bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on corrosion characteristics of SS316L by thermal spray coating technique using Ni-80Cr alloy
Authors: Kumari Sinha Ragini , Nagpal Yatan , Sharma Rohit , Kumar Niraj
Published: February 2022

In the current study, an investigation was carried out to evaluate the corrosion characteristics of thermal spray coated SS316L with Ni-80Cr as a coating material developed by Detonation-Gun method. The corrosion behavior was investigated on uncoated SS, single layer coated SS316L and multilayer coated SS316L by conducting the corrosion test for 90 hours in stagnant seawater. Results showed that corrosion resistance of SS316L was found to be increased by single and multilayer coating of Ni-80Cr. The coating of Ni-80Cr alloy was found to enhance corrosion resistance.
Selection of blends of ethanol with petrol for SI engine using TOPSIS and VIKOR methods
Authors: Kamble AG , Bhosale VA , Naranje VG
Published: February 2022

India and other agricultural countries grow large quantities of sugar cane and ethanol is a by-product of the sugarcane industry. The blending of ethanol with petrol can save tremendous amount of petrol. In the present study, experiment was carried on the SI engine by means of various blends of ethanol with petrol such as E5, E8, E10 and E12, and the various engine performance variables were recorded such as brake thermal efficiency, volumetric efficiency, air-to-fuel ratio and exhaust heat. The two selected multi attribute decision making methods viz: technique for order preference by similar to ideal solution and compromise ranking method have been utilized in determining the rank of blends. It has been seen from the ranks obtained using both the methods that the blend E10 is the best alternative with petrol, E5 is the second best where as E8 and E12 are third and fourth best alternative respectively.
Research on Heating and Power Load Optimal Dispatch Based on the Particle Swarm Optimization Algorithm Combined with the Levy Flight
Authors: Tu Chaoyang , Chen Guobao , Zheng Tianshuai , Yu Xiaobing , Huang Xicong , Hui Binbin , Yang Li , Liu Xueliang
Published: February 2022

Optimal dispatch of heat and power loads for combined heat and power (CHP) power plants is an effective solution to further improve energy efficiency and reduce energy consumption. To obtain a better load dispatch effect, this paper used the Particle Swarm Optimization (PSO) algorithm based on Levy flight (Levy-PSO algorithm) to solve the optimal dispatch problem. Meanwhile, the constraint condition processing method which is based on the characteristics of the internal thermoelectric load and external total load of electricity and heat network of thermoelectric units is also proposed to combine with the Levy-PSO algorithm for solving the problem. The optimal results are obtained via using the PSO and Levy-PSO algorithms for a typical CHP plant of seven units. The results show that the power generation cost obtained from the Levy-PSO algorithm is the lowest (10121.84$), which is close to the results of the literature and is better than the optimization results of the traditional PSO algorithm. Moreover, the results show that the constraint processing method adopted in this paper can well solve the characteristics of multiple constraints of load optimal dispatch problem. Meanwhile, the comparison results between the PSO algorithm and Levy-PSO algorithm indicate that the Levy-PSO algorithm has more obvious advantages in the performance of the algorithm. When combining with the proposed constraint processing scheme, the Levy-PSO algorithm shows better convergence and robustness, which is more suitable for solving similar practical engineering problems of heating and power optimal load distribution.
Birth-and-Death-Based Multipath Cluster Channel Model for Massive MIMO
Authors: Lu Yanping , Liu Liu , Liu Kai
Published: February 2022

In this paper the propagation characteristics of large-scale multi-antenna communication system are investigated. we give an insight into sub-channel correlation, and from which the non-stationary characteristics are deduced. Some in-field channel sounding are carried out with interesting frequencies of 1.4725GHz and 4.5GHz. Regarding to the channel measurements and data analysis we take an educated guess, and construct a birth-and-death-based Markov Model to characterize the multipath cluster’s evolution over the array, which explained the micro-changes of the radiation propagation environment. And the model is found to be highly coincide with propagation theory.
Research on Improved Current Predictive Control of Permanent Magnet Synchronous Motor
Authors: Yang Dongxue , Lu Huacai , Zhang Chenyan
Published: February 2022

