Diseño y Simulación de un Deshidratador Mixto Indirecto de Frutas/Design and simulation of an Indirect Mixed Fruit Dehydrator

En el presente estudio se determinaron las características del diseño para un Deshidratador Mixto Indirecto (DMI) con una capacidad de 50 kg. Este deshidratador está constituido por el colector solar, placa de absorción, cubierta, ducto de succión, ventilador, resistencias eléctricas, zona de secado y ducto de aireación. Los elementos fueron diseñados mediante el programa SolidWorks, que permitió la simulación mecánica y termodinámica del proceso de secado, mediante el cual se pudieron determinar las características de los elementos del equipo. Se calculó que la temperatura óptima para la deshidratación de las frutas está entre los 40 y 70 ∘C. El calor específico del compartimiento de secado fue uniforme, con un valor de 2860,8 J/(kg.K); con la ayuda del ventilador se logró homogenizar el flujo del aire a la temperatura de deshidratación: a 50∘C fue homogénea en la zona de secado. Los resultados obtenidos en la simulación vaticinan un correcto funcionamiento del equipo. The present study determined the design characteristics for an Indirect Mixed Dehydrator (IMD) with a capacity of 50 kg. The solar collector, absorption plate, cover, suction duct, fan, electric resistances, drying zone and aeration duct constitute this dehydrator. The elements were designed trough the SolidWorks program, which allowed the mechanical and thermodynamic simulation of the drying process; by which it was possible to determine the elements' characteristics of the equipment. The optimum temperature for the dehydration of fruits was between 40 and 70 ∘C. The specific heat of the drying compartment was uniform and has a value of 2860.8 J / (kg K), with the help of the fan it is possible to homogenize the air flow at the dehydration temperature: at 50 ∘C it was homogeneous in the drying zone. The results obtained in the simulation guarantee the correct functioning of the equipment. Palabras Clave: Deshidratador Mixto Indirecto, Deshidratador de Frutas, simulación mecánica y termodinámica. Keywords: Indirect Mixed Dehydrator, Fruit Dehydrator, mechanical and thermodynamics simulatio

PARAMETROS FISICOS Y QUIMICOS QUE INFLUYEN SOBRE LA APTITUD DE UN SITIO DESTINADO A LA DISPOSICION DE RESIDUOS MUNICIPALES

RESUMEN En un terreno considerado para tiradero controlado se determinaron parámetros fisicoquímicos; porosidad, textura C.I.C., pH y contenido salino como características que influyen en la permeabilidad del medio subyacente, y por ende en la atenuación de sustancias que pueden afectar al agua subterránea. Este terreno se le identificó como Solonack y Solonetz con drenaje imperfecto, ubicado en una zona baja y próximo al mar, mostrando un contenido salino importante en las fuentes muestreadas; su textura proporciona porosidades mayores de 20% en el 50% del terreno. Al hacer la correlación con la Capacidad de Intercambio Catiónico, el tipo de arcilla y el extracto de saturación se considera que las características del terreno permitirá que éste pueda administrarse con mínimo riesgo de contaminación siempre y cuando los residuos requieran un tratamiento y manejo de acuerdo a los mismos. INTRODUCCION Al ser considerado al suelo como cuerpo natural las características físico -químicas como la textura, porosidad, pH, conductividad eléctrica, Capacidad de Intercambio Cationico toman mayor importancia. La textura forma parte de la fase sólida del suelo y se refiere a los separados de limo, arena y arcilla contenida en él. La proporción de estos componentes afecta el movimiento y el almacenamiento de agua en el suelo (Baver 1988, Personal de laboratorio de los E.U. 1973) situación que puede presentarse de igual manera para fluidos similares. La clasificación se basa generalmente en el tamaño de las partículas menores de 2 mm de diámetro. La porosidad varia con el tipo y tamaño de las partículas que lo conforman, se expresa por la relación entre el volumen de su parte vacía u ocupada por aire y/o agua y su volumen total; en general las partículas de menor diámetro tendrán mayor porosidad, y los suelos con mayor porosidad presentan una menor permeabilidad, a menos que el arreglo de los poros sea adecuado o existan fracturas en ellos, aunque esta no es una medida estricta de la permeabilidad (Cepeda 1991, Coras 19878). La concentración de sales, la turbiedad, pH, C.I.C. del fluido son denominados factores extrínsecos cuya influencia se refleja en la permeabilidad del suelo. La turbidez disminuye con el tiempo la permeabilidad y la intensidad de infiltración. La concentración de sales produce una floculación o defloculación con los coloides del suelo, por lo tanto puede disminuir o aumentar la permeabilida

