medición del ángulo de contacto. En cuanto al acabado superficial de nanotubos se ha llevado a cabo un tratamiento térmico para evaluar la influencia de este proceso en la reducción del contenido de flúor. El objetivo de este estudio es evaluar la influencia de la morfología y composición de la superficie en la mojabilidad de la aleación. La medición del ángulo de contacto se realizó empleando un goniómetro óptico. La microscopía electrónica de barrido de emisión de campo (FESEM) ha permitido realizar un estudio del diámetro y espesor de los nanotubos. El análisis de espectrometría de dispersión de energía de rayos X (EDS) se empleó para analizar la composición superficial. Como resultados, destacar que la energía superficial de los nanotubos no fotoinducidos es superior a las superficies desbastadas o grabadas con ácido. Por lo tanto, el tratamiento térmico permite reducir la ratio F/Ti en los nanotubos, reduciendo así, el ángulo de contacto e incrementando la energía superficial de los nanotubos con lo que la interacción de superficies se mejora.
[en] The corrosion product of archaeological iron objects is supposed to be removed because it causes re-corrosion. So far it is removed by scapel and sand blaster but they depend on the skill and experience of a conservator and the glass-dust of the sand blaster is harmful to humans. Therefore this study applies a laser cleaning system which is used in various industrial cleaning processes, to remove corrosion product from archaeological iron objects. In addition, this work studies the alternation of corrosion product after laser irradiation, which evaluates the reliability of the laser cleaning system. Optical microscopy, SEM-EDS, XRD, Raman have been used to observe and analyse the surface of the objects. The results show the capacity of laser cleaning some corrosion product, but blackening appears with increasing pulses and laser energy, and some corrosion products, goethite and hematite, are partially altered to magnetite. These problems, blackening and alternation of corrosion product, should be solved by further studies which find the optimal laser irradiation condition and use a wetting agent.
[en] Domain boundaries in a solid can be wetted by the layer of a new phase of the host material. The formation of such a layer is considered for the case where the defect moves under an external force, and where the order parameter of the wetting film is a conserved quantity. (author)
[en] The essential experiments are the preparation of contaminated standard samples, variation of decontamination paste composition, study of the paste effectiveness in relation to composition and of the behaviour of their components on waste treatment and solidification and estimation of waste production rates in comparison to liquid decontamination chemicals followed by the development of an application technique in thin layers for the paste. Basically the same experiments are carried out with molten salts. Optimization experiments are to be started for better cleansing effectiveness with a liquid cleanser and decontamination chemicals. (orig.)
[de]Die wichtigsten Versuche sind die Herstellung von kontaminierten Standardproben, die Variation der Zusammensetzung der Dekontaminationspaste, eine Untersuchung ueber die Wirksamkeit des Reinigers im Hinblick auf seine Zusammensetzung und ueber das Verhalten seiner Komponenten bei Abfallbehandlung und -verfestigung, eine Schaetzung des Anfalls an Abfaellen im Vergleich zu fluessigen Dekontaminationsmitteln sowie die Entwicklung eines Anwendungsverfahrens (in duennen Schichten) fuer die Paste. Nahezu die gleichen Versuche werden auch mit geschmolzenem Salz durchgefuehrt. Es werden Optimierungsversuche im Hinblick auf die Reinigungswirkung von fluessigen Reinigungsmitteln und Dekontaminationschemikalien angestrebt. (orig.)
[en] The United States Department of Energy (DOE) sponsors the largest surplus nuclear facility decommissioning program in the United States. This program includes over 300 retired nuclear facilities that have been earmarked for decontamination and decommissioning. Since the program's inception in 1978, the Defense Decontamination and Decommissioning (D and D) Program has successfully decontaminated and decommissioned 43 facilities. As a result, the implementation and completion of these projects have demonstrated a number of decommissioning tools and techniques that have subsequently become the backbone of the DOE's ongoing decommissioning program. Among the decommissioning methods employed, many decontamination, demolition, cutting, and waste management tools have been used throughout the DOE's decommissioning program, and new techniques have been developed for use with these tools. This article discusses the advantages of using various tools and techniques, including the cost effectiveness of using certain methods
[en] It was shown a possibility for improving radiation situation by means of simple treatment methods: wasting buildings and asphalted territory by jets of water and detergent SF-2U, soil removal and dust suppression. For room decontamination were used the TAJFUN washing machines and manual wiping with a damp cloth. Decontamination efficiency was estimated. 2 tabs
[en] The Argonne research center (USA) has developed a 'super-gel' compound, a polymer close to those used in baby's diapers, which can reach a 90% efficiency in the radioactive decontamination of porous materials, like bricks or concrete. The contaminated materials are sprayed with a mixture of polymer gel and wetting agent with nano-particulates in suspension. Under the action of the wetting agent, radioactivity migrates from the pores to the gel and is trapped by the nano-particulates. The drying and recycling of the gel allows to reduce the volume of radioactive wastes. Short paper. (J.S.)
[en] Efficacy of cleaning by injection of PES-51, applied to eight-year old spill oil from the Exxon Valdez that remained on armored portions of beaches in Prince William Sound, Alaska, was evaluated. The evaluation was based on comparing amounts of oil beneath treated and untreated quadrats of 10,000 sq.m. of beach area used historically for subsistence food gathering. The first samples were taken within a month after injection, the second a year later. Material was excavated to below depth of oil penetration, the oil was extracted with dichloromethane and measured gravimetrically. Mean oil reduction of 62 per cent was observed in treated quadrats two weeks after cleaning, with further reductions observed during the ensuing year. The combined reductions were significantly higher than in un-treated reference quadrats. However, newly visible oiled sites appeared as a result of winter storms following the 1997 cleanup, an indication that substantial amounts of oil was buried and inaccessible to this cleaning technique. The relatively moderate weathering characteristic of some of this oil indicates that it remains potentially toxic to fish following dispersal of storm events. With the formidable armor protection of the boulders, the suggestion is that oil will be protected in some pockets for many years as it has been during the past decade. 13 refs., 4 figs