271 research outputs found
Ice morphology modification and solute recovery improvement by heating and annealing during block freeze-concentration of coffee extracts
Several treatments on ice blocks can be applied during block freeze-concentration to increase the solute recovery from the ice. In the present study, the changes in the ice block’s temperature and the application of annealing during the block freeze-concentration of aqueous coffee extracts were studied. The ice block was subjected to heating and annealing prior to the thawing stage. The effect of coolant temperature during ice block heating (T = -10 and -5 °C) and the application of annealing (+, -) on solute recovery and ice structure morphology was evaluated. The use of annealing during block freeze-concentration modified the ice crystal morphology and increased the solute recovery only when it is applied at the highest temperature. In general, the annealing process increased the size and circularity of the ice crystals, consequently improving the solute recovery. Thus, annealing can be used to increase the solute recovery during block freeze-concentration.Postprint (published version
Estudio comparativo de la composición química del aceite esencial de Calycolpus moritzianus (Myrtaceae) proveniente de cinco regiones de Norte de Santander.Colombia
Los Aceites Esenciales (AEs) fueron obtenidos a partir de hojas de la especie Calycolpus moritzianus, recolectada en cinco egiones del departamento Norte de Santander: Chinácota, Ocaña, Pamplonita, Salazar y Toledo, por el método Destilación-Extracción con Solvente Simultánea (DES). El análisis cualitativo de los constituyentes volátiles mayoritarios del AE, se realizó por la técnica de Cromatografía de Gases de Alta Resolución (CGAR), utilizando el Detector de Ionización de Llama (FID) y el Detector Selectivo de Masas (MSD). Se logró la identificación de treinta y dos (32) compuestos, destacándose por su abundancia el Limoneno (17-38%), el 1,8-Cineol o Eucaliptol (12- 43.3%),el α-Pineno (2.3-5.6%), el β-Cariofileno (0.1-8.9%), α-Terpineol (0.2-5.5%) y el Guaiol (0.3- 20.2%), los cuales varían su concentración relativa según la región de procedencia. El análisis cuantitativo de los componentes volátiles mayoritarios se realizó empleando la técnica de normalización, estandarización externa e interna y finalmente, con los datos obtenidos se efectuó el respectivo análisis estadístico de los componentes principales (PCA)
Anxiety, distress, and turnover intention of healthcare workers in Peru by their distance to the epicenter during the COVID-19 crisis
We conducted a cross-sectional survey to assess the anxiety, distress, and turnover intention (likelihood to leave their current job) of healthcare workers in Peru during the COVID-19 pandemic. Our results reported that 21.7% healthcare workers in Peru experienced severe anxiety, whereas 26.1% of them experienced severe mental distress. A higher level of education related with a lower level of anxiety. Younger workers had a higher level of turnover intention than their older colleagues did. Healthcare workers in the private sector had a higher turnover intention than those in the public sector. Most importantly, people who were geographically far from Lima, the epicenter in Peru, during the outbreak experienced less anxiety and mental distress, corroborating the ripple effect and disconfirming the typhoon eye theory. However, the direction of these relationships can change depending on the type of institutions (public versus private) and the type of employees' contract (full time versus part time). Our research helps provide insights for clinical professionals in identifying the vulnerable groups to mental disorders in Peru. This is the first study to assess anxiety, mental distress, and turnover intention in healthcare workers in Peru during the COVID-19 pandemic. Copyrigh
Desarrollo y acumulación de Ulva spp. en la costa de la Bretaña francesa: por una necesaria reorientación de las investigaciones
