Economic and Social Deficiency: Their Influence on Students’ Academic Performance

This study ascertained to find out relationship between economic and social deficiency and their influence on education students’ academic performance at West Visayas State University-Janiuay Campus, School Year 2014-2015.  The descriptive-correlational method was used with academic performance as dependent variable and economic and social deficiency as independent variables.  The participants were the 266 students selected through stratified random sampling.  Data were gathered through questionnaire-checklist and Grade Point Average.  The statistical tools used were frequency, rank, mean, standard deviation, and Pearson's r computed through SPSS. The results show that the top three predominant economic deficiencies are inability to join in school activities; inability to pay for photocopy of hand outs and other reference materials; inability to spend any amount for snacks/lunch.  Likewise, the top three most social deficiencies are understanding community norms; having social perception, making choices and self- monitoring; perceiving how others are feeling and sharing empathy.  Further, education students have a “moderate extent” social deficiency and the overall performance was “very good”.  Moreover, a negative correlation but no significant relationship existed between economic and social deficiency and between social deficiency and academic performance.  The economic deficiency and academic performance revealed a positive and no significant relationship.

Planck pre-launch status: The optical system

Planck is a scientific satellite that represents the next milestone in space-based research related to the cosmic microwave background, and in many other astrophysical fields. Planck was launched on 14 May of 2009 and is now operational. The uncertainty in the optical response of its detectors is a key factor allowing Planck to achieve its scientific objectives. More than a decade of analysis and measurements have gone into achieving the required performances. In this paper, we describe the main aspects of the Planck optics that are relevant to science, and the estimated in-flight performance, based on the knowledge available at the time of launch. We also briefly describe the impact of the major systematic effects of optical origin, and the concept of in-flight optical calibration. Detailed discussions of related areas are provided in accompanying papers

Modelización de la difusividad de la humedad, la energía de activación y el consumo específico de energía para el grano de maíz húmedo en un secador convectivo de lecho fijo y fluidizado

Thin layer drying characteristics of high moisture corn under fixed, semi fluidized and fluidized bed conditions with high initial moisture content (66.82% wb) in a laboratory fluidized bed convective dryer was studied at air temperatures of 50, 65, 80 and 95°C. In order to find a suitable drying curve, seven thin layer-drying models were fitted to the experimental data of moisture ratio. Among the applied mathematical models, Midilli et al. model was the best for drying behavior prediction in corn thin layer drying. This model presented high values for correlation coefficient (R2). Fick´s second law was used to compute moisture diffusivity with some simplifications. Computed values of moisture diffusivity varied at the boundary of 4.87 × 10–11 – 2.90 × 10–10 m2 s–1 and 1.02 × 10–10 – 1.29 × 10–9 m2 s–1 during the first and second drying falling-rate, respectively. Values of effective moisture diffusivity for corn were also increased as input air temperature was increased. Value of activation energy varied from a minimum of 18.57 to a maximum of 50.74 kJ mol–1 from 50 to 95°C with drying conditions of fixed to fluidized bed. Specific energy consumption (SEC) for thin-drying of high moisture corn was found to be in the range of 0.33 × 106 – 1.52 × 106 kJ kg–1 from 50 to 95°C with drying condition of fluidized and fixed bed, respectively. Increase in air temperature in each air velocity caused decrease in SEC value. These corn properties would be necessary to design the best dryer system and to determine the best point of drying process.Se estudiaron las características del secado en capa delgada del grano de maíz húmedo en condiciones de lecho fijo, semi-fluidizado y fluidizado con alto contenido de humedad inicial (66,82%), en un secador de convección de lecho fluidizado de laboratorio a las temperaturas del aire de 50, 65, 80 y 95°C. Con el fin de encontrar una curva de secado apropiada, se ajustaron siete modelos matemáticos de secado en capa delgada a los datos experimentales de la ratio de humedad. Entre los modelos aplicados, el de Midilli et al., con un alto coeficiente de correlación (R2), fue el mejor para predecir el secado del maíz en capa delgada. Se utilizó la segunda ley de Fick para calcular, con algunas simplificaciones, la difusividad de la humedad, que dio unos valores entre 4,87 × 10–11 – 2.90 y 1,02 × 10–11 – 1.29 m2 s–1 durante la primera y segunda fase de secado de rapidez decreciente, respectivamente. Los valores de la difusividad efectiva de la humedad para el maíz también aumentaron al aumentar la temperatura de entrada del aire. El valor de la energía de activación varió desde un mínimo de 18,57 a un máximo de 50,74 kJ mol–1 entre 50 y 95°C, con condiciones de secado del lecho fijo a fluidizado. El consumo específico de energía (SEC) para secado en capa delgada del grano de maíz húmedo fue entre 0,33 × 106 y 1,52 × 106 kJ kg–1 entre 50 y 95°C, en lecho fluidizado y fijo, respectivamente. Un aumento de la temperatura en la velocidad del aire disminuye el valor de SEC. Es necesario conocer estas propiedades del maíz para diseñar el mejor sistema de secado y para determinar el mejor punto del proceso de secado

