525 research outputs found

    Preliminary design of the wavefront sensor for CCAT

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    CCAT1 is a submillimeter telescope currently under development that will be located at an altitude of 5600 meters in the Andes mountains of northern Chile. The atmospheric transmission at this site will allow CCAT to achieve high sensitivity over a wide field of view and a broad wavelength range to provide an unprecedented capability for deep, large area multicolor submillimeter surveys. In order to achieve high aperture efficiencies out to frequencies of ~ 1 THz, the 162 individual panels that form the 25 meter aperture of CCAT must be aligned to a tolerance of a few microns rms. The design of a wavefront sensor to achieve this goal is presented

    Completely splittable representations of affine Hecke-Clifford algebras

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    We classify and construct irreducible completely splittable representations of affine and finite Hecke-Clifford algebras over an algebraically closed field of characteristic not equal to 2.Comment: 39 pages, v2, added a new reference with comments in section 4.4, added two examples (Example 5.4 and Example 5.11) in section 5, mild corrections of some typos, to appear in J. Algebraic Combinatoric

    Recent progress on indoor organic photovoltaics : from molecular design to production scale

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    Recently, indoor photovoltaics have attracted much interest for their ability to power small electronic devices and sensors, especially with the growth of the Internet of Things (IoT). Due to their absorption covering ambient emission spectra and tunable electronic structures, π-conjugated polymers and small molecules are well-suited for these applications. Among many benefits, including their ink processability, lightweight and flexibility; indoor organic photovoltaics (IOPVs) show power conversion efficiencies (PCE) over 26%. It represents a power output over 30 μW cm-2 under office light (500 lux), which is sufficient to operate many electronic devices and sensors with a relatively small photovoltaic area. This focus review highlights the major advances in the material design for IOPVs and includes some industrial insights to reach the production scale criteri

    La caractérisation chimique de cherts du Bas-Saint-Laurent et de la Gaspésie : vers le développement d’une méthode d’analyse non destructrice

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    En raison de la grande résolution des photographies des échantillons, celles-ci se trouvent dans un fichier complémentaire, puisque les conditions de forme imposées ne permettaient pas l'affichage intégral de ces images au sein du mémoire.Ce projet a comme objectif général de participer au développement et de tester le potentiel de la méthode d’analyse par fluorescence aux rayons X du laboratoire de caractérisation non destructrice de l’Université de Montréal, en procédant à la caractérisation chimique de cherts provenant de deux carrières distinctes, exploitées à diverses périodes au cours de la préhistoire, soit celle de La Martre (DhDm-8, Gaspésie) et celle du site CkEe-28 (Témiscouata). En fonction des comportements de chacun des éléments, six d’entre eux furent sélectionnés pour effectuer la caractérisation, parmi lesquels on compte trois éléments majeurs (Si, Al, Fe) et trois éléments traces (Ba, La, Ce). D’un point de vue méthodologique, les résultats confirment que l’appareillage du laboratoire est apte à procéder à ce genre d’analyse non destructrice, tandis que sur le plan archéométrique, il s’est avéré possible de discriminer les cherts sur la base de graphiques et d’une analyse statistique discriminante. Afin de vérifier si cette caractérisation est utile et pertinente dans un cadre archéologique, l’analyse d’artéfacts en chert provenant des sites de l’anse à la Vache (DaEi-6, île Verte), Turcotte-Lévesque (DaEi-8, île Verte) et de Rimouski (DcEd-1) fut aussi effectuée dans le but de localiser l’un ou l’autre des cherts au sein des assemblages. Les résultats démontrent que la caractérisation est fonctionnelle dans un cadre archéologique, puisque les cherts des carrières de La Martre et Touladi furent repérés sur chacun des sites, à l’exception du site de Rimouski, où seul le chert Touladi semble présent.The main objective of this project is to test, and to participate in the development of the non-destructive energy dispersive x-ray fluorescence chemical characterization method developed at the “Laboratoire de caractérisation non destructive de l’Université de Montréal”. To do so, I analyzed chert originating from two different prehistoric quarries, the La Martre quarry DhDm-8, Gaspé Peninsula, and that of quarry CkEe-28, Témiscouata, Québec. Both quarries were exploited intermittently from the Late PaleoIndian through the Archaic and into the Woodland periods. The six elements involved in the characterization, three major elements (Si, Al, Fe) and three trace elements (Ba, La, Ce), were selected because of their specific features. On one hand, results confirm that the Université de Montréal EDXRF analyzer is able to analyze with precision solid rock chips. On the other hand, by using bivariate and ternary plots, as well as discriminant analysis, I was able to distinguish one chert from the other. In order to ensure the validity of the chemical analysis, archaeological samples from sites on the St. Lawrence Estuary including Rimouski (DcEd-1), l’Anse à la Vache and Turcotte-Lévesque (DaEi-6 and DaEi-8) were tested and compared to the results for the quarry samples. Results show that the characterizatoin can be applied on archaeological artefacts since both cherts were located on every sites, except for Rimouski, where only Touladi chert was present

