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This study dealt with evaluating the (J85-GE-5H) military turbojet engine (TJE) in terms of exergetic and advanced exergetic analyses at Military (MIL) and Afterburner (AB) process modes by utilizing kerosene (JP-8) and hydrogen (H2) fuels. First, exergy and advanced exergy analyses of the engine were performed using JP-8 fuel as per actual engine operating conditions. These analyses of the turbojet engine using hydrogen fuel were also examined parametrically. The performance evaluation of the engine was lastly executed by comparing the obtained results for both fuels. Based on the parametric studies undertaken, the entire engine’s exergetic efficiency with JP-8 was reckoned 30.85% at the MIL process mode while it was calculated as 16.98% at the AB process mode. With the usage of H2, the efficiencies of the engine decreased to 28.62% and 15.33% for the above mentioned two modes, respectively. As the supreme exergy destructions occurred in the combustion chamber (CC) and afterburner exhaust duct (ABED) segments, the new technological developments should be considered to design more efficient engines. As a result, the engine worked less efficiently with hydrogen fuel due to the enhancement in exergy destructions. Conversely, the greenhouse gas (GHG) emission parameters lessened with the utilization of H2 fuel.

In the present study, we investigated the relationship between personality and motivation for physical activity while introducing perceived parental support and social physical anxiety in adolescent girls ( N  = 318, M age : 16.19 ± 0.51 years). The present study was a retrospective correlational study that was conducted to analyze of a path model. Dark triad traits: Machiavellianism, narcissism, and psychopathy, student’s motivation for physical activity, social physique anxiety, and participants’ perceptions of parents’ behaviors were measured. The findings indicated that psychopathy and Machiavellianism were directly and indirectly associated with motivation for physical activity, but Narcissism could only directly predict the motivation for physical activity. Also, need-thwarting (the most), need-supportive and social physical anxiety could predict motivation for physical activity. This model of the result suggests that among adolescent girls, dark triad personality could, directly and indirectly, predict motivation with need-supportive and need-thwarting and also social physical anxiety. It seems that the sense of importance and more attention to oneself in adolescent girls, which exists in the narcissistic personality, can directly lead to more motivation for physical activity. Also, the duplicitous ways of Machiavellian people in pursuing their motives were confirmed in this research.

A conventional and advanced exergy analysis of a turbofan engine is presented in this paper. In this framework, the main exergy parameters of the engine components are introduced while the exergy destruction rates within the engine components are split into endogenous/exogenous and avoidable/unavoidable parts. Also, the mutual interdependencies among the components of the engine and realistic improvement potentials depending on operating conditions are acquired through the analysis. As a result of the study, the exergy efficiency values of the engine are determined to be 25.7 % for actual condition, 27.55 % for unavoidable condition and 30.54 % for theoretical contion, repectively. The system has low improvement potential because the unavoidable exergy destruction rate is 90 %. The relationships between the components are relatively weak since the endogenous exergy destruction is 73 %. Finally, it may be concluded that the low pressure compressor, the high pressure compressor, the fan, the low pressure compressor, the high pressure compressor and the combustion chamber of the engine should be focused on according to the results obtained.

This paper deals with the performance analyses of exergetic, exergoeconomic, sustainability and environmental damage cost for J85 turbojet engine at Idle (ID), Intermediate (INT), Military (MIL) and Afterburner (AB) operation modes. The exergetic efficiency of whole engine is calculated to be 0.24 % at ID, 18.67 % at INT, 29.81 % at MIL and 22.77 % at AB modes, respectively. The unit exergy cost of product is accounted to be 30,423.94 $/GJ at ID, 269.35 $/GJ at INT, 121.47 $/GJ at MIL and 133.47 $/GJ at AB modes. The sustainable cost index is found to be 30,350.92 $/GJ at ID, 224.45 $/GJ at INT, 85.26 $/GJ at MIL and 103.0 $/GJ at AB modes while the sustainability index is obtained to be 1.0 at ID, 1.2 at INT, 1.43 % at MIL and 1.3 at AB modes. On the other hand, the environmental damage cost rate of engine are calculated to be 180.22 $/h at ID, 271.34 $/h at INT, 657.95 $/h at MIL and 1992.55 $/h at AB modes while the total cost rates of engine are determined to be 974.07 $/h at ID, 1357.15 $/h at INT, 2641.76 $/h at MIL and 6573.04 $/h at AB modes, respectively. The results indicate that J85 engine operates the exergetic-efficiently and cost-effectively at MIL mode.

In this study, utilization of a bio-based fuel in a turbojet engine is comprehensively monitored with adapting various useful indicators for the scope of the study based on thermodynamic principles. In this regard, extensive energy and exergy, thermoecologic, environmental, enviroeconomic and sustainability analyses are performed for both the turbojet engines fueled by jet kerosene and fueled by a bio-based fuel. As per the main findings, the mass stream of combustion emissions is measured to be 4.547 kg s −1 , when the engine is powered by biofuel. The specific fuel consumption and specific thrust are determined as 0.13 kg kN −1  s −1 and 147.81 kNs kg −1 for jet kerosene-powered case, while they are calculated as 0.15 kg kN −1  s −1 and 148.23 kNs kg −1 for biofuel-powered case. If biofuel is selected over jet-kerosene fuel, it is observed that the engine has better energy efficiency performance by 18.18%. The engine’s environmental effect factor value is found as 4.88 for jet-kerosene usage condition, while it is found to be 4.93 for biofuel utilization case. The overall emitted CO 2 emissions is measured as 336,672 kg-CO 2 year −1 for jet-kerosene usage condition, while it is estimated as 222,012 kg-CO 2 year −1 for the biofuel utilization case. Also, as far as biofuel is chosen as alternative to jet-kerosene, the environmental damage cost stream, namely the enviroeconomic parameter of the engine, falls from 59,254.27 US$ year −1 to 39,074.11 US$ year −1 . It is observed that sustainable efficiency factor and exergetic sustainability index outputs of the components of air compressor are the same for jet-kerosene and biofuel utilization cases, which are 8.31 and 7.31, respectively.

