Air Power Research Articles

Achieving One Part Per Billion Hydrogen Sulfide (H2S) Level Detection through Optimizing Composition and Crystallinity of Gold-Decorated Tungsten Trioxide (Au-WO3) Nanofibers.

As a common environmental pollutant and an important breath biomarker for several diseases, it is essential to develop a hydrogen sulfide gas sensor with a low-ppb level detection limit to prevent harmful gas exposure and allow early diagnoses of diseases in low-resource settings. Gold doped/decorated tungsten trioxide (Au-WO3) nanofibers with various compositions and crystallinities were synthesized to optimize H2S-sensing performance. Systematically experimental results demonstrated the ability to detect 1 ppb H2S with a response value (Rair/Rgas) of 2.01 using a 5 at % Au-WO3 nanofibers with average grain sizes of around 15 nm. Additionally, energy barrier difference of sensing materials in air and nitrogen (ΔEb) and power law exponent (n) were determined to be 0.36 eV and 0.7, respectively, at 450 °C indicating that O- is predominately ionic oxygen species and adsorption of O- significantly altered the Schottky barrier between the grain. Such quantitative analysis provides a comprehensive understanding of H2S detection mechanism.

The spirit of man: air power and the human factor

The spirit of man: air power and the human factor

Australian perspectives on global air and space power: past, present, future

Australian perspectives on global air and space power: past, present, future

Experimental Investigation of Novel Configuration of Compressed Air Energy Storage (CAES)

Compressed air energy storage (CAES) is a technology that harnesses the power of compressed air to store energy for future use. However, a drawback of compressed air energy storage lies in the relatively inefficient nature of the expanders used. To tackle this challenge, a novel configuration is proposed and thoroughly investigated through experimentation. The core concept of the system revolves around introducing compressed air into a water-filled cylinder, which then propels an oscillating mass back and forth. Magnets, generating a magnetic field, are strategically positioned around the cylinder. As the oscillating mass moves to and fro inside the main cylinder, it triggers specific valves at predetermined intervals, resulting in the generation of voltage. The peak voltage produced is used to calculate the power output and efficiency of the system. The calculated electrical power efficiency of the proposed configuration is determined to be 5.33%. This relatively low efficiency can primarily be attributed to the lower frequency of oscillations and the presence of resistance effects. However, the results also indicate that when considering mechanical efficiency, the concept achieves a significantly higher value of 52.14%. This finding suggests that the configuration holds greater potential for sustainable mechanical output. While this mechanism demonstrates promising capabilities as an air expander, the induction of voltage through this method proves to be inefficient for energy utilization.

PEMELIHARAAN SATUAN TEMBAK PELURU KENDALI STARSTREAK GUNA MENDUKUNG KESIAPAN OPERASI PERTAHANAN UDARA

The world has experienced a very rapid development of air power technology such as aircraft, missiles, drones, bringing the consequences of the emergence of an air attack threat from one country to another. Indonesia as one of the countries is likely to experience the threat of air attacks from other countries that can endanger national security and territorial sovereignty so that Indonesia needs a strong and resilient air defence. In addition to aircraft as the main element of air defence, there is a ground-to-air missile weapon system, one of which is the Starstreak missile currently owned by the Army Air Defence Artillery unit which is incorporated in the Starstreak missile firing unit in each unit. The weapon system can be operationalised if it is in good condition and ready for operation, so a good maintenance activity is needed and in accordance with procedures. The purpose of the study was to analyse the maintenance of the Starstreak missile firing unit in the Arhanud 8/MBC Battalion to support the implementation of air defence operations that are the responsibility of the unit. The type of research used is descriptive qualitative with a phenomenological approach, using the IITCA theory (Integrative, Interactive, Transparency, Controlling, Accountability). Data were obtained from informants who were determined and then analysed with qualitative analysis techniques. The results showed that the implementation of maintenance of the Starstreak missile firing unit was not in accordance with the provisions or procedures so that there was still damage that occurred proving that maintenance had not been carried out optimally

Drones, Bodies, Necropolitics

The article reflects the discourses surrounding the military use of drones in the context of their employment in Afghanistan and Waziristan in the last two decades with a special emphasis on its necropolitical dimensions. It does so by first summarizing different critical accounts of a single well documented case in Afghanistan, underscoring historical continuities between drone warfare, state terror and air power. Second, the article puts a special emphasis on relations on the ground such as ambiguous legal constructions enabling the use of lethal force, and the weaponization of Pashtun culture for the purposes of different governments.

