Repositorio Universidad de Santander :: Buscando por browse.metadata.type "Documento de Conferencia"

Examinando por Tipo de Material "Documento de Conferencia"

Mostrando 1 - 20 de 40

Acceso abierto
An analysis of the types of innovation capabilities in medium-sized enterprises
(2019-07-30) Pertuz-Peralta, Vanessa Paola; Perez-Orozco, Adith Bismarck
Acceso abierto
Analysis of the atmospheric macro-physical using spatial methods
(2020-12-01) Andrades-Grassi, J. E.; Cuesta-Herrera, L.; Torres-Mantilla, H. A.; López-Hernández, J. Y.
The central western area of Venezuela has an unequal distribution of precipitation. Due to its agricultural importance, is necessary to plan water accounting and this requires a evaluation of spatial and temporal variability of precipitation and an estimate of local geophysical effect from the relief. In this research we use an iterative computationally lattice approach to perform a confirmatory analysis of the variability and the spatial correlation structure in monthly precipitation stations. Spatial correlograms and pooled empirical semivariogram were applied to evaluate the most appropriate spatial weighting matrix to estimate the Moran’s I. The altitude effect over monthly rainfall was estimated through spatial regression algorithm which determine the predominant spatial process in each slice. A homogeneous spatial stochastic process with positive spatial autocorrelation is evidenced. There is a trend towards a higher frequency of spatial error and spatial auto-regressive processes between the months of June and August whilst there are not dominant process between October and December. This response is caused by the dynamics of the intertropical convergence zone, which generates a seasonal effect on precipitation. These estimations allows decision-making in modeling and will lead to an improvement for analysis and forecasting in areas strongly affected by climate change and water stress.
Restringido
Análisis y Simulación de Modelos Económicos Complejos mediante el Enfoque de Dinámica de Sistemas
(2018-03) Orlandoni Merli, Giampaolo; Ramoni Perazzi, Josefa
Los fenómenos socio-económicos se han ido conformando cada vez más en fenómenos altamente complejos, cuyo análisis y solución requiere de metodologías y herramientas también más complejas e innovadoras. Basándose en el modelo de caos de Lorenz, este trabajo estudia modelos económicos que generan comportamientos caóticos, utilizando como metodología de análisis la dinámica de sistemas, enfoque que permite representar, analizar y resolver las ecuaciones diferenciales no lineales que definen dichos modelos. Del mismo modo, se simulan diferentes trayectorias para las ecuaciones planteadas, haciendo cambios en las condiciones iniciales de las variables de estado, y se hace análisis de sensibilidad sobre los parámetros relevantes de los sistemas definidos. Además, este trabajo presenta una breve sinopsis de la metodología de dinámica de sistemas y simula este tipo de modelos complejos caóticos; para ello se construyen modelos de simulación que pueden generar trayectorias dinámicas para las variables de estado consideradas, usando software apropiado para tal fin, como Madonna y Powersim,
Acceso abierto
Bioconversion of post-culture wastewater from farm fisheries for the production of high-value algal biomass
(Journal of Physics: Conference Series, 2019-11-01) Gámez-Ortiz, Lorainis Paola; González-Soto, Maria Johana; Perez-Roa, M E; García-Martinez, J B; Urbina-Suarez, N A; Diaz Castañeda, Claudia-Elizabeth
Post-consumption water from inland fisheries possesses a tremendous environmental impact on aquatic ecosystems due to their high load of nutrients such as Nitrates, Phosphates, Urea and organic load. Due to the high cost of current water treatment systems, most of the waters from inland fisheries are discharged without any treatment, thus generating a significant environmental impact in rivers of different localities. Cyanobacteria are a group of photosynthetic microorganisms that can grow in different environments including wastewater. Among the most industrially exploited cyanobacteria, Spirulina (Arthrospira) maxima is the most relevant microorganism, due to its capacity to produce large quantities of protein and colourants (especially phycocyanins) for the food and feed industry. The objective of this project is to determine the maximum production capacity of Spirulina in post-consumption waters of fish farming as a system for the treatment of this type of water through the biological capture of the various nutrients and the production of biomass of industrial interest. S. maxima was produced on 3 different media (wastewater + Zarouk, wastewater + K2HPO4, NaNO3, NaHCO3 and wastewater without any modification) for 30 days. Results shown that S. maxima can effectively grow on wastewater supplemented with NaNO3 (2.5 g/L), NaHCO3 (16.8 g/L) and K2HPO4 (0.5 g/L) to obtain up to 1.18 g/L of total biomass and 0.23 g/L of phycocianins. The scaling of culture at 10 L showed a minimal reduction on final biomass and phycocyanin (1.05 and 0.21 g/L respectively), this result indicates that the production of biomass and phycobiliproteins from S. maxima in wastewater from inland fisheries can be a possible candidate for the simplification of biomass and high-value metabolites process production.