Aiming at the motion control problem in permanent magnet synchronous motor speed control system, an improved deadbeat current predictive control algorithm based on fuzzy PID control is proposed. In this algorithm, the traditional PID control uses fuzzy control to realize real-time parameter adjustment, it eliminates the overshoot of the system; The improved deadbeat current predictive control is adopted in the current loop, and the control output of the speed loop is taken as the input of the current loop. the output speed of the motor is adjusted, so feedback control is formed to obtain accurate and fast track performance. The simulation results show that the control algorithm is fast and robust under no-load and disturbance conditions, which verifies the feasibility and effectiveness of the algorithm.
A study of dynamics of marine circuit breakers based on vibration
Authors: Sun Tao , Yang Lian , Shu Peng
Published: February 2022

Marine circuit breaker is an important equipment on board, its mechanical failure generated by the vibration can cause the power system failure. Therefore, it is necessary to evaluate the structure of the circuit breaker system. The finite element method is used to establish the dynamics model of the whole circuit breaker system under the vibration, and the dynamic response analysis of the circuit breaker is carried out with real vibration load. According to the analysis results, the overall structural strength of the circuit breaker and the occurrence of mis-operation are evaluated, then the sensitive weak position of the circuit breaker structure are identified, and finally the structural optimization design is carried out.
Study on engineering process and equipment operation of total treatment project of leachate and concentrated solution
Authors: Chen Changzhong , Jia Qiang
Published: February 2022

The accumulation of a large amount of leachate and concentrated liquid caused by MSW is a serious potential safety hazard and environmental hazard. A full treatment project of leachate and concentrate were performed, with treatment capacity of leachate 1100 t/d and concentrate 550 t/d. The leachate treatment process adopts “pretreatment + second-stage A/O biochemistry + ultrafiltration + chemical softening + second-stage DTRO+HPRO+RO+ ion exchange”. The main processing equipment is jet aerator, submersible mixer, centrifugal pump, ultrafiltration membrane assembly, softening membrane assembly, DT membrane column, RO system, ion exchange tank, sludge mixer, sludge dehydrator, etc. The concentrated liquid treatment process adopts “pretreatment +MVR forced circulation evaporation + triple-effect evaporation +RO+ ion exchange”. The main processing equipment is filter press, feed pump, compressor, MVR heater, circulating pump, discharge pump, original liquid pump, triple-effect evaporator, RO system, ion exchange tank, etc. The treatment results show that each indicator of external drainage meets the standard requirements of GB16889-2008 and DB37/3416.4-2018. The engineering process and equipment of the project run stably, with high recovery rate, and can properly solve the problem of concentrated liquid. So, engineering process and equipment operation of total treatment project of leachate and concentrated solution were studied, which has important reference significance for the full treatment of leachate from the national waste treatment plant.
Fracture Failure Analysis of Gear Teeth
Authors: Liu Chunjiang , Ouyang Kang , Jiang Tao , Liu Changkui
Published: February 2022

Gears are important transmission components in the field of aviation industry. Failure cases such as fatigue fracture and fatigue spalling often occur due to poor conditions, and the status of teeth surface is usually one of the important elements for the failure cause analysis, but few have analyzed how the machining status of gear end surface affects the fracture failure. In this paper, one engagement failure of two gears was studied, and the failure phenomenon is as follows: all teeth of the driving gear fractured, two adjacent teeth of the driven gear fractured and several locations of teeth bottom cracked. According to the fracture morphology of the gear, it is judged that the driven gear fatigue-cracked firstly, and the fatigue zone is located at the lower end surface rather than the tooth bottom. Material structure, machining status of gear end surface, and the thickness of nitriding layer were inspected. In addition, the difference of the machining status between the lower and the upper end surface was analyzed. The results show that compared to the upper end surface, the lower end surface is smoother and the grinding amount is relatively larger. The residual stress tested by XRD shows that there is a residual compressive stress of about 84 MPa on the upper end surface and a residual tensile stress of about 238 MPa on the lower end surface. The tensile stress and the working stress cause the local stress level of the lower end surface of the gear to be higher than the fatigue strength, causing fatigue cracking from the lower end surface.
Design of Flash Dryer Cum-UV for Improving the Quality of Drying Cassava Chip
Authors: Hermanuadi D , Brilliantina A , Sari EKN
Published: February 2022