Community structure informs species geographic distributions

This is the author accepted manuscript. The final version is available from Public Library of Science via the DOI in this recordUnderstanding what determines species’ geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species’ large-scale distributions, and this information can improve the predictions of species distributionsThis work was funded by FCT Project “QuerCom” (EXPL/AAG-GLO/2488/2013) and the ERA-Net BiodivERsA project “EC21C” (BIODIVERSA/0003/2011). A.M.N. was supported by a Bolsa de Investigacao de Pos-doutoramento (BI_Pos-Doc_UEvora_Catedra Rui Nabeiro_EXPL_AAG-GLO_2488_2013) and postdoctoral fellowships from the Ministry of Economy and Competitivity (FPDI-2013-16266 and IJCI‐2015‐23498). MGM acknowledges support by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (FORECOMM). J. Vicente is supported by POPH/FSE funds and by National Funds through FCT - Foundation for Science and Technology under the Portuguese Science Foundation (FCT) through Post-doctoral grant SFRH/BPD/84044/2012. AE has a postdoctoral contract funded by the project CN-17-022 (Principado de Asturias, Spain). We are grateful to OneGeology for providing the geological data

Validation of models with constant bias: an applied approach

Objective. This paper presents extensions to the statistical validation method based on the procedure of Freese when a model shows constant bias (CB) in its predictions and illustrate the method with data from a new mechanistic model that predict weight gain in cattle. Materials and methods. The extensions were the hypothesis tests and maximum anticipated error for the alternative approach, and the confidence interval for a quantile of the distribution of errors. Results. The model evaluated showed CB, once the CB is removed and with a confidence level of 95%, the magnitude of the error does not exceed 0.575 kg. Therefore, the validated model can be used to predict the daily weight gain of cattle, although it will require an adjustment in its structure based on the presence of CB to increase the accuracy of its forecasts. Conclusions. The confidence interval for the 1-α quantile of the distribution of errors after correcting the constant bias, allows determining the top limit for the magnitude of the error of prediction and use it to evaluate the evolution of the model in the forecasting of the system. The confidence interval approach to validate a model is more informative than the hypothesis tests for the same purpose

IMF - metallicity: a tight local relation revealed by the CALIFA survey

Variations in the stellar initial mass function (IMF) have been invoked to explain the spectroscopic and dynamical properties of early-type galaxies. However, no observations have yet been able to disentangle the physical driver. We analyse here a sample of 24 early-type galaxies drawn from the CALIFA survey, deriving in a homogeneous way their stellar population and kinematic properties. We find that the local IMF is tightly related to the local metallicity, becoming more bottom-heavy towards metal-rich populations. Our result, combined with the galaxy mass-metallicity relation, naturally explains previous claims of a galaxy mass-IMF relation, derived from non-IFU spectra. If we assume that - within the star formation environment of early-type galaxies - metallicity is the main driver of IMF variations, a significant revision of the interpretation of galaxy evolution observables is necessary.Comment: Accepted for publication in ApJL. 6 pages, 4 figure

Variable speed liquid chiller drop-in modeling for predicting energy performance of R1234yf as low-GWP refrigerant

This paper presents a model for a variable-speed liquid chiller integrating a compressor model based on Buckingham π-theorem to accurately predict the system performance when R134a is replaced with R1234yf, using a wide range of data obtained from an experimental setup. Relevant variables such as temperature, pressure, mass and volumetric flow rates, compressor power consumption and rotation speed were measured at several positions along the refrigeration and secondary circuits and were used to validate the developed model. Model results show that cooling capacity and power consumption predicted values are in good agreement with experimental data, within ±5%, being slightly higher for the deviation obtained for R134a than for R1234yf. Moreover, model results indicate that R1234yf has a reduction of coefficient of performance (COP) compared with R134a (between 2 and 11.3%), and that R1234yf COP reduction is diminished at intermediate volumetric flow rate and higher inlet temperature for the evaporator secondary fluid, respectively. On the other hand, an environmental analysis based on TEWI (total equivalent warming impact) method showed that direct emissions are almost negligible for R1234yf. However, there are no environmental benefits in terms of indirect greenhouse gas emissions using R1234yf without system modifications (as for instance the addition of internal heat exchanger or R1234yf new design components), which are required to reduce the liquid chiller climate change contribution using it as low GWP alternative in comparison with the typically used R134a refrigerant

