Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Context: Climate change and the challenges faced by humanity in terms of sustainability encourage institutions in all sectors to take measures to reduce the impact of their activities. The purpose of the article is to analyze energy projects in the field of healthcare as an opportunity for continuous improvement. Method: A descriptive qualitative approach is employed to explore the recent literature on energy projects in healthcare. To this end, scientific articles published in the last five years in both English and Spanish were reviewed. Results: Energy management in healthcare institutions is present as an important component of global operations. However, there is still room for improvement in but in Latin America. 57% of green hospitals in Colombia have achieved energy sustainability goals, with the Cañaveralejo Hospital in the city of Cali being the main point of reference. Conclusions: Fundamental principles such as an ethical commitment to change, a self-management character, the participation and responsibility of the personnel involved, and the leadership and control of management are essential for achieving a successful change model.

Context: Advanced Measurement Approach (AMA) has been the umbrella to identify the models used for modeling the capital to cover Operational Risk (Total Operational Value at Risk, OpVaR) in financial institutions in developed countries. The Loss Distribution Approach (LDA) has been the most popular model used by international banks for OpVaR calculation. However, the operational losses frequently have multivariate dependences that are not accounted for in the LDA. This paper applies a Gaussian copula to model the multivariate dependences in operational losses. Method: Two models were compared to estimate capital requirement for operational risk. Model (i) is the standard LDA model (BCBS 2004). Model (ii) incorporates a multivariate Gaussian copula into the LDA to model multivariate dependence between operational losses (severities). This research analyzes an operational loss data set, SAS® Operational Risk Global Data (SAS OpRisk Global Data), in order to model operational risk at financial institutions in emerging markets between 1990 and 2013. Results: The impact of Model (ii) was evaluated on the estimates of the total regulatory capital for operational risk and compared with the one predicted by (i). The results confirm the existence of diversification benefit up to 33%. Conclusions: Modeling explicitly the multivariate dependence between operational losses has a clear impact on capital requirement for institutions in emerging markets. The implementation of a Gaussian copula into the LDA model provides a sophisticated tool to estimate operational risk capital in emerging markets, as well as the possibility for diversification benefit. Acknowledgements: To SAS for providing the database used in this research.

Context: The energy crisis is a global problem. In Colombia, research aimed at the efficient use of renewable energies is being conducted. For example, in the case of bio-inspired wind generators, a monitoring system is required to observe the output variables (voltage and frequency). Method: LoRaWAN technologies are used to deploy the wireless link since the generators are separated from the base station. In addition, the Gateway coverage area is simulated with HTZ Communications software for future smart grid improvements. Results: The implemented system allows constant monitoring over a long period of time and stores its information in online, open-source databases, which allows remotely visualizing the status of the network, with a total of 3 samples per minute and a range of up to 3,47 km. Conclusions: The data acquisition system can be implemented for remote monitoring. Moreover, since it is a low power system, it can be utilized in non-interconnected areas, as well as for storing data for up to 6 months. However, for the characterization of a model of wind generators, it is advisable to modify the system so that the sampling time is lower.

This article presents the critical analysis on the current state of the tools for monitoring and management in distribution transformers in the face of the integration of distributed energy resources, a current topic and of great relevance for the Colombian electricity sector given the high integration of Distributed energy resources (DER), which makes it necessary to provide the productive sector with this work which summarizes the main tools used worldwide to monitor and supervise the distribution transformers that leave the system without any supervision.

Context: Coffee is a popular drink obtained from the seed of a shrub called cafeto, which is ground and toasted in order to obtain the powder used for the elaboration of the drink. For its transformation, it is necessary to use different types of machines, which is an important market niche in the country’s economy. Therefore, it is necessary to identify opportunities for improvement in the activities of the process involving ordering, production, and dispatch of coffee pulping machines in a Colombian company. Method: By using simulation as a tool, a model is built which appropriately represents the reality of the company, starting with the delimitation of the problem, continuing the identification of key variables, the taking of samples and their statistical analysis, the construction of the simulation with its respective validation and verification processes, and ending with the analysis of results and possibilities of application in the company, together with the conclusions of the process. Results: Based on the scenarios elaborated, it is recommended to design a dispatch area to access information quickly and in a timely manner, together with the development of specialized software that allows digitizing orders and referrals, as well as with the planning of delivery routes for prioritized orders according to the key variables of the process. With the implementation of the suggestions above, the queue of assembled and non-dispatched machines was reduced by 51%, and the dispatches of coffee pulping machines increased by 49%, thus improving customer satisfaction. Conclusions: The investment required to implement the solution scenario represents medium-term returns, which, together with customer satisfaction, allows the company to be made competitive. A study of the logistics of dispatching orders is proposed, since this part of the problem is evident, but cannot be solved by simulation.