Acceso abierto
Biofertilizing potential of a fertilizer based on cienego and native microorganisms in corn seeds
(Journal of Physics: Conference Series, 2019-11-29) Diaz Castañeda, Claudia-Elizabeth; Daza, D.; Arámbula, Claudia-Ivonne
In the development of the productive process of stone aggregates, during the stage of washing and extraction of sludge from the decanter wells, a "cienego" sand is produced in an approximate quantity of 24.75 tons per day, of which only 10% per day is commercialized, the remaining 90% must be discarded, causing financial detriment, impact on the environment in terms of pollution by handling the product that is discarded, occupation of useful areas and landscape degradation, among other impacts negatively affecting the companies in the sector, and their environment. The objective of this research was to evaluate a fertilizer based on cienego and three native microorganisms (Azotobacter sp, 1 Azotobacter sp, 2 and Pseudomonas sp) in corn seeds. For this purpose, three native strains of diazotrophic bacteria were isolated from soil samples of oil palm crops in Tibú, located at Norte de Santander, Colombia, which were biochemically identified using traditional culture media. These isolates were inoculated into corn seeds in trays with sterile soil plus ciénego at 70/30 ratio respectively, and the plant growth-promoting effect was recorded every 4 days, by measuring morphological variables such as height, number of leaves, number of roots, length and germination rate. The results showed that Azotobacter sp, 2 treatment presented a higher production of roots, reached greater height (cm), number of leaves and germination rate in comparison to control treatment after 12 days of monitoring, besides directly influencing the percentage of organic matter in the substrate and elements such as calcium, potassium and phosphorus, allowing greater productivity and corn seed yield once these were germinated.
Acceso abierto
Biomechanical analysis of grip strength in upper limb rehabilitation
(2022-01-05) Hernandez-Vergel, V.K.; Prada-Nunez, R.; Hernandez-Suarez, C.A.
This research is based on biomechanics as a science that involves concepts of engineering, mechanics, physic, anatomy, physiology, and many others, to study the human body with the desire to solve certain problems that may affect the performance of an individual in their work or personal level. This work is an investigative process in these areas of scientific and applied disciplines, in which the attention is focused on the hand as a valuable tool for the occupational performance of the human being, since through it is possible to touch, move, grasp, or manipulate objects. Injuries to this limb may be due to various causes, which require complex surgeries and long periods of rehabilitation to be reversed. This research highlights the importance of certain physical concepts that must be understood by the rehabilitation expert in order not to affect the surgery and thus guarantee the maximum functionality of the patient at the end of the recovery cycle.
Acceso abierto
Cell lysis analysis for respiratory viruses through simulation modeling
(2022-01-02) Cuesta-Herrera, L.; Pastenes, L.; Cordova-Lepe, F.; Arencibia, A.D.; Torres-Mantilla, Hugo A.
An ordinary system of differential equations leading to a simulation model is propose as methodological approach to analysis the incidence of infectious-contagious diseases, in this case using SARS-CoV-2 virus as pathogenic model. The dynamics of the model are drive by the interaction between susceptible cells contemplating respiratory epithelial cells and viral infection mediated by two types of lysis response. To perform the simulations, values of some variables and parameters were selected from referenced sources, considering that previous reports suggested that the viral load in the lower respiratory tract might reach its peak in the second week after the beginning of disease symptoms. The scenarios described in the simulations evidence the performance of the cell lysis response from susceptible cells that have been infected. The recommend model shows that an excess response from both the original virus and the mutated virus leads to an increase in the approximate time to control viral infection within the organism.
