This paper summarizes the spectrum of options that can be employed during the initial design and construction of pulverized coal (PC), and integrated gasification and combined cycle (IGCC) plants to ...reduce the capital costs and energy losses associated with retrofitting for CO
2 capture at some later time in the future. It also estimates lifetime (40 year) net present value (NPV) costs of plants with differing levels of pre-investment for CO
2 capture under a wide range of CO
2 price scenarios. Three scenarios are evaluated—a baseline supercritical PC plant, a baseline IGCC plant and an IGCC plant with pre-investment for capture. This analysis evaluates each technology option under a range of CO
2 price scenarios and determines the optimum year of retrofit, if any. The results of the analysis show that a baseline PC plant is the most economical choice under low CO
2 prices, and IGCC plants are preferable at higher CO
2 prices (e.g., an initial price of about $22/t CO
2 starting in 2015 and growing at 2%/year). Little difference is seen in the lifetime NPV costs between the IGCC plants with and without pre-investment for CO
2 capture. This paper also examines the impact of technology choice on lifetime CO
2 emissions. The difference in lifetime emissions become significant only under mid-estimate CO
2 price scenarios (roughly between $20 and 40/t CO
2) where IGCC plants will retrofit sooner than a PC plant.
The TileCal Demonstrator is a prototype for the future upgrade of the ATLAS hadron calorimeter when the Large Hadron Collider increases luminosity in year 2023 (HL-LHC). It will be used for ...functionality and performance tests. The Demonstrator has 48 channels of upgraded readout and digitizing electronics and a new digital trigger capability, but is backwards-compatible with the present detector system insofar as it also provides analog trigger signals and can communicate as the present system. The on-detector part of the Demonstrator is comprised of 4 identical mechanical mini-drawers, each equipped with up to 12 photomultipliers (PMTs). The on-detector electronics includes 45 Analog Front-End Boards, each serving an individual PMT; 4 Main Boards, each to control and digitize up to 12 PMT signals, and 4 corresponding high-speed Daughter Boards serving as data hubs between on-detector and off-detector electronics. It is fully compatible with the present system, accepting ATLAS triggers, timing and slow control commands for the data acquisition, detector control, and detector operation monitoring. We plan to insert one fully functional Demonstrator module into the present ATLAS TileCal detector for the LHC RUN 2 in Christmas shutdown in 2015 or 2016.
Alley cropping is an agroforestry system that offers a promising land use alternative for the temperate zone. On the same field, the sustainable production of food and biomass is possible, while ...simultaneously, especially in marginal areas, the ecological function of the landscape can be improved. Thus, alley cropping corresponds with the increasing demand for renewable energy resources and for a specific adaptation to the predicted changes of climatic conditions within Central Europe.
However, presently, little knowledge exists regarding the effects of alley cropping on the environment. In this study a literature survey was undertaken to provide an overview of the different ecological benefits arising from alley cropping systems within temperate Europe. Abiotic factors (nutrient cycle, microclimate), biotic factors (biodiversity) and the effects on the carbon cycle are discussed in detail.
Summarising, the results showed that alley cropping may be an ecologically advantageous land use system for sustainable food and biomass production in comparison with conventional agricultural practices. As a very flexible, but low-input system, alley cropping can supply biomass resources in a sustainable way and at the same time provide ecological benefits.
