Revista Facultad de Ingeniería Universidad de Antioquia

Preliminary

Revista Facultad de Ingeniería Universidad de Antioquia — Fri, 19 Nov 2021 00:00:00 -0500

Water supply failure probability under influence of climate change - Balsillas river basin case study

Mon, 19 Oct 2020 00:00:00 -0500

This project assesses the risk of water supply failure for the agricultural sector under climate change conditions by implementing hydrological models that support decision-making for satisfying consumptive demands in times of scarcity. This project was developed using hydrological modeling tools such as the HydroBID software and the SIMGES and SIMRISK water resource management models of AQUATOOL DSS. The flow series for a future scenario were obtained for different climate change scenarios from a Global Climate Model (GCM) and the Coordinated Regional Experiment on Climate Reduction (CORDEX) by downscaling the results from the global scale to basin-scale using a statistical method based on chaos theory. These projections show that under conditions of climate change, the agricultural sector of the Balsillas basin will not suffer significant impacts since they will be able to satisfy most demand points.

Molecular dynamics simulations of themechanical behavior of nanostructured andamorphous Al80Ti15Ni5alloy

Tue, 27 Oct 2020 00:00:00 -0500

Classical deformation mechanisms based on crystalline defects of metallicpolycrystals are not entirely suitable to describe the mechanical behavior of nanocrystallineand glassy materials. Their inherent complexity creates a real challenge to understand theacting physical phenomena. Thus, the molecular dynamics approach becomes interestingbecause it allows evaluating the mechanical properties and its related atomic structure. Tostudy the atomic structure’s influence on the deformation mechanisms at the nanoscale levelof the Al80Ti15Ni5alloy, molecular dynamics simulations, and post-processing techniques wereused in the present work. The results revealed a significant dependency between the Youngmodulus and the atomic structure. Moreover, the type of structure, i.e., nanocrystalline oramorphous, governs the deformation mechanism type. For the nanocrystalline alloy, grainboundary sliding and diffusion seem to be the dominant deformation processes followed bythe less essential emissions of partial dislocations from the grain boundaries. Concerningthe amorphous material, the shear transformation zones begin to form in the elastic regimeevolving to shear bands, these being the main mechanisms involved in the deformation process.The results also indicate the amorphous structure as a lower limit-case of the nanocrystal. TheAl80Ti15Ni5elastic moduli values were below expectations; for this reason, the effects of unaryand ternary interatomic potentials were evaluated for each element.

Control scheme selection and optimal tuningin industrial process control using factorialexperiment design

Thu, 29 Oct 2020 00:00:00 -0500

In this study, a novel experimental approach for the optimal selection of anactuator-based control strategy is presented. The proposed approach is a two-stagemethod: first, a two-level factorial experiment design with n factors (2n) was appliedto compare different control schemes. Schemes comparison was carried out in termsof energy consumption and closed-loop performance. For the best relative scheme, aCentral Composite Face-centered (CCF) design was completed obtaining the controllerparameters that optimize the performance in terms of the Integral Absolute Error (IAE)while operating in a region of low energy consumption. The proposed approach wasexperimentally tested using real data obtained from a laboratory prototype plant. Someexperimental tests illustrating the suitability of our method are shown at the end of thisarticle.

Heavy metal removal by biopolymers-based formulations with native potato starch/nopal mucilage

Fri, 20 Nov 2020 00:00:00 -0500

The contamination of water bodies by heavy metals is a critical problem for human health and ecosystems, and it can bioaccumulate in organisms to toxic levels and even lead to the living being’s death. This research aimed to synthesize and characterize a biopolymer with the capacity to remove heavy metals in wastewater, elaborated from
potato starch, glycerin, and nopal mucilage. Native potato starch of the Allcca sipas variety was extracted by conventional methods; the mucilage was extracted with ethanol. Four formulations of biopolymers were synthesized at 60 and 70 °C. The solubility, structural characteristics, and adsorption capacity of heavy metals were evaluated.
Starch, mucilage, and biopolymers presented predominant functional groups as -OH, -C-O-, -NH-, -C-H-, -C-OH determined by FTIR, allowing to remove up to 50.18% of Al, 56.81% of As, 35.95% of Cr, 37.43% of Hg and 73.22% of Pb determined through an ICPE-OES, for a contact time of 100 minutes at pH 5.0, heavy metal removal and solubility were significantly influenced (p-value<0.05) by the addition of starch and mucilage. The synthesized biopolymers present a high capacity for heavy metal removal in wastewater.

