865 resultados para ISO standards
The nitric oxide ISO photocatalytic reactor system: Measurement of NOx removal activity and capacity
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Although the NO removal-based air-purification ISO method ISO 22197-1:2007 is well established, its preconditioning requirements mean that only the initial activity of the photocatalyst under test is measured owing to the often-reported, gradual alteration of the surface kinetics for NO oxidation by air through the accumulation of surface HNO3. Herein, we compare the photocatalytic NO removal abilities of a number of different, common TiO2 materials, surface-saturated with photogenerated HNO3, with their behaviours observed during the typical 5 h-long ISO standard test. It is found that all the TiO2 materials studied eventually become largely NO to NO2 converters after sufficient exposure to NO under irradiation (>5 h) due to the accumulation of surface HNO3. The UV exposure time, t*, necessary to reach this HNO3 saturated condition is different for each different catalyst. As a consequence, an alternative preconditioning process for the ISO method is proposed which can be used to provide a more realistic measure of the photocatalytic activity of the underlying material and provide a measure of the NOx removing capacity of the photocatalytic material under test.
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Monitoring of BCR-ABL transcripts has become established practice in the management of chronic myeloid leukemia. However, nucleic acid amplification techniques are prone to variations which limit the reliability of real-time quantitative PCR (RQ-PCR) for clinical decision making, highlighting the need for standardization of assays and reporting of minimal residual disease (MRD) data. We evaluated a lyophilized preparation of a leukemic cell line (K562) as a potential quality control reagent. This was found to be relatively stable, yielding comparable respective levels of ABL, GUS and BCR-ABL transcripts as determined by RQ-PCR before and after accelerated degradation experiments as well as following 5 years storage at -20 degrees C. Vials of freeze-dried cells were sent at ambient temperature to 22 laboratories on four continents, with RQ-PCR analyses detecting BCR-ABL transcripts at levels comparable to those observed in primary patient samples. Our results suggest that freeze-dried cells can be used as quality control reagents with a range of analytical instrumentations and could enable the development of urgently needed international standards simulating clinically relevant levels of MRD.
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The end of Dennard scaling has promoted low power consumption into a firstorder concern for computing systems. However, conventional power conservation schemes such as voltage and frequency scaling are reaching their limits when used in performance-constrained environments. New technologies are required to break the power wall while sustaining performance on future processors. Low-power embedded processors and near-threshold voltage computing (NTVC) have been proposed as viable solutions to tackle the power wall in future computing systems. Unfortunately, these technologies may also compromise per-core performance and, in the case of NTVC, xreliability. These limitations would make them unsuitable for HPC systems and datacenters. In order to demonstrate that emerging low-power processing technologies can effectively replace conventional technologies, this study relies on ARM’s big.LITTLE processors as both an actual and emulation platform, and state-of-the-art implementations of the CG solver. For NTVC in particular, the paper describes how efficient algorithm-based fault tolerance schemes preserve the power and energy benefits of very low voltage operation.
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We assess informal institutions of Protestants and Catholics by investigating their economic resilience in a natural experiment. The First World War constitutes an exogenous shock to living standards since the duration and intensity of the war exceeded all expectations. We assess the ability of Protestant and Catholic communities to cope with increasing food prices and wartime black markets. Literature based on Weber (1904, 1905) suggests that Protestants must be more resilient than their Catholic peers. Using individual height data on some 2,800 Germans to assess levels of malnutrition during the war, we find that living standards for both Protestants and Catholics declined; however, the decrease of Catholics’ height was disproportionately large. Our empirical analysis finds a large statistically significant difference between Protestants and Catholics for the 1915–19 birth cohort, and we argue that this height gap cannot be attributed to socioeconomic background and fertility alone.
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We assess informal institutions of Protestants and Catholics by investigating their economic
resilience in a natural experiment. The First World War constitutes an exogenous shock to living standards since the duration and intensity of the war exceeded all expectations. We assess the ability of Protestant and Catholic communities to cope with increasing food prices and wartime black markets. Literature based on Weber (1904, 1905) suggests that Protestants must be more resilient than their Catholic peers. Using individual height data on some 2,800 Germans to assess levels of malnutrition during the war, we find that living standards for both Protestants and Catholics declined; however, the decrease of Catholics’ height was disproportionately large. Our empirical analysis finds a large statistically significant difference between Protestants and Catholics for the 1914-19 birth cohort, and we argue that this height gap cannot be attributed to socioeconomic background and fertility alone.