Modeling of moisture diffusivity, activation energy and specific energy consumption of high moisture corn in a fixed and fluidized bed convective dryer

Thin layer drying characteristics of high moisture corn under fixed, semi fluidized and fluidized bed conditions with high initial moisture content (66.82% wb) in a laboratory fluidized bed convective dryer was studied at air temperatures of 50, 65, 80 and 95°C. In order to find a suitable drying curve, seven thin layer-drying models were fitted to the experimental data of moisture ratio. Among the applied mathematical models, Midilli et al. model was the best for drying behavior prediction in corn thin layer drying. This model presented high values for correlation coefficient (R2). Fick´s second law was used to compute moisture diffusivity with some simplifications. Computed values of moisture diffusivity varied at the boundary of 4.87 × 10�11 � 2.90 × 10�10 m2 s�1 and 1.02 × 10�10 � 1.29 × 10�9 m2 s�1 during the first and second drying falling-rate, respectively. Values of effective moisture diffusivity for corn were also increased as input air temperature was increased. Value of activation energy varied from a minimum of 18.57 to a maximum of 50.74 kJ mol�1 from 50 to 95°C with drying conditions of fixed to fluidized bed. Specific energy consumption (SEC) for thin-drying of high moisture corn was found to be in the range of 0.33 × 106 � 1.52 × 106 kJ kg�1 from 50 to 95°C with drying condition of fluidized and fixed bed, respectively. Increase in air temperature in each air velocity caused decrease in SEC value. These corn properties would be necessary to design the best dryer system and to determine the best point of drying process.Se estudiaron las características del secado en capa delgada del grano de maíz húmedo en condiciones de lecho fijo, semi-fluidizado y fluidizado con alto contenido de humedad inicial (66,82%), en un secador de convección de lecho fluidizado de laboratorio a las temperaturas del aire de 50, 65, 80 y 95°C. Con el fin de encontrar una curva de secado apropiada, se ajustaron siete modelos matemáticos de secado en capa delgada a los datos experimentales de la ratio de humedad. Entre los modelos aplicados, el de Midilli et al., con un alto coeficiente de correlación (R2), fue el mejor para predecir el secado del maíz en capa delgada. Se utilizó la segunda ley de Fick para calcular, con algunas simplificaciones, la difusividad de la humedad, que dio unos valores entre 4,87 × 10�11 � 2.90 y 1,02 × 10�11 � 1.29 m2 s�1 durante la primera y segunda fase de secado de rapidez decreciente, respectivamente. Los valores de la difusividad efectiva de la humedad para el maíz también aumentaron al aumentar la temperatura de entrada del aire. El valor de la energía de activación varió desde un mínimo de 18,57 a un máximo de 50,74 kJ mol�1 entre 50 y 95°C, con condiciones de secado del lecho fijo a fluidizado. El consumo específico de energía (SEC) para secado en capa delgada del grano de maíz húmedo fue entre 0,33 × 106 y 1,52 × 106 kJ kg�1 entre 50 y 95°C, en lecho fluidizado y fijo, respectivamente. Un aumento de la temperatura en la velocidad del aire disminuye el valor de SEC. Es necesario conocer estas propiedades del maíz para diseñar el mejor sistema de secado y para determinar el mejor punto del proceso de secado

A comparative study on the effects of dry and wet grinding on mineral flotation separation–a review

Water scarcity dictates to limit the use of water in ore processing plants particularly in arid regions. Since wet grinding is the most common method for particle size reduction and mineral liberation, there is a lack of understanding about the effects of dry grinding on downstream separation processes such as flotation. This manuscript compiles various effects of dry grinding on flotation and compares them with wet grinding. Dry grinding consumes higher energy and produces wider particle size distributions compared with wet grinding. It significantly decreases the rate of media consumption and liner wear; thus, the contamination of pulp for flotation separation is lower after dry grinding. Surface roughness, particle agglomeration, and surface oxidation are higher in dry grinding than wet grinding, which all these effects on the flotation process. Moreover, dry ground samples in the pulp phase correlate with higher Eh and dissolved oxygen concentration. Therefore, dry grinding can alter the floatability of minerals. This review thoroughly assesses various approaches for flotation separation of different minerals, which have been drily ground, and provides perspectives for further future investigations. © 2019 The Author