Rainfall-intensity effect on landslide hazard assessment due to climate change in north-western Colombian Andes

Mon, 14 Dec 2020 00:00:00 -0500

Landslides triggered by rainfall are one of the most frequent causes of disasters in tropical countries and mountainous terrains. Recent studies show an upsurge in landslide occurrence as an expected impact of human-induced climate change. This paper presents the analysis and implementation of two different physically-based models, SHALSTAB and TRIGRS, to evaluate the effect of rainfall on landslide hazard assessment in the north-western Colombian Andes. Intensity-Duration-Frequency curves were used in climate change scenarios for different return periods. According to the results, although higher rainfall intensities increase, landslide occurrence does not escalate in a direct or proportional relationship. Considering a steady infiltration process (SHALSTAB), the results show an expansion of d unstable areas, compared with a transient infiltration process (TRIGRS). A greater influence of rainfall duration instead of rainfall intensity was observed. The results highlight the need for studies that incorporate the scenarios of variability and climate change in the hazard assessment and land planning in the long term.

Analysis of beam-column elements on non-homogeneous soil using the differential transformation method

Tue, 16 Feb 2021 00:00:00 -0500

This paper describes an analytical approach to conduct an analysis of beam-column elements with generalized end-boundary conditions on a homogeneous or non-homogeneous Pasternak elastic foundation. The mathematical formulation utilized herein is that presented by the senior author in a recent work. The differential equation (DE) governing the behavior of the beam-column element is solved using the differential transformation method (DTM). The DTM offers practical advantages over other conventional approaches when solving the proposed structural model. The proposed formulation provides the flexibility to account for i) combined lateral and axial load at the ends of the element, ii) homogeneous or non-homogeneous soil, iii) Pasternak elastic foundation, and iv) an external arbitrary transverse load acting on the element. The effects of various slenderness ratios, pile-soil stiffness ratios, and classical and semirigid boundary conditions can be easily studied with the proposed formulation. Examples are presented to validate the accuracy of the model and its applicability over a wide range of analyses.

Water quality in the municipalities of Sincerínand Gambote, Bolívar, Colombia (2017-2018)

Mon, 08 Feb 2021 00:00:00 -0500

This study evaluates the water quality for human consumption in the municipalities ofSincerín and Gambote. It was measured through physico-chemical (color, turbidity, conductivity,pH, dissolvedoxygen, hardness, andheavymetals) andmicrobiological (totalcoliforms, Escherichiacoli) parameters before and after a partial form of water treatment was used (alum and chlorineaddition in Gambote and Sincerín municipalities, respectively). This investigation was done inaccordance with the maximum permissible values established by the Resolution 2115 of 2007 ofthe Ministry of Environment, Housing, and Territorial Development of Colombia (MAVD in Spanish).Additionally, the IRCA (Water Quality Risk Index) was calculated to determine the degree ofrisk of disease occurrence. The results indicated concentrations higher than the recommendedvalues for: (a) hardness (in Sincerín); (b) iron (Fe), turbidity (only before being treated), E. coli(inGambote); and (c) mercury (Hg), and total coliforms. The water supplies of the municipalitiespresented unsafe IRCA. Therefore, it is expected that the results of this study could be used forproposing strategies for improving these conditions by means of the design and implementation ofan adequate treatment system.

On the issue of automatic form accuracy during processing on CNC machines

Tue, 17 Nov 2020 00:00:00 -0500

This work aims to develop technical solutions that allow providing the specified parameters of the accuracy of the shape of parts in the cross-section during processing on a CNC machine. Experimental studies were performed on a screw-cutting lathe. An acoustic signal in the range from 6 to 12 kHz was used as a diagnostic sign to assess the wear of the cutting tool, since during preliminary studies, it was found that this range is most sensitive to changes in processing modes. Studies were performed at different values of wear of the cutting tool (estimated by the width of the wear chamfer). For estimating the life of a cutting tool, a neuro-fuzzy model has been developed. Using models of this class allows adjusting to specific conditions (machine, tool), and correctly evaluating the tool life. The model error for the test sample does not exceed 10%. The test results showed that using the proposed solutions makes it possible to increase the accuracy of the manufacturing of shut-off valve parts by 20-30%.

