Search results

1 – 10 of 48
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 20 August 2019

Merlina A. Navarro Villanueva, Luis A. Soto Hernández, Melquisedec Vicente Mendoza, Ángel de J. Morales Ramírez and Fernando Juárez López

This paper aims to study the microstructural hot corrosion behaviour of the sintered Y2SiO5 ceramic silicate under a Na2SO4 + V2O5 mixture at an engine representative temperature…

136

Abstract

Purpose

This paper aims to study the microstructural hot corrosion behaviour of the sintered Y2SiO5 ceramic silicate under a Na2SO4 + V2O5 mixture at an engine representative temperature of 1150°C. Y2SiO5 is a promising candidate for thermal barrier coatings (TBC) due to its excellent chemical stability at high temperatures. As a continuous source of Y3+, it is expected that Y2SiO5 environmental barrier coating may prolong the lifetime of TBC systems by stopping the degradation caused by the loss of the Y2O3 stabilizer.

Design/methodology/approach

Two routes were chosen for the yttria silicate powder synthesis by sol-gel from TEOS and APTES precursors as the difference in Si source changed the ratio of Y2SiO5/Y2Si2O7 phases. Hot corrosion studies using Na2SO4 and V2O5 mixtures were conducted on both surfaces of APTES and TEOS tablets at 1150°C for 8 h in atmospheric air. The morphology and microstructure analyses of the silicate samples after hot corrosion tests were carried out using a SEM and X-ray diffraction analyse techniques.

Findings

Based on the degradation, the general status of the APTES tablet after hot corrosion presents a better hot corrosion resistance at a temperature of 1150°C than does that of the TEOS tablet. In the TEOS tablet, the crystal morphology of NaY9Si60O26 woodchip shapes with a size of 60 µm is developed on the surface for finally initiating some cracks. In the APTES case, the crystal morphology of rod-like shapes with a size of 100 µm is developed; hence, a dense thick layer predominately postpones the reaction of V2O5 and Na2SO4 with yttria silicate, and consequently, less damage is observed.

Originality/value

Coating yttria silicate preparation is very complicated; the problems of a high synthesis temperature, long production period and low yield still need to be solved. Under these perspectives, ceramics prepared via spark plasma sintering (SPS) can reach theoretical high densities and a fine grain size can be retained after the SPS process; hence, well resistance to the corrosion in molten salts is expected to obtain for the sintered yttria silicate tablets.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Access Restricted. View access options
Book part
Publication date: 23 April 2024

William Dextre-Martinez, Rosario Huerta-Soto, Eduardo Rocca-Espinoza, Manuel Chenet-Zuta and Luis Angulo-Cabanillas

The study set out to understand how the regional competitiveness index (RCI) in the department of Ancash related to the human development index (HDI) from 2008 to 2021. For a more…

Abstract

The study set out to understand how the regional competitiveness index (RCI) in the department of Ancash related to the human development index (HDI) from 2008 to 2021. For a more complete understanding of the findings, each component or dimension of the RCI was analyzed. Ancash's HDI and its competitiveness index over a 14-year period were used as the population for this applied, longitudinal, descriptive-correlational study, which was based on secondary data extracted from the “Instituto Nacional de Estadística e Informática” (INEI) and business school of the Pontificia Universidad Católica del Perú (CENTRUM) statistical databases. Multiple linear regression was used to find the relationship. The research found a strong and positive correlation between regional competitiveness and human development between 2008 and 2021. No correlations were found between the HDI and the health, education, employment, or institutional dimensions of regional competitiveness, but direct and significant correlations were established between the economic environment and the HDI and between the infrastructure dimension and the HDI.

Details

Technological Innovations for Business, Education and Sustainability
Type: Book
ISBN: 978-1-83753-106-6

Keywords

Access Restricted. View access options
Article
Publication date: 17 January 2022

Luis Diego Soto Kiewit and Bianca Vienni Baptista

This paper aims to analyse innovation models and interdisciplinarity in science, technology and innovation (STI) policy in Costa Rica between 2015 and 2021. The core focus is to…

292

Abstract

Purpose

This paper aims to analyse innovation models and interdisciplinarity in science, technology and innovation (STI) policy in Costa Rica between 2015 and 2021. The core focus is to evaluate the public policy in light of the groundwork that sustains the designed and proposed actions.

Design/methodology/approach

The authors applied a qualitative approach to build a set of dimensions and conducted content-analysis of selected documents. The analysis encompasses all current STI public policy documents in Costa Rica, including the planning instruments of the Central Government and the National Policy on STI.

Findings

The main findings show that STI policy in Costa Rica is based on different innovation models, but the projects and instruments themselves show the predominance of the reductionist model. Innovation receives a residual role. In turn, interdisciplinarity is based on the concept of convergence, which limits disciplinary collaboration to the natural, physical and engineering sciences, minimising contributions from other fields of knowledge to an instrumental role in innovation processes.

Practical implications

The authors conclude that the interlinkage between open innovation models, the participation of diverse societal actors and the inclusion of an interdisciplinary perspective leads to inclusive and more democratic public policy, allowing more sectors and organisations to benefit from innovation processes. This would imply a greater reach and impact of the policy, conditions that translate into innovation achievements and a better return on public investment.