Context:  Measuring the directivity characteristics and the frequency response of acoustic sources is a difficult process, as the dimensions and boundary conditions of the testing rooms used could constrain the measurement procedure. The testing room should guarantee a free-field condition, which is usually satisfied by using big acoustic absorbers with fibrous materials with high absorption coefficients. However, standing wave patterns can be easily developed due to the frequency range exciting the testing room. Method: The sound field separation method can isolate the radiated field of an acoustic source by sampling the sound field around it over two holographic spheres. The coordinates of the sampling points are used in a set of equations, whose solution can estimate the radiated field. In this paper, the effect of the variability on the actual positions of these sampling points is investigated. Results: Two numerical simulations with and without external sources outside the holographic spheres were performed. In all simulations, variations in the radial position of the sampling points were induced, and the relative reconstruction error, the directivity index, and the frequency response were studied. The results indicate that, for the estimation of the directivity of low-frequency acoustic sources, regardless of the presence of external sources, radial positioning of the sensors does not have to be exact to obtain an accurate reconstruction. Conclusions: This study suggests that, in the experimental characterization in conventional testing rooms of the radiated field from acoustic sources whose main frequency region corresponds to low frequencies, e.g. subwoofers, the SFS method could be used, thus obtaining high accuracy in the estimation of the directivity of the source.

Context: The conservation of minimally processed fruits is a very important topic in the food industry due to the increased consumption of this type of food. This work studies the effects caused by edible coatings based on aloe vera and cassava starch on minimally processed pineapple.Method: Properties such as texture and color were evaluated, and microbial analysis was conducted after 12 days of storage at 4 °C. Four treatments (T1, T2, T3, and T4) were tested: Honey Gold pineapple with coating solutions of different aloe vera/starch concentrations (T1:75/25, T2:50/50, T3:25/75), and a control treatment (T4) consisting of the fruit without coating. Coating was carried out by immersing the fruit for 1 min. Results: The results indicated that the T2 treatment achieved the best texture, and that T4 showed a higher luminosity. The microbiological parameters remained within those established by the Colombian Technical Standard (NTC 4519) for minimally processed fruit during the 12 days of conservation. Conclusion: Edible coatings can maintain the texture and inhibit the growth of microorganisms in Honey Gold pineapple. However, fruit luminosity may be affected by the use of these edible coatings.

Context:  Thermographic inspections are currently used to assess energy efficiency in electrical equipment and civil structures or to detect failures in cooling systems and electrical or electronic devices. However, thermal images lack texture details, which does not allow for a precise identification of the geometry of the scene or the objects in it. Method: In this work, the development of the software tool called DepTherm is described. This tool allows performing intrinsic and extrinsic calibration between infrared and RGBD cameras in order to fuse thermal, RGB, and RGBD images, as well as to record thermal and depth data. Additional features include user management, a visualization GUI for all three types of images, database storage, and report generation. Results: In addition to the integration tests performed to validate the functionality of DepTherm, two quantitative tests were conducted in order to evaluate its accuracy. A maximum re-projection error of 1,47±0,64 pixels was found, and the maximum mean error in registering an 11 cm side cube was 4,15 mm. Conclusions: The features of the DepTherm software tool are focused on facilitating thermographic inspections by capturing 3D scene models with thermal data.

Context:  Since structures are nowadays being affected due to the environment in which they are located, as well as by strong seismic movements, leading them in some cases to collapse. Method: A search of scientific articles for the period 2014-2021 was carried out in different databases. 56 research works that applied fibers were collected. To this effect, keywords such as hormigón reforzado, reinforced concrete, and mechanical properties of concrete were used. Results: The mechanical characteristics of concrete which should be prioritized for improvement should be compression resistance capacity, tensile strength, modulus of elasticity, durability properties such as resistance to chemical attack, shrinkage properties, permeability properties, and physical properties such as drying time, unit weight, erosion, and absorption. Conclusions: Among the artificial fibers most used by researchers, metallic fibers stand out. In the same way, among the natural fibers, banana, rice husk, and sugar cane bagasse stand out.

Context: Vertical-axis wind turbines, and Savonius-type turbines in particular, outstrip other types of turbines in applications that include erratic and low-speed winds. Although their efficiency is among the lowest, this can be compensated by their low cost, turning them into a sustainable alternative which is also appealing for this type of applications. This research seeks to select the highest-performance geometry for the blade of a Savonius-type wind turbine. Method: To this effect, various geometric configurations used in this type of turbines, which were consulted in the literature, are numerically analyzed. All the profile models are studied under the same computational fluid dynamics parameters and models through the ANSYS Fluent software. Results: Through computational simulations, the optimal performance conditions of each of the geometries are estimated. These conditions allow comparing the performance of the profiles under the same terms, as well as identifying the ones with the highest performance. It is determined that the conventional semicircular profile and the one known as the modified Bach have power coefficients of 0,287 and 0,395, respectively, which represents a performance increase of 37,8%. Conclusions: These superior results motivate a detailed analysis of the modified Bach profile which allows finding the optimal geometric proportions for its aerodynamic performance.