Durante décadas, las investigaciones desarrolladas sobre la proliferación de Ulva en Bretaña han postulado la hipótesis de que los flujos de nitrógeno vertidos al mar por los cursos de agua en el mes de junio son los responsables del desarrollo de estas algas; y que por lo tanto su reducción durante la primavera constituye el principal medio de control. Los Programas de Acción implantados asumen esta hipótesis, así como los modelos que la integran. La drástica reducción de aportes de nitrógeno que se plantea, además de inalcanzable y probablemente ineficaz, parece poco consistente. Se revisan aquí los argumentos que cuestionan este postulado y se propone el desarrollo de nuevas investigaciones, a fin de obtener los suficientes datos fiables que permitan profundizar en la ecología de este fenómenoFor several decades, research on Ulva blooms in
Brittany, have postulated the hypothesis that the flow of
nitrogen discharged by rivers in June, was responsible for
the growth of algae and that to reduce the nitrogen flow in
the spring, is the controlling factor. Action programs
implemented and models that integrate it reflect this
assumption. The drastic reduction of nitrogen, in addition to
being inaccessible and probably ineffective, actually seems
poorly supported. We review the arguments that challenge
the current theory and we recommend deploying new
research in order to obtain sufficient reliable data and better
understand the ecology of this phenomenonS
Correlación entre la act ividad antibacteriana y los componentes del aceite esencial de Calycolpus moritzianus
El aceite esencial (AE) de hojas de Calycolpus moritzianus, recolectado en las veredas de Pamplonita, Chinácota, Toledo, Salazar y Ocaña del departamento de Norte de Santander-Colombia fue obtenido por Arrastre con Vapor y analizado por Cromatografía de Gases de Alta Resolución acoplada a Espectrometría de Masas. Se identificaron 32 componentes, los cuales representaron el 98.7 % del total de constituyentes. Loscomponentes mayoritarios fueron el Limoneno (30.73 ± 11.13%) y el Eucaliptol (28.04 ± 10.81%), seguidos del -Pineno (6.80 ± 1.85%), -Cariofileno (6.73 ± 2.13%), Guaiol (3.46 ± 1.80%), -Terpineol (3.24 ± 1.26%), Oxido de Cariofileno (2.99 ± 3.04%), -Copaeno (1.39 ± 0.62%) y Germacreno-B (0.76 ± 0.60%).El aceite esencial fue efect ivo contra Bacillus subtilis ATCC 6633, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923 y Proteus mirabilis ATCC 4307, encontrándose como Concentraciones Mínimas Inhibitorias (CMI) 39 g/mL 106 g/mL 836.4 g/mL y 892.2 g/mL respectivamente. El análisis delcoeficiente de actividad antibacteriana de los componentes mayoritarios, demostró que el -Copaeno fue el más influyente en dicha actividad
Definition of wind blowers for vehicles testing at chassis-dyno facilities using a CFD approach
[EN] The need to increase measurement accuracy of fuel consumption and pollutant emissions
in vehicles is forcing the market to develop chassis-dyno test cells that reproduce on-road
conditions realistically.
Air-cooling is key to vehicle performance. It is therefore critical that the design of a test
cell guarantees realistic cooling of all vehicle components, as important errors in fuel consumption
and emissions measurements may otherwise arise. In a test-room, a blower
placed in front of the vehicle supplies the cooling air. While there are some guidelines in
the literature for the selection of fans required for emissions measurements for standard
driving cycles, the information for designing the air supply system for specific tests in other
areas is scarce.
New Real Driving Emissions (RDE) legislation will force manufacturers to perform onroad
measurements of pollutants. This represents a significant challenge due to the variability
of conditions coming from non-controlled parameters. In order to optimize vehicles,
different tests are performed in cells equipped with a chassis-dyno where the on-road flow
field around the vehicle is reproduced as closely as possible.
This work provides some guidelines for the definition of the airflow supply system of
chassis-dyno facilities for vehicle optimization tests, based on a CFD analysis of the flow
characteristics around the vehicle. By comparison with the solution obtained for a vehicle
in real road driving conditions, the exit section of the blower and the distance between the
blower exit and the car that best reproduce realistic on-road flow conditions in a test room
are determined.
