Search results

The purpose of this study is to numerically and experimentally investigate the natural convection heat transfer in flat plates and plates with square, trapezoidal and triangular corrugations.

This work is an extension of the previous studies by Verderio et al. (2021a, 2021b, 2021c, 2021d, 2022a). An experimental apparatus was built to measure the plates’ temperatures during the natural convection cooling process. Several physical parameters were evaluated through the experimental methodology. Free and open-source computational tools were used to simulate the experimental conditions and to quantitatively and qualitatively evaluate the thermal plume characteristics over the plates.

The numerical results were experimentally validated with reasonable accuracy in the range of studied RaLP for the different plates. Empirical correlations of Nu¯LPexp=f(RaLP), h¯conv=f(RaLP) and Nu¯LPexp⋅(A/AP)=f(RaLP), with good accuracy and statistical representativeness, were obtained for the studied geometries. The convective thermal efficiency of corrugated plates (Δη), as a function of RaLP, was also experimentally studied quantitatively. In agreement with the findings of Oosthuizen and Garrett (2001), the experimental and numerical results proved that the increase in the heat exchange area of the corrugations has a greater influence on the convective exchange and the thermal efficiency than the disturbances caused in the flow (which reduce h¯conv). The plate with trapezoidal corrugations presented the highest convective thermal efficiency, followed by the plates with square and triangular corrugations. It was also proved that the thermal efficiency of corrugated plates increases with RaLP.

The results demonstrate that corrugated surfaces have greater thermal efficiency than flat plates in heating and/or cooling systems by natural convection. This way, corrugated plates can reduce the dependence on auxiliary forced convection systems, with application in technological areas and Industry 4.0.

The empirical correlations obtained for the corrected Nusselt number and thermal efficiency for the corrugated plate geometries studied are original and unpublished, as well as the experimental validation of the developed three-dimensional numerical code.

The purpose of this study is to analyze the influence of the main physical–numerical parameters in the computational evaluation of natural convection heat transfer rates in isothermal flat square plates in the laminar regime. Moreover by experimentally validate the results of the numerical models and define the best parameter settings for the problem situation studied.

The present work is an extension of the study by Verderio Junior et al. (2021), differing in the modeling, results analysis and conclusions for the laminar flow regime with Rade=1×105. The analysis of the influence and precision of the physical–numerical parameters: boundary conditions, degree of mesh refinement, refinement layers and κ – ω SST and κ – ε turbulence models, occurred from the results from 48 numerical models, which were simulated using the OpenFOAM® software. Comparing the experimental mean Nusselt number with the numerical values obtained in the simulations and the analysis of the relative errors were used in the evaluation of the advantages, restrictions and selection of the most adequate parameters to the studied problem situation.

The numerical results of the simulations were validated, with excellent precision, from the experimental reference by Kitamura et al. (2015). The application of the κ – ω SST and κ – ε turbulence models and the boundary conditions (with and without wall functions) were also physically validated. The use of the κ – ω SST and κ – ε turbulence models, in terms of cost-benefit and precision, proved to be inefficient in the problem situation studied. Simulations without turbulence models proved to be the best option for the physical model for the studies developed. The use of refinement layers, especially in applications with wall functions and turbulence models, proved unfeasible.

Use of the physical–numerical parameters studied and validated, and application of the modeling and analysis methodology developed in projects and optimizations of natural convection thermal systems in a laminar flow regime. Just like, reduce costs and the dependence on the construction of experimental apparatus to obtain experimental results and in the numerical-experimental validation process.

Exclusive use of free and open-source computational tools as an alternative to feasible research in the computational fluid dynamics area in conditions of budget constraints and lack of higher value-added infrastructure, with applicability in the academic and industrial areas.

The results and discussions presented are original and new for the applied study of laminar natural convection in isothermal flat plate, with analysis and validation of the main physical and numerical influence parameters.

This paper aims to study, experimentally validate and select the main physical and numerical parameters of influence in computational numerical simulations to evaluate mean heat flux by natural convection on square flat plates.

