Ingenieria Quimica Y Bioquimica

El número de Reynolds es un valor que ayuda a identificar la naturaleza de un flujo en una tubería, ya sea laminar, en transición o turbulento. Depende de la densidad, la velocidad, el diámetro o longitud y la viscosidad dinámica, en términos de esta; y de la velocidad, diámetro y viscosidad cinemática, en términos de esta.
Reynolds (1874) estudió las características de flujo de los fluidos inyectando un trazador dentro de un líquido que fluía por una tubería. A velocidades bajas del líquido, el trazador se mueve linealmente en la dirección axial. Sin embargo, a mayores velocidades, las líneas del flujo del fluido se desorganizan y el trazador se dispersa rápidamente después de su inyección en el líquido. El flujo lineal se denomina Laminar y el flujo errático obtenido a mayores velocidades del líquido se denomina Turbulento

Fruit preservation by hurdle technology is based on combinations of low levels of various antimicrobial factors (hurdles) acting synergistically resulting in a shelf stable high moisture, fresh-like product. The objective of this work was to evaluate the stability of mango cubes obtained by combining the following hurdles: water activity reduction, pH reduction, and chemical preservation. Tommy Atkins mangoes, previously washed, sanitized and peeled, were cut into cubes of approximately 8 cm³. The cubes were osmotically dehydrated under stirring (150 rpm) at 46ºC in a sucrose solution at 65.5oBrix added with 2% citric acid and 0.2% potassium sorbate, during two hours. The product was drained, packed in low-density polyethylene bags and stored at room temperature (about 25ºC) during three months. The combination of hurdles on the final product (water activity, 0.96; pH, 3.99; potassium sorbate content, 396 mg.kg-1) was not effective to make it shelf stable, since the count of yeasts ...

INTRODUCTION To value the asthma quality care is necessary to have right information and useful measure tools. AIM We want to build quality indicators that to measure asthma care in primary care. METHODS We use a modified RAND: systematic review of the literature on Quality Agencies and databases Embase, Cochrane and PubMed. After evaluating a number of indicators, we translated into Spanish. We invite 97 experts from across Spain through e-mail, to value each indicator, which was composed of various dimensions, using a Liker in two pass. We calculated the mean and median value for each indicator and its dimensions and the percentage agreement between them. RESULTS 105 asthma indicators were selected from the review; 46 were sent to expert’s panel. In second phase Delphi, 44 people respond (28 paediatricians primary care, 8 pulmonologists, 3 nurses, and 2 allergists. 32 indicators exceeded 70% of valuation, with agree of the expert panel. We measure aspects such as access to care, c...

Una torre de enfriamiento humedo debe enfriar 40 kg/seg de agua de 40 a 30 °C. El aire atmosferico entra a la torre de enfriamiento a 1 atm, con temperaturas de bulbo seco y humedo de 22 y 16°C, respectivamente , y sale a 32 °C con una humedad relativa de 95%. Usando la carta psicrométrica, determinar: a) flujo volumetrico de aire a la entrada de la torre de enfriamiento y b) el flujo másico de agua de reposición necesaria. Aire Agua 32°C 40 kg/seg 95% 40 Aire Agua 22°C ma 16°C 30°C Propiedades termodinamicas del sistema tablas de vapor: entalpia del agua liquida saturada a (40°C) h3 = 167.571 kj/kg de aire entalpia del agua liquida saturada a (30°C) h4 = 125.803 kj/kg de aire De carta psicrometrica a una humedad relativa de 95% entalía del aire h1(22°C) 62 kj/kg de aire entalpia del aire h2 (32°C) 105 kj/kg de aire humedad especifica del aire w1(22°C) 0.016 kgA/kgB humedad especifica del aire w2(32°C) 0.0285 kgA/kgB volumen específico v1 (22°C) 0.862 kg aire seco Balance de materia balance de masa de aire seco ma1=ma2=ma3 balance de masa de agua m3+ma2w1 = m4 + ma2w2 Balance de energia entradas = salidas ∑m h(entrada) = ∑m h(salida) Despejando ma ma = m3(h3-h4) = 1670.72 = 40.32880363 (h2-h1)-(w2-w1)h4 41.4274625 m3 = 40 kg/seg Flujo volumetri de aire 1 atm