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Article
Publication date: 8 June 2021

Ana Pinto Borges, João M. Lopes, Catarina Carvalho, Bruno Miguel Vieira and Jorge Lopes

The purpose of this study is to analyze the entrepreneurial intentions of higher education students in a private higher education institution (HEI), enrolled in the following…

857

Abstract

Purpose

The purpose of this study is to analyze the entrepreneurial intentions of higher education students in a private higher education institution (HEI), enrolled in the following courses: Business Management, Hospitality Management, Tourism and Business Relations.

Design/methodology/approach

A quantitative methodology was used through the application of a questionnaire in a private HEI located in the northern region of Portugal and 228 valid responses were collected.

Findings

We have found out that (1) the elder the students are, the higher is the probability that they will consider entrepreneurship as the first option to enter the job market; (2) the courses of Business Management and Hotel Management are those that influence the entrepreneurial intentions most positively; (3) the more prepared a student feels in order to start a business, the more likely he will become an entrepreneur; (4) to consider entrepreneurship as the first option to enter the job market is positively influenced by the dimensions of the Attitude Toward Enterprise (ATE), namely, leadership, creativity, achievement and personal control; (5) to have a business idea could be motivated by the course in which the students are enrolled in, if they feel they are prepared to start a business, and by the dimensions of ATE.

Practical implications

HEIs and/or regional governments may have an entrepreneurship support office, where students can get assistance in the process of creating their companies and develop innovative entrepreneurial models adapted to older students. The creation of “senior entrepreneurial ecosystems” can be an interesting path to be explored. HEIs can make extracurricular activities available to students. Policymakers must introduce entrepreneurship to primary and secondary education.

Originality/value

This study increases the understanding of the individual characteristics of the students in a private HEI, as well as the courses that positively influence entrepreneurial intentions.

Details

Education + Training, vol. 63 no. 6
Type: Research Article
ISSN: 0040-0912

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Article
Publication date: 12 December 2018

Jorge Pedro Lopes, Rui Alexandre Oliveira and Maria Isabel Abreu

The purpose of this paper is to present the estimates of the value of the built environment stock in Cape Verde, a Sub-Saharan African country that is scattered through ten…

378

Abstract

Purpose

The purpose of this paper is to present the estimates of the value of the built environment stock in Cape Verde, a Sub-Saharan African country that is scattered through ten relatively small islands.

Design/methodology/approach

It applies the perpetual inventory method in a long series of construction investment data at 1980 and 2007 constant prices published by the Cape Verde’s National Statistics Office.

Findings

The results show that the capital-output ratio is similar to those in the advanced industrial countries. The high value of this indicator suggests that the country should shift its focus from building new investment projects to managing the considerable amount of built stock.

Originality/value

The main originality of the paper comes from the use of different data sets from the National Statistical Office to construct the indicators of the construction industry activity in a comprehensive way.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 5
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 10 June 2020

Camila Fernandes Higa, Thatyanne Gradowski, Selene Elifio-Esposito, Marcelo Fernandes de Oliveira, Paulo Inforçatti, Jorge Vicente Lopes da Silva, Fred Lacerda Amorim and Michelle Sostag Meruvia

This study aims to investigate the production of scaffolds by selective laser sintering (SLS) using poly(vinyl alcohol) (PVA) polymer, for in vitro studies, a relatively new and…

154

Abstract

Purpose

This study aims to investigate the production of scaffolds by selective laser sintering (SLS) using poly(vinyl alcohol) (PVA) polymer, for in vitro studies, a relatively new and growing area in which scaffolds could be used in the design of three-dimensional models for in vitro disease model or tissue equivalent for safety and effectiveness tests.

Design/methodology/approach

The influence of the SLS process parameters laser power, 26 W and 32 W, and number of laser scans, 1, 2, 4 and 6, on the surface microstructure of the samples and on the degree of crystallinity and chemical stability of PVA material, was investigated using powder with particle size of 20-320 µm. Laser sintered PVA samples were subjected to cell culture tests using osteoblastic cells derived from human osteosarcoma (SaOs-2).