Several numerical models were built to study the influence of physical and numerical parameters about the predictions of the natural convection heat transfer rates on the surface of a flat plate with aspect ratio = 1, in isothermal conditions, turbulent regime and using the free and open-source software OpenFOAM®. The studied parameters were: boundary conditions (using or not using wall functions in properties ε, κ, ν_t and ω), degree of mesh refinement, refinement layers and turbulence models [κ – ε and κ – ω Shear Stress Transport (SST)]. From the comparison of the values of the mean Nusselt number, obtained from numerical simulations and literature experimental results, the authors evaluated the precision of the studied parameters, validating and selecting the most appropriate to the analyzed problem situation.

The validation and agreement of the numerical results could be proven with excellent precision from experimental references of the technical scientific literature. More refined meshes with refinement layers were not suitable for the studies developed. The κ – ε and κ – ω SST turbulence models, in meshes without refinement layers, proved to be equivalent. Whether or not to use wall functions in turbulent boundary conditions proved to be irrelevant as to the accuracy of results for the problem situation studied.

Use of the physical and numerical parameters is studied and validated for various applications in natural convection heat transfer of technology and industry areas.

Use of free and open-source software as a research tool in the Computational Fluid Dynamics (CFD) area, especially in conditions without large financial resources or state-of-the-art infrastructure.

To the best of the authors’ knowledge, this work is yet not available in existing literature.

Despite the growing interest regarding the Brazilian rice industry, there is not much literature focusing on the role of the institutions in the process of technological capability accumulation and in the formation of the technological trajectories within this industry. This paper aims to discover the role of local institutions in the generation and dissemination of knowledge for creating the technological capability that can define different technological trajectories, using the Brazilian rice industry as an empirical field.

To achieve said objective, this paper uses secondary data (documental research) and a multiple case study design based on primary empirical evidence (content analysis and direct observation) about the Brazilian rice industry.

The paper’s main contribution is the empirical application of a framework that allows us to evaluate the institutions’ roles and activities and how these capabilities evolve as the firms’ technological levels progress and the technological trajectory is formed. Regarding aspects related to public policy, the authors found some implications that are mainly related to the need to consolidate this type of institution in developing countries with the goal of strengthening its technological capabilities, allowing these countries to operate on the technological boundary and to compete with developed countries.

There are few attempts to relate the technological capability, technological trajectories and institutions in the Brazilian rice industry. Therefore, to the best of the authors’ knowledge, the novelty of this study lies in the analysis of these theoretical approaches in this industrial sector, more specifically, in the Brazilian rice industry.

This paper surveys the social security system in several Latin American countries. Specifically, the cases of Bolivia and Brazil are documented in order to determine if the Chilean model is a viable one in the Latin America and Caribbean region. An institutional approach suggests that while there has been a marked interest in tailoring pension funds a la Chile, policy makers of the region must be aware of the similarities and differences in the politico‐social‐economic environment. The macroeconomic transformation undertaken in Chile was a unique one obeying to specific conditions of time and process. It is indicated, however, that even in the case of developed nations, some features of the Chilean model may be very appealing as well.

The purpose of this study is to qualitatively explore the impact of family separation and transnational parenthood on Haitian migrant women’s mental health living in Santiago, Chile.

Sixteen in-depth interviews were conducted with Haitian men and women living in Santiago de Chile, and based on an inductive perspective, a thematic analysis was performed.

The process of family reunification has been specifically hard in the past years, therefore, almost no one has been able to bring their children to Chile despite having a permanent visa. An important aspect of their testimonies is that they feel guilty about having someone else taking care of their children, even though sometimes they are the ones financially supporting the entire extended family.

This study’s findings show how family separation, ransnational parenthood, and migration experiences particularly affect Haitian igrant women’s mental health and provides relevant information on its onsequences for their quality-of-life. However, it is surprising that having plans to move out was a protective factor against symptoms of depression.

