Influence of the pulse wave in the stratification of high density particles in a JIG device

Se estudió el movimiento de partículas sometidas a cuatro perfiles de pulsación en un concentrador gravimétrico, mediante lechos fluidizados pulsados tipo jig, el cual es muy utilizado en la industria minera para la concentración de minerales pesados. Los perfiles de pulsación utilizados en la simulación fueron senoidal, triangular, diente de sierra atrasado y diente de sierra adelantado. Las velocidades locales bidimensionales del campo de flujo de agua se calcularon a partir de las ecuaciones de continuidad y momentum, por medio de técnicas CFD mediante la implementación del algoritmo SIMPLE. El movimiento de las partículas se modela mediante un balance de fuerzas aplicando la segunda ley de movimiento de Newton. Las fuerzas de interacción sólido-líquido se calculan mediante el modelo matemático Euleriano-Lagrangiano, extendido a una suspensión de partículas que poseen distribución amplia de tamaño y densidad. Para analizar el movimiento de las partículas, se deriva una ecuación de trayectoria que muestra la respuesta en el tiempo de las partículas, que incluye las fuerzas de masa virtual, gravedad, gradiente de presión, arrastre y Basset. El estudio mostró que la trayectoria de las partículas es muy sensible a la forma de onda aplicada en la condición de frontera a la entrada de la cámara del jig.A study of particle motion subjected to four different pulsation profiles on a pulsated fluidized bed jig concentrator was carried out. The profiles used in the simulation were – sinusoidal, triangle, sawtooth-backward and sawtooth-forward. Two-dimensional local velocities of the water flow field were calculated from the continuity and momentum equations by CFD techniques implementing SIMPLE algorithm. The particle motion is modeled by a forces balance applying the Newton’s second law of motion. Liquid-solid interactions forces are calculated by the mathematical Euler-Lagrangian model extended to a particle suspension having a wide size and density distribution. To analyze the particle motion in jig, we derived a trajectory equation for the response time of particle that include virtual mass, gravity, pressure gradient, drag and Basset forces. The study demonstrates significant differences in the particle trajectories for various pulsation profiles applied to the boundary condition at the inlet to the jig chamber

Influence of the pulse wave in the stratification of high density particles in a JIG device

Se estudió el movimiento de partículas sometidas a cuatro perfiles de pulsación en un concentrador gravimétrico, mediante lechos fluidizados pulsados tipo jig, el cual es muy utilizado en la industria minera para la concentración de minerales pesados. Los perfiles de pulsación utilizados en la simulación fueron senoidal, triangular, diente de sierra atrasado y diente de sierra adelantado. Las velocidades locales bidimensionales del campo de flujo de agua se calcularon a partir de las ecuaciones de continuidad y momentum, por medio de técnicas CFD mediante la implementación del algoritmo SIMPLE. El movimiento de las partículas se modela mediante un balance de fuerzas aplicando la segunda ley de movimiento de Newton. Las fuerzas de interacción sólido-líquido se calculan mediante el modelo matemático Euleriano-Lagrangiano, extendido a una suspensión de partículas que poseen distribución amplia de tamaño y densidad. Para analizar el movimiento de las partículas, se deriva una ecuación de trayectoria que muestra la respuesta en el tiempo de las partículas, que incluye las fuerzas de masa virtual, gravedad, gradiente de presión, arrastre y Basset. El estudio mostró que la trayectoria de las partículas es muy sensible a la forma de onda aplicada en la condición de frontera a la entrada de la cámara del jig.A study of particle motion subjected to four different pulsation profiles on a pulsated fluidized bed jig concentrator was carried out. The profiles used in the simulation were – sinusoidal, triangle, sawtooth-backward and sawtooth-forward. Two-dimensional local velocities of the water flow field were calculated from the continuity and momentum equations by CFD techniques implementing SIMPLE algorithm. The particle motion is modeled by a forces balance applying the Newton’s second law of motion. Liquid-solid interactions forces are calculated by the mathematical Euler-Lagrangian model extended to a particle suspension having a wide size and density distribution. To analyze the particle motion in jig, we derived a trajectory equation for the response time of particle that include virtual mass, gravity, pressure gradient, drag and Basset forces. The study demonstrates significant differences in the particle trajectories for various pulsation profiles applied to the boundary condition at the inlet to the jig chamber