Acceso abierto
Characterization of biodeteriorating microorganisms in buildings in Bucaramanga, Colombia
(2019) Mantilla, K.; Suárez Barrera, M.; Rueda Forero, Nohora Juliana; Guarín Villamizar, Oscar Darío; Gómez Camargo, Fausto-Ramón; Durán, S.M.; Tiria Sandoval, Luis-Carlos
The action of the microorganisms upon the integrity of the constructing material is termed Biodeterioration, concrete resistance to the action of the microorganisms is considered an indirect measurement of its durability and could be used as a marker of the integrity of the structure. In Colombia, the studies considering this parameter are rare. The objective of this study was to isolate and characterize the microbial communities present in areas with evident deterioration in the selected buildings. To accomplish this, isolation, culturing and molecular identification of the isolates was performed. Results showed that Cladosporium spp, Aspergillus spp, Mucor spp, Penicillium spp, Penicillium spp, Rhizopus spp, Fusarium spp, Geotrichum spp, and bacterial genera such as Bacillus spp and Amphibacillus spp, coexist within the biofilms sampled. This study is a description and a starting point to deepen the characterization of these communities and to understand the role they perform in the integrity of the building materials considering the climatic and environmental conditions.
Acceso abierto
Clean production strategies for flour milling industry : A case study
(2015-07) Morales Méndez, Jonathan David; Garcés, Martha I; Calderón, Angélica M.; Silva Rodríguez, Ramón
Acceso abierto
Comparative analysis between asphaltites and extra heavy oil asphaltenes
(2020-12-05) Bustos, N.; Diaz, E.; Jerez, E.; Roa, M.
The asphaltite material receives many names depending on the country, or area of knowledge, for this reason it is also known as bitumen, asphalt and gilsonite, its composition is a mixture of high molecular weight organic substances, mainly polyaromatic compounds characterized by a black color, and they appear in a semi-solid or solid state. Asphaltenes correspond to the oil fraction with the highest molecular weight, this characteristic provides a high viscosity to hydrocarbons, which contain, in their composition, a concentration equal to or greater than 10%, although the exact structure of this is not known. molecular family, it has been possible to elucidate the functional groups present, such as carbonyl acids, thiols and pyridines, implying the presence of heteroatoms, such as nitrogen, sulfur and oxygen, but the most characteristic part of this type of molecules is their nucleus polyaromatic, which can contain up to 20 or more benzene rings. A sample of Colombian asphaltite was taken and compared with a sample of asphaltenes from a Colombian extra-heavy crude, solubility tests, a spectroscopic characterization by Ultraviolet-Visible, infrared, a thermal evaluation by Thermogravimetry and Differential Scanning Calorimetry were carried out. , in addition to an analysis by X-ray diffraction, in order to determine if the behavior and composition of both The objective of this investigation is to be analyzed by comparing a traditional asphaltite and an asphaltite, if the latter has the same properties and composition, with a view to being used as an energy source .The results obtained reveal that despite the fact that both substances present a similar composition, their glass transitions are different, as well as the crystalline phases present in each of the materials.
Acceso abierto
Comparing the identification of sites with high risk of landslides using isohyets of precipitation vs alterations of rainfall by La Niña in Santander Colombia
(2015) Gutiérrez, Juan David
Extreme meteorological events associated with climate change are a real issue and have important impact over the economy of infrastructure sector, including highways, hydrocarbon transport by pipelines, mines, etc., because saturation of soils by water can produce landslides and it could produce the fracture of pipelines or other kind of tangible assets. For example, an assessment of historical geotechnical failures in Ecopetrol (Colombian Oil Company) vs. extreme meteorological events shows that during La Niña (extreme rainfall period) geotechnical failures are three times greater. This work shows a method to identify places of risk by extreme meteorological events, mainly La Niña phenomenon, with focus in most probably alteration of rainfall. Our results illustrate the hot spots where there is a high probability of slight excess (120–160% of average rainfall) and high excess (>160%) of average rainfall. The results were intersected in a GIS with pipelines and mass movement risk maps to identify the places of high risk along Santander region.
Acceso abierto
Crecimiento Económico y Dinámica de Sistemas. Aprendizaje mediante experimentación
(Instituto Internacional de Informática y Sistémica, IIIS, 2020-03-29) Ramoni Perazzi, Josefa; Orlandoni Merli, Giampaolo; Callaos NC; de Castro SHR; Albuerne YL; Ruiz-Ledesma EF; Sánchez B.
