Mostrando ítems 241-260 de 1587

Evaluation of the Light/Dark Cycle and Concentration of Tannery Wastewater in the Production of Biomass and Metabolites of Industrial Interest from Microalgae and Cyanobacteria

Urbina-Suarez, Nestor Andres; Ayala González, Darly D.; Rivera Amaya, Jennyfer D.; Barajas Solano, andres F; Machuca-Martinez, Fiderman (WaterSuiza, 2022-01-25)

The tanning industry transforms animal skins into leather and produces liquid effluents with a high organic and inorganic pollutant load. This work evaluated the effect of the tannery wastewater (TWW) concentration and ...
Cellulase Production from Trichoderma harzianum: a Framework Modeling for Evaluating Different Operating Mode Strategies

Mora, D; Carrillo, F; Gelves Gelves, Elizabeth (Reino Unido, 2021-09-12)

The cellulase enzyme has been used in essential applications in the textile industry and the formulation of some medicines. Therefore, a mathematical model based on previous reports is proposed for cellulase enzyme ...
Computer-Aided Evaluation of Ethanol Production from a Continuous Operating Mode using Simulink

Alvarado, K; Niño, L. Elisa; Gelves Gelves, Elizabeth (Reino Unido, 2021-09-10)

Fossil fuels have become a great energy source worldwide. However, its prolonged use has caused severe environmental pollution problems. Biofuels generated from biomass as a product of microbial biotechnology emerge as ...
The Circular Economy Approach to Improving CNP Ratio in Inland Fishery Wastewater for Increasing Algal Biomass Production

García Martínez, Janet B.; Sanchez Tobos, Leidy P.; Carvajal Albarracin, Nicolaz A ; Barajas Solano, andres F; Barajas Ferreira, Crisostomo; Kafarov, Viatcheslav; ZUORRO, Antonio (WaterSuiza, 2022-02-26)

In this work, the capacity of wastewater from an inland fishery system in Colombia (Norte de Santander) was tested as culture medium for Chlorella sp. and Scenedesmus sp. Due to insufficient N and P concentrations for ...
Modeling of Clavulanic Acid Production from Streptomyces clavuligerus using a Continuous Operation Mode

Ariza, L; Rubio, J; Moreno, V; Niño, L. Elisa; Gelves Gelves, Elizabeth (Reino Unido, 2021-09-12)

Clavulanic acid is a β-lactam inhibitor produced by fermentation with Streptomyces clavuligerus cells, and it is usually used to prevent resistance to certain antibiotics. However, CA production is limited at the bioreactor ...
Natural Clay-Based Materials for the Removal of Antibiotics from Contaminated Water

Coviello, Donatella; García-Martinez, Janet; Buccione, Roberto; Scrano, Laura; Barajas Solano, andres F; Brienza, Monica (CHEMICAL ENGINEERING TRANSACTIONS, 2021-10)

The release of antibiotics into the environment has increased remarkably due to the extensive use of these pharmaceuticals worldwide. Sulfamethoxazole (SMX) and trimethoprim (TMP), two antibiotics proposed in the 3rd Watch ...
Application of Chlorella sp. and Scenedesmus sp. in the Bioconversion of Urban Leachates into Industrially Relevant Metabolites

Ortiz Betancur, Jeimy J.; Herrera Ochoa, Marla S.; García Martínez, Janet B.; Urbina-Suarez, Nestor Andres; López Barrera, Germán L.; Barajas Solano, andres F; Bryan, Samantha; ZUORRO, Antonio (Applied SciencesSuiza, 2022-02-26)

: This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon ...
Adaptive nodes algorithm to solve the orphan nodes problem in a ZigBee Tree WSN

Escobar Amado, Christian David; Celis, Jose Miguel; Sepúlveda, Sergio; Castro Casadiego, Sergio ; Medina Delgado, Byron; Guevara, Dinael (IngeniareChile, 2021-06)

We have developed an algorithm based on hybrid nodes composed of an XBee S2C module configured in API mode with escape and connected to a microcontroller ATMEGA 328P to solve the orphan node problem of a ZigBee tree ...
Entorno social y bienestar emocional en el adulto mayor

Hernandez Vergel, Viviana Karina; Solano Pinto, Natalia; Ramirez Leal, Pastor (Revista Venezolana de GerenciaVenezuela, 2021-07-16)

Lo que se presenta a continuación es un estudio basado en una metodología teórica documental que tiene como objetivo principal describir la relación que existe entre el entorno social y el bienestar ...
Predictive model of mass flows of gaseous emissions from beehive ovens

mendoza lizcano, sonia maritza; palacios alvarado, wlamyr; Medina Delgado, Byron (Journal of Physics: Conference SeriesReino Unido, 2021-08-09)

