Matheus Francisco, João Pereira, Lucas Oliveira, Sebastião Simões Cunha and G.F. Gomes
The present paper aims at the multi-objective optimization of a reentrant hexagonal cell auxetic structure. In addition, a parametric analysis will be carried out to verify how…
Abstract
Purpose
The present paper aims at the multi-objective optimization of a reentrant hexagonal cell auxetic structure. In addition, a parametric analysis will be carried out to verify how each of the design factors impact each of the responses.
Design/methodology/approach
The multi-objective optimization of five different responses of an auxetic model was considered: mass, critical buckling load under compression effort, natural frequency, Poisson's ratio and failure load. The response surface methodology was applied, and a new meta-heuristic of optimization called the multi-objective Lichtenberg algorithm was applied to find the optimized configuration of the model. It was possible to increase the failure load by 26.75% in compression performance optimization. Furthermore, in the optimization of modal performance, it was possible to increase the natural frequency by 37.43%. Finally, all 5 responses analyzed simultaneously were optimized. In this case, it was possible to increase the critical buckling load by 42.55%, the failure load by 28.70% and reduce the mass and Poisson's ratio by 15.97 and 11%, respectively. This paper addresses something new in the scientific world to date when evaluating in a multi-objective optimization problem, the compression and modal performance of an auxetic reentrant model.
Findings
It was possible to find multi-objective optimized structures. It was possible to increase the critical buckling load by 42.82%, and the failure load in compression performance by 26.75%. Furthermore, in the optimization of modal performance, it was possible to increase the natural frequency by 37.43%, and decrease the mass by 15.97%. Finally, all 5 responses analyzed simultaneously were optimized. In this case, it was possible to increase the critical buckling load by 42.55%, increase the failure load by 28.70% and reduce the mass and Poisson's ratio by 15.97 and 11%, respectively.
Originality/value
There is no work in the literature to date that performed the optimization of 5 responses simultaneously of a reentrant hexagonal cell auxetic structure. This paper also presents an unprecedented statistical analysis in the literature that verifies how the design factors impact each of the responses.
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Matheus Francisco, Lucas Roque, João Pereira, Susiane Machado, Sebastião Simões da Cunha Jr and Guilherme Ferreira Gomes
This study aims to address a deep statistical analysis on transtibial prostheses made of composite isogrid carbon/epoxy structure.
Abstract
Purpose
This study aims to address a deep statistical analysis on transtibial prostheses made of composite isogrid carbon/epoxy structure.
Design/methodology/approach
For the methodological procedure, an experimental arrangement was created using design of experiments, and the response surface methodology (RSM) was used. The RSM was obtained from the decision variables of the isogrid model, which consists of angle, circular width and helical width. All modeling was performed numerically using the finite element method.
Findings
Results obtained through analysis of variance (ANOVA) indicated the sensitivity of each decision variable (manufacture) in the mechanical responses. The results obtained in this study provide a starting point in formulating optimization problems for researchers and engineers.
Originality/value
A noteworthy thing about structural analysis and structural optimization is that some parameters and decision variables are more significant than others in certain responses (Major et al., 2011). Knowing the sensitivity of these parameters is essential for the correct formulation of an optimization problem. To handle these obstacles, design of experiments and ANOVA are used to solve and obtain the main effects on the structural performance. Nevertheless, to the best of the authors’ knowledge, very few efforts have been devoted to the development to show the factors that influence the various responses of a lower limb prosthesis isogrid tube.
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Djoko Sigit Sayogo, Sri Budi Cantika Yuli and Firda Ayu Amalia
This study aims to identify and outline the critical challenges affecting the inclination of executives to use data as the basis for making decisions at a local government level.
Abstract
Purpose
This study aims to identify and outline the critical challenges affecting the inclination of executives to use data as the basis for making decisions at a local government level.
Design/methodology/approach
The study conducted in-depth interviews with 21 public officials comprising middle- and top-level executives from 18 agencies and offices at the Bojonegoro Regency, one of Indonesia’s most progressive regencies in pursuing open government and smart cities.
Findings
The findings demonstrate that ensuring a good quality data architecture, nurturing data culture and developing analytics capability are essential in the case of a developing country such as Indonesia. However, insufficient policies and regulations, a nonexistent evaluative framework for data quality, disruptive local tradition and the ingrained autocratic administration represent significant and unique challenges to implementing data-driven decision-making in the local government in Indonesia.
Research limitations/implications
The chosen research approach may result in a need for more generalizability beyond Indonesia, accentuating the necessity for the geographical objects to include other developing countries in future research.
Practical implications
The findings showcase that lack of awareness and acceptance from public officials and the general public of the importance of a data-driven approach; as such, a better understanding of the change in attitudes and mindsets of public officials is invariably one of the critical practical determinants.
Originality/value
The findings signify the importance of creating robust accountability systems and evaluative frameworks that consider the many variables influencing decisions that capture the significance of organizational and local culture.
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Alessandro Silva de Oliveira, Gustavo Quiroga Souki, Dirceu da Silva, Matheus Alberto Rodrigues Silva and Francisco de Assis da Silva Medeiros
E-commerce platforms offer service guarantees (SGs) to improve consumers’ perceived quality and satisfaction. This survey aimed to test the direct and indirect effects of SGs on…
Abstract
Purpose
E-commerce platforms offer service guarantees (SGs) to improve consumers’ perceived quality and satisfaction. This survey aimed to test the direct and indirect effects of SGs on consumers’ perceived quality and satisfaction concerning the services of an international e-commerce platform.
