Departamento de Ingeniería Civil y Ambiental

Se desarrolló un modelo computacional del pulgar con el fin de evaluar los esfuerzos y deformaciones a los que se en¬cuentra sometida la articulación trapecio metacarpiana. Utilizando tomografías axiales computarizadas se rea¬lizó la reconstrucción de la geometría 3D del pulgar, y con base en un análisis anatómico y funcional se generó un modelo computacional para simular el comportamiento de la articulación bajo condiciones normales de servi¬cio. Del análisis del modelo por el método de elementos finitos, se obtuvieron las fuerzas musculares y la distribución de esfuerzos, para condiciones normales de funcionamiento y en posiciones anatómicas específicas de agarre.

A computational model for the thumb was developed in order to evaluate the stresses and strains in the Trapeziometacarpal joint under physiological conditions. A reconstruction of the 3D geometry of the thumb was performed through image processing of computerized axial tomographies. Based on anatomical and functional analysis of the thumb, a computational model was generated to simulate the behavior of the joint under normal working conditions. The tendon forces and the distribution of stresses in the joint were obtained by means of mechanics analysis using the finite element method; these analyses were performed for regular usage conditions and specific anatomical grip positions.

In order to demonstrate the relevance of considering Vortex-Induced Vibrations (VIV) in the structural design of marine structures, this study proposes an alternative experimental and analytical approach in wet conditions to measure the fluid–structure interaction in the near field and quantify the viscous damping with measured structural and 3D hydrodynamic accelerations. It was demonstrated that VIV caused and incremented 5.00% of the structural damping coefficient, and the extreme wind loading increased 74% of the offshore monopile’s structural damping, demonstrating the relevance of the high non-linear hydrodynamics effects during selecting parameters into the structural design in offshore applications.

Objective: To evaluate technically the results of the application of Selectively Advanced Microorganisms in the removal of pollutant loads from the sanitary sewer of the city of Riohacha (La Guajira). Materials and methods: A comparative analysis of the pilot test with the baseline of the period 2012-2016 of the physico-chemical parameters Biological Oxygen Demand (BOD5) and Total Suspended Solids (TSS) was performed. For the evaluation, a mixture of non-pathogenic strains from bacilli, actinomycetes, fungi and yeasts was used in 21 points of the sewage system during the 60-day process. Three weekly samples were taken according to the established protocol and the data were processed statistically with the software SPSS and STATGRAPHICS, in order to analyze the normality of the data, obtain statistics, confidence intervals, hypothesis test, linear trend models, % Removal and forecasting. Results: Load reduction projections were higher than 40% for periods 11 and 19, for the parameters DBO5 and SST, respectively. Conclusions: The efficiency of bioremediation in the treatment of wastewater was verified in the removal of the load levels of the parameters DBO5, SST and the environmental cost-effectiveness of its implementation. Linear trend models predict reduction targets for the DBO5 and SST parameters around 90 mgl-1, in compliance with Resolution 631 of 2015 of the Ministry of Environment.

Particulate matter (PM) is considered as one of the major pollutants that affect the health of humans, especially for the fine and ultrafine fraction, which can adsorb greater concentrations of toxic compounds, e.g., polycyclic aromatic hydrocarbons (PAHs). PAHs are a group of several complex organic compounds consisting of carbon and hydrogen, and two or more condensed benzene rings and represent one of the most stable families of organic compounds known. The known carcinogens isomers are primarily associated with particulate material and, usually, the highest concentrations are in the respirable fraction <5 µm. High PAHs levels in ambient air of large metropolitan areas are usually associated with vehicular emissions, including diesel and gasoline vehicles. Particle-bound PAHs in the fine and ultrafine fraction present a higher risk because they can deposit in the respiratory tract, hence aggravating the potentially negative health effects. In addition, some PAHs are possibly or probably carcinogenic to humans (benzo[a]anthracene, benzo[b]fluoranthene, benzo[k] fluoranthene, benzo[a]pyrene, dibenzo[a,h] anthracene, and indeno[1,2,3-cd]pyrene). Thus, there is considerable concern about the relationship between PAHs exposure in the ambient air and the potential to contribute to human cancer incidence. The objective of this study was to conduct an assessment of carcinogenic and mutagenic risks of the studied PAHs in the PM1.0, PM2.5 and PM2.5-10 samples. The toxic equivalent factors were calculated to characterize more accurately the risk of cancer from PAH exposure in the PM samples. This was based on the contribution of the carcinogenic potency of benzo[a]pyrene. The ambient concentrations of 12 PAHs, beginning from fluorene, and their toxic equivalence factor (TEF) were used in the calculation. The carcinogenic risk for five carcinogenic PAHs (Chr, BaA, BaP, Ind, and DahA) in the PM2.5 and PM2.5–10 fractions ranged from 44.9% to 56.8%, of DahA ranged from 35.12% to 44.63%, and of Ind ranged from 5.24% to 6.65% of the total carcinogenic activity in the study area. For PM1.0 fraction, BaP and DahA dominated the BaPeq levels. The carcinogenicity activity contribution of BaP was in the range of 27.1% (Canoas summer) up to 44.0% (Sapucaia winter); and the contribution of DahA was of 22.7% (Sapucaia winter) up to 45.3% (Canoas summer). The contribution of Ind for the BaPeq levels was of 15.0% (Sapucaia summer) up to 17.8% (Sapucaia winter). Since 2006 to 2013, the highest BaPeq levels were observed in winter in the study, and there has not been an increase in the contribution in the BaPeq levels of potentially carcinogenic PAHs, except for Ind. The recent established air quality limit of the European Parliament, the scientific publication of the IARC and the carcinogenic risk demonstrate the importance that these pollutants require maximum reduction and their study. These results may help the environmental agency and government to have tools to control PAHs in ambient air.