In this paper, environmental impact analysis is applied to the various auxiliary power units (APUs) used for commercial aircraft in air transportation sector. The exhaust emissions of different auxiliary power units used in commercial aircraft are investigated. The emission index ( EI ), global warming potential ( GWP ) rate, global warming potential index ( GWPI ), environmental impact ( EnI ) rate, environmental impact index ( EnII ), environmental damage cost ( EDC ) rate, and environmental damage cost index ( EDCI ) of the exhaust emissions of APUs are computed. The GTCP36-300 model APU has the lowest total emission rate (TER) with 1.333 kg/h, the GTC85-129 model APU has the maximum total environmental index (TEI) by 24.719 g/kg-fuel, the GTCP36-300 model APU has the best total global warming potential value with 2709.176 kg/h CO 2_eqv , the TSCP700 model APU has the worst global warming potential index rate as 52.481 kg/kWh CO 2_eqv , the best total environmental damage cost rate is calculated to be 3.717 €/h for GTC85-72 model APU, the TSCP700 model APU has the highest environmental damage cost index with 0.130 €/kWh, the maximum total environmental impact is computed to be 5656.378 mPts/h for GTCP660 model APU, and the best total environmental impact index is determined for the GTC85-72 model APU.

The rapid growth of airlines over the last period has led to the development of the aviation industry, resulting in increased requirements for ancillary services. Nowadays, the demand for the use of paper-based documents is increasing day by day as airlines encourage passengers to use more ancillary products. One of the most important issues in the aviation industry is flight safety. The procedures and instructions required for all aviation operations are organized in accordance with the regulations and printed on paper in accordance with the demands. For this reason, since it is mandatory to keep all aircraft maintenance, repair, and operation records on printed paper and to keep them for a certain period of time, aircraft fly with almost their entire weight on paper. Considering the global hazards in the world, although the aviation sector is the least environmentally damaging of all transportation sectors, new solutions have been sought to make aviation operations less harmful to the environment, minimize errors and risks, allow for faster communication, and be safer and more sustainable. In order to meet the demands, studies on reducing the use of paper have been brought to the agenda. In this study, after a literature review, real data from a maintenance, repair, and overhaul organization are used to suggest digital conveniences that can save costs, increase productivity, save space, facilitate documentation and information sharing, keep personal information more secure, and help the environment through paperless living.

Purpose This study aims to investigate the aviation, energetic, exergetic, environmental, sustainability and exergoeconomic performances of a micro turbojet engine used in unmanned aerial vehicles at four different modes. Design/methodology/approach The engine data were collected from engine test cell. The engine performance calculations were performed for four different operation modes. Findings According to the results, maximum energy and exergy efficiency were acquired as 19.19% and 18.079% at Mode 4. Total cost rate was calculated as 6.757 $/h at Mode-1, which varied to 10.131 $/h at Mode-4. Exergy cost of engine power was observed as 0.249 $/MJ at Mode-1, which decreased to 0.088 $/MJ at Mode-4 after a careful exergoeconomic analysis. Originality/value The novelty of this work is the capability to serve as a guide for similar systems with a detailed approach in the thermodynamic, thermoeconomic and environmental assessments by prioritizing efficiency, fuel consumption and cost formation. This investigation intends to establish a design of the opportunities and benefits that the thermodynamic approach provides to turbojet engine systems.

It is expected that basic motor skills will be able to perform correctly at the end of the preschool period. The fundamental motor skills that children masterfully perform will lead them to an active life & will increase their likelihood of participating in physical activity in their lifetime. It is known that motor skills are influenced by many factors such as age, gender, & BMI. The purposes of this study were to determine the motor proficiency level of preschool children & to examine the role of age, gender, & BMI. Participants of this study were 103 preschool children (MAge=61.10±8.75month) from a public preschool of Denizli in Turkey. The Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2) was used to assess children's motor proficiency. A multiple linear regression was conducted to test whether the participant's age, gender, & BMI predicted the participant's motor proficiency levels. The results of the study show that all the sub-tests & BOT-2 total scores have significant increases with age. In addition, the results indicated that girls have significantly higher scores than boys on the fine-motor precision, the fine-motor integration, manual dexterity, & BOT-total scores. When the sub-tests, which girls had a higher score, were examined, it can be realized that all are related to fine motor skills. Future studies are needed to determine whether these explanations are to generalize.

This paper presents the results of exergy and exergoeconomic analyses applied to a combined heat and power system with micro-gas turbine (MGTCHP). Quantative balances of the exergy and exergy cost for each component and for the whole system are carefully considered, while exergy consumption and cost generation within the system are determined. The exergy analysis indicates that the exergetic efficiency of the MGTCHP system is 35.80% with 123 kW (as 99.15 kW-electrical power and 24.46 kW-hot water@363.15 K). On the other hand, the exergoeconomic analysis results show that the unit exergy cost of electrical power and hot water produced by the MGTCHP system are accounted as 26.808 € (GW)−1 and 7.737 € (GW)−1, respectively.