Drying is a scientific operation, which includes the transient transfer of heat and mass at some rate of process. The purpose of this study was to design and create a flash system dryer, which is equipped with UV. The selection of flash system dryers is based on conditions where some materials to be dried are sensitive to hot air contact due to prolonged drying. As a heat source, this dryer uses a heater to heat the air. In order to spread the heat evenly in the dryer room, the blower is installed on the heater. The intake of air blower is 60 m/s, while the air temperature on the air heater is conditioned at 50 and 60ºC. In order to collect data of air temperature, a thermocouple is placed on heat channel pipe and dryer room. The performance test of the dryer by using cassava chips, showed that the lowest cassava chip water content was 7,2% at 50ºC treatment temperature, and the highest water content by 18.5% at treatment temperature of 60ºC.
Fermented meat and digestive tract of snail as amino acid supplements for functional feed of native chickens
Authors: Suryadi U , Hertamawati R T , Imam S
Published: February 2022

Sources of amino acids and lactic acid bacteria have been developed from the hydrolysis of snail meat and its digestive tract through a fermentation process using a consortium of microorganisms present in cow’s milk whey, which is fermented by microorganisms from rice washing water with internal microorganisms from snails. The fermentation process used the Submerged Fermentation (SmF) method. The fermentation process was carried out using Lactic Acid Bacteria (LAB) inoculants contained in rice washing water. This product was researched and developed with the aim of being a feed supplement to reduce the use of fish meal or other protein sources such as concentrates in the preparation of feed for poultry. Product development studies were carried out on the LAB content in rice washing water and fermented snail meat and its digestive tract, as well as their amino acid content. The results of the study showed that at the dilution of rice washing water, approximately 3 different colonies of LAB were found, the dilution of 10-1 to 10-4 could not be counted but at the dilution of 10-5, 50 colonies of LAB were obtained with an amount of 5 x 107 CFU/ml. The fermented snail meat and its digestive tract contained approximately 4 different LAB colonies and found 3 x 104 CFU/ml at a dilution of 10-3, and contained 6 types of amino acids, namely; alanine, glycine, cysteine, arginine, lysine, and proline. The conclusion of this research is that fermented snail meat and digestive tract have potential as an amino acid supplement for functional feed for native chickens.
Mini-Review: The potential of raffinose as a prebiotic
Authors: Anggraeni A A
Published: February 2022

Prebiotics are dietary fiber components that cannot be digested by the human gastrointestinal tract but can be selectively fermented by bacteria in the gastrointestinal tract. Therefore, prebiotics provides health effects for humans. The specificity of prebiotics is determined by the bacteria that are specifically capable of fermenting the prebiotic substrate. The characteristics of prebiotic substrate need to be investigated in-vitro and in-vivo to determine the function and effectiveness of the substrate as a prebiotic. The prebiotic production process must be able to keep the prebiotic components stable. Raffinose is an oligosaccharide that has potential as a prebiotic. This article will discuss raffinose chemical structure, degrading enzymes, and health benefits as a prebiotic. Raffinose consists of 3 monomers, namely α-D-galactose, α-D-glucose, and α-D-fructose. Substrates containing raffinose-family oligosaccharides (RFOs) are the source of raffinose. Those substrates can be degraded to raffinose by the α-1,6-galactosidase. Raffinose can increase the growth of lactic acid bacteria, suppress the growth of pathogenic bacteria, increase short-chain fatty acids (SCFA), reduce constipation, inhibit the formation of putrefactive compounds from protein, and reduce the risk of cardiovascular diseases.
Low-cost on-line monitoring system for agriculture based on raspberry pi zero
Authors: Setyohadi D P S , Kautsar S , Rosdiana E , Riskiawan H Y , Firgiyanto R , Putra D E
Published: February 2022

