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The purpose of this paper is to provide an overview of the computational progress in the development of hydrogen-fired gas turbines. This review aims to identify suitable combustion models, appropriate NO_x chemistry mechanisms and NO_x emission levels for effective utilization of hydrogen as an alternative fuel in gas turbines.

Hydrogen is recognized as a potential alternative fuel for achieving exceptionally low emissions in gas turbines. The developments in conventional, trapped vortex combustor and micromix combustors are discussed, along with various computational models aimed at accurately predicting combustion and emission characteristics. The results of numerical simulations were then discussed with emphasis on their role in optimizing the combustor geometry.

Computational studies that were used to optimize the combustor geometry to reduce NO_x emissions and the flashback phenomenon are discussed. To retrofit existing gas turbines for hydrogen fuel, minor modifications that are required were discussed by analyzing extensive literature. The influence of key design and geometrical parameters on NO_x emissions and the appropriate selection of combustion models for numerical simulations in optimizing various combustion systems are elaborated.

The review emphasizes the computational studies in the progress of hydrogen-fired gas turbine developments. The previous reviews were primarily focused on the combustion technologies for hydrogen-fired gas turbines. This comprehensive review focuses on the key design parameters, flame structure, selection of combustion models, combustion efficiency improvement and impact of parametric studies on NO_x formation of various combustion systems, in particular hydrogen combustion for gas turbine applications.

Place-based, social studies teaching and learning has the potential to foster engaged citizens connected and committed to improving their communities. This study explored the research question, “In what ways do classroom and field-based experiences prepare teacher candidates (TCs) to make connections between place-based education and elementary social studies education?”

This qualitative case study examined how elementary TCs learned about, researched, curated and created place-based social studies educational resources related to community sites. Data collection included TCs’ Pre- and Post-Course Reflections as well as Self-Evaluations, which were analyzed using an inductive approach and multiple rounds of concept coding. Several themes emerged through data analysis.

The authors organized their findings around three themes: connections (i.e. place becomes personal), immersion (i.e. learning about place to learning in place) and bridge building (i.e. local as classroom). The classroom and field-based experiences in the elementary social studies methods course informed the ways in which TCs learned about and connected to the concept of place, experienced place in a specific place (i.e. downtown Statesboro, Georgia), and reflected upon the myriad ways that they could utilize place in their future elementary social studies classrooms.

TCs (as well as in-service teachers and teacher educators) must become more informed, connected and committed to places within their local communities in order to consider them as resources for elementary social studies teaching and learning.

This study aims to identify Critical Success Factors (CSFs) for tourism route development and proposes a tailored conceptual model. It addresses a comprehensive range of tourism routes, considering their respective goals and performance.

The authors applied a qualitative approach to investigate five tourism routes, interviewing 31 current and former members and examining secondary data from organisational documents. A conceptual model was developed through content analysis of transcripts and secondary data.

Based on the identified CSFs, the model is organised into six components: Product, Goals, Resources, Governance, Activities and Performance assessment.

The study analyses various tourism routes concerning their products, implementation levels, goals, performance and perceived success.

Most respondents are public authorities from European countries. Besides, consideration should be given to developing quantitative research to validate the derived theory.

The model may facilitate participants in enhancing and developing tourism routes, thereby contributing to achieving sustainable development goals related to rural-urban connections and tourism partnerships.

The development of tourism routes is expected to impact socio-economic development in rural/peripheral areas positively.

本研究旨在确定旅游线路开发的关键成功因素 (CSFs), 并提出量身定制的概念模型。本文提出了一系列旅游线路, 考虑了各自的目标和绩效。

我们采用定性方法探究了五条旅游线路, 采访了 31 名现任和前任成员, 并检查了组织文件中的二手数据。通过对记录和二手数据的内容分析, 开发了一个概念模型。

根据识别的关键成功要素, 该模型分为六个部分：产品、目标、资源、治理、活动和绩效评估。

本研究分析了各种旅游线路的产品、实施水平、目标、绩效和感知成功。

大多数受访者是来自欧洲国家的公共当局。此外, 还应考虑开展定量研究来验证所得出的理论。

该模型可帮助参与者改善和发展旅游路线, 从而有助于实现与城乡联系和旅游伙伴关系相关的可持续发展目标。

旅游路线的发展预计将对农村/边缘地区的社会经济发展产生积极影响。

Esta investigación se centra en diversas tipologías de rutas turísticas, buscando identificar Factores Críticos de Éxito (FCE) y proporcionar un modelo conceptual adaptado.