La teoría clásica del crecimiento económico es un tema ampliamente analizado con un fuerte basamento matemático. Este trabajo plantea, como metodología educativa alternativa, enfocar su estudio mediante dinámica de sistemas, ofreciendo una visión más intuitiva y experimental que permite incorporar de manera gráfica las interrelaciones de feedback presentes en las estructuras que definen esos modelos. Se analizan algunas ideas clásicas de crecimiento económico, como las teorías de Adam Smith y de David Ricardo, plasmadas en sus respectivas obras, “La Riqueza de las Naciones” y “Principios de Economía Política”, construyendo así un laboratorio informático para realizar experimentos con modelos complejos en el campo de la economía. El principal producto es la construcción de un instrumento educativo para realizar experimentos de política económica, basándose en los principios de la dinámica de sistemas, utilizando software apropiado, como Powersim.
Acceso abierto
Design and content validity verification of an instrument to evaluate access to hospital infrastructure in Colombia
(IOP Publishing Ltd, 2019-08) Martínez Marín, Rocío del Pilar; Bueno, L. A.; Gómez Camargo, Fausto-Ramón; Tiria Sandoval, Luis-Carlos
The present study determined the content validity of an instrument to assess Colombian health institutions physical access. The questionnaire was designed by the authors of the study, based on the Colombian Technical Standard of Accessibility to the Physical Environment 6047 framework. The content validity was carried out by six experts. To the score the content validity, the researchers designed a qualification template, and calculated a content validity index dividing the relevance and pertinence score of each item/question by the number of experts who evaluated the question. Based on methodological recommendations from the literature, items with content validity index ≤ 0.78 were eliminated from the questionnaire or modified in their wording in accordance with the recommendations of the expert reviewers. The content validity index of the scale was found to be excellent (0.95). In total, 2 questions were eliminated due to their low relevance index (≤ 0.78). The final questionnaire has 69 questions. The importance of determining the validity of the scale in the present study, lies in the fact that a firm scientific basis must be constructed to verify whether such an instrument accurately measures reality.
Acceso abierto
Determination of the gelification kinetics of a correction gel of injection profiles by ultraviolet-visible spectroscopy
(2020-08-05) Sanchez, E.; Villamizar, J.; Mantilla, G.; Rodriguez, J.; Roa, M.
Mature wells in which, for a long time, water injection has been used, as a method of recovery they reach a point where the water cut increases or remains constant. thus decreasing the recovered hydrocarbon factor; This phenomenon occurs because the water injected, has preferential recordings in the porous medium, and does not reach the hydrocarbon available in other areas of the formation, in this type of deposits the injection of polyacrylamide gels, crosslinked with acetate of chromium, these gels make a plugging, in areas of high water permeability, causing the change of path of the same, as well as move the hydrocarbon in other areas of the porous medium. At present, the kinetics of gelation of this type of substances is monitored qualitatively by means of the "Syddansk" code, which analyzes its consistency and elasticity, only by observation. Although this method is practical, it is not very descriptive and depends a lot on the opinion and criteria of the observer, being little reproducible. Given this situation, and the increase in chemical recovery projects in the country, a methodology is described that describes the moment of gelation, reproducibly and without the injection of the analyst. During the gelation process, different polyacrylamide-chromium gels were monitored in relationships used in field operations, using ultraviolet-visible spectroscopy, detecting a change in absorbances, of the spectra, which were analyzed to plant a kinetic model of gelation, in addition to generating the approach of a method, to identify the state of gelation based on the variation in absorbance.