In recent decades, there has been an important growth of Latin American cities; therefore, the demand for resources and services has increased for cities to function and meet the needs of their inhabitants. Latin American cities are growing rapidly and this process affects the quality of life of citizens. The purpose of this paper is to characterize the logistics of an area of the city of Lima, Peru; through the analysis of the practices of the last mile distribution, and in this way, contribute with information that can be used for decision-making and for the proposal of public policies that improve the efficiency of logistics operations in the area.

Regarding the methodology applied, first, we identified the district to be analyzed using marketing information from the districts of Lima. Next, the authors collected information using forms following the methodology of the last Mile/Km²-MIT. Finally, the project planning finished in 15 days.

It was found that most of the stores in the area are nanostores that sell diverse products, the community does not have parking lots or loading and unloading areas and the majority of deliveries are made to wholesalers and supermarkets. In addition, a relationship between business density and the traffic congestion was identified and taxis are the most widely used means of distribution of goods. Most of the streets do not have signage, they are mainly one-way and do not have exclusive routes for public transportation.

Due to not having georeference information about the specific stores location and statistics data about its suppliers, the research results may show a primarily scope. Based on the results, the authors are encouraged to do more research using data analytics as in the next steps.

The paper reinforces the importance and challenge of working collaboration between suppliers, owners and local government.

The paper provides opportunities to create new policies, as well as an incentive plan for personal workers, suppliers and ecosolution proposals.

Currently, as per the authors’ knowledge, there is no varied literature that characterizes and analyzes the logistic profile of the districts of Lima city and serves as a basis for the implementation of solutions and public policies.

El objetivo de esta investigación es caracterizar la logística de un área de la ciudad de Lima, Perú; a través del análisis de las prácticas de la distribución de la última milla y, de esta manera, contribuir con información que se puede utilizar para la toma de decisiones y para la propuesta de políticas públicas que mejoren la eficiencia de las operaciones logísticas en el área.

Con respecto a la metodología aplicada, primero, se identificó el distrito a analizar utilizando información de mercadeo de los distritos de Lima; a continuación, se recopiló información utilizando formularios siguiendo la metodología de la última milla/Km²-MIT; finalmente, la planificación del proyecto terminó en 15 días.

Se encontró que la mayoría de los establecimientos son pequeñas tiendas que venden productos diversos, no tienen estacionamientos o áreas de carga y descarga y la mayoría de las entregas se realizan a mayoristas y supermercados. Además, existe una relación entre la densidad comercial y la congestión de tráfico, siendo los taxis los medios de distribución más utilizados. La mayoría de las calles no tienen señalización, son de un solo sentido y no tienen carriles exclusivos para el transporte público. Estos hallazgos son relevantes para la implementación de políticas públicas para la mejora de la infraestructura y eficiencia de las operaciones logísticas.

Actualmente no existe una literatura variada que caracterice y analice el perfil logístico de los distritos de la ciudad de Lima y sirva de base para la implementación de soluciones y políticas públicas.

Palabras clave Planificación, Planeamiento urbano, Distribución, Submegaciudades, Megaciudades, Urbanismo, Recursos

Artículo de investigación

O objetivo desta investigação é caracterizar a logística de uma área da cidade de Lima, Peru; através da análise das práticas de distribuição da última milha e, desta forma, contribuir com informações que possam ser utilizadas na tomada de decisão e pela proposição de políticas públicas que melhorem a eficiência das operações logísticas na área.

Com relação à metodologia aplicada, primeiro, o distrito a ser analisado foi identificado usando informações de marketing dos distritos de Lima; em seguida, as informações foram coletadas por meio de formulários seguindo a metodologia da última milha/Km²-MIT; finalmente, o planejamento do projeto terminou em 15 dias.

Constatou-se que a maioria das lojas comercializa diversos produtos, não possui estacionamentos ou áreas de carga e descarga e sendo a maioria das entregas realizadas para atacadistas e supermercados. Além disso, existe uma relação entre a densidade comercial e o congestionamento de tráfego, sendo os táxis os meios de distribuição mais utilizados. A maioria das ruas não possui sinalização, são de sentido único e não possuem pistas exclusivas para o transporte público. Essas constatações são relevantes para a implementação de políticas públicas para melhorar a infraestrutura e a eficiência das operações logísticas.