Thermosensitive Scattering Hydrogels Based on Triblock Poly-Ethers: A Novel Approach to Solar Radiation Regulation.

Energy conservation in buildings is paramount, especially considering that glass accounts for 50% of energy consumption. The solar heat gain coefficient (SHGC) of glass is a critical energy-saving index for transparent structures. However, the fixed SHGC of ordinary glass makes it difficult to provide both summer shading and winter heating. In this study, we synthesized a hydrogel with a thermosensitive scattering (TS) property using triblock polyether and acrylamide. This hydrogel can realize the transition of clearness and atomization based on the temperature. When sealed within a glass cavity, it exhibits a high SHGC of 0.682 in its transparent state and a low SHGC of less than 0.31 when atomized. The lower critical solution temperature (LCST) of the TS glass can be adjusted from 0 to 70 °C to suit different regions. The photothermal properties of the material remained stable after 200 hot and cold cycles and 200 h of ultraviolet irradiation. This glass can prevent solar radiation from entering the room in summer, thereby reducing air conditioning usage and power consumption. In winter, it allows solar heat radiation to enter the room, minimizing the need for artificial heating. Its adaptable temperature design makes it an excellent solution for designers to create energy-efficient building exteriors.

Wide-bandgap III-V materials for high efficiency air and underwater optical photovoltaic power transmission

High-power optical transmission (HPOT) enables the uninterrupted transfer of power in the order of hundreds of watts over several kilometers, freeing power systems from traditional wiring constraints. Its vast versatility of applications ranges from the ocean depths to outer space. In recent years, particular emphasis has been placed on the development of efficient methods to transfer substantial amounts of power from future space-based solar power stations, which intend to generate clean energy 24/7, to Earth. Despite the immense potential of HPOT, further endeavors should be undertaken in order to enhance overall system efficiency, currently hindered below 20%. A contributing factor to this unsatisfactory performance is the state-of-the-art selection of semiconductors that constitute the receivers of the monochromatic light: the optical photovoltaic converters (OPCs). Therefore, this work aims to identify the most suitable semiconductor materials for high power (∼100 Wcm−2) and beyond transmissions in terrestrial and underwater environments. In addition, the first analytical model capable of evaluating, predicting and designing OPCs and its electrical characteristics is provided. The results indicate that III-V wide-bandgap semiconductors (≈2.5 eV), such as InGaN and InAlN, could yield significant efficiency improvements in air and, especially, in subaquatic domains with respect to existing GaAs-based devices.

Američki realisti i rat u Bosni 1992-1995.

While there is a significant body of literature on U.S. policy towards Bosnia in the early 1990s, the role and policy recommendations of American realists have been largely overlooked. Realism is a school of thought in international relations which holds that states are the key actors motivated by interests which seek to maximize their power and security in an anarchic world. Adherents of this worldview emphasize the pursuit of national interests and the importance of power and force in achieving it. Realists are generally opposed to military interventions where a vital national interest is not at stake. The purpose of this article is to fill this gap by analysing both realist policymakers and academics and how they responded to the war in Bosnia from 1992 to 1995. Several top officials of the George H. W. Bush Administration including the President, Secretary of State James Baker and National Security Adviser Brent Scowcroft were realists and this worldview shaped the US response to the outbreak of the war in Bosnia. Focused on a host of other foreign policy issues at the time, the Bush Administration was adamant not to get involved militarily in Bosnia. James Baker’s statement „We don't have a dog in that fight“ came to define the Bush Administration's Bosnia policy. Its realist outlook combined with the presidential campaign priorities in 1992 to ensure that the Western response to the war in Bosnia was handed over to the Europeans. With realist policymakers in power from the outbreak of the war in spring 1992 through early 1993, many Bosnians hoping for a Western military intervention at the time would later come to realise how far-fetched those hopes were. In addition to realist policymakers, several prominent realists in the American academia also weighed in on how the US should respond to the war in this part of Southeast Europe in the early 1990s. Academic realists published their opinions and recommended policy options in leading media outlets throughout the three-and-a-half year war. Though their worldview was not shared by the first Bill Clinton Administration, academic realists continued offering policy recommendations on Bosnia. Academic realists like Robert Pape and Michael Desch opposed the use of air power in Bosnia arguing that it would be ineffective. John Mearsheimer together with Pape called for partition of Bosnia and establishment of homogeneous states in the Balkans and arming of Bosnian Muslims. Kissinger was opposed to a military commitment to Bosnia but did not lay out specific policy recommendations. In sum, both policymakers and academics argued that there was no vital US national interest at stake in Bosnia warranting deployment of ground troops. Even after the Dayton peace talks concluded in late 1995, American realists continued weighing in on Bosnia and offering generally bleak assessments. While the majority of those recommended policy options were not implemented, realists’ views on Bosnia in the 1990s still deserve scholarly attention. Studying American realists provides an overview of how both practitioners and intellectual adherents of a key theory in international relations perceived the war and its outcome. This analysis will also provide a more nuanced understanding of the variety of American responses to the war in Bosnia.