One-dimensional Cooper pairing

We study electron pairing in a one-dimensional (1D) fermion gas at zero temperature under zero- and finite-range, attractive, two-body interactions. The binding energy of Cooper pairs (CPs) with zero total or center-of-mass momentum (CMM) increases with attraction strength and decreases with interaction range for fixed strength. The excitation energy of 1D CPs with nonzero CMM display novel, unique properties. It satisfies a dispersion relation with \textit{two} branches: a\ phonon-like \textit{linear }excitation for small CP CMM; this is followed by roton-like \textit{quadratic} excitation minimum for CMM greater than twice the Fermi wavenumber, but only above a minimum threshold attraction strength. The expected quadratic-in-CMM dispersion \textit{in vacuo }when the Fermi wavenumber is set to zero is recovered for \textit{any% } coupling. This paper completes a three-part exploration initiated in 2D and continued in 3D.Comment: 12 pages, 6 figure

Comparative evaluation of R1234yf, R1234ze(E) and R450A as alternatives to R134a in a variable speed reciprocating compressor

A comparative energetic evaluation of R1234yf, R1234ze(E) and R450A as alternatives to R134a in a variable speed compressor is carried out. A compressor model based on dimensionless numbers was obtained using the Buckingham p -theorem, which was validated with experimental data; showing that the prediction error of the model is lower than ± 10% and ± 2 K for temperature. The experimental data were obtained by testing R134a, R1234yf, R1234ze(E) and R450A for a wide range of operating condi- tions. Results obtained with the validated model, show that the dimensionless approach provides a similar estimation of energy parameters compared with the experimental results, such as power con- sumption, refrigerant mass fl ow rate, cooling capacity, COP, discharge temperature and compressor ef- fi ciencies for each refrigerant tested using the dimensionless approach proposed. The comparative evaluation of the compressor predictions shows a reduction in the cooling capacity obtained with R1234yf, R450A and R1234ze(E), in comparison with R134a. Also, COP values for R1234yf, R450A, and R1234ze(E) are lower than those obtained from R134a. Finally, results shows that the dimensionless correlation compressor model can be used to predict the performance of other reciprocating compres- sors, at similar operating conditions for a wide range of compressor rotation speed, with a reasonable accuracy.The authors thankfully acknowledge to the "Consejo Nacional deCiencia y Tecnología (CONACYT)” for their support to this study, and to the “Ministerio de Educación, Cultura y Deporte” (Grant number FPU12/02841) for sponsoring this work through “Becas y Contratosde Formación de Profesorado Universitario del Programa Nacional de Formación de Recursos Humanos de Investigación del ejercicio 2012”

Progressive Shifts in the Gut Microbiome Reflect Prediabetes and Diabetes Development in a Treatment-Naive Mexican Cohort.

Type 2 diabetes (T2D) is a global epidemic that affects more than 8% of the world\u27s population and is a leading cause of death in Mexico. Diet and lifestyle are known to contribute to the onset of T2D. However, the role of the gut microbiome in T2D progression remains uncertain. Associations between microbiome composition and diabetes are confounded by medication use, diet, and obesity. Here we present data on a treatment-naive cohort of 405 Mexican individuals across varying stages of T2D severity. Associations between gut bacteria and more than 200 clinical variables revealed a defined set of bacterial genera that were consistent biomarkers of T2D prevalence and risk. Specifically, gradual increases in blood glucose levels, beta cell dysfunction, and the accumulation of measured T2D risk factors were correlated with the relative abundances of four bacterial genera. In a cohort of 25 individuals, T2D treatment-predominantly metformin-reliably returned the microbiome to the normoglycemic community state. Deep clinical characterization allowed us to broadly control for confounding variables, indicating that these microbiome patterns were independent of common T2D comorbidities, like obesity or cardiovascular disease. Our work provides the first solid evidence for a direct link between the gut microbiome and T2D in a critically high-risk population. In particular, we show that increased T2D risk is reflected in gradual changes in the gut microbiome. Whether or not these T2D-associated changes in the gut contribute to the etiology of T2D or its comorbidities remains to be seen