2017 Elsevier Ltd. All rights reserved.Broatch, A.; Margot, X.; Gil, A.; Galindo, E.; Soler, R. (2017). Definition of wind blowers for vehicles testing at chassis-dyno facilities using a CFD approach. Transportation Research Part D Transport and Environment. 55:99-112. doi:10.1016/j.trd.2017.06.029S991125
ME20-S as a Potential Biomarker for the Evaluation of Uveal Melanoma
PURPOSE: We previously identified the presence of the melanocyte-specific secreted (ME20-S) glycoprotein in secretomes of uveal melanoma (UM) cultures. The aim of this study was to test for the presence and levels of ME20-S in the serum of patients with choroidal nevi and UM and correlate these levels with individual clinical data. METHODS: Serum ME20-S levels were determined by ELISA in 111 patients distributed into four categories (53 choroidal nevi, 30 untreated UM, 11 10-year disease-free [DF] UM, 17 hepatic metastatic UM) and 32 age- and sex-matched controls. ME20-S levels were correlated with individual clinical data. RESULTS: The UM and the metastatic groups showed significantly higher levels of serum ME20-S than the other groups (P < 0.001). ME20-S levels in the DF patients did not differ from those in the control group. In addition, log-transformed serum ME20-S levels showed a positive correlation with the thickness of the lesion mass in UM patients (regression coefficient 0.0689, 95% confidence interval 0.0689-0.1123, R2 = 27.1%). CONCLUSIONS: Elevated ME20-S serum levels are associated with tumor size and advanced stages of UM while low levels are characteristic of DF patients. ME20-S might be a promising serum marker for UM and useful for monitoring metastatic disease
Ultrafast transient liquid assisted growth of high current density superconducting films
The achievement of high growth rates in YBaCuO epitaxial high-temperature superconducting films has become strategic to enable high-throughput manufacturing of long length coated conductors for energy and large magnet applications. We report on a transient liquid assisted growth process capable of achieving ultrafast growth rates (100 nm s −1) and high critical current densities (5 MA cm −2 at 77 K). This is based on the kinetic preference of Ba-Cu-O to form transient liquids prior to crystalline thermodynamic equilibrium phases, and as such is a non-equilibrium approach. The transient liquid-assisted growth process is combined with chemical solution deposition, proposing a scalable method for superconducting tapes manufacturing. Additionally, using colloidal solutions, the growth process is extended towards fabrication of nanocomposite films for enhanced superconducting properties at high magnetic fields. Fast acquisition in situ synchrotron X-ray diffraction and high resolution scanning transmission electron microscopy (STEM) become crucial measurements in disentangling key aspects of the growth process. High throughput manufacturing of long length coated conductors requires fast epitaxial growth of high-temperature superconducting films. Here, Soler et al. report an ultrafast growth rates and high critical current densities of YBaCuO films using a transient liquid-assisted growth method
Fractionation of eucalyptus globulus wood by glycerol-water pretreatment: optimization and modeling
A glycerol-organosolv process can be a good alternative for Eucalyptus wood fractionation into its main
compounds, improving the enzymatic saccharification of the cellulose. A study of process variables - glycerol−water percent
content, temperature, and process time - was carried out using a Box-Behnken experimental design. The cellulose obtained from
pretreated solids was recovered almost quantitatively, leading to a solid with a high percentage of cellulose (77 g/100 g of
pretreated solid), low lignin content (9 g/100 g of pretreated solid), and 18% of residual hemicellulose in the solid at 200 °C,
56% of glycerol−water and 69 min. The enzymatic saccharification was enhanced achieving 98% cellulose-to-glucose conversion
(under conditions: liquid to solid ratio 20 g/g and enzyme loading 20 FPU/g of solid). This study contributes to the
improvement of biomass fractionation by exploring an eco-friendly treatment which allows for almost complete wood
fractionation into constituents and high levels of glucose recovery available for subsequent yeast fermentation to bioethanol.The authors A. Romani and F. B. Pereira thank to the Portuguese Foundation for Science and Technology (FCT, Portugal) for their fellowships (grant number: SFRH/BPD/77995/2011 and SFRH/BD/64776/2009, respectively)
Análisis de la energía cinética turbulenta en un tanque de agitación aplicando velocimetría por imágenes de partículas
La aplicación de los tanques de agitación se extiende a lo largo de una gran variedad de industrias, como la alimentaria, la química, la minera, la farmacéutica entre otras, teniendo como principal objetivo alcanzar una mezcla homogénea de su contenido, donde la energía mecánica se transforma en energía cinética. Esto produce un incremento de la velocidad y conlleva a la creación de patrones de flujo que se encuentran dentro del tanque. En este trabajo se analizó la energía cinética turbulenta (TKE, por sus siglas en inglés, Turbulent Kinetic Energy) mediante la técnica de la velocimetría por imágenes de partículas (PIV, por sus siglas en inglés, Particle Image Velocimetry), utilizando la metodología de la resolución angular. Lo cual permitirá observar su variación conforme el impulsor cambia su posición angular con respecto al plano de medición.The employment of the stirred tank extends among a wide industry process, such as the food, the chemical, the mineral processing, the pharmaceutical, and so on. Been its principal aim to achieve a homogeneous mixture of its content. Here the mechanical energy is converted to kinetic energy. Yielding to an increase of the velocity flow and the generation of fluid patterns inside the tank. In this work the Turbulent Kinetic Energy (TKE) was evaluated by means of the Particle Image Velocimetry using the angled-resolved approach. This allow to observe the variation of the TKE when the impeller changes its angular position according to the measured plane
- …