    EARLY METAL AGE POTTERY FROM FATU AKI ANIK KNUA, TIMOR-LESTE AND THE APPEARANCE OF CERAMICS IN THE WALLACEAN ISLANDS SUPPLEMENTARY FILE 4: FAAK OPEN SITE CATALOGUE—DECORATED BODY SHARDS

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    This catalogue presents descriptions and observations on 128 diagnostic decorated body shards from the Faak Open site

    EARLY METAL AGE POTTERY FROM FATU AKI ANIK KNUA, TIMOR-LESTE AND THE APPEARANCE OF CERAMICS IN THE WALLACEAN ISLANDS SUPPLEMENTARY FILE 4: FAAK OPEN SITE CATALOGUE—DECORATED BODY SHARDS

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    This catalogue presents descriptions and observations on 128 diagnostic decorated body shards from the Faak Open site

    Early Metal Age Pottery from Fatu Aki Anik Knua, Timor-Leste and the Appearance of Ceramics in the Wallacean Islands.

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    Fatu Aki Anik Knua is an archaeological site in the mountainous interior of Timor-Leste comprising of a limestone cave and open site locale. Excavations in 2015 yielded an extraordinary quantity of earthenware pottery with over 13,000 potsherds recovered, all dating within the last 1800 years. The Faak pottery is described and examined in the context of Timor-Leste and eastern Indonesian assemblages more widely. The intensification of ceramic technology transfers and initial pottery use, which occurred at many sites in the region during the Paleometallic era, is highlighted. The essential features of this hinterland site assemblage show affinities with Early Metal Age pottery occurring extensively throughout eastern Indonesia after 2500 BP

    EARLY METAL AGE POTTERY FROM FATU AKI ANIK KNUA, TIMOR-LESTE AND THE APPEARANCE OF CERAMICS IN THE WALLACEAN ISLANDS SUPPLEMENTARY FILE 1: FAAK CAVE CATALOGUE

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    This catalogue presents descriptions on 16 diagnostic shards: rims (11), decorated rims (3), and decorated body shards (2) from the Faak Cave

    EARLY METAL AGE POTTERY FROM FATU AKI ANIK KNUA, TIMOR-LESTE AND THE APPEARANCE OF CERAMICS IN THE WALLACEAN ISLANDS SUPPLEMENTARY FILE 2: FAAK OPEN SITE CATALOGUE—RIMS

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    This catalogue presents descriptions and observations on 172 diagnostic rim shards from the Faak Open site

    EARLY METAL AGE POTTERY FROM FATU AKI ANIK KNUA, TIMOR-LESTE AND THE APPEARANCE OF CERAMICS IN THE WALLACEAN ISLANDS SUPPLEMENTARY FILE 5: FAAK THIN SECTIONS CATALOGUE

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    This catalogue presents a record of the preliminary petrographic analysis of 21 thin section samples from the Faak Cave and Faak Open Site. It also includes an unpublished report by Dickinson (2011) that has been referred to in the main text: Summary Petrographic Evaluation of Temper Sands in Protohistoric Sherds from East Timor
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