Search results

Diesel has traditionally been considered the best-suited and most widely used fuel in various sectors, including manufacturing industries, power production, automobiles and transportation. However, with the ongoing crisis of fossil fuel inadequacy, the search for alternative fuels and their application in these sectors has become increasingly important. One particularly interesting and beneficial alternative fuel is biodiesel derived from bio sources.

In this research, an attempt was made to use biodiesel in an unconventional micro gas turbine engine. It will remove the concentric use of diesel engines for power production by improving fuel efficiency as well as increasing the power production rate. Before the fuel is used enormously, it has to be checked in many ways such as performance, emission and combustion analysis experimentally.

In this paper, a detailed experimental study was made for the use of Spirulina microalgae biodiesel in a micro gas turbine. A small-scale setup with the primary micro gas turbine and secondary instruments such as a data acquisition system and AVL gas analyser. The reason for selecting the third-generation microalgae is due to its high lipid and biodiesel production rate. For the conduction of experimental tests, certain conditions were followed in addition that the engine rotating rpm was varied from 4,000, 5,000 and 6,000 rpm. The favourable and predicted results were obtained with the use of microalgae biodiesel.

The performance and combustion results were not exactly equal or greater for biodiesel blends but close to the values of pure diesel; however, the reduction in the emission of CO was at the appreciable level for the used spirulina microalgae biodiesel. The emission of nitrogen oxides and carbon dioxide was a little higher than the use of pure diesel. This experimental analysis results proved that the use of spirulina microalgae biodiesel is both economical and effective replacement for fossil fuel.

This study aims to provide an example of curriculum development for vocational higher education in aviation, specifically in the aircraft maintenance engineering program, while considering the anticipated technological changes in the industry.

Qualitative methods, including document analysis, in-depth interviews, and focus group discussions, were utilized to collect, and analyse data.

The findings demonstrate that redesigning the curriculum through course reconstruction, integrating independent learning methods, and adopting blended learning approaches holds significant potential for enhancing the education of future aircraft maintenance engineers.

These endeavours contribute to the cultivation of highly skilled graduates who are adept at navigating technological advancements and making valuable contributions to the competitiveness and safety of the aviation industry.

Tourism is integral to the United Nations’ Sustainable Development Goals (UN SDGs) and is closely linked to air transport. This paper aims to explore their relationship, emphasising impacts on accessibility, connectivity and collaborative efforts between airlines, destination management organisations and stakeholders. Improved air transport contributes to tourism-led growth, economic development, job creation and cultural exchange. However, environmental challenges prompt innovation with cleaner technologies and sustainable aviation fuels.

Opinion piece.

Linking aviation and tourism to the UN SDGs, the paper showcases contributions done to date to environmental, social and economic aspects. The paper suggests a focused strategy for aviation to align more closely with the UN SDGs. Actions such as exploring alternative fuels, prioritising energy-efficient aircraft, addressing local impacts and fostering global collaboration are crucial in addressing gender disparities for a more inclusive future.

This piece examines air transport developments from 1946 to 2020, revealing transformative periods marked by regulatory agreements, technological advancements and sustainability initiatives. The paper also addresses COVID-19 impacts, highlighting vulnerabilities, resilience and lessons for adaptability and sustainability.

旅游业是联合国可持续发展目标的组成部分, 与航空运输密切相关。本文探讨了它们之间的关系, 强调了对航空公司、目的地管理组织 (DMO) 和利益相关者之间的可达性、连通性和协作的影响。改善航空运输有助于旅游业主导的增长、经济发展、创造就业机会和文化交流。然而, 环境挑战促使清洁技术和可持续航空燃料的创新。

观点文章。

该文章将航空和旅游业与联合国可持续发展目标联系起来, 展示了迄今为止在环境、社会和经济方面所做的贡献。该文章提出了一项有针对性的航空战略, 从而更紧密地配合联合国可持续发展目标。探索替代燃料、优先考虑节能飞机、解决当地影响和促进全球合作等行动对于解决性别差异、创造更具包容性的未来至关重要。