Fragmentation model for tensile behavior of intermingled hybrid composites and optimal mixing ratio

Juan David Vanegas- Jaramillo, Luis Javier Cruz-Riaño, Iván David Patiño-Arcila — Wed, 07 Apr 2021 00:00:00 -0500

A numerical fragmentation model is proposed to predict the mechanical response of intermingled, unidirectional hybrid composites under tensile loads. The model is based on a previously developed for unidirectional composites considering the critical number of fiber breaks and the correction of the fiber-matrix interfacial strength. Hybrids comprising two reinforcements are considered, and the energetic contribution of reinforcements is evaluated during the damage process. Additionally, the pseudo-ductile strain, yield strength, and the level of degradation of each reinforcement are estimated. The present model is compared with a progressive failure model and micromechanical finite element simulations, obtaining some similarities in the stress-strain behavior. Results show that both low elongation and high elongation fiber sub-composite experience a linear tensile response where fibers remain intact (IF), and fragmentation (FM) where breaking appears. The sliding/separation phenomenon (SS) occurs in one of the sub-composites when crack saturation is obtained, and failure occurs when the other one undergoes the crack saturation. Results also show that the IF, FM, and SS phenomena are conditioned by the fiber mixing ratio, α. The model allows estimating the optimal value of α for which the highest pseudo-ductile strain and hybrid effect are reached.

Literature review of deploying small transmitters on a spectrum sharing scheme

Juan Guillermo Torres, Roberto Bustamante, Carlos E. Caicedo — Fri, 16 Apr 2021 00:00:00 -0500

Nowadays, there are a lot of misinformation and myths related to both the deployment of antennas for 5G and the frequency bands used in such technology. Many of these myths arise from the lack of serious research documents released in common language to be understood by different knowledge areas. This work makes a small contribution in this regard and shows a bibliographic review of the most relevant characteristics related to the problem of deployment of transmitters (a.k.a. base stations), and also takes into account a spectrum sharing scheme. As a case study, we will analyze the CBRS regulation used in the United States for the deployment of 5G, it will provide an overview of engineering problems and also, the areas of research that still need to be explored.

Chromatographic analysis of phytochemicals in the peel of Musa paradisiaca to synthesize silver nanoparticles

Fri, 21 May 2021 00:00:00 -0500

This research work used Musa paradisiaca(banana) peels as a natural solvent, assorted with the precursor AgNO3 (10 mM) to perform the green synthesis of silver nanoparticles. The phytochemical components present in the Musa paradisiaca peel extracts were determined by gas chromatography coupled to a mass spectrometer (GC-MS), and it was possible to identify the compounds: 1.2 Ethanediol (60.0261 %) and 2.3 Butanediol (11.2 %); these -diols represent a highly reducing agent for metals, since they act as a solvent for the metal precursor behaving as a reducing agent, and facilitating the formation of nanoparticles. Likewise, the synthesized silver nanoparticles were subjected to a washing and drying treatment to be subsequently characterized by means of UV-Vis and XRD techniques, resulting in a wavelength of 411 nm, which is characteristic of these metallic nanoparticles, and achieving the identification of the face-centered cubic structure (fcc) of the metallic silver, with an average particle size of 21.8 nm according to the Debye-Scherrer equation.

Use of agro-industrial residues of plantain (Musa paradisiaca) in the adsorption of Ni (II)