Based on data from the National Defense Agency, the trend of conversion of agricultural land in the 1990s reached around 30,000 ha/year. However, in 2011 there was an increase of 110,000 ha/year and reached 150,000 ha/year in 2019. In fact, with the growing human population, the need for food is increasing from year to year. On the other hand, the slow regeneration of farmers and the lack of dissemination & technological innovation to increase agricultural productivity are challenges in realizing food security. In line with the ongoing industrial revolution in the industrial era 4.0, it has brought very significant changes, not only the type of technology that has shifted, but more importantly a change in mindset in this industrial era. This has a real impact on the direction of national development and has an impact on the agricultural system. The agricultural system is no longer just a cultivation activity, but agriculture is also part of the industrial system which is characterized by a transformation, both in terms of raw materials, economy, social and environment. The development of modern agriculture is marked by mindset changing of using biological and non-biological resources by the needs. The precise use of resources in agricultural production systems is then called precision agriculture. Precision agriculture is an agricultural concept with a systems approach towards low-input, high-efficiency, and sustainable agriculture. In a previous study, a CNC-based precision farming system (Farming-BOT) was developed. The device could perform vegetable crop cultivation automatically. To properly observe the development of cultivation, an online monitoring device based on the minicomputer was developed. The Raspberry Pi Zero, equipped with a 5MP camera and a temperature & humidity sensor, is used. The device is placed on the top of the Farming-BOT device. Image data, temperature, and humidity are sent to the cloud database periodically every day. Users can access the data through the website and Android application. Based on the testing result, with a stable internet connection, data on environmental conditions can be monitored perfectly.
The enlightenment of foreign power market monitoring index system design to China’s power market
Authors: Yu Dan , Guo Yuhan , Tang Ren
Published: February 2022

China is currently in the process of power market reform. With the continuous deepening of power reform, there will be more and more uncertain factors in the future power market. Although the advancement of marketization will bring benefits to market players, it will also Bringing huge risks. Thus, a power market monitoring indicator system is of great significance to achieve market risk management. The indicator system needs to fully consider the particularity of power commodities. In the design process, the power market indicator system should be designed in accordance with local conditions and local conditions. This article first studies the risks faced by the power generation side, power sales companies and user side transaction entities in the power market environment. And expounding the reasons for these risks, and proposes countermeasures to adapt to the power market transaction risks. And then analyzing and summing up the United States, Nordic, and Singapore electricity market monitoring indicator system design. Finally putting forward reasonable suggestions for the design of China’s electricity market indicator system, which has an enlightening effect on the countermeasures of multiple transaction entities in China’s electricity market.
Quantitative analysis of renewable energy system structure based on the weather condition in Cambridge, London, and Oxford
Authors: Chen Yutong
Published: February 2022

Renewable resources have been a rising star in energy generation and consumption. This paper is going to talk about the data sets of the solar and wind energy in three different cities, and fin the patterns to those data sets using contribution factors, probabilities, and normal distributions.
A detection method for biological electric shock based on improved sample entropy
Authors: Xiong Xiaoyi , Shi Yunyun
Published: February 2022

Biological electric shock detection is the key to safeguarding of persons in grids. However, present methods cannot make protectors trip correctly by extracting the characteristics of living things. To improve the situation, this paper presents an innovation by which the protectors can be adaptive to trip correctly when the biological electric shock happens. The basic principle of proposed method is extracting biological electric shock characteristics (BESC) from measured current based on the sample entropy (SampEn). It can distinguish whether the electric shock is caused by mammals or not. Besides, for practical need, a fast BESC calculation method is proposed in order to reduce redundant computation. Moreover, an execution module for electric shock protection based on DSP is developed. And electric shock experiments have been carried out to validate the effectiveness of proposed method. The results show that accuracy of biological electric shock detection is improved and proposed method is practical even in strong noise environment.
Investigating the effect of interstage pressure on cooling performance of a real-world CO2 heat pump system
Authors: Wang Ji , Belusko Martin , Semsarilar Hesam , Evans Michael , Liu Ming , Bruno Frank
Published: February 2022

