Abstract
Estimating the amount of flow carried by the sanitary sewer system in a locality is essential for the design of new facilities. Having a record of the flow rates allows the adequate ...hydraulic design of a drainage system. The objective of this work is to determine the physical parameters for the estimation of the return coefficient that allows estimating the flow rates for the sanitary sewer of the La Chivera watershed, San José de Cúcuta, Colombia. In this sense, dry weather monitoring of the wastewater in the study area was carried out. The data collected in the field were used to construct the hourly flow variation curve or inflow hydrograph in the drainage system. The average hourly flow parameters were estimated with a value of 205.7 m
3
/h, a value recorded at the 11th hour of the day. Similarly, the average daily flow was determined with a value of 180.3 m
3
/h, while the maximum peak factor was 1.14. Finally, through the physical parameters of the sanitary sewer, the return coefficient was determined, which is 0.72, a value that represents the conditions of the study area.
Abstract
The integration of mathematical models allows the simulation of the spatiotemporal behavior of water quality parameters of a river. The representation of reality and different scenarios ...through simulation makes it possible to know the variations in water quality of a receiving water source associated with liquid discharges. Therefore, for this study, the mathematical model QUAL2K was applied to simulate the water quality of the Magdalena River in the section that crosses the city of Barrancabermeja, Colombia. For this purpose, a database of hydro-climatological records from 1977 to 2020 was used. Among the analyses, dissolved oxygen and biochemical oxygen demand were considered as water quality parameters. As a result of the initial data processing of the distribution tests and Kolmogorov goodness of fit, the best fit with the normal distribution was obtained for the estimation of flow rates. The concentrations of the water quality parameters dissolved oxygen and biochemical oxygen demand were represented in the mathematical model, which shows the dilution capacity of the pollutant loads of the wastewater, due to the high flow of the Magdalena River in the study section.
The in-gas laser ionization and spectroscopy (IGLIS) technique is used to produce and to investigate short-lived radioactive isotopes at on-line ion beam facilities. In this technique, the nuclear ...reaction products recoiling out of a thin target are thermalized and neutralized in a high-pressure noble gas, resonantly ionized by the laser beams in a two-step process, and then extracted from the ion source to be finally accelerated and mass separated. Resonant ionization of radioactive species in the supersonic gas jet ensures very high spectral resolution because of essential reduction of broadening mechanisms. To obtain the maximum efficiency and the best spectral resolution, properties of the supersonic jet and the laser beams must be optimized. To perform these studies a new off-line IGLIS laboratory, including a new high-repetition-rate laser system and a dedicated off-line mass separator, has been commissioned. In this article, the specifications of the different components necessary to achieve optimum conditions in laser-spectroscopy studies of radioactive beams using IGLIS are discussed and the results of simulations are presented.
This document presents cost analysis through system dynamics (SD) focused on the Colombian residential sector for Building Integrated Photovoltaic Systems (BIPVS). The study considers the ...socioeconomic strata of Colombia. Strata are a classification of houses used in Colombia to charge different utility fees according to the residents’ purchasing power. Studies were conducted to cover 100% of households’ electric charge, calculating the price per energy unit through the Levelized cost of energy technique, which associates investment and maintenance costs based on the amount of energy generated during the equipment’s lifetime. Also, grid parity and savings percentages in each stratum were calculated for each city under study. Main results reveal that the highest grid parity index is found in Stratum 1 for Bogotá, Cali, and Medellín at values of 0.90, 0.86, and 0.96, respectively. For Barranquilla, the highest index is reported for Stratum 2 at a value of 0.54. The highest savings rate is reported for Strata 5 and 6 in Barranquilla at 71% and 72%, respectively. Using SD, the analysis of the avoided CO2 emissions revealed that, by 2050, the residential sectors of Bogotá, Cali, Medellín, and Barranquilla would stop releasing 7,106.51 tons of CO2, 2,636.11 tons of CO2, 5,262.14 tons of CO2, and 3,291.52 tons of CO2, respectively, due to the use of photovoltaic (PV) solar energy in the residential sector.
Display omitted
Abstract
The design and operation of sanitary sewerage systems are based on the knowledge of peak and the average daily wastewater flows. The maximum peak factor is obtained through the ratio of the ...maximum flow and the average discharge flow of wastewater generated in a system. In this sense, the maximum peak factor was estimated by monitoring wastewater flow in an urban sector of the city of San José de Cúcuta, Colombia. This urban sector represents 45.6% of the sanitary sewerage of the city. Stochastic modeling of the peak flow was performed, and a mathematical model was constructed to estimate the maximum peak factor using a correlational study using statistical methodology. Through linear regression analysis, a model was obtained that estimates the value of the maximum peaking factor based on knowledge of the average daily wastewater flow. The results indicate that the model is potential, and the expression is statistically significant and satisfies the assumptions established for the classical linear regression model.