Caloric reductions needed to achieve obesity goals in Mexico for 2030 and 2040: A modeling study

Background In Mexico, obesity prevalence among adults increased from 23% in 2000 to 36% in 2018, approximately. Mexico has not defined short- or long-term obesity goals, obscuring the level of effort required to achieve a relevant impact. We aimed to explore potential obesity goals for 2030 and 2040 in Mexico and to estimate the required caloric reductions to achieve them. Methods and findings We obtained anthropometric and demographic information on the Mexican adult population (age ≥20 years) from the Health and Nutrition Surveys conducted in 2000, 2006, 2012, 2016, and 2018 (n = 137,907). Each survey wave is cross-sectional, multistage, and representative of the Mexican population at the national, regional, and urban/rural levels. Obesity prevalence was projected for 2030 and 2040 by combining population projections of energy intake by socioeconomic status (SES) with a weight-change microsimulation model taking into account individual-level information on sex, age, physical activity, and initial body weight and height. If current trends continue, Mexico’s obesity prevalence is expected to increase from 36% (95% CI 35% to 37%) in 2018 to 45% (uncertainty interval [UI] 41% to 48%) in 2030 and to 48% (UI 41% to 55%) in 2040. Based on expert opinion, we identified 3 obesity goals scenarios: (1) plausible (38% in 2030 and 36% in 2040); (2) intermediate (33% in 2030 and 29% in 2040); and (3) ideal based on the average prevalence of Organization for Economic Co-operation and Development countries (OECD; 19%). We estimated the caloric reductions needed to achieve the goal scenarios using the microsimulation model. Obesity was projected to increase more rapidly in the low SES (around 34% in 2018 to 48% (UI 41% to 55%) in 2040), than in the middle (around 38% to 52% (UI 45% to 56%)), or high SES group (around 36% to 45% (UI 36% to 54%)). Caloric reductions of 40 (UI 13 to 60), 75 (UI 49 to 95), and 190 (UI 163 to 215) kcal/person/day would be needed to reach the plausible, intermediate, and the ideal (OECD) average scenarios for 2030, respectively. To reach the 2040 goals, caloric reductions of 74 (UI 28 to 114), 124 (UI 78 to 169), and 209 (UI 163 to 254) kcal/person/day would be required, respectively. Study limitations include assuming a constant and sedentary physical activity level, not considering cohort-specific differences that could occur in the future, and assuming the same caloric trends under no intervention and the obesity goal scenarios. Conclusions To reach the 3 obesity goals in 2040, caloric reductions between 74 and 209 kcal/day/person would be needed in Mexico. A package of new and stronger interventions should be added to existing efforts such as food taxes and warning labels on non-nutritious food

Influencia de la forma de onda de pulsación en la estratificación de partículas de alta densidad en un equipo JIG

Se estudió el movimiento de partículas sometidas a cuatro perfiles de pulsación en un concentrador gravimétrico, mediante lechos fluidizados pulsados tipo jig, el cual es muy utilizado en la industria minera para la concentración de minerales pesados. Los perfiles de pulsación utilizados en la simulación fueron senoidal, triangular, diente de sierra atrasado y diente de sierra adelantado. Las velocidades locales bidimensionales del campo de flujo de agua se calcularon a partir de las ecuaciones de continuidad y momentum, por medio de técnicas CFD mediante la implementación del algoritmo SIMPLE. El movimiento de las partículas se modela mediante un balance de fuerzas aplicando la segunda ley de movimiento de Newton. Las fuerzas de interacción sólido-líquido se calculan mediante el modelo matemático Euleriano-Lagrangiano, extendido a una suspensión de partículas que poseen distribución amplia de tamaño y densidad. Para analizar el movimiento de las partículas, se deriva una ecuación de trayectoria que muestra la respuesta en el tiempo de las partículas, que incluye las fuerzas de masa virtual, gravedad, gradiente de presión, arrastre y Basset. El estudio mostró que la trayectoria de las partículas es muy sensible a la forma de onda aplicada en la condición de frontera a la entrada de la cámara del jig