One of the techniques used in the industry for the control of variables is, from their magnitudes, such as fuel flow, air volume, amount of material mass, among others. The ceramic industry needs to measure and control ...
Utilization of agro-industrial waste to improve thermal behavior of products made of fired clay for traditional masonry

Sanchez Molina, Jorge; Diaz Fuentes, Carmen Xiomara; Colmenares Uribe, Andrea Paola (Journal of Physics: Conference SeriesReino Unido, 2021-08-09)

The reutilization of agro-industrial waste in the manufacture of fired clay products is a sustainable strategy that aims at the circular economy. The most known waste in Norte de Santander, Colombia, are coffee husk and ...
Gramalote: Gobernanza climática y planificación del desarrollo en contexto

Avendaño Castro, William Rodrigo; rueda vera, gerson; Luna Pereira, Henry Orlando (Revista Venezolana de GerenciaVenezuela, 2022-03-14)

El objetivo de este artículo es analizar la gobernanza climática a partir de la planificación del desarrollo y partiendo de una experiencia reciente en Colombia. Se trata de un estudio de corte cualitativo ...
Impact of Antibiotics as Waste, Physical, Chemical, and Enzymatical Degradation: Use of Laccases

Gamboa Mora, María Cristina; Rincón Gamboa, Sandra M.; Ardila Leal, Leidy Diana; Poutou-Piñales, Raúl Alberto; Pedroza, Aura; Quevedo, Balkys (MoleculesSuiza, 2022-07-11)

The first traces of Tetracycline (TE) were detected in human skeletons from Sudan and Egypt, finding that it may be related to the diet of the time, the use of some dyes, and the use of soils loaded with microorganisms, ...
Novel method for stress history analysis in normally consolidated clays

Martinez, J H; Ruge Cárdenas, Juan Carlos; Rojas Suárez, Jhan Piero (Journal of Physics: Conference SeriesReino Unido, 2021-06-09)

The historical investigation of stresses in a clay material is essential to predict the compressible behaviour of a soil layer that, in most cases functions as a foundation support of superstructures. Because the stresses ...
Experimental assessment of swelling potential in montmorillonite soils

Pérez, J C; Rojas Suárez, Jhan Piero; Orjuela Castro, Javier Arturo; Ruge Cárdenas, Juan Carlos; Cáceres, J R (Journal of Physics: Conference SeriesReino Unido, 2021-06-09)

The study of the physicochemical activity of clays is essential to understand the mechanical-hydraulic behavior. The experimental analysis of the expansivity of soils is linked to the content of clay minerals present in ...
Dominio del inglés frente al proyecto de vida: percepciones de estudiantes universitarios

Avendaño Castro, William Rodrigo; rueda vera, gerson; Garcí, Orlando (Formación UniversitariaChile, 2022-06)

El objetivo de esta investigación es describir las percepciones de un grupo de estudiantes universitarios de pregrado frente al dominio del inglés en relación con su proyecto de vida. La metodología es de paradigma emp ...
Thermodynamic study of a supercritical carbon dioxide Brayton cycle based on main compression intercooling configuration

Orjuela Abril, Martha Sofia ; Bustos Urbano, Víctor Jhoel ; PABON LEON, JHON ANTUNY (Journal of Physics: Conference SeriesReino Unido, 2021-06-09)

This study presents detailed thermodynamic modeling of a supercritical Brayton cycle operating with carbon dioxide as a working fluid for electric power generation. The study incorporates a main compression intercooling ...
Physical-mathematical model to determine the structural efficiency of sections shaped as ellipses and parallelograms when used in reinforced concrete columns

MARQUEZ-PEÑARANDA, JORGE FERNANDO; Vergel Ortega, Mawency; GALLARDO PÉREZ, HENRY DE JESÚS (Journal of Physics: Conference SeriesReino Unido, 2021-06-09)

Current practice of structural design of reinforced concrete columns uses mainly rectangular and circular sections. Among other reasons, this preference is linked to its ease of construction and spatial efficiency, and ...
Estimation of missing data in a geophysical series of precipitation

GALLARDO PÉREZ, HENRY DE JESÚS; Vergel Ortega, Mawency; Rojas Suárez, Jhan Piero (Journal of Physics: Conference SeriesReino Unido, 2021-06-09)

The analysis of dynamic systems is a topic of great interest in the basic sciences since it allows direct inference of the behavior of different systems. The study of physical phenomena provides large databases that, if ...
Modeling and simulation of an improvement proposal through the method mechanized transplanting

Orjuela Abril, Martha Sofia ; Trujillo, luis eduardo; Pabón León, Jhon Antuny (Journal of Physics: Conference SeriesReino Unido, 2021-06-09)

Rice agriculture in Colombia has high costs and low profitability, compared to rice agriculture in leading countries that are supported in different ways by their governments worldwide. Part of these high costs is due ...