The use of Russian air power in the Russian-Ukrainian war, Part 3

A 2022 februárjában megkezdődött – a legtöbb katonai szakértő szerint eredetileg rövid lefolyásúnak tervezett – katonai műveletekUkrajnában mindkét fél légi haderőnemének széles körű, de több esetben szokatlan felhasználását hozták. Tanulmányában a szerző röviden ismerteti a bevetett orosz repülőeszközöket, valamint alkalmazásuk módját, és az elért eredményeket (természetesen figyelembe véve az esetenként korlátozottan rendelkezésre álló információk jelentette kihívásokat).

Wideband Antennas of Passive Seekers for Anti Radiation Missiles

Suppression of Enemy Air Defence (SEAD) is a fundamental element of Air Power application by means of in protecting friendly air attackers and destroying the enemy’s ability to defend against air attack. Most of the SEAD operation even today relies on Anti-radiation missile (ARM) which is an air-to-surface tactical missile designed to detect, seek, attack and destroy opponent’s radar. Passive seeker of ARM is a miniaturized ESM receiver which is capable of extracting the necessary angular data from the enemy radar emissions. Single head passive seeker covering wide frequency range from L to Ku band is the preferred choice. Wideband antennas have been designed and utilized for Direction Finding applications of ESM/ELINT receivers for ground, air and ship borne platforms. Unlike these platforms, there are several restrictions for passive seeker based compact ESM receiver for missile borne platform specially air to surface missile where lesser diameter is one of the preferred design parameter. This review paper mainly discusses the existing wideband antennas such as spiral, log-periodic, printed circuit vivaldi and all-metal vivaldi antennas and the comparison of their various parameters for passive seeker. The paper also suggests their suitability with respect to their placement on the missile for three configurations: concealed inside the radome, flush-mounted and conformal antenna based. The paper also brought about the specific test facility required for testing and evaluation of passive seeker to characterize it with missile radome which is the most challenging and time consuming task. Among the three passive seeker configuration discussed, conformal antenna based passive seeker using all-metal Vivaldi is the best option avoiding radome aberration correction which is being utilized in the present third generations of ARM. The second commonly and established passive seeker configuration is concealed inside the radome using spiral antennas where handling radome aberration correction is a limitation.

Thermodynamic analysis and optimization of liquid air power plant integrated with parabolic trough solar collectors

ABSTRACT As to investigate the impact of parabolic trough collector optical characteristics on the comprehensive performance of solar-driven liquid-gas energy storage power plants, this study establishes a mathematical analysis model for a liquid-gas energy storage power plant with a parabolic trough collector. The effects of direct irradiance, collector tracking mode, and component configuration on collector efficiency, round-trip efficiency, and exergy efficiency are analyzed. The results show that when the direct irradiance exceeds 400 W/m2, the round-trip efficiency of the system decreases while the exergy efficiency increases. For every 100 W/m2 increase in irradiance, the round-trip efficiency decreases by 1.54%, and the exergy efficiency increases by 2.36%. The north-south axis tracking mode is superior to the east-west axis tracking mode and dual-axis tracking mode. The component configuration improves the collector efficiency and round-trip efficiency but decreases the thermal efficiency. In low irradiance conditions (direct irradiance less than or equal to 400 W/m2), the system performance is optimal when the collector optical efficiency is maintained at 74%. Under these conditions, the system achieves a maximum net energy output of 495.12 kW·s/kg, the exergy efficiency of 54.5%, and the round-trip efficiency of 18.96%. In high irradiance conditions (direct irradiance greater than 400 W/m2), a 10% increase in collector optical efficiency leads to a 1.94 kW·s/kg decrease in net energy output, a 3.14% decrease in exergy efficiency, and a 0.05% decrease in round-trip efficiency.

Crude at Latitude: Fuel Supply and Force Projecting Air Power

Crude at Latitude: Fuel Supply and Force Projecting Air Power

Air pollution forecasting based on wireless communications: review.