Design/methodology/approach
The survey sample consisted of 378 consumers of an international e-commerce platform. Structural equation modelling (SEM) tested two structural models.
Findings
The first hypothetical model demonstrated that SGs positively and directly affects perceived quality and consumers' satisfaction on an e-commerce platform. This model also revealed that the perceived quality directly and positively impacted consumer satisfaction. The second hypothetical model confirmed that perceived quality mediates the relationship between SGs and satisfaction. Moreover, SGs positively and indirectly impacts consumer satisfaction.
Practical implications
This study suggests that e-commerce platforms use SGs as a marketing strategy in their business models to increase perceived quality and consumer satisfaction. However, to positively impact the perception of quality and consumer satisfaction, such SGs must have the following characteristics: unconditional, easy to understand and communicate, meaningful, easy and painless to invoke, and easy and quick to collect.
Originality/value
This research demonstrated the direct effects of SGs on perceived quality and consumer satisfaction on an international e-commerce platform. SGs directly impacts consumer satisfaction with the platform, even if they have not experienced its quality attributes (reliability, customisation, security and design). The indirect effects of SGs on consumer satisfaction were also proven, mediated by perceived quality. No previous study demonstrated such relationships simultaneously on e-commerce platforms.
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Francisco Elíseo Fernandes Sanches, Matheus Leite Campos, Luiz Eduardo Gaio and Marcio Marcelo Belli
Higher education institutions (HEIs) should assume their role as leaders in the search for a sustainable future. Consequently, such institutions need to incorporate sustainability…
Abstract
Purpose
Higher education institutions (HEIs) should assume their role as leaders in the search for a sustainable future. Consequently, such institutions need to incorporate sustainability into their activities. However, this needs to be done holistically and not with isolated and independent actions. Therefore, this study aims to develop a structure of sustainability action archetypes to help HEIs holistically incorporate sustainability in their strategies.
Design/methodology/approach
A systematic review of the literature was conducted focusing on the subject of sustainability in HEIs.
Findings
A structure of sustainability action archetypes for HEIs was proposed. Further, based on scientific literature, examples of actions were presented within each archetype.
Practical implications
This study provides HEI administrators and other organizations with a practical structure to enable the systemic incorporation of sustainability objectives and actions into institutional activities.
Originality/value
This study adapts the tool “sustainable business model archetypes” for a new purpose. This tool was initially developed to classify innovations of sustainable business models.
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Jaime A. Ramirez, William P.D. Figueiredo, Joao Francisco C. Vale, Isabela D. Metzker, Rafael G. Santos, Matheus S. Mattos, Elizabeth R.S. Camargos and David A. Lowther
– This paper aims to investigate the electroporation phenomenon in a single cell exposed to ultra short (μs) and high voltage (kV) electric pulses.
Abstract
Purpose
This paper aims to investigate the electroporation phenomenon in a single cell exposed to ultra short (μs) and high voltage (kV) electric pulses.
Design/methodology/approach
The problem is addressed by two complementary approaches. First, numerical simulations based on an asymptotic approximation derived from the Smoluchowski theory are used to calculate the pore generation, growth and size evolution at the membrane of a spherical cell model, immersed in a suspension medium and consisting of cytoplasm and membrane. The numerical calculations are solved using the finite difference method. Second, an in vitro experiment with LLC-MK2 cells is carried out in which electroporation was monitored with molecules of propidium iodide. This part also comprehended the design and manufacturing of a portable electric pulse generator capable of providing rectangular pulses with amplitude of 1,000 V and duration in the range of 1-μs to 100-μs. The pulse generator is composed of three modules: a high voltage DC source, a control module, and an energy storage and high voltage switching.
Findings
The numerical simulations considered a 5-μm radius cell submitted to a 500 kV/m rectangular electric pulse for 1-μs. The results indicate the formation of around 3,500 pores at the cell membrane, most of them, around 950, located at the poles of the cell aligned to the applied electric pulse, with radii sizes varying from 0.5-nm to 13-nm. The in vitro experiment considered exposition of LLC-MK2 cells to pulses of 200 V, 500 V, and 700 V, and 1-μs. Images from fluorescence microscopy exhibit the LLC-MK2 cells with intense red, a strong evidence of the electroporation.
Originality/value
The work presents a thorough study of the electroporation phenomenon combining two complementary approaches, a rigorous numerical simulation and a detailed in vitro experiment.
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The paper aims to provide a non‐technical introduction to the new procedures being used to extract knowledge from databases. The reasons for developing knowledge discovery methods…
Abstract
The paper aims to provide a non‐technical introduction to the new procedures being used to extract knowledge from databases. The reasons for developing knowledge discovery methods are discussed ± primarily, the current production of very large databases that may include many data relations not explicit in the database structure. The background in machine learning is indicated. The methods used are described for such techniques as classification (sorting data into predefined classes), clustering (developing ab initio a data classification) and the detection of deviations from pre‐established norms. Examples of the applications of these methods are given. The paper concludes with some brief thoughts about the potential use of knowledge discovery in the information field.