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The photocatalytic reactor described in the NOx removal ISO 22197-1:2007 is used to study the kinetics of the process, using a film of P25 TiO2 which has either been conventionally pre-irradiated in a stream of air, or unconventionally in a stream of NO (1 ppmv). In the former case it is shown that the system does not achieve steady state exit levels of NO, probably due to the gradual accumulation of HNO3 on the surface of the photocatalyst. The NO-preconditioned TiO2 film demonstrated excellent steady-state levels when monitored as a function of NO concentration, [NO] and UV irradiance, ρ. However, in this case the photocatalytic reaction under study is NOT NOx removal, but the conversion of NO to NO2. It is shown that the kinetics of this steady state process fit very well to a kinetic expression based on a disrupted adsorption reaction mechanism, which has also been used by others to fit their observed (non-steady state) kinetics for NOx removal on conventionally-(air) preconditioned films of P25. The appropriateness of this model for either system is questioned, since in both systems the kinetics appear to have a significant mass transport element. These findings suggest that mass transport and non-steady-state kinetics are likely to be significant features for most active photocatalytic samples, where the %NO conversion is >7%, and so limits the usefulness of the NOx removal ISO 22197-1:2007.
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The ecological quality of lakes and other surface water bodies in the European Union is determined by the quality of the structure and functioning of the aquatic ecosystem. The depletion rate of oxygen in the hypolimnion is an important process in thermally stratified lakes and the distribution of consumption between water and sediment an important structural characteristic. It is shown that the variation of volumetric oxygen consumption rate with trophic state can be used to select lake water total phosphorus and chlorophyll concentrations that correspond to changes in the functioning of the lake. Lake morphometry has little effect on this aspect of lake function and the relative amount of oxygen consumption in the water and sediment changes only a little with trophic state, most of the consumption being in the water. Suggestions for the reference condition, good and moderate ecological quality are made using the changes in this aspect of lake function and they are presented as lake water total phosphorus and chlorophyll concentration.
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Digital image analysis is at a crossroads. While the technology has made great strides over the past few decades, there is an urgent need for image analysis to inform the next wave of large scale tissue biomarker discovery studies in cancer. Drawing parallels from the growth of next generation sequencing, this presentation will consider the case for a common language or standard format for storing and communicating digital image analysis data. In this context, image analysis data comprises more than simply an image with markups and attached key-value pair metrics. The desire to objectively benchmark competing platforms or a push for data to be deposited to public repositories much like genomics data may drive the need for a standard that also encompasses granular, cell-by-cell data.
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Dissertação de mestrado, Qualidade em Análises, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
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Document outlines how South Carolina can achieve national educational goals.
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Document outlines how South Carolina can achieve national educational goals.
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Teacher commitment has been found to be a critical predictor of teachers’ work performance, absenteeism, retention, burnout and turnover, as well as having an important influence on students’ motivation, achievement, attitudes towards learning and being at school (Firestone (1996). Educational Administration Quarterly, 32(2), 209–235; Graham (1996). Journal of Physical Education, Recreation and Dance, 67(1), 45–47; Louis (1998). School Effectiveness and School Improvement, 9(1), 1–27; Tsui & Cheng (1999). Educational Research and Evaluation, 5(3), 249–268). It is also a necessary ingredient to the successful implementation, adaptation or resistance reform agendas. Surprisingly, however, the relationship between teachers’ motivation, efficacy, job satisfaction and commitment, and between commitment and the quality of their work has not been the subject of extensive research. Some literature presents commitment as a feature of being and behaving as a professional (Helsby, Knight, McCulloch, Saunders, & Warburton (1997). A report to participants on the professional cultures of Teachers Research Project, Lancaster University, January). Others suggest that it fluctuates according to personal, institutional and policy contexts (Louis (1998). School Effectiveness and School Improvement, 9(1), 1–27) and identify different dimensions of commitment which interact and fluctuate (Tyree (1996). Journal of Educational Research, 89(5), 295–304). Others claim that teachers’ commitment tends to decrease progressively over the course of the teaching career (Fraser, Draper, & Taylor (1998). Evaluation and Research in Education, 12 (2), 61–71; Huberman (1993). The lives of teachers. London: Cassell). In this research, experienced teachers in England and Australia were interviewed about their understandings of commitment. The data suggest that commitment may be better understood as a nested phenomena at the centre of which is a set of core, relatively permanent values based upon personal beliefs, images of self, role and identity which are subject to challenge by change which is socio-politically constructed.
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When and why did the Portuguese become the shortest Europeans? In order to find the answer to this question, we trace the trend in Portuguese living standards from the 1720s until recent times. We find that during the early nineteenth century average height in Portugal did not differ significantly from average height in most other European countries, but that when, around 1850, European anthropometric values began to climb sharply, Portugal's did not. In a panel analysis of 12 countries, we find that delay in human-capital formation was the chief factor hindering any improvement in the biological standard of living in Portugal.