Acceso abierto
Dose-Optimization of Respiratory-Gated Auricular Vagal Afferent Nerve Stimulation (RAVANS) for Blood Pressure Modulation in Hypertensive Patients
(2019-09-05) Stowell, Jessica; Garcia, Ronald G.; Staley, Rachel; Sclocco, Roberta; Fisher, Harrison; Napadow, Vitaly; Goldstein, Jill; Barbieri, Riccardo
The objective of this study was to determine the optimal frequency of respiratory-gated auricular vagal afferent nerve stimulation (RAVANS) for the modulation of blood pressure in hypertensive patients. Twelve hypertensive subjects (52.5±6.0 years, 8 females) underwent five randomized stimulation sessions, during which they received exhalatory-gated stimulation at frequencies of 2, 10, 25, and 100 Hz or sham stimulation. A continuous blood pressure signal was collected during a 30-minute stimulation period and a 10-minute recovery period using a Finometer device (Finapress Medical System, the Netherlands). LabChart (ADInstruments, Colorado Springs, CO, USA) was used to process and compute blood pressure responses. A significantly greater reduction of systolic blood pressure values during stimulation was observed in the 100 Hz session compared to sham (p=0.02). In addition, significant reductions in diastolic blood pressure (p=0.04) and mean arterial pressure (p=0.04) values were observed during RAVANS stimulation compared to baseline during the 100 Hz session. Evaluation of other stimulation frequencies did not reveal significant results. RAVANS exhibits a frequency-dependent effect on the modulation of arterial blood pressure levels of hypertensive subjects.
Restringido
Effects of climate change on the resources of the rural ecosystem, a view from farmer perspectives
(IOP Conf. Series: Journal of Physics: Conf. Series 1386 (2019) 012147, 2019-10-24) Núñez Rodríguez, José-de-Jesús
This paper presents the results obtained from the categorization of the social representations of farmer groups on the effects of climate change on the biodiversity of their farms, developed in a rural area of the Colombian Andes. A mixed methodology was used throughout the analysis of the behavior of rainfall and temperature between the years 2010-2017 and the implementation of an open survey on 144 farmers, of which its data was analyzed using descriptive and inferential statistics through descriptive estimators and an analysis of variance and multiple comparison mean tests, respectively. Furthermore, a qualitative analysis, supported by Corbin and Strauss' Grounded Theory, was carried out on 18 farmer families using semi-structured interviews. The hypothesis testing determined the existence of significant differences between the mean temperatures of the years observed when obtaining a value of Fc = 3.50, highly significant at 1%, and a value of Fc = 2.79, significant at 5%, P<0.05, for the mean rainfall. In the descriptive analysis, farmers' perception of the negative effects of climate change was evident in the decrease in the availability of water from natural sources (80.6%), deterioration in water quality (50.0%), variations in rainfall intensity (82.0%) and in local bimodal rainfall patterns (79.0%). The inferential analysis determined that the proportion of farmers reporting a disappearance of species due to intense heat or rainfall differs significantly from the level of p<0.05, over those who reported that these conditions have not caused variations in flora and fauna. The qualitative analysis verified the effects of climate change on rural biodiversity resources, which were expressed in 4 emerging categories: 1) Biodiversity resources in the process of extinction, 2) resilient resources, 3) emerging biodiversity, and 4) new agricultural business opportunities. The findings reveal that from a farmers' perspective climatic variations are affecting species of fauna and flora in rural communities.
Acceso abierto
Estimation of potential hydrogen production from palm kernel shell in Norte de Santander, Colombia
(Journal of Physics: Conference Series, 2019-11) Acevedo-Páez, Juan Camilo; Solano, S P; Durán-Pinzón, Jessica Marlen; Posso Rivera, Fausto René; Arenas, E.
This work sought to estimate the economic and environmental potential of palm kernel shell for hydrogen production as energy vector in Norte de Santander, Colombia. A field research determined that the department generates monthly 14082 t of palm biomass of which 12501 of palm kernel shell remain available for their use. The proximate and ultimate analyses of the palm kernel shell report high heating value (19.53 MJ/kg) compared with other agro-industrial biomasses, high content of volatile material (69.82% w/w) and fixed carbon (21.68% w/w), promoters of chemical reactions in pyrolysis and gasification processes, respectively. In the Aspen Plus® simulation process of the palm kernel shell gasification at 900 °C and steam/biomass ratio of 1.5, a yield is obtained of hydrogen production of 40.7%, equivalent to a monthly production in Norte de Santander of 51.6 t. Using H2 in the generation of electric power permits producing 470.9 MWh/month that represent theoretical utilities of US$27734.5. In another scenario, 55848.8 gal/month of gasoline are substituted, equivalent to US$11708.6 through the sale of carbon credits. Regarding diesel, 45905.1 gal are replaced per month, which add US$9725.4 through the commercial transaction in the carbon market. It is concluded that using palm kernel shell as primary source to obtain H2, has, in principle, a favorable economic and environmental impact for sustainable development of the department of Norte de Santander, besides contributing to the knowledge base on the penetration of this vector in Colombia's energy matrix; however, more detailed technical and economic studies are needed to conclude regarding the economic viability of this energy conversion process.