Findings

The laser power has no significant influence on the microstructure of the laser-sintered samples, however the number of scans has a considerable influence on the sintering degree; the SLS process causes a decrease in the degree of crystallinity and changes the chemical structure of the as-received PVA, especially when using higher laser power and more number of scans. Preliminary in vitro cell culture tests show that the laser-sintered PVA material is biocompatible with SaOs-2 cells.

Originality/value

SLS offers good potential for the fabrication of scaffolds and thus, may be applied as an alternative to conventional scaffold fabrication processes to overcome their limitations.

Details

Rapid Prototyping Journal, vol. 26 no. 6
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 29 October 2021

Edwin Sallica-Leva, Fernando Henrique da Costa, Cláudio Teodoro Dos Santos, André Luiz Jardini, Jorge Vicente Lopes da Silva and João Batista Fogagnolo

This paper aims to describe the obtainment of Ti-6Al-4V parts with a hierarchical arrangement of pores by additive manufacturing, aiming at designing orthopedic implants.

383

Abstract

Purpose

This paper aims to describe the obtainment of Ti-6Al-4V parts with a hierarchical arrangement of pores by additive manufacturing, aiming at designing orthopedic implants.

Design/methodology/approach

The experimental methodology compares microstructural and mechanical properties of Menger pre-fractal sponges of Ti-6Al-4V alloy, manufactured by laser powder bed fusion (LPBF) and electron beam powder bed fusion (EBPBF), with three different porosity volumes. The pore arrangement followed the formation sequence of the Menger sponge, with hierarchical order from 1 to 3.

Findings

The LPBF parts presented a martensitic microstructure, while the EBPBF parts presented an α + ß microstructure, independently of its wall thickness. The LPBF parts presented higher mechanical resistance and effective stiffness than the EBPBF parts with similar porosity volume. The stiffness values of the Menger pre-fractal sponges of Ti-6Al-4V alloy, between 4 and 29 GPa, are comparable to those of the cortical bone. Furthermore, the deformation behavior presented by the Menger pre-fractal sponges of Ti-6Al-4V alloy did not follow the Gibson and Ashby model's prediction.

Originality/value

To the best of the authors' knowledge, this is the first study to obtain Menger pre-fractal sponges of Ti-6Al-4V alloy by LPBF and EBPBF. The deformation behavior of the obtained porous parts was contrasted with the Gibson and Ashby model's prediction.

Details

Rapid Prototyping Journal, vol. 28 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 14 March 2022

José Luis Dávila, Bruna Maria Manzini, Marcos Akira d'Ávila and Jorge Vicente Lopes da Silva

This study aims to report the development of an open-source syringe extrusion head for shear-thinning materials. The target is to adapt open-source 3D printers to be helpful in…

530

Abstract

Purpose

This study aims to report the development of an open-source syringe extrusion head for shear-thinning materials. The target is to adapt open-source 3D printers to be helpful in research lines that use gels, hydrogels, pastes, inks, and bio-inks.

Design/methodology/approach

This hardware was designed to be compatible with a Graber i3-based 3D printer; nevertheless, it can be easily adapted to other open-source 3D printers.

Findings

The extrusion head successfully deposits the material during the 3D printing process. It was validated fabricating geometries that include scaffold structures, which are a possible application of bioprinting for tissue engineering. As reported, the extruded filaments allowed the porous samples' structuration.

Practical implications

This system expands the applications of open-source 3D printers used at the laboratory scale. It enables low-cost access to research areas such as tissue engineering and biofabrication, energy storage devices and food 3D printing.

Originality/value

The open-source hardware here reported is of simple fabrication, assembly and installation. It uses a Cardan coupling and a three guides system to transfer the stepper motor motion. This approach allows continuous movement transfer to the syringe piston, producing an adequate deposition or retraction. Thus, the effect of misalignments is avoided, considering that these latter can cause skipping steps in the motor, directly affecting the deposition.