Polystyrene nanocomposites containing a fraction of silica nanoparticles of different geometries (sphere, cube and regular tetrahedron) have been investigated by coarse-grained molecular dynamics ...simulations. Structural and dynamic properties of the polymer chains in the presence of the nanoparticles have been analyzed as a function of the nanoparticle mass fraction and geometrical shape. It has been found that the dimension of the polymer chains in the interphase expands due to the polymer-nanoparticle interaction. Their global dimension (averaged over the whole sample), however, shrinks when increasing the total surface area of the nanoparticles. The conformational changes of polymer chains in the interphase are monitored by a chain orientation parameter. The profiles of the chain dimension and orientation as a function of their distance from the nanoparticle center of mass show that the interphase thickness is roughly equal to the radius of gyration of the polymer chains. Moreover, the dynamic behavior of the polymer chains in nanocomposites is analyzed by the center of mass diffusion coefficient, the relaxation time of the chain end-to-end vector and the characteristic escape time of the polymer chains from the interphase. Compared with neat polymers, both the global and local chain dynamics in nanocomposites are hindered with an increasing nanoparticle mass fraction and with an increasing surface area. The local chain dynamics in the interphase is stronger affected by the surface area of the nanoparticles than the global one. Specifically, the global diffusion coefficient of polymer chains is almost linearly reduced with the total surface area of the nanoparticles, whereas the global relaxation time of the chain end-to-end vector increases almost linearly with it. The interphase relaxation time of the polymer chains increases superlinearly with the surface area of an individual nanoparticle. Additionally, the characteristic escape time of polymer chains from the interphase is largely influenced by the geometrical shape of the nanoparticle. Due to their larger surface area, tetrahedral nanoparticles impede the global and local chain dynamics stronger than cubic nanoparticles, followed by spherical nanoparticles. Uniaxial tensile tests show that both the Young's modulus and yield strength of polymer nanocomposites increase monotonically with their total interphase area. Our simulations demonstrate that polymer structural and dynamic properties are both largely influenced by a common parameter, i.e. the interphase area which has a fundamental influence on the mechanical properties of polymer nanocomposites.
Objective This study examines the relationship between self-recorded resident work hours and Orthopedic In-training Examination (OITE) scores, resident clinical performance, and American Board of ...Orthopedic Surgery pass rates. The hypothesis of this study is that increasing duty hours would have a positive correlation with clinical and OITE performance. Design Total duty hours and recorded operating room hours from a single orthopedic residency program were extracted from 2006 to 2012. During the same time span, OITE scores, resident clinical scores from the E-Valuation system, and American Board of Orthopedic Surgery pass rates were collected. The correlation between the variables was assessed using the Pearson correlation coefficient’s precision statistic. Setting A large public tertiary academic center in the upper Midwestern United States. Participants A total of 82 orthopedic surgery residents over 7 years. Results A total of 82 residents were matriculated between 2006 and 2012. The average weekly recorded duty hours were as follows: postgraduate year 2 (PGY2) = 60 hours/week (Standard Deviation (SD) ± 4), PGY3 = 59 hours/week (SD ± 5), PGY4 = 51 hours/week (SD ± 4), PGY5 = 49 hours/week (SD ± 3). There was significant variability in the average number of hours worked among residents (range: 2128-3753 h/y) for the full academic year. The OITE scores and the work hours were found to be independent of each other ( ρ = 0.017, p = 0.825), and no correlation was found between OITE scores and the resident E-value scores ( ρ = 0.071, p = 0.34). Residents spent 36% to 48% of their time in the operating room. Second year residents logging more hours scored higher on faculty evaluation of overall competency ( ρ = 0.31, p = 0.035). Faculty assessment of technical skills had a positive correlation with operating room duty hours for PGY5 class ( ρ = 0.346, p = 0.025). Conclusions A large variation in duty hours exists between resident-logged duty hours. No correlation exists between in-training scores and duty hours. There is a positive correlation between senior resident operating room hours and technical skill scores.
Several toxic diseases cause mortality in cattle in southern Rio Grande do Sul State, Brazil. The aim of this study was to carry out a comparative analysis to determine the evolution of the main ...intoxications that occurred in cattle in southern Rio Grande do Sul from 1979 to 1999 and from 2000 to 2020. The spatial distribution and trend of occurrence of these intoxications over the 42 years in southern Rio Grande do Sul were determined using data from the Regional Diagnostic Laboratory of the Faculty of Veterinary Medicine at the Federal University of Pelotas (LRD-UFPel), which will make it possible to predict their occurrence in the coming years. From January 1979 to December 1999, 3,753 bovine materials were received for diagnosis at LRD-UFPel, and 3,653 cases were received from 2000 to 2020. Of the total number of materials received, 394 were diagnosed as intoxications, with 140 cases from 1979 to 1999 and 252 cases from 2000 to 2020. Out of 140 cases diagnosed in the first 21 years of operation of the LRD-UFPel, 113 (80.7%) were poisoning by plants, 22 (15.7%) by fungi outbreaks, and five (3.57%) by chemical substances. From 2000 to 2020, of the 252 diagnosed outbreaks 224 (88.8%) were caused by toxic plants, 10 (3.96%) by fungi, 12 (4.76%) by chemical substances, and six (2.38%) by insects. In the temporal trend analysis, a significant linear trend was observed with values of p=0.03 and an annual percentage change (APC) of 2.5 for the increase in the number of diagnoses of poisoning in general over the 42 years of the study. When analyzing the temporal trend of poisoning by Senecio spp., there was an increase in the occurrence of the diagnosis, with different characteristics and inflection points over time, with an annual growth rate of 9% in diagnoses during the first 21 years. There was a decrease in the occurrence of poisoning by Solanum fastigiatum, Echium plantagineum, and Claviceps paspali. Furthermore, poisoning by Ramaria flavo-brunnescens and Baccharis coridifolia maintained a similar percentage throughout the study period. It is concluded that toxic diseases will likely remain important causes of cattle death in the region.
