392 research outputs found
Ceramic matrix composite turbine engine vane
A vane has an airfoil shell and a spar within the shell. The vane has an outboard shroud at an outboard end of the shell and an inboard platform at an inboard end of the shell. The shell includes a region having a depth-wise coefficient of thermal expansion and a second coefficient of thermal expansion transverse thereto, the depth-wise coefficient of thermal expansion being greater than the second coefficient of thermal expansion
Methodological tests of the use of trace elements as tracers to assess root activity
peer-reviewedN.J.H. was funded by the Irish Research Council, co-funded by Marie Curie Actions under FP7. The field experiments A, B and G were supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under the grant agreements FP7-266018 (AnimalChange) and FP7- 244983 (MultiSward). Experiment F was supported by the German Science Foundation (FOR 456).Background and aims
There is increasing interest in how resource utilisation in grassland ecosystems is affected by changes in plant diversity and abiotic conditions. Research to date has mainly focussed on aboveground responses and there is limited insight into belowground processes. The aim of this study was to test a number of assumptions for the valid use of the trace elements caesium, lithium, rubidium and strontium as tracers to assess the root activity of several grassland species.
Methods
We carried out a series of experiments addressing the reliability of soil labelling, injection density, incubation time, application rate and the comparability of different tracers in a multiple tracer method.
Results
The results indicate that it is possible to achieve a reliable labelling of soil depths. Tracer injection density affected the variability but not the mean level of plant tracer concentrations. Tracer application rates should be based on pilot studies, because of site- and species-specific responses. The trace elements did not meet prerequisites to be used in a multiple tracer method.
Conclusions
The use of trace elements as tracers is potentially a very useful tool to give insight into plant root activity at different soil depths. This work highlights some of the main benefits and pitfalls of the method and provides specific recommendations to assist the design of tracer experiments and interpretation of the results.N.J.H. was funded by the Irish Research Council, co-funded by Marie Curie Actions under FP7. The field experiments A, B and G were supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under the grant agreements FP7-266018 (AnimalChange) and FP7- 244983 (MultiSward). Experiment F was supported by the German Science Foundation (FOR 456).European Unio
Diacetyl and other Alpha-Dicarbonyl compounds with special reference to the flavor of butter
Diacetyl is an important flavor contributor of butter and various other foods. Similarity in chemical structure suggests that a number of other a-diketones would be similar in certain properties, including odor, to diacetyl, the simplest member of the series. Diacetyl and various homologs were synthesized long ago their reactions studied and certain similar chemical behaviors noted. However, the descriptions of the odors originally given would hardly suggest that diacetyl is involved in the flavor of certain foods. The work of van Niel, Kluyver and Derx (81) showed the importance of diacetyl as a flavor contributor of butter. Epstein and Harris (22-25) patented the use of certain a-diketones as flavoring materials for various foods. Taufel and Thaler (74) incidentally mentioned that in practice acetylpropionyl was sometimes used as a substitute for diacetyl
Preventing respiratory viral transmission in long-term care: Knowledge, attitudes, and practices of healthcare personnel
OBJECTIVETo examine knowledge and attitudes about influenza vaccination and infection prevention practices among healthcare personnel (HCP) in a long-term-care (LTC) setting.DESIGNKnowledge, attitudes, and practices (KAP) survey.SETTINGAn LTC facility in St Louis, Missouri.PARTICIPANTSAll HCP working at the LTC facility were eligible to participate, regardless of department or position. Of 170 full- and part-time HCP working at the facility, 73 completed the survey, a 42.9% response rate.RESULTSMost HCP agreed that respiratory viral infections were serious and that hand hygiene and face mask use were protective. However, only 46% could describe the correct transmission-based precautions for an influenza patient. Correctly answering infection prevention knowledge questions did not vary by years of experience but did vary for HCP with more direct patient contact versus less patient contact. Furthermore, 42% of respondents reported working while sick, and 56% reported that their coworkers did. In addition, 54% reported that facility policies made staying home while ill difficult. Some respondents expressed concerns about the safety (22%) and effectiveness (27%) of the influenza vaccine, and 28% of respondents stated that they would not get the influenza vaccine if it was not required.CONCLUSIONSThis survey of staff in an LTC facility identified several areas for policy improvement, particularly sick leave, as well as potential targets for interventions to improve infection prevention knowledge and to address HCP concerns about influenza vaccination to improve HCP vaccination rates in LTCs.Infect Control Hosp Epidemiol 2017;38:1449–1456</jats:sec
Dynamic Properties of Network Motifs Contribute to Biological Network Organization
Biological networks, such as those describing gene regulation, signal transduction, and neural synapses, are representations of large-scale dynamic systems. Discovery of organizing principles of biological networks can be enhanced by embracing the notion that there is a deep interplay between network structure and system dynamics. Recently, many structural characteristics of these non-random networks have been identified, but dynamical implications of the features have not been explored comprehensively. We demonstrate by exhaustive computational analysis that a dynamical property—stability or robustness to small perturbations—is highly correlated with the relative abundance of small subnetworks (network motifs) in several previously determined biological networks. We propose that robust dynamical stability is an influential property that can determine the non-random structure of biological networks
Atmosfera modificada, adsorvedor de etileno e vácuo parcial na pós-colheita de bananas prata-anã cultivadas na Amazônia.
Métodos para a climatização de bananas ‘prata-anã’ produzidas na Amazônia Setentrional brasileira.
O objetivo, neste trabalho, foi avaliar o uso da climatização para a uniformização de bananas 'Prata-Anã' produzidas em Boa Vista-RR. Após colhidos, os frutos foram selecionados no formato de buquês, sanitizados, climatizados por abafamento com lona plástica ou por imersão em solução de Ethrel®, embalados com filme de polietileno de baixa densidade e armazenados por quatro períodos de tempo (0; 10;20 e 30 dias) a 12 ± 1 ºC e 93 ± 2% de UR. Após cada período de armazenamento refrigerado (AR) os frutos foram submetidos ao armazenamento em condições ambiente (22 ± 1 ºC e 75 ± 3% UR), retirados das embalagens plásticas e sendo analisados após 1; 2; 3 e 4 dias. As seguintes análises foram realizadas: perda de massa fresca, coloração da casca, produção de etileno e CO2, atividade das enzimas pectinametilesterase e poligalacturonase, acidez titulável (AT), pectina total e solúvel, amido e sólidos solúveis (SS). Não houve diferenças significativas entre os métodos de climatização, porém verificou-se que, quanto maior o período de AR e de condicionamento, menor foi o período de conservação das bananas 'Prata-Anã'. Ficou evidenciado, também, que a climatização, independentemente do método utilizado, deve ser realizada em até 20 dias após a colheita, nas condições de AR aqui testadas. Nessas condições, foi possível manter a qualidade sensorial das bananas por até 3 dias após a retirada dos frutos do armazenamento refrigerado
Ceramic matrix composite turbine engine vane
A vane has an airfoil shell and a spar within the shell. The vane has an outboard shroud at an outboard end of the shell and an inboard platform at an inboard end of the shell. The spar has a first chamber essentially along the suction side and a second chamber along the pressure side opposite the first chamber
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