87 research outputs found
Assessing the feasibility of impregnating phase change materials in lightweight aggregate for development of thermal energy storage systems
This paper assesses the feasibility of impregnation/encasement of phase change materials (PCMs) in
lightweight aggregates (LWAs). An impregnation process was adopted to carry out the encasement study
of two different PCMs in four different LWAs. The leakage of the impregnated/encased PCMs was studied
when they were submitted to freeze/thawing and oven drying tests, separately. The results confirmed
that, the impregnation/encasement method is effective with respect to the large thermal energy storage
density, and can be suitable for applications were PCMs cannot be incorporated directly such as asphalt
road pavements.The authors acknowledge the funding given by Centre for Coordination and Regional Development Committee (CCDR-C) through the research project CENTRO-07-ST24_FEDER-002020 "Environmentally-Friendly Aeronautical Transport Systems Integrated Program (EFATRAS)", http://efatrasubi.wordpress.com. Supply of Expanded Clay materials by ARGEX - Argila Expandida, S.A and Cork materials by Sofalca - Sociedade Central de Productos de Cortica, Lda are also acknowledged
A laboratory study on cold-mix, cold-lay emulsion mixtures
This paper describes laboratory experiments and presents
results for the performances of cold-mix, cold-lay
emulsion mixtures. The main objective of the experiments
was to evaluate and improve the properties of the cold
mixtures. The mixture properties evaluated were:
volumetric properties, indirect tensile stiffness modulus
(ITSM), repeated load axial creep and fatigue. These
properties were compared with conventional hot asphalt
mixtures not containing any waste/recycled materials. To
optimise the performances of the mixtures, a target of
ITSM value of 2000 MPa was selected. At full curing
conditions, the stiffness of the cold mixes was found to be
very similar to that of hot mixtures of the same
penetration grade base bitumen (100 pen). Test results
also show that the addition of 1–2% cement significantly
improved the mechanical performance of the mixes and
significantly accelerated their strength gain. The fatigue
behaviour of the cold mixes that incorporated cement was
comparable with that of the hot mixtures
A parametric study of the lensing properties of dodecagonal photonic quasicrystals
We present a study of the lensing properties of two-dimensional (2-D)
photonic quasicrystal (PQC) slabs made of dielectric cylinders arranged
according to a 12-fold-symmetric square-triangle aperiodic tiling. Our
full-wave numerical analysis confirms the results recently emerged in the
technical literature and, in particular, the possibility of achieving focusing
effects within several frequency regions. However, contrary to the original
interpretation, such focusing effects turn out to be critically associated to
local symmetry points in the PQC slab, and strongly dependent on its thickness
and termination. Nevertheless, our study reveals the presence of some peculiar
properties, like the ability to focus the light even for slabs with a reduced
lateral width, or beaming effects, which render PQC slabs potentially
interesting and worth of deeper investigation. Key words: Photonic
quasicrystals; negative refraction; superlensing.Comment: 12 pages, 8 figures, to be pubblished in Photonics and Nanostructures
- Fundamentals and Application
Opportunistic screening for skin cancer using a mobile unit in Brazil
Abstract
Background
Skin cancer is the most common malignancy in the white population worldwide. In Brazil, the National Cancer Institute (INCA) estimates that in 2010 there will be 119,780 and 5,930 new cases of non-melanoma skin cancer and melanoma, respectively. The aim of this study was to evaluate the use of a mobile unit in the diagnosis and treatment of skin cancer in several poor regions of Brazil.
Methods
The diagnosis of skin cancer was accomplished through active medical screening in the prevention Mobile Unit (MU) of Barretos Cancer Hospital (BCH). The study population consisted of patients examined in the MU between 2004 and 2007, and their suspicious lesions were subjected to histopathological evaluation. Data were collected prospectively from standardized forms and analyzed.
Results
During the screening, 17,857 consultations were carried out. A total of 2012 (11.2%) cases of skin cancer were diagnosed. The predominant histological type reported was basal cell carcinoma (n = 1,642 or 81.6%), followed by squamous cell carcinoma (n = 303 or 15.1%), Bowen's disease (n = 25 or 1.2%), malignant melanoma (n = 23 or 1.1%), basosquamous cell carcinoma (n = 3 or 0.1%), miscellaneous lesions (12 or 0.6%), and metatypical carcinoma (n = 4 or 0.2%). Only 0.6% of lesions were stage III. There were no stage IV non-melanoma skin lesions, as well as no melanomas stages III and IV, found.
Conclusions
It was observed that the MU can be a useful tool for early skin cancer diagnosis and treatment. This program probably is important, especially in developing countries with inadequate public health systems and social inequality
Use of oral glucocorticoids and risk of skin cancer and non-Hodgkin's lymphoma: a population-based case–control study
In North Jutland County, Denmark, we investigated whether use of oral glucocorticoids was associated with an increased risk of developing basal cell carcinoma (BCC), squamous cell carcinoma (SCC), malignant melanoma (MM), and non-Hodgkin's lymphoma (NHL). From the Danish Cancer Registry we identified 5422 BCC, 935 SCC, 983 MM, and 481 NHL cases during 1989–2003. Using risk-set sampling we selected four age- and gender-matched population controls for each case from the Civil Registration System. Prescriptions for oral glucocorticoids before diagnosis were obtained from the Prescription Database of North Jutland County on the basis of National Health Service data. We used conditional logistic regression to estimate incidence rate ratios (IRRs), adjusting for chronic medical diseases (information about these were obtained from the National Patient Registry) and use of other immunosuppressants. We found slightly elevated risk estimates for BCC (IRR, 1.15 (95% CI: 1.07–1.25)), SCC (IRR, 1.14 (95% CI: 0.94–1.39)), MM (IRR, 1.15 (95% CI: 0.94–1.41), and NHL (IRR, 1.11 (95% CI: 0.85–1.46)) among users of oral glucocorticoids. Our study supports an overall association between glucocorticoid use and risk of BCC that cannot be explained by the presence of chronic diseases or concomitant use of other immunosuppressants
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