Aplicamos un enfoque cualitativo para investigar cinco rutas turísticas. Entrevistamos a 31 miembros y examinamos datos secundarios de documentos organizativos. Se desarrolló un modelo conceptual mediante el análisis de contenido de transcripciones y datos secundarios.

Basado en los FCE identificados, el modelo está organizado en seis componentes: Producto, Objetivos, Recursos, Gobernanza, Actividades y Evaluación del desempeño.

El estudio analiza diversas rutas turísticas en relación con sus productos, ubicaciones y nivel de implementación, así como los objetivos, rendimiento y éxitos percibidos de los involucrados.

La mayoría de los encuestados son autoridades públicas de países europeos. Se debe considerar el desarrollo de investigaciones cuantitativas para validar la teoría derivada de este estudio.

El modelo puede potencialmente ayudar a los participantes a mejorar y desarrollar rutas turísticas, contribuyendo así a lograr los objetivos de desarrollo sostenible relacionados con las conexiones rural-urbanas y las asociaciones turísticas.

Se espera que el desarrollo de rutas turísticas tenga un impacto positivo en el desarrollo socioeconómico en áreas rurales/periféricas.

Small-scale farmers are highly heterogeneous with regard to their types of farming, levels of technology adoption, degree of commercialization and many other factors. Such heterogeneous types, respectively groups of small-scale farming systems require different forms of government interventions. This paper applies a machine learning approach to analyze the typologies of small-scale farmers in South Africa based on a wide range of objective variables regarding their personal, farm and context characteristics, which support an effective, target-group-specific design and communication of policies.

A cluster analysis is performed based on a comprehensive quantitative and qualitative survey among 212 small-scale farmers, which was conducted in 2019 in the Limpopo Province of South Africa. An unsupervised machine learning approach, namely Partitioning Around Medoids (PAM), is applied to the survey data. Subsequently, the farmers' risk perceptions between the different clusters are analyzed and compared.

According to the results of the cluster analysis, the small-scale farmers of the investigated sample can be grouped into four types: subsistence-oriented farmers, semi-subsistence livestock-oriented farmers, semi-subsistence crop-oriented farmers and market-oriented farmers. The subsequently analyzed risk perceptions and attitudes differ considerably between these types.

This is the first typologisation of small-scale farmers based on a comprehensive collection of quantitative and qualitative variables, which can all be considered in the analysis through the application of an unsupervised machine learning approach, namely PAM. Such typologisation is a pre-requisite for the design of more target-group-specific and suitable policy interventions.

Taking instances from extant findings from the literature, the study aims to examine the community perception toward renewable energy (RE) off-grid (mini-grid/microgrid) intervention, the underlying rationales for engagement of communities in RE off-grid projects, the different alternatives/models to engage communities in various phases of RE off-grid project deployment.

The study has followed the structured literature review to explore the identified research question of the study.

Based on findings from the review, the framework for effective community engagement in RE mini-grid projects is suggested. Furthermore, the study also draws suggestions and implications for future research and practice.

Based on such understanding the present study offers the framework which suggests the steps for the engagement of the communities in the off-grid projects. The key steps are managing the perception of the community (including generation of awareness among the community), planning for the benefits of the community, linkage the sustainable development goals (SDG), planning for the inclusion of the community and measuring performance (in the line of social and economic criteria and SDG).

This study finds the gap in the literature on the nexus of community, off-grid energy projects and SDG. Following the findings from the scholars in this field, a few gaps in the policy and practice have been highlighted which could be useful for practitioners and policymakers in this area.