Envíos recientes

Evaluation of the Light/Dark Cycle and Concentration of Tannery Wastewater in the Production of Biomass and Metabolites of Industrial Interest from Microalgae and Cyanobacteria
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Urbina-Suarez, Nestor Andres | 2022-01-25

The tanning industry transforms animal skins into leather and produces liquid effluents with a high organic and inorganic pollutant load. This work evaluated the effect of the tannery wastewater (TWW) concentration and the light/dark cycle on the production of biomass, carbohydrates, proteins, lipids, and pigments (carotenoids and phycobiliproteins) on two microalgae (Chlorella sp. and Scenedesmus sp.) and one cyanobacterium (Hapalosiphon sp.). A non-factorial central experimental design with a response surface was implemented using the STATISTICA 7.0 software. High removal percentages for nitrates (97%), phosphates (73.3%), and chemical oxygen demand (93.2%) were achieved with the three strains. The results also highlight that the use of a constant light regime (24:0) and the concentration of real TWW affect the biomass production, since the highest concentration of biomass recorded was 1.31 g L−1 of Hapalosiphon sp. with 100% undiluted wastewater.

LEER
Cellulase Production from Trichoderma harzianum: a Framework Modeling for Evaluating Different Operating Mode Strategies
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Mora, D | 2021-09-12

The cellulase enzyme has been used in essential applications in the textile industry and the formulation of some medicines. Therefore, a mathematical model based on previous reports is proposed for cellulase enzyme enhancement. First, the kinetic constants were taken from the literature. Then, two operating strategies were carried out to maximize cellulase production using 10g/L of cellulose and 0.4g/L of cells as a first strategy using a batch mode. Alternatively, a second operating mode is simulated using continuous cellulose feeding. Finally, a comparative analysis was made for determining the best operating mode related to maximal cellulase production. Interestingly, the continuous mode shows a high cellulase concentration lasting a shorter time than the batch mode to avoid inhibiting enzyme production. One of the most important findings of this work focuses on increasing cellulase production with values of 1800 FPT/L simulating the continuous mode. The latter suggests that cellulase production could be double the concentration obtained with the traditional batch mode (800FPU/L). Results obtained in this research may be promising for the enzyme production industry. Using simulation techniques, it is possible to determine an enhancement without requiring excessive experimentation and resources.

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Computer-Aided Evaluation of Ethanol Production from a Continuous Operating Mode using Simulink
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Alvarado, K | 2021-09-10

Fossil fuels have become a great energy source worldwide. However, its prolonged use has caused severe environmental pollution problems. Biofuels generated from biomass as a product of microbial biotechnology emerge as an alternative to the use of compounds derived from oil. Therefore, their production results in complex experiments and source investment. That is why engineering studies implementation using mathematical models and simulation techniques should be specified in bioprocesses. The latter focused on optimizing the process parameters, maximizing productivity, generating greater profitability, and reducing cost. This research aimed at the computer-assisted evaluation of obtaining bioethanol from Saccharomyces cerevisiae to determine the most critical factors in the production process using a continuous mode. It was determined that the feed rate significantly influences the bioethanol volumetric productivity.

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The Circular Economy Approach to Improving CNP Ratio in Inland Fishery Wastewater for Increasing Algal Biomass Production
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García Martínez, Janet B. | 2022-02-26

In this work, the capacity of wastewater from an inland fishery system in Colombia (Norte de Santander) was tested as culture medium for Chlorella sp. and Scenedesmus sp. Due to insufficient N and P concentrations for successful algae growth, the effect of wastewater replenishment with NO3 , PO4 , and Na2CO3 or NaHCO3 as a carbon source was analyzed using a three-factor nonfactorial response surface design. The results showed that the addition of NaNO3 (0.125 g/L), K2HPO4 (0.075 g/L), KH2PO4 (0.75 g/L), and NaHCO3 (0.5 and 2 g/L for Chlorella sp. and Scenedesmus sp. respectively) significantly increased the biomass of Chlorella sp. (0.87 g/L) and Scenedesmus sp. (0.83 g/L). Although these results show that the addition of other nutrients is not necessary (Na, Mg, SO4 , Ca, etc.), it is still essential to determine the quality of the biomass produced in terms of its application as a feed supplement for fish production.