RESUMO: Na região sul do Rio Grande do Sul, dentre as principais enfermidades que causam mortalidade em bovinos estão diversas doenças tóxicas, destacando-se as intoxicações por plantas e micotoxicoses. O objetivo deste trabalho foi realizar um estudo comparativo para determinar a evolução das principais intoxicações que ocorreram em bovinos na região sul do Rio Grande do Sul de 1979 a 1999 e de 2000 a 2020, estabelecendo a distribuição espacial e a tendência de ocorrência dessas intoxicações nos 42 anos de atividades do Laboratório Regional de Diagnóstico da Faculdade de Veterinária da Universidade Federal de Pelotas (LRD-UFPel), possibilitando prever sua ocorrência nas próximas décadas. Foram recebidos no laboratório de janeiro de 1979 a dezembro de 1999 e de janeiro de 2000 a dezembro de 2020, 3.753 e 3.653 materiais de bovinos para diagnóstico, respectivamente. Do total de materiais recebidos, 392 foram diagnosticados como intoxicações, sendo 140 entre os anos de 1979 a 1999 e 252 casos de 2000 a 2020. Dos 140 casos diagnosticados nos primeiros 21 anos de funcionamento do LRD-UFPel, 113 (80,7%) foram intoxicações por plantas, 22 (15,7%) intoxicações por fungos e cinco (3.6%) intoxicações por substâncias químicas. Entre os anos de 2000 e 2020 dos 252 casos diagnosticados 224 (88,8%) foram por plantas tóxicas, 10 (3,9%) por fungos, 12 (4,8%) por substâncias químicas e seis (2,4%) foram por insetos. Na análise de tendência temporal foi observada uma tendência linear significativa com valores de p=0,003 e mudança percentual anual (APC) de 2,5 no crescimento do número de diagnósticos de intoxicações em geral ao longo de todo o período de funcionamento do LRD-UFPel. Quando analisada a tendência temporal da intoxicação por Senecio spp. houve aumento na ocorrência do diagnóstico, com características e pontos de inflexão diferentes ao longo do tempo, sendo observado crescimento anual de 9% nos diagnósticos durante os primeiros 21 anos. Conclui-se que houve queda na ocorrência das intoxicações por Solanum fastigiatum, Echium plantagineum e Claviceps paspali e que as intoxicações por Ramaria flavo-brunnescens e Baccharis coridifolia mantiveram um percentual semelhante em todo o período. Além disso, as doenças tóxicas provavelmente permanecerão como importantes causas de morte de bovinos na região apesar de bem conhecidas, devido em parte, às dificuldades em fazer o controle das mesmas.
Sampling Pulses for Optimal Timing Bousselham, A.; Bohm, C.
IEEE transactions on nuclear science,
04/2007, Letnik:
54, Številka:
2
Journal Article
Recenzirano
When extracting unknown band-limited pulses from sampled data, the Nyquist criterion defines the minimum sampling frequency. With well-defined pulse shapes and a stationary noise environment one can ...use matched filters to recover time and amplitude, but this is usually not the case with scintillation detectors. If the noise is not stationary other methods must be used. Our study investigates different timing strategies and how the timing precision depends on ADC resolution and sample rate. It also compares the timing precision with data obtained from an analogue setup. Pulses from an LSO crystal with photomultiplier readout are studied experimentally. Our best method gives in this case a 10% improvement in timing compared to a matched filter approach. Some simulation results are also reported
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