本文探讨了 1946 年至 2020 年航空运输的发展, 揭示了以监管协议、技术进步和可持续发展举措为标志的变革时期。该文章还讨论了 COVID-19 的影响, 强调了脆弱性、复原力以及适应性和可持续性的经验教训。

El turismo forma parte integral de los ODS de la ONU y está estrechamente vinculado al transporte aéreo. Este documento explora su relación, haciendo hincapié en las repercusiones sobre la accesibilidad, la conectividad y los esfuerzos de colaboración entre las aerolíneas, las organizaciones de gestión de destinos (DMOs) y las partes interesadas. La mejora del transporte aéreo contribuye al crecimiento impulsado por el turismo, al desarrollo económico, a la creación de empleo y al intercambio cultural. Sin embargo, los retos medioambientales impulsan la innovación con tecnologías más limpias y combustibles de aviación sostenibles.

Artículo de opinión.

Al vincular la aviación y el turismo con los ODS de la ONU, el artículo muestra las contribuciones realizadas hasta la fecha a los aspectos medioambientales, sociales y económicos. El documento sugiere una estrategia centrada para que la aviación se alinee más estrechamente con los ODS de la ONU. Acciones como explorar combustibles alternativos, priorizar aeronaves energéticamente eficientes, abordar los impactos locales y fomentar la colaboración global son cruciales, así como abordar las disparidades de género para un futuro más inclusivo.

Este artículo examina la evolución del transporte aéreo desde 1946 hasta 2020, revelando periodos transformadores marcados por acuerdos normativos, avances tecnológicos e iniciativas de sostenibilidad. El artículo también aborda los impactos del COVID-19, destacando las vulnerabilidades, la resistencia y las lecciones para la adaptabilidad y la sostenibilidad.

This study aims to chart the impact of technological advancements on tourism from the post–Second World War era to the present and forecast their influence until 2050. It assesses how technologies have reshaped travel experiences and operations, with a focus on upcoming innovations such as the metaverse, Web 3.0 and AI, and their implications for sustainable and ethical tourism.

This study uses a hybrid approach, combining historical analysis and future projections. It analyzes archival data, industry reports and academic literature.

This study identifies crucial technological milestones that have significantly impacted tourism, including the rise of commercial aviation, the internet and AI. Future trends suggest emerging technologies will further transform the sector. Challenges in sustainability, ethics and inclusivity are highlighted as critical considerations for future development.

This paper offers a unique longitudinal perspective on technology’s influence on tourism, bridging past trends with future projections.

本研究采取混合方法, 融合历史分析与未来趋势预测。研究分析了丰富的档案数据、行业报告以及学术文献。

旨在勾勒从二战后至今技术进步对旅游业的影响, 并展望至2050年的潜在影响。本研究着重评估技术如何重塑旅游体验和运作, 特别是对元宇宙、网络3.0和人工智能等即将到来的创新技术及其对可持续和伦理旅游的意义。

识别了旅游业中关键的技术里程碑, 包括商业航空、互联网和人工智能的崛起。研究指出, 未来趋势显示新兴技术将继续深刻改变旅游业。同时强调, 可持续性、伦理和包容性是未来发展中不可忽视的关键要素。

本文从独特的纵向视角出发, 深入探讨了技术对旅游业的历史与未来影响, 将过去发展趋势与未来展望紧密结合。

Este estudio emplea un enfoque híbrido que combina el análisis histórico y las proyecciones de futuro. Analiza datos de archivo, informes del sector y bibliografía académica.

La investigación pretende trazar el impacto de los avances tecnológicos en el turismo desde la era posterior a la Segunda Guerra Mundial hasta la actualidad y prever su influencia hasta 2050. Evalúa cómo las tecnologías han reconfigurado las experiencias y las operaciones de viaje, centrándose en las próximas innovaciones como el Metaverso, la Web 3.0 y la IA, y sus implicaciones para un turismo sostenible y ético.

El estudio identifica hitos tecnológicos cruciales que han tenido un impacto significativo en el turismo, como el auge de la aviación comercial, Internet y la IA. Las tendencias futuras sugieren que las tecnologías emergentes transformarán aún más el sector. Los retos en sostenibilidad, ética e inclusividad se destacan como consideraciones críticas para el desarrollo futuro.