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Modeling of Clavulanic Acid Production from Streptomyces clavuligerus using a Continuous Operation Mode
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Ariza, L | 2021-09-12

Clavulanic acid is a β-lactam inhibitor produced by fermentation with Streptomyces clavuligerus cells, and it is usually used to prevent resistance to certain antibiotics. However, CA production is limited at the bioreactor level due to its low performance. The latter generates expensive processes and challenging to operate on a large scale. In this research, a mathematical model is proposed to simulate the clavulanic acid production from an operation strategy based on continuous mode. The preceding, to identify trends allowing to improve the productivity of the mentioned metabolite. Results are compared to the traditional operating batch mode. According to the results found, the final concentration of the β-lactam inhibitor could be increased by up to 60% regarding the simulated data in batch mode. Results obtained demonstrate the importance of computational techniques in bioprocess engineering since bioprocess simulation focuses on identifying critical operating parameters as a starting point in antibiotic production optimization.

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Natural Clay-Based Materials for the Removal of Antibiotics from Contaminated Water
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Coviello, Donatella | 2021-10

The release of antibiotics into the environment has increased remarkably due to the extensive use of these pharmaceuticals worldwide. Sulfamethoxazole (SMX) and trimethoprim (TMP), two antibiotics proposed in the 3rd Watch List (WL) under the Water Framework Directive (Directive 2000/60/EC) and often prescribed together, were selected as representative pollutants. This study investigates volcanic soil collected from Monte Vulture (PZ, Italy) as a material tested to remove SMX and TMP from wastewater. XRD showed that volcanic soil was composed of 33.95 % pyroxene, 34.41 % olivine, 21.25 % albite, and 10.39 % muscovite. Preliminary tests revealed that this material was an excellent adsorbent of TMP but not of SMX. The presence of metal like Fe and Al makes it capable of activating oxidizing agents such as potassium peroxymonosulfate (PMS). In fact, experiments showed that the SMX was efficiently degraded under the test conditions. Additionally, a systematic study was performed to evaluate the influence of the most critical factors, such as initial antibiotic concentrations, liquid-to-solid ratio, and reaction time on the removal efficiency. The range of levels evaluated for each factor was selected according to the level of information they can provide. A central composite design coupled with response surface methodology was used. From a statistical analysis of the results, the main effects and interactions between variables were estimated. A polynomial model was also developed and validated to provide a mathematical description of the removal process. Overall, the results of this study suggest that the proposed approach could represent a valuable strategy for in situ and ex situ remediation of antibiotic-contaminated waters and soils.

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Application of Chlorella sp. and Scenedesmus sp. in the Bioconversion of Urban Leachates into Industrially Relevant Metabolites
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Ortiz Betancur, Jeimy J. | 2022-02-26

: This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon source (Na2CO3 , and NaHCO3 ) were tested to improve biomass production, metabolites synthesis, and removal of NO3 and PO4 . The result shows that both strains can effectively grow in media with up to 5% (v/v) leachate, while significantly reducing the concentrations of NO3 , and PO4 (80 and 50%, respectively). The addition of NaHCO3 as a carbon source improved the final concentration of biomass, lipids, carbohydrates, and the removal of NO3 and PO4 in both strains.

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Adaptive nodes algorithm to solve the orphan nodes problem in a ZigBee Tree WSN
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Escobar Amado, Christian David | 2021-06

We have developed an algorithm based on hybrid nodes composed of an XBee S2C module configured in API mode with escape and connected to a microcontroller ATMEGA 328P to solve the orphan node problem of a ZigBee tree topology. The sensor nodes have both features End Device and Router that may alternate depending on the situation, and the node can adapt itself to keep the network integrality as much as possible. On the other hand, the coordinator node comprises an XBee S2C module and the embedded system Raspberry Pi 3, which hosts the algorithm and is set up as an access point, a database server, and a web server. Using the proposed algorithm, we were able to recover up to 42.8% of the network coverage, but it comes with an energy cost due to the switch from End Device to Router. Additionally, a mobile application integrated with notification service and Google Maps was developed to monitor every node’s behavior in the Wireless Sensor Network.

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Entorno social y bienestar emocional en el adulto mayor
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Hernandez Vergel, Viviana Karina | 2021-07-16

Lo que se presenta a continuación es un estudio basado en una metodología teórica documental que tiene como objetivo principal describir la relación que existe entre el entorno social y el bienestar emocional de los adultos mayores. En el desarrollo del artículo se define lo que es entorno social y bienestar emocional, así como se muestran las características que describen la etapa evolutiva de la vejez, edad adulta tardía o tercera edad, con la finalidad de mostrar la relación que existe entre cada una de esas definiciones. Los adultos mayores viven una etapa del desarrollo evolutivo determinada por el declive natural de las condiciones físicas, biológicas, intelectuales y psicoemocionales, lo cual es propio de las personas después de los 65 años, sin embargo, es necesario asumirlo desde la perspectiva de vejez positiva. Para ello es necesario conscienciar el potencial indiscutible de estímulo externo que posee el entorno social del adulto mayor para crear las condiciones objetivas y subjetivas que hagan de este momento vital una etapa satisfactoria.