Thu, 22 Apr 2021 00:00:00 -0500

The presence of heavy metals in aqueous media represents a severe threat to ecosystems because they are non-biodegradable, toxic, and carcinogenic. In the present work, the utilization of agro-industrial residues from obtaining plantain starch for removing Ni (II) was studied, establishing the effect of temperature, adsorption dose, and initial concentration. The kinetics, equilibrium, and thermodynamic parameters that determine the process were studied. For this purpose, tests were carried out in a batch system maintaining constant stirring (200 rpm), pH (2), and solution volume (100 mL). The remaining metal concentration was determined by atomic adsorption at 237 nm. It was found that the best adsorption conditions were given at 55 ºC, 0.6775 g, and 368 mg/L obtaining a maximum adsorption capacity of 47.57 mg/g corresponding to a removal of 87%. The kinetic model that best fits the experimental data was a pseudo-second-order model, and the isotherm that describes the process is Langmuir and Freundlich, so the adsorption is given by chemisorption and multilayers. The thermodynamic parameters determined suggest that the process is favourable, not spontaneous, endothermic, and irreversible under the studied conditions. The results show that the residual biomass from the obtaining of plantain starch is a good precursor for absorbing Ni (II) in an aqueous solution.

Human activity recognition using penalized support vector machines and hidden Markov models

Mon, 24 May 2021 00:00:00 -0500

Human activity detection has evolved due to the advances and developments of machine learning techniques, which have enabled solutions to new challenges without ignoring prevalent difficulties that need to be addressed. One of the challenges is the learning model’s sensitivity regarding the unbalanced, atypical, and overlapping information that directly affects the performance of the model. This article evaluates a methodology for the classification of human activities that penalizes defective information. The methodology is carried out through two redundant classifiers, a penalized support vector machine that detects the sub-movements (micro-movements) and the Marvok Hidden Model that predicts the activity given the micro- movements sequence. The performance of the method was compared with state-of-the-art techniques, and the findings suggested significative advance in the detection of micro-movements compared to the data obtained with non-penalized paradigms. In this research, an adequate performance is found in the classification of primitive movements, with hit rates of 95.15% for the Kinect One®, 96.86% for the IMU sensor network, and 67.51% for the EMG sensor network.

Analysis and comparison of metal-doped on Graphene-Genistein using QM/MM calculations

Marziyeh Choupani, Afshar Alihosseini, Majid Monajjemi, Hossein Sakhaeinia — Tue, 15 Jun 2021 00:00:00 -0500

Genistein (5,7,4’-trihydroxyisoflavone) is an isoflavone abundantly found in soy and other legumes and acts as a selective estrogen receptor modulator (SERM). When testing for similar abilities among other flavonoids, it has been found to be a strong topoisomerase inhibitor. Similar to some high-dose chemotherapy drugs, it was strongly toxic to normal cells. In this study, the adsorption of genistein on the surface of exclusive graphene and Ni, Ti, Cr, and Se-doped graphene was theoretically evaluated by means of density functional theory calculation. Initially, we varied the position of genistein from the surface of pristine and decorated graphene by changing the distances between (1-5 Å) and gained the Ead and Egap for each situation. Our calculation indicated that adsorption energies (Ead) of pristine genistein to graphene with Ni decorated graphene, Ti-decorated graphene, and Cr-decorated graphene and Se-decorated graphene are: 954.984, 318.168, 797.480, 946.725, 958.154 kcal/mole, respectively, and the calculated values of adsorption energy in the equilibrium distance (de=3.9180A.) of genistein to Ni-decorated graphene reveal that apparently genistein- Ni-decorated graphene as the most energetically favorable position was correctly selected in comparison with other atom-decorated graphene. In consequence, we explain the density of states (Doss) and frontier molecular orbitals HOMO and LUMO for Ni-decorated graphene and complexes with genistein; therefore, data confirmed that a positive charge of Ni-decorated graphene for nucleophile molecules could be achieved.

Buffer allocation problem in a shoe manufacturing line: A metamodeling approach

Fri, 09 Jul 2021 00:00:00 -0500

Footwear production is subject to the variability inherent in any process, and producers often need to apply tools that allow them to make the right decisions. This work documents the process to optimize the buffer allocation in a shoe manufacturing line minimizing the cycle time in the system, applying a metamodeling approach. It was found that the Front sewing operation, and the interaction between the Lining sewing operation and the assembly operation have the greatest effect on the flow time of the product within the process; the optimum assignment of spaces follows a non-uniform arrangement on the line saturating the slower stations; the cycle time follows a non-linear behavior vs. the total number of spaces (N) in the line. For a certain value of N, the cycle time reaches a minimum value.

Editorial

Maryory Astrid Gómez Botero — Fri, 19 Nov 2021 00:00:00 -0500