Este artículo ofrece una perspectiva longitudinal única sobre la influencia de la tecnología en el turismo, tendiendo un puente entre las tendencias pasadas y las proyecciones futuras.

Temperature anomalies in the upper troposphere have become a reality as a result of global warming, which has a noticeable impact on aircraft performance. The purpose of this study is to investigate the total air temperature (TAT) anomaly observed during the cruise level and its impact on engine parameter variations.

Empirical methodology is used in this study, and it is based on measurements and observations of anomalous phenomena on the tropopause. The primary data were taken from the Boeing 747-8F's enhanced flight data recorder, which refers to the quantitative method, while the qualitative method is based on a literature review and interviews. The GEnx Integrated Vehicle Health Management system was used for the study's evaluation of engine performance to support the complete range of operational priorities throughout the entire engine lifecycle.

The study's findings indicate that TAT and SAT anomalies, which occur between 270- and 320-feet flight level, have a substantial impact on aircraft performance at cruise altitude and, as a result, on engine parameters, specifically an increase in fuel consumption and engine exhaust gas temperature values. The TAT and Ram Rise anomalies were the focus of the atmospheric deviations, which were assessed as major departures from the International Civil Aviation Organizations–defined International Standard Atmosphere, which is obvious on a positive tendency and so goes against the norms.

Necessary fixed flight parameters gathered from the aircraft's enhanced airborne flight recorder (EAFR) via Aeronautical Radio Incorporated (ARINC) 664 Part 7 at a certain velocity and altitude interfacing with the diagnostic program direct parameter display (DPD), allow for analysis of aircraft performance in a real-time frame. Thus, processed data transmits to the ground maintenance infrastructure for future evaluation and for proper maintenance solutions.

A real-time analysis of aircraft performance is possible using the diagnostic program DPD in conjunction with necessary fixed flight parameters obtained from the aircraft's EAFR via ARINC 664 Part 7 at a specific speed and altitude. Thus, processed data is transmitted to the ground infrastructure for maintenance to be evaluated in the future and to find the best maintenance fixes.

This paper aims to conduct an experimental and theoretical investigation into fuel pre-delivery effects for a heavy fuel crankcase scavenged spark ignition two-stroke cycle engine for unmanned aerial vehicle application.

One-dimensional computational fluid dynamic modelling of the engine system using WAVE software supported by experimental dynamometer testing of the subject engine with kerosene JET A-1 and gasoline and fuels.

The experimental research has shown performance improvements using fuel preheating via use of auxiliary transfer port fuel injection. Computational simulation has allowed comparisons with auxiliary transfer port injection and direct in-cylinder injection to be made.

While some heavy fuel engines are now available for unmanned aerial vehicles the best solution to meet the military equipment single fuel policy remains an area of evolving research. The findings within this study show possibilities for fuel pre-treatment.

One-dimensional computational fluid dynamic modelling of the engine system using WAVE software supported by experimental dynamometer testing of the subject engine with kerosene JET A-1 and gasoline fuels.

This study aims to validate the linear flow theory with computational fluid dynamics (CFD) simulations and to propose a novel shape for the airfoil that will improve supersonic aerodynamic performance compared to the National Advisory Committee for Aeronautics (NACA) 64a210 airfoil.

To design the new airfoil shape, this study uses a convex optimization approach to obtain a global optimal shape for an airfoil. First, modeling is conducted using linear flow theory, and then numerical verification is done by CFD simulations using ANSYS Fluent. The optimization process ensures that the new airfoil maintains the same cross-sectional area and thickness as the NACA 64a210 airfoil. This study found that an efficient way to obtain the ideal airfoil shape is by using linear flow theory, and the numerical simulations supported the assumptions inherent in the linear flow theory.

This study’s findings show notable improvements (from 4% to 200%) in the aerodynamic performance of the airfoil, especially in the supersonic range, which points to the suggested airfoil as a potential option for several fighter aircraft. Under various supersonic conditions, the optimized airfoil exhibits improved lift-over-drag ratios, leading to improved flight performance and lower fuel consumption.

