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American Society for Testing and Materials

Transparent conductors as solar energy materials: A panoramic review

Descriptions of student-identified benefits of undergraduate research expe- riences are drawn from analysis of 76 first-round student interviews gathered at the end of summer 2000 at four participating liberal arts colleges (Grinnell, Harvey Mudd, Hope, and Wellesley). As part of the interview protocol, students commented on a checklist of possible benefits derived from the literature. They also added gains that were not on this list. Students were overwhelmingly positive: 91% of all statements referenced gains from their experiences. Few negative, ambivalent, or qualified assessments of their research ex- periences were offered. The benefits described were of seven different kinds. Expressed as percentages of all reported gains, they were personal/professional gains (28%); "thinking and working like a scientist" (28%); gains in various skills (19%); clarification/confirmation of career plans (including graduate school) (12%); enhanced career/graduate school prepa- ration (9%); shifts in attitudes to learning and working as a researcher (4%); and other benefits (1%). C

/pdf/establishing-the-benefits-of-research-experiences-for-5199176upt.pdf

Establishing the benefits of research experiences for undergraduates in the sciences: First findings from a three-year study

Review of physical vapor deposited (PVD) spectrally selective coatings for mid- and high-temperature solar thermal applications

This paper is a catalogue of all syntaxa from class to association ever described and recognized in Spain and Portugal (Iberian Peninsula, Balearic, Madeira, Azorean and Canary Islands), according with Braun-Blanquet approach (Braun-Blanquet 1964, Dierschke 1994) and the International Code of Phytosociological Nomenclature (Weber, Moravec & Theurillat 2000). The literature contents near all the publications cited in this paper, particularly those of portuguese and spanish syntaxa authors. The "Syntaxonomical Checklist of Spain and Portugal", prepared during the last ten years as a bassis of the Luso-Hispaniae Prodromus of the Plant Communities (in progress), has been reciprocally utilized to carry out the "Syntaxonomical Project of European Community Countries" (Biondi, Gehu, Grabherr, Pott & Rivas-Martinez, in progress), to assist the European Vegetation Survey (Rodwell, Mucina, Pignatti, Schaminee & Chytrý 1997), and to develop the phytosociological knowledge in the interpretation and evaluation of European Habitat Directive for conservation and management purposes

Syntaxonomical checklist of vascular plant communities of Spain and Portugal to association level

Natural potential vegetation broadly distributed throughout the Boreal and Temperate North American territories is globally studied, basically following the Braun-Blanquet phytosociological methodology. Potential coniferous forests and their respective deciduous secondary woodlands are characterized and systematized according to bioclimatic features, biogeographic distribution, as well as floristic and dynamic patterns. All the potential climactical plant communities are included in a broad, and newly-proposed phytosociological class: Linnaeo americanae-Piceetea marianae, which comprises eight orders, nineteen alliances and sixty-four associations. This monograph also includes a comprehensive compilation of bioclimatic and biogeographic syntheses: The Worldwide Bioclimatic Classification System, the Worldwide Biogeographic Approach at regional level, the Synoptic Biogeographic Approach of America at provincial level and the Synoptic Biogeographic Approach of North America North of Mexico at subsectorial level. Several thematic maps are given (including an attached and newly-proposed biogeographic map of North America), as well as some original vegetation transections (catenas), various original keys to identify the diversity of potential plant communities, a checklist of the characteristic species and plant names used and finally, the bibliographic references. This monograph on North America Boreal and Western Temperate potential natural vegetation follows that previously published (Itinera Geobot. 10: 5-148. 1997) on Mediterranean and Tropical vegetation in Western and South-Western United States North of Mexico (Heteromelo arbutifoliae-Quercetea agrifoliae, Calocedro decurrentis-Pinetea jeffreyi, Prosopido torreyanae-Fouquierietea splendentis and Artemisio tridentatae-Juniperetea osteospermae classes).

North American Boreal and Western temperate forest vegetation: (Syntaxonomical synopsis of the potential natural plant communities of North America, II)

Spectrally selective composite coatings of Cr-Cr2O3 and Mo-Al2O3 for solar energy applications

A major problem in thermal barrier coatings (TBC) applied to gas turbine components is the spallation of ceramic coating under thermal cycling processes. In order to prevent spallation and improve the thermomechanical behaviour of the TBC, graded ceramic coatings can be produced. For this purpose we are developing a new concept of Thermal Barrier Coating (TBC) that consist of a conventional NiCoCrAlY bond coat and an atmospheric plasma sprayed ZrO2–8 wt.%Y2O3 top coat graded in porosity on an Inconel 738 LC substrates. The aim of this work is to produce coatings with low thermal conductivity and better thermomechanical behaviour due to the gradient in porosity which reflects a gradient in the elastic properties. Absolute porosity was measured with a mercury porosimetry and by image analysis. The second technique was also used to estimate the porosity variation along the cross-section. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) were used to observe the morphology and coating microstructure. The microhardness was measured with a Vickers indenter and 0.981 N load. The microhardness has been evaluated for coatings in as-sprayed condition and after annealing at 1100 °C during 100 h. The results show a fast increase of the hardness after annealing. After thermal shock heating at 1000 °C, 1 h and quickly cooling in water no spallation was observed for 100 cycles.

Characterization of thermal barrier coatings with a gradient in porosity

A noncontact optical microtopographer based on an active, discrete triangulation procedure has been under development for some time at the physics department of the University of Minho. Our experi- ence has shown that this kind of triangulation-based surface inspection system can be applied, not only to long-distance range sensing, but also to smaller samples or other surfaces with height resolutions that can go down to the submicron range. In our system, the topographic information is obtained from the horizontal shift of the bright spot created by an oblique collimated light beam on a surface when it is displaced vertically. A laser beam is focused onto a small, diffraction-limited spot on the surface and is made to scan it over the desired region. The horizontal position of the bright spot is perpendicularly imaged onto a linescan cam- era and the information on the individual detectors that are activated, above a certain controllable intensity threshold level, is used to compute the corresponding horizontal spot's shift on the reference plane. Thus we can compute the distance between the surface and a reference plane at each sampled point. A map of the surface topography can then be built and statistical surface characterization parameters may be calculated. Our versatile laboratory setups have been used for different inspection tasks such as thickness measurements and relief mapping of different kinds of films (polyethylene, thin sputtered copper, tin dioxide and silver films) and several kinds of fabrics, and roughness measure and topo- graphic inspection of polyethylene molds and graphite samples. In this communication we briefly describe our method. The current configura- tion of our laboratory setup is described. A hand-held version of our system and also the setup for long-distance dimensional assessments are briefly presented. © 1996 Society of Photo-Optical Instrumentation Engineers. Subject terms: rough surfaces; microtopography; electro-optical sensors; rough- ness.

Surface inspection by an optical triangulation method

https://repositorium.sdum.uminho.pt/bitstream/1822/5262/1/SurfaceLaserGlazingofPSTBC.pdf

Manuel F. M. Costa

Papers

North American Boreal and Western temperate forest vegetation: (Syntaxonomical synopsis of the potential natural plant communities of North America, II)

Spectrally selective composite coatings of Cr-Cr2O3 and Mo-Al2O3 for solar energy applications

Characterization of thermal barrier coatings with a gradient in porosity

Surface inspection by an optical triangulation method

Surface laser-glazing of plasma-sprayed thermal barrier coatings