The method of laser spectroscopy in supersonic gas jets was proposed for high-resolution and high-efficiency in-gas laser ionization and spectroscopy studies of short-lived nuclei. The flow ...properties of such supersonic gas jets have been characterized under off-line conditions. Planar laser-induced fluorescence spectroscopy of seeded copper atoms has been applied to nonintrusively measure velocity, temperature, and relative density profiles of gas jets formed by different de Laval nozzles. For validation, planar laser-induced fluorescence spectroscopy was applied on supersonic free jets with well-known flow parameters. The performance of the in-gas-jet laser spectroscopy method is determined by the achievable spectral resolution, which requires an optimization and a precise manufacturing of the nozzle inner contour as well as a pressure matching of the background medium at the nozzle exit. Our studies now enable a thorough understanding and quantification of these requirements and a determination of the final performance of the in-gas-jet method. Additionally, a comparison between the experimental results and the numerical calculations was performed for the temperature, velocity, and Mach number profiles of underexpanded and quasiuniform jets formed by a de Laval nozzle.
This study compared physical characteristics (body height, body mass BM, body fat BF, and free fatty mass FFM), one repetition maximum bench-press (1RM (BP)), jumping explosive strength (VJ), ...handball throwing velocity, power-load relationship of the leg and arm extensor muscles, 5- and 15-m sprint running time, and running endurance in two handball male teams: elite team, one of the world's leading teams (EM, n = 15) and amateur team, playing in the Spanish National Second Division (AM, n = 15). EM had similar values in body height, BF, VJ, 5- and 15-m sprint running time and running endurance than AM. However, the EM group gave higher values in BM (95.2 +/- 13 kg vs. 82.4 +/- 10 kg, p < 0.05), FFM (81.7 +/- 9 kg vs. 72.4 +/- 7 kg, p < 0.05), 1RM (BP) (107 +/- 12 kg vs. 83 +/- 10 kg, p < 0.001), muscle power during bench-press (18 - 21 %, p < 0.05) and half squat (13 - 17 %), and throwing velocities at standing (23.8 +/- 1.9 m . s (-1) vs. 21.8 +/- 1.6 m . s (-1), p < 0.05) and 3-step running (25.3 +/- 2.2 m . s (-1) vs. 22.9 +/- 1.4 m . s (-1), p < 0.05) actions than the AM group. Significant correlations (r = 0.67 - 0.71, p < 0.05 - 0.01) were observed in EM and AM between individual values of velocity at 30 % of 1RM (BP) and individual values of ball velocity during a standing throw. Significant correlations were observed in EM, but not in AM, between the individual values of velocity during 3-step running throw and the individual values of velocity at 30 % of 1RM (BP) (r = 0.72, p < 0.05), as well as the individual values of power at 100 % of body mass during half-squat actions (r = 0.62, p < 0.05). The present results suggest that more muscular and powerful players are at an advantage in handball. The differences observed in free fatty mass could partly explain the differences observed between groups in absolute maximal strength and muscle power. In EM, higher efficiency in handball throwing velocity may be associated with both upper and lower extremity power output capabilities, whereas in AM this relationship may be different. Endurance capacity does not seem to represent a limitation for elite performance in handball.
Considering the impact of photovoltaic installations and the fact that their performance depends on the type of day, this paper presents a classifier that makes use of fuzzy logic to classify daily ...irradiance profiles as a human would do. To do this, the system must be linguistically interpretable, so the classifier must be simple enough, but without losing accuracy. This is why the article combines the use of data mining and supervised learning algorithms to obtain an initial system and then exploits simplification techniques such as the concept of fuzzy classifiers with incomplete rule bases, as well as fuzzy tabular simplification of rules to obtain a compact and simple final system. The classifier obtained handles the ambiguity presented by the daily irradiance profiles with precision. Once the system has been obtained, a large number of days in southern Spain are classified, analysing the performances of a photovoltaic plant obtained in each of the classes. Then, a neuro-fuzzy system is designed to predict the performance of the photovoltaic installation, considering the type of day, the maximum ambient temperature reached during the day, and the degradation of the installation over time, proving its usefulness in alerting about anomalous behaviour of the system.
We describe the case of a 24-year-old pregnant woman with no history of note who was admitted with a diagnosis of bilateral pneumonia caused by the new coronavirus. Due to clinical worsening, she ...required urgent cesarean section with general anaesthesia and intubation for decubitus intolerance. After extubation, she presented altered mental state that required a differential diagnosis of encephalitis/meningitis secondary to SARS-CoV-2. CT and CT-angiography were normal, spinal fluid tests were non-specific, and magnetic resonance imaging reported posterior reversible encephalopathy syndrome (PRES) (due to radiological features suggestive of white matter vasogenic edema affecting the parietal, temporal and occipital lobes, along with altered mental state) secondary to gestational hypertension. Eleven days after the cesarean section the patient began to develop hypertension that required treatment. PRES is associated with certain clinical (headache, altered mental state, visual disturbances and convulsions) and radiological (reversible changes in white substance mainly affecting the parietal, temporal, and occipital lobes) characteristics suggestive of vasogenic oedema In pregnant SARS-CoV-2 patients, the differential diagnosis of hypertension and altered mental state is often extremely complicated because complementary tests can be normal and there is no immediate sign of peripartum hypertension. SARS-CoV-2 genome sequencing in spinal fluid could have provided a definitive diagnosis, but the treatment would not have differed.
PDF