The development of contemporary artificial intelligence (AI) methods such as artificial neural networks (ANNs) has given researchers around the world new opportunities to address climate change and air quality issues. The small size, low cost, and low power consumption of sensors can facilitate obtaining the values of polluting gases in the atmosphere. However, several problems with using air pollution technique relate to various effects such as sensing accuracy, sensor drifts, and sluggish reactions to changes in pollution levels. Recently, machine learning has made it feasible to build a more intelligent, context-aware system that can anticipate events and monitor present conditions. This paper focuses on the use of environment sensors for detecting air pollution based on several types of wireless protocols, including Wi-Fi, Bluetooth, ZigBee, LoRa, Global Positioning System (GPS), and 4G/5G. Furthermore, it classifies previous published articles on the topic according to the wireless protocol and compared in terms of several performance metrics such as the adopted air pollution sensors, hardware platform, adopted algorithm, power consumption or power savings, and sensing accuracy. In addition, this work highlights the challenges and limitations facing drones during their mission for detecting air pollution. As a result, we suggest to build and implement at base station an intelligent system based on backpropagation (BP) neural networks, which provides flexibility to track and predict the true values of polluting gases in the atmosphere to overcome the above problems. Finally, this work addresses the advantages of using drones in the air pollution field.

Study on Wave Energy Conversion Problem of Turbine-Integrated OWC Chamber

An oscillating water column (OWC) device is a promising wave energy converter (WEC) to utilize ocean wave energy resources. The OWC chamber absorbs the kinetic energy of ocean waves and converts the water column motion to reciprocating airflow. A power take-off system (PTO-system) of the OWC-WEC consists of an air turbine, generator, and power control system. An airflow drives an air turbine, which rotates a generator to produce electricity. The air turbine induces a pressure fluctuation due to its aerodynamic characteristics, which directly affects the fluid motion inside the chamber. In this study, the wave energy conversion problem of the OWC-WEC was discussed based on the experimental and numerical simulation results, considering the turbine-chamber interaction. The wave energy conversion problem from wave to power was solved using the finite element method (FEM)-based numerical wave tank in the time domain. The air turbine was numerically modeled based on aerodynamic coefficients and inertia properties. The validity of the present numerical method was examined by comparing it with the experimental results conducted in a two-dimensional wave flume at the Korea Research Institute of Ships and Ocean Engineering (KRISO). The effect of the turbine-chamber interaction on the energy conversion performance was investigated regarding the various rotational speeds of the air turbine based on experimental and numerical analysis. It was observed that the rotational speed conditions of the turbine, where the hydrodynamic performance of the OWC chamber and the aerodynamic performance of the turbine could be maximized, were different from each other. Therefore, it can be seen that a control technology considering the combined performance of the chamber and air turbine is required to maximize the energy conversion performance of the OWC-WEC.

Unveiling the Complex Tapestry: A Historical Analysis of the Vietnam War and its Impact on America

This journal article presents a comprehensive historical analysis of the Vietnam War and its profound impact on the United States. The study delves into the intricate layers of the conflict, shedding light on its causes, progression, and aftermath. By examining both the military and socio-political dimensions, the article aims to provide a nuanced understanding of the war's complexity and its lasting implications for American society, politics, and foreign policy. The Vietnam War, intricately woven from geopolitical strategies, ideological clashes, and military tactics, holds enduring significance. Emerging from colonial legacies and Cold War dynamics, its escalation echoed the domino theory and containment policy. Amidst guerrilla warfare and air power strategies, the war's reach extended beyond battlefields, resonating in the anti-war movement, cultural expressions, and societal rifts.

UAVs - The Indian Road Map for Development

The last century saw the birth of the 'First Engine Powered heavier than air' aircraft flight by the Wright Brothers' and within fifty years air power became the key to supremacy in the war game. Today the focus has shifted to include 'Unmanned Aerial Vehicles'(UAVs). UAVs range from the 100 gram Micro-UAV to the High Altitude, Long Endurance and Unmanned Combat aircraft. Primary roles even today are 'Intelligence, Surveillance and Reconnaissance' (ISR) but 'Combat UAVs' are expected to come into operation within l5 to 20years. UAVs conceived originally as desirable low cost, 'eyes-in-the sky' are today key assets in the military tool kit. The paper focuses on some of the issues and technology challenges associated with UAVs and provides a glimpse into the DRDO road map for development of UAVs.

