Search

Oxidation of ZrB2 + SiC composites is investigated using isothermal measurements to study the effects of temperature, time, and gas flow on oxidation behavior and microstructural evolution. A test method called dynamic nonequilibrium thermal gravimetric analysis (DNE-TGA), which eliminates oxidation during the heating ramp, has been developed to monitor mass change from the onset of an isothermal hold period (15 min) as a function temperature (1000°C–1600°C) and gas flow (50 and 200 mL/min). In comparing isothermal to nonisothermal TGA measurements, the scale thicknesses from isothermal tests are up to 4 times greater, indicating that oxidation kinetics are faster for isothermal testing, where the oxide scale thickness is 110 μm after 15 min at 1600°C in air. Isothermal oxidation followed parabolic kinetics with a mass gain that is temperature dependent from 1000°C–1600°C. The mass gain increased from ~5 to 45 g/m2 and parabolic rate constants increased from 0.037 to 2.2 g2/m4·s over this temperature range. The effect of flow velocity on oxidation is not significant under the given laminar flow environment where the gas boundary layer is calculated to be 4 mm. These values are consistent with diffusion of oxygen through the glass-ceramic surface layer as rate limiting.

The oxyacetylene torch facility is used to measure the ablation rates of graphite and the surface temperatures of different aerospace materials. The free-stream flame environment is characterized as a function of flame chemistry for heat flux, pO2, and flow velocity. Measured ablation rates for graphite increase as a function of increasing heat flux and pO2, which are validated by applying an oxygen diffusion based model. The model uses experimentally measured values for temperature, pO2, and gas velocity in order to confirm torch testing results are reliable and reproducible. Surface temperatures of ultra-high temperature ceramic composites are measured as a function of increasing heat flux and show an enthalpic cooling effect on the flame during oxidation testing.

In the framework of preparatory activities for the SPECTRA (Surface Processes and Ecosystems Changes Through Response Analysis) ESA Earth Explorer Core Mission, CHRIS/PROBA acquisitions over the Barrax Core Site in Spain were used to compile a reference dataset for future in-depth studies. Taking advantage of the possibility of consecutive days of acquisitions, multiple-angular acquisitions finally included 10 different view angles from CHRIS, in Mode 1 with 62 spectral, and a ground resolution of about 34 m. Additional ROSIS and HYMAP sensors, flying simultaneously with CHRIS overpass, provided detailed images for validation of CHRIS data, particularly in the spectral domain. Moreover, up to 3 angles per sample from airborne HYMAP data were acquired, with high spectral and spatial resolution, and then both spectral and angular domains can be exploited with the combined CHRIS/HYMAP/ROSIS dataset. Detailed soil/vegetation and atmospheric measurements complete the SPARC data, and data from other satellites (MERIS, SEVIRI, SPOT, Landsat) were collected as well, to address scaling issues. Methods for data analysis and exploitation have been developed in the context of SPARC activities, and preliminary results about retrievals of biophysical information from multi-angular hyperspectral data are already available. The whole SPARC dataset represents a reference for the exploitation of CHRIS data, allowing the development of new processing and retrieval algorithms, and the validation of such algorithms by means of ground measurements and complementary airborne and satellite data. More details on several processing aspects of the CHRIS/PROBA data acquired within the SPARC campaign are presented in other papers in this conference.