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Predictive model of mass flows of gaseous emissions from beehive ovens
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mendoza lizcano, sonia maritza | 2021-08-09

One of the techniques used in the industry for the control of variables is, from their magnitudes, such as fuel flow, air volume, amount of material mass, among others. The ceramic industry needs to measure and control the polluting gases of its fixed sources in a less costly way, based on tools that allow agility in decision making to mitigate the adverse effects, not only to comply with a legal standard, but also for environmental and management commitment. The objective of the research is to design a predictive model of the concentration of polluting gases in the beehive ovens based on the results of the balance of matter and energy in the beehive ovens. An exploratory descriptive methodology was used, where data on beehive ovens and fourteen (14) continuous quantitative variables were considered through the statistical technique of multiple regression to analyze the predictive behavior of the pollutant concentration variables. As a result, the predictive capacity of the resulting model was high, explaining 79% of the total variation of the variable. The multiple correlation coefficient of the complete model was 0.79. During the analysis of the model assumptions, the Durbin Watson score reached a value of 1.971, evidencing compliance with the assumption of independence of the errors.

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Utilization of agro-industrial waste to improve thermal behavior of products made of fired clay for traditional masonry
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Sanchez Molina, Jorge | 2021-08-09

The reutilization of agro-industrial waste in the manufacture of fired clay products is a sustainable strategy that aims at the circular economy. The most known waste in Norte de Santander, Colombia, are coffee husk and rice husk. For this reason, this research studies the thermal impact of their insulating properties in traditional masonry products made of fired clay to be considered as insulating additives. The methodology involves the simulation of heat transfer and heat flux of the multiperforated brick and H10 block manufactured in mixtures of 100% clay and 95% clay and 5% additive to wastes in North Santander, Colombia, in the software ANSYS under the finite element method in extreme conditions of San José de Cúcuta. The results demonstrate that the residues of rice husk and coffee husk act as insulating technological nutrients with a reduction of temperatures of the interior surfaces of the products between 0.22 °C and 0.88 °C, respectively. The reutilization of residual raw materials from alternate construction industries is a sustainable consideration to evaluate new possibilities for the manufacture of products with less embedded energy and, therefore, with a lower carbon footprint than traditional fired clay products.

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Gramalote: Gobernanza climática y planificación del desarrollo en contexto
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Avendaño Castro, William Rodrigo | 2022-03-14

El objetivo de este artículo es analizar la gobernanza climática a partir de la planificación del desarrollo y partiendo de una experiencia reciente en Colombia. Se trata de un estudio de corte cualitativo enmarcado en el paradigma interpretativo. Se utilizó como instrumento de recolección de información el análisis documental aplicado sobre un conjunto de planes de desarrollo municipal. La información fue analizada a través de un método de codificación y categorización. Resultados: Se analizaron 119 unidades de texto y se identificaron 106 códigos abiertos distribuidos en catorce códigos axiales y siete categorías selectivas. Los hallazgos indican que la planificación del desarrollo ha integrado el medio ambiente y el cambio climático como variables transversales a las dinámicas sociales, productivas y económicas. Se concluye si bien existe la presencia de diversos procesos de gobernanza ambiental, existen múltiples retos para impulsar la participación de la comunidad.

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Impact of Antibiotics as Waste, Physical, Chemical, and Enzymatical Degradation: Use of Laccases
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Gamboa Mora, María Cristina | 2022-07-11

The first traces of Tetracycline (TE) were detected in human skeletons from Sudan and Egypt, finding that it may be related to the diet of the time, the use of some dyes, and the use of soils loaded with microorganisms, such as Streptomyces spp., among other microorganisms capable of producing antibiotics. However, most people only recognise authors dating between 1904 and 1940, such as Ehrlich, Domagk, and Fleming. Antibiotics are the therapeutic option for countless infections treatment; unfortunately, they are the second most common group of drugs in wastewaters worldwide due to failures in industrial waste treatments (pharmaceutics, hospitals, senior residences) and their irrational use in humans and animals. The main antibiotics problem lies in delivered and non-prescribed human use, use in livestock as growth promoters, and crop cultivation as biocides (regulated activities that have not complied in some places). This practice has led to the toxicity of the environment as antibiotics generate eutrophication, water pollution, nutrient imbalance, and press antibiotic resistance. In addition, the removal of antibiotics is not a required process in global wastewater treatment standards. This review aims to raise awareness of the negative impact of antibiotics as residues and physical, chemical, and biological treatments for their degradation. We discuss the high cost of physical and chemical treatments, the risk of using chemicals that worsen the situation, and the fact that each antibiotic class can be transformed differently with each of these treatments and generate new compounds that could be more toxic than the original ones; also, we discuss the use of enzymes for antibiotic degradation, with emphasis on laccases.