Details

Rapid Prototyping Journal, vol. 28 no. 8
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 20 June 2016

Nino Pereira, A.Fernando Ribeiro, Gil Lopes and Jorge Lino

The purpose of this paper is to characterise the TWIN-RRT* algorithm which solves a motion planning problem in which an agent has multiple possible targets where none of them is…

287

Abstract

Purpose

The purpose of this paper is to characterise the TWIN-RRT* algorithm which solves a motion planning problem in which an agent has multiple possible targets where none of them is compulsory and retrieves feasible, “low cost”, asymptotically optimal and probabilistically complete paths. The TWIN-RRT* algorithm solves path planning problems for both holonomic and non-holonomic robots with or without kinematic constraints in a 2D environment.

Design/methodology/approach

It was designed to work equally well with higher degree of freedom agents in different applications. It provides a practical implementation of feasible and fast planning, namely where a closed loop is required. Initial and final configurations are allowed to be exactly the same.

Findings

The TWIN-RRT* algorithm computes an efficient path for a single agent towards multiple targets where none of them is mandatory. It inherits the low computational cost, probabilistic completeness and asymptotical optimality from RRT*.

Research limitations/implications

It uses efficiency as cost function, which can be adjusted to the requirements of any given application. TWIN-RRT also shows compliance with kinematic constraints.

Practical implications

The practical application where this work has been used consists of an autonomous mobile robot that picks up golf balls in a driving range. The multiple targets are the golf balls and the optimum path is a requirement to reduce the time and energy to refill as quickly as possible the balls dispensing machine.

Originality/value

The new random sampling algorithm – TWIN-RRT* – is able to generate feasible efficient paths towards multiple targets retrieving closed-loop paths starting and finishing at the same configuration.

Details

Industrial Robot: An International Journal, vol. 43 no. 4
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 10 June 2014

Grazielle de Oliveira Setti, Marcelo Fernandes de Oliveira, Izaque Alves Maia, Jorge Vicente Lopes da Silva, Raluca Savu and Ednan Joanni

The purpose of this paper is to compare the results from mechanical testing with measurements of surface-dependent properties performed on polyamide parts made by selective laser…

1202

Abstract

Purpose

The purpose of this paper is to compare the results from mechanical testing with measurements of surface-dependent properties performed on polyamide parts made by selective laser sintering (SLS) to assess a possible correlation between them.

Design/methodology/approach

Fabrication of Nylon 12 (Duraform PA®) samples using different laser power levels and their characterization by tensile testing, roughness and Raman scattering measurements.

Findings

Among the surface methods investigated, the results from Raman spectroscopy are the best ones, but methods dependent on surface analysis are not really suitable as indicators of the mechanical properties. The correlation coefficients for linear fitting obtained when the normalized results of mechanical properties are plotted against the surface properties are too low. Furthermore, the ambiguity between surface and mechanical data makes it impossible to use these surface properties for prediction purposes in the industrial environment.

Originality/value

Quantitative evaluation and correlation between mechanical properties and surface properties of SLS-made samples.

Details

Rapid Prototyping Journal, vol. 20 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 11 March 2014

Grazielle de Oliveira Setti, Jorge Vicente Lopes da Silva, Marcelo Fernandes de Oliveira, Izaque Alves Maia, Dosil Pereira de Jesus, Raluca Savu, Thebano Emilio de Almeida Santos, Rita de Cássia Zacardi de Souza and Ednan Joanni

The purpose of this paper is to characterize polyamide parts prepared by the SLS process using techniques that are dependent on surface properties and compare the results to…

631

Abstract

Purpose

The purpose of this paper is to characterize polyamide parts prepared by the SLS process using techniques that are dependent on surface properties and compare the results to density measurements in order to assess which technique better reflects the degree of densification achieved using different laser power levels.