Atualmente não existe uma literatura variada que caracterize e analise o perfil logístico dos distritos da cidade de Lima e sirva de base para a implementação de soluções e políticas públicas.

Palavras-chave Planejamento, Planejamento urbano, Distribuição, Sub megacidades, Megacidades, Planejamento urbano, Recursos

Artigo de pesquisa

Based on a decolonial perspective from Latin America, this paper aims to offer a different history of the creation of Brazil’s Consumer Defense Code (CDC), analyzing the process through which Eurocentric influences, especially coming from Consumers International (CI), became present in the development of the code.

A qualitative historical research was developed using marketing amnesia and decolonialism as its theoretical backdrop. Primary and secondary data are used as source of information. Primary data were obtained through interviews with two authors of the CDC. Secondary data were collected from academic articles and books, reports, magazines and consumer organization websites, as well as journalistic articles.

During the drafting of the CDC and after its promulgation, the presence of Eurocentric forces was constant, given the interests of CI and other agents in influencing Brazil’s consumer practices, subordinating them to those of the Global North. This Eurocentric presence was accepted by the Brazilian jurists that drafted the CDC, which led to the incorporation of both laws and bills from Eurocentric countries and the United Nations Guidelines for Consumer Protection into the code.

Such discussions are scarce in marketing, due to the area’s amnestic state regarding the past. While selectively forgetting certain pasts, marketing fails to both acknowledge its tendency to subordinate consumerist actions to those accepted by the Eurocentric world, and to establish analyses that deal with mimetic processes, to minimize asymmetries between companies and consumers, especially in emerging economies, and, even more, dichotomies between the Global North and the Global South.

This paper aims to explore the effective factors that influence the treatment of drug addiction in therapeutic communities (TCs) and to determine its essential elements in the Peruvian, Nicaraguan and Czech context.

The qualitative data were collected during semi-structured interviews with inpatients/clients of seven TCs based in Peru (Takiwasi), Nicaragua (Centro de Especialiades en Adicciones, Centro de Rehabilitación del Alcohólico y Adicto a Otras Drogas and Albergue de Miembros Adictos en Recuperación) and the Czech Republic (Renarkon, Sejrek and Kladno-Dubi). All 90 interviews were manually transcribed, and content analysis was performed. Codes were created using the grounded theory method.

The effective factors of TC, treatment in Peru, Nicaragua and Czechia are identical in conditions such as the presence of a personal therapist, the use of psychotherapy and the importance of group cohesion. In Peru, the administration of medicinal plants and diet was perceived as a principal part of the treatment. Nicaraguan TCs were specific for practicing 12 steps. In Czechia, an emphasis is put on the therapeutic program, workshops and leisure activities. Spirituality and religion play a main role in the Peruvian and Nicaraguan TCs only.

The current study presents a unique insight into the factors considered effective by inpatients/clients of TCs in different socio-cultural contexts.

This empirical study examines the drivers of consumer intention to adopt wearable technology for healthcare in a South American country. Specifically, it proposes and tests a model of nonuser consumer intention to adopt fitness trackers for healthcare purpose in Chile.

This study draws on the technology acceptance framework UTAUT2 to develop and test a conceptual model of wearable technology adoption. Data were collected through an online survey applied to 470 nonusers of wearable technology in Santiago, Chile.

Findings indicate that hedonic motivation, social influence and perceived usefulness have the strongest influence on intention to adopt fitness trackers in Chile for healthcare. In addition, health motivation is an indirect predictor of consumer's intention to adopt wearable technology through its effect on perceived usefulness.

The study contributes to a better understanding of consumer intention to adopt wearable technology for healthcare objectives in a less developed country in South America. Findings are useful for wearable technology managers, retail business and public policymakers.

Despite the vast growth and importance of wearable technology for healthcare purposes, academic research considering less developed countries is scarce, especially the South American region. The proposed model and findings can extend this research gap. Theoretical and managerial implications are discussed as well as implications for public policy.