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Novel method for stress history analysis in normally consolidated clays
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Martinez, J H | 2021-06-09

The historical investigation of stresses in a clay material is essential to predict the compressible behaviour of a soil layer that, in most cases functions as a foundation support of superstructures. Because the stresses underwent in the geological past provide useful information to understand the response of the soil today. There are numerous methods for the interpretation of the preconsolidation stress, defined by the standard unidimensional consolidation test. The concept of preconsolidation stress is extremely useful in the geotechnical field to analyze and estimate settlements in a clay deposit, in addition to normalizing other parameters for comparative purposes. Through mineralogical analysis and consolidation tests based on different models for the estimation of the vertical consolidation coefficient, preconsolidation stress is evaluated by applying disparate constitutive methods. In order to observe the dispersion of results for a particular soil. A new technique is proposed for the determination of the preconsolidation stress prescribed in differential terms and with a high degree of objective interpretation.

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Experimental assessment of swelling potential in montmorillonite soils
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Pérez, J C | 2021-06-09

The study of the physicochemical activity of clays is essential to understand the mechanical-hydraulic behavior. The experimental analysis of the expansivity of soils is linked to the content of clay minerals present in the tactoid tissue, which affect is directly in proportion to the volumetric change that soil may undergo. This work aims to carry out an analysis to understand the expansive behavior of the proposed clay materials, using different techniques, both conventional and modern. For this purpose, the bentonite clay used with a majority montmorillonite component was analyzed through petrographic tests and images analysis. The samples with a base material and different contents of montmorillonite were prepared. Montmorillonite is a clay mineral with a very high swelling potential because even when it was used in low proportions on a sandy base material, the influence of the material is strong and the expansivity remained high.

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Dominio del inglés frente al proyecto de vida: percepciones de estudiantes universitarios
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Avendaño Castro, William Rodrigo | 2022-06

El objetivo de esta investigación es describir las percepciones de un grupo de estudiantes universitarios de pregrado frente al dominio del inglés en relación con su proyecto de vida. La metodología es de paradigma empírico-analítico, con enfoque cualitativo de nivel descriptivo y con diseño no experimental-transeccional. El instrumento utilizado es un cuestionario tipo Likert con 34 preguntas, aplicado a 683 estudiantes de pregrado de una universidad pública de la ciudad de Cúcuta en Colombia. Los datos se analizan a través de procedimientos de estadística descriptiva. Los resultados muestran que los estudiantes universitarios manifiestan una percepción generalmente favorable hacía el aprendizaje del inglés, y lo asocian de manera directa con su proyecto de vida profesional, laboral y, particularmente, personal. Se concluye que esta motivación se proyecta hacía una gran variedad de futuros escenarios que incluyen acceso a mejores oportunidades laborales, socializar en espacios multiculturales, viajes turísticos y emigrar

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Thermodynamic study of a supercritical carbon dioxide Brayton cycle based on main compression intercooling configuration
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Orjuela Abril, Martha Sofia | 2021-06-09

This study presents detailed thermodynamic modeling of a supercritical Brayton cycle operating with carbon dioxide as a working fluid for electric power generation. The study incorporates a main compression intercooling configuration while elucidating the effect of operational parameters on the overall performance based on energy and exergy perspectives. The model was carefully validated with relevant authors. Moreover, two different optimization methodologies, namely particle swarm optimization and fmincom, are evaluated based on convergence criteria. The results demonstrated that the fmincom reduced the iteration time between 140 s - 180 s. The cycle pressure played a central role in the stability of the thermophysical properties of the working fluid. The energy and exergy efficiencies present a direct relation with the inlet temperature. The air cooling and regenerators represent the biggest contributor to exergy destruction, whereas the compressors featured minimal impact on the exergy degeneration. Overall, the proposed configuration demonstrated robust performance to implement with high-grade heat sources, especially in non-interconnected areas.