Design/methodology/approach

Fabrication of Nylon 12 (Duraform PA) samples and their characterization by apparent density measurements, perfilometry, Raman spectroscopy, scanning electron microscopy, specific surface area and contact angle measurements.

Findings

Methods dependent on surface analysis are not suitable indicators of the degree of sample densification. Among the surface methods, the results from Raman spectroscopy are the ones with the best performance. Incipient sintering of the superficial layers and raw material powder on the surface, inherent to the parts made by the SLS process, strongly interfere with the characterization.

Originality/value

Quantitative comparison of a number of surface probing methods for monitoring densification of SLS parts. Characterization of sample surfaces with and without raw material powder.

Details

Rapid Prototyping Journal, vol. 20 no. 2
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 10 June 2014

Grazielle de Oliveira Setti, Marcelo Fernandes de Oliveira, Izaque Alves Maia, Jorge Vicente Lopes da Silva and Ednan Joanni

This paper aims to demonstrate the functionalization of polyamide parts made by selective laser sintering (SLS) for application as substrates for chemical analysis by…

263

Abstract

Purpose

This paper aims to demonstrate the functionalization of polyamide parts made by selective laser sintering (SLS) for application as substrates for chemical analysis by surface-enhanced Raman scattering (SERS).

Design/methodology/approach

Fabrication of Nylon 12 (Duraform PA®) samples using two laser power levels and deposition of a layer of gold-coated zinc oxide nanostructures. Performance of these substrates in the detection of a known compound was tested by Raman spectroscopy.

Findings

The hydrothermal synthesis proved to be a good method for functionalizing the surface of polyamide parts made by the SLS process. By varying the synthesis temperature, ZnO nanoparticles and nanorods attached to the sample surfaces could be obtained. The degree of sample sintering had an effect on the growth of the nanostructures. The gold-coated functionalized surfaces enhanced the Raman signal from crystal violet by more than three orders of magnitude. ZnO nanorods grown on well-sintered SLS parts showed the best performance from the set of samples tested in this work.

Originality/value

ZnO nanostructures were grown directly on untreated surfaces of SLS-made polyamide. These substrates were used for chemical analysis by SERS.

Details

Rapid Prototyping Journal, vol. 20 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 31 May 2011

Inês Flores‐Colen, Jorge Manuel Caliço Lopes de Brito and Vasco Peixoto de Freitas

The purpose of this paper is to present a methodology in order to improve inspections' diagnosis during façades' service life through in‐service criteria. On‐site performance…

941

Abstract

Purpose

The purpose of this paper is to present a methodology in order to improve inspections' diagnosis during façades' service life through in‐service criteria. On‐site performance assessment and deciding on the maintenance of renders can only be improved if quantitative parameters are pre‐established at the design stage and monitored under service conditions.

Design/methodology/approach

The methodology is based on a set of in‐service parameters inferred from visual observation and measurements and their methods of assessment (based on visual inspections, auxiliary techniques, in‐situ and laboratorial testing). These have been arrived at by inspecting the façade rendering on 44 buildings (cement‐based renders), of different ages and types of degradation.

Findings

This paper focuses on 23 proposed mechanical and physical‐chemical parameters that can complement the ones already established by standards or technical data, obtained in lab conditions, using standard specimens or small models. They are assessed by techniques that have been applied to renders or other façade elements such as concrete or timber structures. The reliability of this in‐service performance assessment is discussed together with its potential as an aid to deciding on predictive maintenance action after an inspection's diagnosis.

Originality/value

The originality of this approach stems from the fact that in‐service parameters derived from both laboratory and in‐situ measurements can improve understanding of the behaviour of façade rendering, which is an important step in planning and monitoring maintenance. Two aspects are emphasised: the behaviour of materials/systems is assessed in real conditions, and the subjectivity of in‐service diagnosis is reduced when more than one performance parameter is assessed.

Details

Structural Survey, vol. 29 no. 2
Type: Research Article
ISSN: 0263-080X

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