Background: Men with germline breast cancer 1, early onset (BRCA1) or breast cancer 2, early onset (BRCA2) gene mutations have a higher risk of developing prostate cancer (PCa) than noncarriers. IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international consortium of 62 centres in 20 countries evaluating the use of targeted PCa screening in men with BRCA1/2 mutations. Objective: To report the first year's screening results for all men at enrolment in the study. Design, setting and participants: We recruited men aged 40-69 yr with germline BRCA1/2 mutations and a control group of men who have tested negative for a pathogenic BRCA1 or BRCA2 mutation known to be present in their families. All men underwent prostate-specific antigen (PSA) testing at enrolment, and those men with PSA > 3 ng/ml were offered prostate biopsy. Outcome measurements and statistical analysis: PSA levels, PCa incidence, and tumour characteristics were evaluated. The Fisher exact test was used to compare the number of PCa cases among groups and the differences among disease types. Results and limitations: We recruited 2481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls). A total of 199 men (8%) presented with PSA > 3.0 ng/ml, 162 biopsies were performed, and 59 PCas were diagnosed (18 BRCA1 carriers, 10 BRCA1 controls; 24 BRCA2 carriers, 7 BRCA2 controls); 66% of the tumours were classified as intermediate-or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3.0 ng/ml in BRCA2 mutation carriers was 48%-double the PPV reported in population screening studies. A significant difference in detecting intermediate-or high-risk disease was observed in BRCA2 carriers. Ninety-five percent of the men were white, thus the results cannot be generalised to all ethnic groups. Conclusions: The IMPACT screening network will be useful for targeted PCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this screening yields a high proportion of aggressive disease. Patient summary: In this report, we demonstrate that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these men resulted in the identification of tumours that were more likely to require treatment. (C) 2014 European Association of Urology. Published by Elsevier B. V. All rights reserved.

WOS:000318440700012 (Nº de Acesso Web of Science) This study combines contributions from both safety climate literature and prominent social influence theories. It was developed to identify the combination of sociocognitive variables that differentiate between different profiles of safety behaviors. This empirical approach has hardly been explored in the literature on behavioral aspects related to safety. The research setting for this study was a transportation company (N = 356). The results of discriminant analysis showed that different combinations of dispositional and situational influences may lead to diverse profiles of compliance and proactive safety behaviors. Perceived behavioral control was revealed to be the variable that best differentiated the group with more safe behaviors from the others. However, results also revealed that high attitudes and perceived behavioral control are very important, but not sufficient, to promote proactive safety. Co-workers’ descriptive safety norms were a major differentiating variable in proactive safety. Theoretical and practical implications of the findings are discussed.

What's known on the subject? and What does the study add? Scientists have found a number of genetic factors that increase prostate cancer risk, including heritable mutations in the genes BRCA1 and BRCA2. These mutations are not common but can have major impact, as a BRCA2 mutation increases risk by up to seven-fold while a BRCA1 mutation is thought to double risk in men under 65. The IMPACT study aims to determine whether targeted screening in men with a known BRCA1 or BRCA2 mutation would lead to earlier diagnosis of prostate cancers. This data from the IMPACT study adds to the increasing evidence that BRCA mutation carriers develop more aggressive disease. Although these are early results, it appears that PSA screening is more accurate at predicting potentially aggressive prostate cancer among men at higher risk of the disease due to a genetic predisposition than general population screening. This study provides support for continued screening in men with genetic mutations. OBJECTIVE To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported. PATIENTS AND METHODS Men aged 40-69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA > 3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (+/- 5 years) who were negative for the familial mutation. RESULTS In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47 center dot 6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant. CONCLUSIONS The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.

25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 4677-4681, The aim of this paper is to prompt a discussion on current power rating standards for PV technologies. The premise taken is that a fundamental purpose of a power rating is to provide a potential off-taker with a quick yet meaningful comparison of the performance of different competing PV technologies and of different products within a technology; a second resulting role is to define the benchmark by which the $/W price is assessed, which is the starting point of any project cost analysis activity. In addition, as our industry matures and will be increasingly led to compete with other energy technologies, consistency and clarity in our ratings will become increasingly important. In parallel, PV and CPV technologies have complex behavior in real and diverse environmental conditions that are challenging to represent in a single rating standard, and that have contributed to the proliferation of rating standards that we have today. It is important to understand and be able to model this behavior to enable the more precise output calculations needed for example for detailed site design and performance guarantees. These conflicting needs lead the authors to conclude that to support the growth of a mature solar PV and CPV industry increasingly able to compete with other power production technologies a separation is required between representative standards for outward estimates and communication, and the detailed technical specifications needed to enable site design and provide performance guarantees. We recommend that an effort be undertaken by the industry to reduce the number of standards and identify approaches that can allow the different PV technologies to be rated using the same set of standards while achieving representative performance results.