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Physical-mathematical model to determine the structural efficiency of sections shaped as ellipses and parallelograms when used in reinforced concrete columns
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MARQUEZ-PEÑARANDA, JORGE FERNANDO | 2021-06-09

Current practice of structural design of reinforced concrete columns uses mainly rectangular and circular sections. Among other reasons, this preference is linked to its ease of construction and spatial efficiency, and the historical inertia of civil works processes. Nowadays, modern design and construction techniques make possible to study the structural beahviour of sections distinctively shaped. If typical sections are extended from circular to elliptical and from rectangular to parallelogram shaped, it is possible to compute mathematical and physical parameters needed for the structural analysis. This work presents a physical–mathematical model to determine the structural efficiency in terms of relative strength and stiffness of sections shaped as ellipses and parallelograms when used in reinforced concrete columns. To solve the model, a Matlab® code for drawing the column interaction diagram of each studied section was written. Each diagram describes, in terms of mechanical physics, the relation between the uniaxial bending and the compression load that defines safety conditions as a mathematical limiting curve. The governing equation has the form P(m,g)=f(M(m,g) in which P describes the axial load strength function, M the bending moment strength function, m the material properties, and g the geometrical characteristics function. Structural efficiency has been expressed as the relative behaviour of each section with respect to comparable rectangular sections. To obtain the results of the model, a Matlab® code was written.

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Estimation of missing data in a geophysical series of precipitation
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GALLARDO PÉREZ, HENRY DE JESÚS | 2021-06-09

The analysis of dynamic systems is a topic of great interest in the basic sciences since it allows direct inference of the behavior of different systems. The study of physical phenomena provides large databases that, if recorded at regular time intervals, constitute time series. However, time series of geophysical data in many cases present missing data and their estimation requires the application of valid methods that allow estimating reliable information to complete the series since some analysis methods require these series to be complete. Two methods are used in this article to estimate the missing values of the precipitation series in the city of San José de Cúcuta, Colombia, the first one consists of considering the univariate data series and applying an adjustment of the sequential conditional expectation method of forecasting with restrictions, the second one refers to analyze the data series of a nearby station and through multivariate methods establish the cointegration between the series, and then use this as a basis for estimating the missing data in the analysis series. The two methods are recursive, a first estimation of the model is made ignoring the missing data, an initial estimation of the missing data is made, then a new estimation of the model parameters and a new estimation of the missing data is made, the algorithm continues running with the new values replacing the values estimated in the previous phase until the difference of the estimated values between successive iterations is less than a value fixed beforehand. Finally, a comparison is made between the estimates made by the two methods.

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Modeling and simulation of an improvement proposal through the method mechanized transplanting
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Orjuela Abril, Martha Sofia | 2021-06-09

Rice agriculture in Colombia has high costs and low profitability, compared to rice agriculture in leading countries that are supported in different ways by their governments worldwide. Part of these high costs is due to the deficient technification of the processes, the absence of standardized procedures and the farmers' lack of resources. This article develops modeling and simulation of the implementation of the indirect seeding method by mechanized transplanting; these results are obtained through the study and definition of technologies for the cultivation method, the description of the process, machinery, equipment, and inputs, which determined the necessary capacity of the production plant through modeling and simulation in software Flexsim. Rice cultivation is one of the main incomes of countries with high population density and poor economy, alternatives and improvement actions are of great importance for the growth of the sector. As a result, there is evidence of improved crop productivity, better water consumption efficiencies by physical analysis (comparison of traditional and technician water consumption) and the necessary capacity of a production plant from harvesting to final packaging.

LEER

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B. Investigación: Envíos recientes

Evaluation of the Light/Dark Cycle and Concentration of Tannery Wastewater in the Production of Biomass and Metabolites of Industrial Interest from Microalgae and Cyanobacteria ﻿

Cellulase Production from Trichoderma harzianum: a Framework Modeling for Evaluating Different Operating Mode Strategies ﻿

Computer-Aided Evaluation of Ethanol Production from a Continuous Operating Mode using Simulink ﻿

The Circular Economy Approach to Improving CNP Ratio in Inland Fishery Wastewater for Increasing Algal Biomass Production ﻿

Modeling of Clavulanic Acid Production from Streptomyces clavuligerus using a Continuous Operation Mode ﻿

Natural Clay-Based Materials for the Removal of Antibiotics from Contaminated Water ﻿

Application of Chlorella sp. and Scenedesmus sp. in the Bioconversion of Urban Leachates into Industrially Relevant Metabolites ﻿

Adaptive nodes algorithm to solve the orphan nodes problem in a ZigBee Tree WSN ﻿

Entorno social y bienestar emocional en el adulto mayor ﻿

Predictive model of mass flows of gaseous emissions from beehive ovens ﻿

Utilization of agro-industrial waste to improve thermal behavior of products made of fired clay for traditional masonry ﻿