Acceso abierto
Evaluation of mineral oils as matrices for AISI/SAE–1020 steel naphthenic corrosion study
(2021-02-05) Conde-Rodríguez, G.R.; Sanabria-Cala, J.A.; Mancilla-Estupiñán, Robinson Andres; Laverde Cataño, D.A.; Núñez Castañeda, M.C.
Petrochemical industry has suffered great economic impact due to light crude oil reserves reduction, so refineries have been processing high acidity heavy crude oils. Studies of corrosion caused by naphthenic acids are interfered by presence of other corrosive agents contained in real crude oils, so naphthenic phenomenon must be isolated using synthetic crude oils. For this reason, in present work two high purity mineral oils were used to evaluate their efficiency as synthetic crude oil matrices in AISI/SAE–1020 steel naphthenic corrosion study. Temperature levels evaluated were 200 °C, 250 °C, and 300 °C, while exposure times evaluated were 5, 10 and 15 hours. Surface morphological characterization of AISI/SAE–1020 steel was carried out using scanning electron microscopy and X–ray diffraction. Gravimetric tests showed that AISI/SAE–1020 steel naphthenic corrosion rate increases with temperature and exposure time for one of the synthetic crude oils. However, results obtained for the other synthetic crude oil did not show increasing behaviour due to presence of sulfur traces in the oil, which caused an interference with AISI/SAE–1020 steel naphthenic corrosion study, reducing the reliability of gravimetric results so they cannot be extrapolated to operating conditions in distillation units.
Acceso abierto
Feature extraction for nonintrusive load monitoring based on S-Transform
(2014-05-01) Jiménez, Yulieth; Duarte, Cesar A.; Petit, Johann; Carrillo Caicedo, Gilberto
The electric energy demand is dramatically growing worldwide and demand reduction emerges as an outstanding strategy; it implies detailed information about the electricity consumption, namely load disaggregation. Typical automatic methods for load disaggregation require high hardware efforts to install one sensor per appliance, whereas Non-intrusive Load Monitoring (NILM) systems diminish the hardware efforts through signal processing and mathematical modeling. One approach to NILM systems is to model the load signatures via artificial intelligence. This paper proposes to employ S-Transform for the feature extraction stage and Support Vector Machines for the pattern recognition problem. Several experiments are presented and the results of the feature extraction with S-Transform and Wavelet Packet Transform are compared. Thus promising feature vectors based on S-Transform are presented with similar or superior performance than the approach based on Wavelet Packet Transform.
Acceso abierto
Gelation kinetics of colloidal dispersion gels by viscoelasticrheological methods
(2020-12-05) Mantilla, G.; Villamizar, J.; Sanchez, E.; Ardila, J.; Roa, M.
Colloidal dispersion gels are one of the methodologies implemented, such as chemical recovery processes, in mature wells, their components are mainly polyacrylamide and aluminum citrate, both aqueous unlike other types of gelling, in this there is an intramolecular process, between the polymer chains and the crosslinker, generating a ball of polyacrylamide of nanometric dimensions. The usual gelling processes increase the viscosity of a fluid because of an increase in the molecular weight of the polymer, but in this case, the viscosity of the fluid decreases to the point of being close to that of the solvent, for this reason a monitoring of its gelation kinetics, in a conventional way is not possible, in view of this problem, this research implements techniques of viscoelastic characterization of fluids, to determine the loss and storage modules G' and G'', as well as the phase angle in the time, in order to learn more about the gelling mechanism, as well as to be able to estimate a reaction speed, from the point of view of viscoelastic variables, the results obtained revealed that despite being gelling, there is a decrease in the storage modulus , to a greater extent than the loss modulus, which implies that the material loses elastic properties, that is, from solid to become a material more viscous or liquid. With this information, an equation was proposed that can be used both in the laboratory and in oil field work. In addition to being extended to fluids with similar behaviors, where the interactions between the polymeric chains and their crosslinker generate a decrease in their elastic properties.

Examinando por Tipo de Material "Documento de Conferencia"

Resultados por página

Opciones de clasificación