Originality/value

This paper contributes to current discussions on STI policy by studying the implications of the link among policies, innovation models and interdisciplinarity.

Details

Journal of Science and Technology Policy Management, vol. 14 no. 2
Type: Research Article
ISSN: 2053-4620

Keywords

Access Restricted. View access options
Book part
Publication date: 8 October 2018

Luis Alfonso Dau, Elizabeth M. Moore and Max Abrahms

This chapter examines the impact of national membership in international organizations on female entrepreneurship. Drawing on the institution-based view from global strategy and…

Abstract

This chapter examines the impact of national membership in international organizations on female entrepreneurship. Drawing on the institution-based view from global strategy and civil society theory from international relations, we show how international organizations can promote entrepreneurship opportunities for women with respect to the United Nations’ sustainable development goals (SDGs). This research has both practical and social implications. From a practical perspective, it provides important insights for policy makers and entrepreneurs. Policy makers can use the findings to understand how the international organizations that countries join affect entrepreneurship, particularly the United Nation’s SDGs Entrepreneurs can also use the findings to advocate mutually beneficial conditions for host environments, particularly those dedicated to female empowerment. A sample of 44 countries, 5 years of data, and 130 country-year observations finds robust support for our assertions.

Access Restricted. View access options
Book part
Publication date: 23 June 2022

Mariana Zerón Félix, Claudia Milena Álvarez Giraldo and Cristian Alejandro Rubalcava de León

The objective of this study is to review the main studies of social entrepreneurship (SE) in Latin America, to categorize them into four categories. To accomplish this, a

Abstract

The objective of this study is to review the main studies of social entrepreneurship (SE) in Latin America, to categorize them into four categories. To accomplish this, a bibliometric literature review is carried out based on data from the Web of Science database, to locate the Latin American collection of studies. In this way, the main studies are described and grouped, following a qualitative scheme that allows to substantiate the main findings of the Latin authors. Consequently, the progress made in the literature of the SE for Latin America is corroborated, by visualizing that the SE turns out to be a forceful fact to manage well-being, but that it is faced with an inconsistent development.

Details

The Emerald Handbook of Entrepreneurship in Latin America
Type: Book
ISBN: 978-1-80071-955-2

Keywords

Access Restricted. View access options
Expert briefing
Publication date: 31 January 2018

The low-key ceremony was accompanied by opposition-led protests in which police deployed tear gas and fired warning shots. Despite violence since the elections, the international…

Details

DOI: 10.1108/OXAN-DB229448

ISSN: 2633-304X

Keywords

Geographic
Topical
Access Restricted. View access options
Article
Publication date: 19 June 2017

Lars Lindner, Oleg Sergiyenko, Moises Rivas-López, Daniel Hernández-Balbuena, Wendy Flores-Fuentes, Julio C. Rodríguez-Quiñonez, Fabian N. Murrieta-Rico, Mykhailo Ivanov, Vera Tyrsa and Luis C. Básaca-Preciado

The purpose of this paper is to present a novel application for a newly developed Technical Vision System (TVS), which uses a laser scanner and dynamic triangulation, to determine…

396

Abstract

Purpose

The purpose of this paper is to present a novel application for a newly developed Technical Vision System (TVS), which uses a laser scanner and dynamic triangulation, to determine the vitality of agriculture vegetation. This vision system, installed on an unmanned aerial vehicle, shall measure the reflected laser energy and thereby determine the normalized differenced vegetation index.

Design/methodology/approach

The newly developed TVS shall be installed on the front part of the unmanned aerial vehicle, to perform line-by-line scan in the vision system field-of-view. The TVS uses high-quality DC motors, instead of previously researched low-quality DC motors, to eliminate the existence of two mutually exclusive conditions, for exact positioning of a DC motor shaft. The use of high-quality DC motors reduces the positioning error after control.

Findings

Present paper emphasizes the exact laser beam positioning in the field-of-view of a TVS. By use of high-quality instead of low-quality DC motors, a significant reduced positioning time was achieved, maintaining the relative angular position error less than 1 per cent. Best results were achieved, by realizing a quasi-continuous control, using a high pulse-width modulated duty cycle resolution and a high execution frequency of the positioning algorithm.

Originality/value

The originality of present paper is represented by the novel application of the newly developed TVS in the field of agriculture. The vitality of vegetation shall be determined by measuring the reflected laser energy of a scanned agriculture zone. The paper’s main focus is on the exact laser beam positioning within the TVS field-of-view, using high-quality DC motors in closed-loop position control configuration.

Details

Industrial Robot: An International Journal, vol. 44 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Access Restricted. View access options
Book part
Publication date: 30 April 2021

María Eugenia Ibarrarán

Abstract

Details

From Human to Post Human Security in Latin America: Examples and Reflections from Across the Region
Type: Book
ISBN: 978-1-80071-253-9

Access Restricted. View access options
Expert briefing
Publication date: 1 December 2017

Defeated candidate Salvador Nasralla, who was leading for much of the count, has refused to concede, alleging fraud. With protesters already on the streets, the tight election…

Available. Content available
Book part
Publication date: 29 October 2024

Free Access. Free Access

Abstract

Details

Intercultural and Inclusive Education in Latin America
Type: Book
ISBN: 978-1-83753-141-7

1 – 10 of 48
Per page
102050