962 resultados para experiment
Resumo:
Currently, the power generation is one of the most significant life aspects for the whole man-kind. Barely one can imagine our life without electricity and thermal energy. Thus, different technologies for producing those types of energy need to be used. Each of those technologies will always have their own advantages and disadvantages. Nevertheless, every technology must satisfy such requirements as efficiency, ecology safety and reliability. In the matter of the power generation with nuclear energy utilization these requirements needs to be highly main-tained, especially since accidents on nuclear power plants may cause very long term deadly consequences. In order to prevent possible disasters related to the accident on a nuclear power plant strong and powerful algorithms were invented in last decades. Such algorithms are able to manage calculations of different physical processes and phenomena of real facilities. How-ever, the results acquired by the computing must be verified with experimental data.
Resumo:
Absolute cross sections for the transitions of the Kr atom into the 4s^1 and 4p^4nl states of the Kr^+ ion were measured in the 4s-electron threshold region by photon-induced fluorescence spectroscopy (PIFS). The cross sections for the transitions of the Kr atom into the 4s^1 and 4p^4nl states were also calculated, as well as the 4p^4nln'l' doubly excited states, in the frame of LS-coupling many-body technique. The cross sections of the doubly-excited atomic states were used to illustrate the pronounced contributions of the latter to the photoionization process, evident from the measurements. The comparison of theory and experiment led to conclusions about the origin of the main features observed in the experiment.
Resumo:
In continuation of our previous work on the quintet transitions 1s2s2p^2 ^5 P-1s2s2p3d ^5 P^0, ^5 D^0, results on other n = 2 - n' = 3 quintet transitions for elements N, 0 and F are presented. Assignments have been established by comparison with Multi-Configuration Dirac-Fock calculations. High spectral resolution on beam-foil spectroscopy was essential for the identification of most of the lines. For some of the quintet lines decay curves were measured, and the lifetimes extracted were found to be in reasonable agreement with MCDF calculations.
Resumo:
En el año 2002, la Secretaría de Educación de Bogotá estipuló la Resolución 2101 que tenía por objeto asegurar el ciclo de la educación completo en los colegios públicos. El propósito de este trabajo es evaluar el impacto de los mecanismos seguidos a la aplicación de esta política sobre la tasa de deserción escolar. Las escuelas tenían tres mecanismos diferentes para alcanzar el objetivo de la presente resolución: expandir los grados escolares ofertados, integrarse con otros colegios de la zona, o ambos. Para ello, utilizo variables instrumentales para resolver el sesgo causado por el hecho de que los colegios que siguen determinada estrategia eran los que tenían altas tasas de deserción inicialmente. Usando datos sobre las características institucionales y las características socio-demográficas de la población cerca del colegio, evalúo el impacto de estos tres mecanismos sobre las tasas de deserción escolar. Los resultados sugieren que las instituciones que aumentaron los grados experimentan un aumento en el número de estudiantes que abandonan el colegio en 12.1 puntos porcentuales, mientras que las instituciones que complementaron este mecanismo con la integración de un colegio próximo pre existente mostraron una reducción en la tasa de deserción escolar de 9.8 puntos porcentuales.
Resumo:
We investigate whether and how the type of unemployment benefit institution affects productivity. We designed a field experiment to compare workers’ productivity under a welfare system, where the unemployed receive an unconditional monetary transfer, with their productivity under a workfare system, where the transfer is received conditional on the unemployed spending some time on ancillary activities. First, we find that having an unemployment benefit institution, regardless of whether it makes transfers conditional or unconditional, increases workers’ productivity. Second, we find that productivity is higher under Welfare than under Workfare. Becoming unemployed under Welfare comes at the psychological cost of a drop in self-esteem, presumably due to the shame or stigma associated with receiving an unconditional unemployment benefit. We document the empirical relevance of precisely this channel. The differences we observe in productivity suggest that this psychological cost acts as an extra nonmonetary incentive for workers under Welfare to put a higher effort in their work.
Resumo:
Ofrece una serie de experimentos que ayudan a los niños a probar y observar los principios científicos básicos del movimiento. En algunos experimentos es necesaria la ayuda de los adultos.
Resumo:
Realiza experimentos con aviones de papel, botellas de plástico, instrumentos musicales de viento caseros, globos llenos de aire caliente, paracaidas, para explicar las propiedades del aire.Tiene un glosario.Para alumnos de primaria.
Resumo:
Ofrece unos sencillos experimentos que ayudan a los niños a probar y observar los principios científicos básicos de la luz. Para fomentar el interés por la investigación al realizar y comprobar en sí mismos los experimentos que se explican claramente con la ayuda de fotografías en color. Para edades comprendidas entre siete y diez años. Tiene un glosario.
Resumo:
Ofrece unos sencillos experimentos que ayudan a los niños a probar y observar los principios científicos básicos del agua. Para fomentar el interés por la investigación al realizar y comprobar en sí mismos los experimentos que se explican claramente con la ayuda de fotografías en color. Para edades comprendidas entre siete y diez años. Tiene un glosario.