Caloric reductions needed to achieve obesity goals in Mexico for 2030 and 2040: A modeling study.

BackgroundIn Mexico, obesity prevalence among adults increased from 23% in 2000 to 36% in 2018, approximately. Mexico has not defined short- or long-term obesity goals, obscuring the level of effort required to achieve a relevant impact. We aimed to explore potential obesity goals for 2030 and 2040 in Mexico and to estimate the required caloric reductions to achieve them.Methods and findingsWe obtained anthropometric and demographic information on the Mexican adult population (age ≥20 years) from the Health and Nutrition Surveys conducted in 2000, 2006, 2012, 2016, and 2018 (n = 137,907). Each survey wave is cross-sectional, multistage, and representative of the Mexican population at the national, regional, and urban/rural levels. Obesity prevalence was projected for 2030 and 2040 by combining population projections of energy intake by socioeconomic status (SES) with a weight-change microsimulation model taking into account individual-level information on sex, age, physical activity, and initial body weight and height. If current trends continue, Mexico's obesity prevalence is expected to increase from 36% (95% CI 35% to 37%) in 2018 to 45% (uncertainty interval [UI] 41% to 48%) in 2030 and to 48% (UI 41% to 55%) in 2040. Based on expert opinion, we identified 3 obesity goals scenarios: (1) plausible (38% in 2030 and 36% in 2040); (2) intermediate (33% in 2030 and 29% in 2040); and (3) ideal based on the average prevalence of Organization for Economic Co-operation and Development countries (OECD; 19%). We estimated the caloric reductions needed to achieve the goal scenarios using the microsimulation model. Obesity was projected to increase more rapidly in the low SES (around 34% in 2018 to 48% (UI 41% to 55%) in 2040), than in the middle (around 38% to 52% (UI 45% to 56%)), or high SES group (around 36% to 45% (UI 36% to 54%)). Caloric reductions of 40 (UI 13 to 60), 75 (UI 49 to 95), and 190 (UI 163 to 215) kcal/person/day would be needed to reach the plausible, intermediate, and the ideal (OECD) average scenarios for 2030, respectively. To reach the 2040 goals, caloric reductions of 74 (UI 28 to 114), 124 (UI 78 to 169), and 209 (UI 163 to 254) kcal/person/day would be required, respectively. Study limitations include assuming a constant and sedentary physical activity level, not considering cohort-specific differences that could occur in the future, and assuming the same caloric trends under no intervention and the obesity goal scenarios.ConclusionsTo reach the 3 obesity goals in 2040, caloric reductions between 74 and 209 kcal/day/person would be needed in Mexico. A package of new and stronger interventions should be added to existing efforts such as food taxes and warning labels on non-nutritious food

Financial Inclusion and Social Protection: A Case for India Post

Analysis of empirical evidence from three Indian states suggests that financial inclusion strategies may be inefficient if designed without accounting for the government social protection programmes. Social protection programmes generate additional needs for financial services among the poor, meeting which can also deepen the impact of such programmes. Being a government department and the largest financial service-providing network, India Post may be most suitably located to implement such synergistic strategies. An examination of the official data on India Post indicates that the approach of diversifying its financial products to target higher-end clients in largely urban areas may not be appropriate due to its competitive disadvantage. We argue that delivery of financial services through post offices, built around social protection, may contribute to financial inclusion in rural areas while improving revenues of India Post