Gramalote: Gobernanza climática y planificación del desarrollo en contexto ﻿

Impact of Antibiotics as Waste, Physical, Chemical, and Enzymatical Degradation: Use of Laccases ﻿

Novel method for stress history analysis in normally consolidated clays ﻿

Experimental assessment of swelling potential in montmorillonite soils ﻿

Dominio del inglés frente al proyecto de vida: percepciones de estudiantes universitarios ﻿

Thermodynamic study of a supercritical carbon dioxide Brayton cycle based on main compression intercooling configuration ﻿

Physical-mathematical model to determine the structural efficiency of sections shaped as ellipses and parallelograms when used in reinforced concrete columns ﻿

Estimation of missing data in a geophysical series of precipitation ﻿

Modeling and simulation of an improvement proposal through the method mechanized transplanting ﻿

Envíos recientes

Evaluation of the Light/Dark Cycle and Concentration of Tannery Wastewater in the Production of Biomass and Metabolites of Industrial Interest from Microalgae and Cyanobacteria

Cellulase Production from Trichoderma harzianum: a Framework Modeling for Evaluating Different Operating Mode Strategies

Computer-Aided Evaluation of Ethanol Production from a Continuous Operating Mode using Simulink

The Circular Economy Approach to Improving CNP Ratio in Inland Fishery Wastewater for Increasing Algal Biomass Production

Modeling of Clavulanic Acid Production from Streptomyces clavuligerus using a Continuous Operation Mode

Natural Clay-Based Materials for the Removal of Antibiotics from Contaminated Water

Application of Chlorella sp. and Scenedesmus sp. in the Bioconversion of Urban Leachates into Industrially Relevant Metabolites

Adaptive nodes algorithm to solve the orphan nodes problem in a ZigBee Tree WSN

Entorno social y bienestar emocional en el adulto mayor

Predictive model of mass flows of gaseous emissions from beehive ovens

Utilization of agro-industrial waste to improve thermal behavior of products made of fired clay for traditional masonry

Gramalote: Gobernanza climática y planificación del desarrollo en contexto

Impact of Antibiotics as Waste, Physical, Chemical, and Enzymatical Degradation: Use of Laccases

Novel method for stress history analysis in normally consolidated clays

Experimental assessment of swelling potential in montmorillonite soils

Dominio del inglés frente al proyecto de vida: percepciones de estudiantes universitarios

Thermodynamic study of a supercritical carbon dioxide Brayton cycle based on main compression intercooling configuration

Physical-mathematical model to determine the structural efficiency of sections shaped as ellipses and parallelograms when used in reinforced concrete columns

Estimation of missing data in a geophysical series of precipitation

Modeling and simulation of an improvement proposal through the method mechanized transplanting

Portales Institucionales

Evaluation of the Light/Dark Cycle and Concentration of Tannery Wastewater in the Production of Biomass and Metabolites of Industrial Interest from Microalgae and Cyanobacteria

Cellulase Production from Trichoderma harzianum: a Framework Modeling for Evaluating Different Operating Mode Strategies

Computer-Aided Evaluation of Ethanol Production from a Continuous Operating Mode using Simulink

The Circular Economy Approach to Improving CNP Ratio in Inland Fishery Wastewater for Increasing Algal Biomass Production

Modeling of Clavulanic Acid Production from Streptomyces clavuligerus using a Continuous Operation Mode

Natural Clay-Based Materials for the Removal of Antibiotics from Contaminated Water

Application of Chlorella sp. and Scenedesmus sp. in the Bioconversion of Urban Leachates into Industrially Relevant Metabolites

Adaptive nodes algorithm to solve the orphan nodes problem in a ZigBee Tree WSN

Entorno social y bienestar emocional en el adulto mayor

Predictive model of mass flows of gaseous emissions from beehive ovens

Utilization of agro-industrial waste to improve thermal behavior of products made of fired clay for traditional masonry

Gramalote: Gobernanza climática y planificación del desarrollo en contexto

Impact of Antibiotics as Waste, Physical, Chemical, and Enzymatical Degradation: Use of Laccases

Novel method for stress history analysis in normally consolidated clays

Experimental assessment of swelling potential in montmorillonite soils

Dominio del inglés frente al proyecto de vida: percepciones de estudiantes universitarios

Thermodynamic study of a supercritical carbon dioxide Brayton cycle based on main compression intercooling configuration

Physical-mathematical model to determine the structural efficiency of sections shaped as ellipses and parallelograms when used in reinforced concrete columns

Estimation of missing data in a geophysical series of precipitation

Modeling and simulation of an improvement proposal through the method mechanized transplanting