This study was conducted mainly for supersonic flow, whereas the subsonic flow is tested for a Mach number of 0.7. This study would be extended for both subsonic and supersonic flights.

Convex optimization and linear flow theory are combined in this work to create an airfoil that performs better in supersonic conditions than the NACA 64a210. By closely matching the CFD results, the linear flow theory's robustness is confirmed. This means that the initial design phase no longer requires extensive CFD simulations, and the linear flow theory can be used quickly and efficiently to obtain optimal airfoil shapes.

The proposed airfoil can be used in different fighter aircraft to enhance performance and reduce fuel consumption. Thus, lower carbon emission is expected.

The unique aspect of this work is how convex optimization and linear flow theory were combined to create an airfoil that performs better in supersonic conditions than the NACA 64a210. Comprehensive CFD simulations were used for validation, highlighting the optimization approach's strength and usefulness in aerospace engineering.

This research aims to examine the US–China policy shift from Obama to Biden emphasizing the centrality of Taiwan question in the geostrategic competition with Beijing and its prospect if the US strategy remains unchanged.

A conceptual framework is outlined, illustrating how the US grand strategy is driven by the ideological foundation of Exceptionalism. The paper highlights the associated US policy changes that evolved from Obama to Trump and then Biden to advance Washington's strategic interests in its rivalry with China over Taiwan.

Biden's policy led to an escalating geopolitical competition with Beijing over Taiwan to maintain US supremacy. The Biden administration is more stringent than the previous administrations on the Taiwan question and there is the conviction that the USA must not back down on Taiwan because the alternative will be a retraction of US world primacy to Beijing. With Washington's persistent hegemonic strategy, the US–China confrontation over Taiwan seems inevitable.

The research highlights how the Biden administration managed a perpetuated Ukraine crisis and forged unprecedented high-level ties with Taiwan, indicating the administration's determination to exacerbate contentions with Beijing over Taiwan rather than de-escalate.

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.

An experimental investigation of hemispherical forebody interaction effects on the drag coefficient of a D-shaped model is carried out for three-dimensional flow in the subcritical range of Reynolds number 1 × 10⁵ ≤ Re ≤ 1.8 × 10⁵. To study the interaction effect, hemispherical shapes of various sizes are attached to the upriver of the D-shaped bluff body model. The diameter of the hemisphere (b₁) varied from 0.25 to 0.75 times the diameter of the D-shaped model (b₂) and its gap from the D-shaped model (g/b₂) ranged from 0.25 to 1.75 b₂.

The experiments were carried out in a low-speed open-circuit closed jet wind tunnel with test section dimensions of 1.2 × 0.9 × 1.8 m (W × H × L) capable of generating maximum velocity up to 45 m/s. The wind tunnel is equipped with a driving unit which has a 175-hp motor with three propellers controlled by a 160-kW inverter drive. Drag force is measured with an internal six-component balance with the help of the Spider 3013 E-pro data acquisition system.

The wind tunnel results show that the hemispherical forebody has a diameter ratio of 0.75 with a gap ratio of 0.25, resulting in a maximum drag reduction of 67%.

The turbulence intensity of the wind tunnel is about 5.6% at a velocity of 18 m/s. The uncertainty in the velocity and the drag coefficient measurement are about ±1.5 and ±2.83 %, respectively. The maximum error in the geometric model is about ±1.33 %.

The results from the research work are helpful in choosing the optimum spacing of road vehicles, especially truck–trailer and launch vehicle applications.

Drag reduction of road vehicle resulting less fuel consumption as well as less pollution to the environment. For instance, tractor trailer experiencing approximately 45% of aerodynamics drag is due to front part of the vehicle. The other contributors are 30% due to trailer base and 25% is due to under body flow. Nearly 65% of energy was spent to overcome the aerodynamic drag, when the vehicle is traveling at the average of 70 kmph (Seifert 2008 and Doyle 2008).

The benefits of placing the forebody in front of the main body will have a strong influence on reducing fuel consumption.