Today, there are many commercial CAM systems available capable of generating NC codes for milling free-form geometries up to 5-axis. However, the quality of these NC codes has not yet been well discussed so far. Apparently, on the computer screen and the geometrical simulation provided by CAM, tool paths calculated by different CAM systems seem to be the same. However, as observed in this work, NC codes differ expressively according to the CAM software applied, and it affects the productivity and quality of the machined surface. Thus, a study was carried out to investigate this issue. A representative workpiece with free-form geometries was designed; a data acquisition system from an open architecture CNC was developed and NC codes were generated by five worldwide commercial CAM systems. The finishing milling operation was evaluated. The results presented difference of up to 30% on the real machining time, differences in the feed rate oscillation and up to 2 times the surface roughness value. This work reveals an essential limitation on the CAM algorithm and arises a new point for benchmarking CAM systems, which brings an opportunity to improve the calculation of tool paths for milling free-form geometries.
In June 2009, the World Health Organization declared a novel influenza A, S-OIV (H1N1), pandemic. We observed 44 consecutive patients during the "first wave" of the pandemic. 70.5% of them showed co-morbidities (hypertension, obesity, chronic respiratory diseases, chronic renal disease, diabetes, pregnancy). Serious cases were admitted to the intensive care unit (ICU), particularly those with severe acute respiratory failure. Some of them developed acute kidney injury (AKI) and required renal replacement therapy (RRT). The average time between admission to the ICU and initiation of RRT was 3.16 ± 2.6 days. At initiation of RRT, most patients required mechanical ventilation. No relationship was found with creatinine-kinase levels. Seventy-five percent of the cases were observed during a 3-week period and mortality, related to respiratory failure, doubling of alanine amino transferase and use of inotropics was 81.8%. In conclusion, the H1N1-infected patients who developed RRT-requiring AKI, in the context of multi-organ failure, showed a high mortality rate. Thus, it is mandatory that elaborate strategies aimed at anticipating potential renal complications associated to future pandemics are implemented.
Un aspecto importante para el control automático de la frecuencia es la medición del coeficiente de amortiguamiento de la carga (estatismo); pues conociendo su valor, se puede calcular con precisión el factor BIAS, fundamental para una calibración eficiente de un Sistema Automático de Control de la Generación (AGC). En la literatura especializada se dan valores típicos del coeficiente de amortiguamiento de la carga y se dice que debe estar entre 1 y 2%. En el presente artículo se describe un método para medir este coeficiente en el Sistema Nacional Interconectado (SNI) del Ecuador, en diferentes horarios del día.
Se presentan los resultados de seguridad y evolución clínica de 87 pacientes que recibieron plasma de convaleciente en la sala de Clínica Médica del Hospital Argerich en Buenos Aires. Tres pacientes tuvieron sobrecarga de volumen. Hubo 33 pases a Terapia Intensiva (37,9%) y 21 casos requirieron asistencia respiratoria mecánica (24,1%). Fallecieron 18 pacientes (20,7%). Tres de ellos por limitación del esfuerzo terapéutico y 15 en Terapia Intensiva. La mortalidad en Terapia Intensiva fue del 45,4%. Hubo solo 10 casos que recibieron plasma dentro de las 72 horas del comienzo de síntomas: de ellos, 1 caso de asistencia respiratoria y 1 fallecido; entre 72 horas y una semana recibieron plasma 25 casos con 26,9% de asistencia respiratoria y 20% de mortalidad, y de los 50 pacientes que recibieron mas allá de la primera semana, 25,4% requirieron de asistencia respiratoria y 24% fallecieron. Nuestra serie no pudo demostrar efecto beneficioso en la administración temprana de plasma y no fue diseñada para medir eficacia. El procedimiento fue bien tolerado en la gran mayoría de los pacientes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.