Data-driven analysis of battery electric vehicle energy consumption under real-world temperature conditions

Demand for battery electric vehicles has grown significantly in recent years as global oil prices have climbed. The current development of battery electric vehicles is still in its infancy, and its energy consumption also requires great attention. Five same model battery electric vehicles' driving condition data of a certain brand in Tianjin area are collected for a whole year, and their energy consumption is analyzed. The results show that the energy consumption of the actual driving conditions in the four seasons is generally higher than the test results under New European Driving Cycle, and only some vehicles' energy consumption in spring and autumn is consistent with the test results under Worldwide Harmonized Light Vehicles Test Cycle. Energy consumption tends to increase at both ends with the change of temperature. The impact of low temperature is greater, because the air conditioner usage rate and power in Winter are higher than those in Summer. Through principal component contribution rate analysis and K-means clustering calculation of micro-trips, the results show that the average energy consumption in urban, suburban and high-speed driving conditions decreases gradually. Driving habits such as rapid acceleration ratio and rapid deceleration ratio also have an impact on energy consumption. The decrease of energy braking recovery indirectly caused by rapid deceleration ratio increase makes the energy consumption per 100 km increase. And the increase of rapid acceleration ratio leads to an increase in energy consumption per 100 km. Finally, the Spearman rank correlation analysis shows that energy consumption has the greatest correlation with the average vehicle speed and air conditioner usage status, followed by the constant speed proportion, idle speed proportion and temperature, and finally the recovery of braking energy per 100 km, acceleration proportion, deceleration proportion and rapid acceleration proportion.

TEACHING AND LEARNING ENGLISH AT HIGHER EDUCATIONAL INSTITUTIONS IN UKRAINE THROUGH PANDEMICS AND WARTIME

The study aimed to analyse online English teaching and learning experience in higher education institutions in Ukraine through pandemics and wartime. To answer our research questions, we employed a mixed-method research design, which considered social, methodological and emotional aspects of education. We conducted quantitative research to collect data on the experience of Ukrainian university teachers of English (N=100) and students (N=277) related to the emergency caused by pandemics and wartime. The qualitative data sources included online interviews and written comments of the participants. The main findings were as follows: teachers experienced challenges during the COVID-19 pandemic such as lack of interaction with students, and unawareness of effective teaching methods in the digital environment. The wartime challenges included: air raids and power outages and, consequently, disrupted communication and isolation, stress and sense of insecurity, excessive workload, with students experiencing technical issues, air raids and communication problems as well as large amount of homework, no access to the software, inconvenient schedule, and their own unwillingness. To solve the problems, teachers introduced an online synchronous mode during the COVID-19 pandemic, supported by blended and asynchronous modes which was a transformational period to teaching and learning English during wartime. The most common among the learning platforms and applications were Zoom and Google Classroom, as well as Moodle, MS Teams, YouTube, and Classtime, listed by both university teachers and students. Social networks such as Telegram, Viber, Facebook etc. were widely used too. To conclude, the COVID-19 pandemic caused Ukrainian teachers and students master new tools to use at online lessons of English, during wartime the demand on already familiar tools, as well as the range of them, increased as they provided more interaction. Considering emotional aspects, the study revealed disturbing data on teachers’ well-being: nearly 50% confessed that they were burned out and emotionally devastated, close to 40% were tired and pushed themselves to continue teaching. Despite these challenges, the majority were able to find solutions in conflict situations with students and colleagues, two-thirds were sure that their work was even more important during the wartime and they found ways to provide emotional support to their students needed in the times of war.

Optimum angle of reflective mirrors integrated on PV/Trombe wall: An experimental assessment

The provision of electricity and hot water is among the most significant human requirements at present. A photovoltaic/Trombe wall (PV/TW) system concurrently provides warm water, hot air, and electrical power for domestic usage. To optimize the amount of incident solar radiation, reflective mirrors were put on each side of the front face of the PV/TW system. The current article aims to determine the optimal angle for these mirrors that improve the thermal and electrical efficiency of the system.The findings indicated the utilization of DC fans, reflecting mirrors and water flowing across a heat exchanger improves thermal and electrical performance. The best angle for the impact of reflective mirrors to enhance electrical efficiency is the angle (30°) when using water cooling, which led to a decrease in the temperature of the photovoltaic panel and thus raised the electrical efficiency to reach (13.86 %). Also, the results confirmed that the system’s thermal efficiency that uses two cooling fluids is the highest relative to the other cases, and the system’s thermal efficiency that contains mirrors at 30° was higher than the other two angles. Finally, the addition of reflective mirrors is a favorable option for obtaining higher energy compared to the system without mirrors.