The study reveals the effect of interstage pressure with the consideration of gas cooler outlet temperature on the cooling performance of an operating CO2 heat pump system currently in use at a dairy plant. Based on the numerical model and CO2 properties, it was found that the maximum mass fraction of liquid allocated for cooling can be achieved in the middle of the operating range of interstage pressure when the enthalpy at the location of the gas cooler outlet is between 341 kJ/kg. K and 399 kJ/kg. K (that is, the gas cooler outlet temperature is between 37.34 °C and 43.02 °C with a fixed discharge pressure of 85 bar), however, the maximum liquid fraction can be achieved at the upper limit of the pressure when the enthalpy is less than 341 kJ/kg. K and can be achieved at the lower limit of the pressure when the enthalpy is higher than 399 kJ/kg. K, respectively. In the comparative study on fixed and variable interstage pressure, it was found that there is small difference in cooling COP when the gas cooler outlet temperature is lower than 38.5 °C , while the COPs with variable interstage pressures surpass those with fixed pressures when the gas cooler outlet temperatures are even higher.
The accumulation characteristics of NO and N2O in A/O-SBR for treating ammonium-rich organic wastewater
Authors: Zhao Junkai , Zhao Jianqiang , Huang Ting , Ma Xiaoqing , Yan Chunxiao , Xie Shuting , Lei Shuhan
Published: February 2022

The emissions of NO and N2O during biological nitrogen removal harm the environment. In this study, a sequencing batch reactor (SBR) was used to treat ammonium-rich organic wastewater. The nitrogen transformation and characteristics of NO and N2O accumulation in typical cycles under different nitrification conditions were monitored, and the mechanisms of NO and N2O production in A/O-SBR were analyzed. The results showed that NO accumulated in the anoxic phase under a fixed concentration of organic carbon source during denitrification with nitrite as electron acceptor or nitrate as electron acceptor. NO production in the aerobic phase could be related to hydroxylamine oxidation and nitrite reduction caused by high ammonia nitrogen. The accumulation of N2O mainly occurred in the aerobic phase, and the cumulative concentration of N2O at the end of the four typical cycles was above 4.02 mg/L. N2O accumulation attributed to the inhibition of free nitrous acid (FNA) and NO, and electronic competition, which made N2O reductase (N2OR) activity insufficient, failing N2O reduction.
The effect of S/N ratio on NO and N2O accumulation during sulfide autotrophic denitrification
Authors: Xie Shuting , Zhao Jianqiang , Dai Wei , Lei Shuhan , Zhao Junkai , Yan Chunxiao , Ma Xiaoqing , Min Jia
Published: February 2022

Nitro oxide (NO) and Nitrous oxide (N2O) are inevitable intermediates of sulfide autotrophic denitrification (SAD) process, and have huge environmental hazard. This study investigated the produce mechanism and accumulation characteristic of NO and N2O in SAD process under different S/N ratios. The results showed that the lower S/N ratio, the higher NO accumulation. Which was due to the strong reducing effect of S2- and the electronic competition between nitrogen reductase. And under S/N ratio = 2, N2O level reached its peak, which was caused by electronic competition. When the S/N ratio = 1, although the electronic competition was more intense, the total amount of electrons was less, thus the N2O produced is lower than that produced when S/N=2. Microbial community analysis showed that Thiobacillus sp. (62.44%) was the predominant genus, and conducted the suldide-oxiding autotrophic denitrification process.
Carbon emission analysis of two crystalline silicon components throughout the life cycle
Authors: Yin Aiming , Zhang Zhen , Jin Xuliang , Wang Haigang , Zhang Meng , Wang Han
Published: February 2022

Take PERC P-type monocrystalline silicon and PERC P-type polycrystalline black silicon modules as examples to establish a life cycle carbon emission inventory of crystalline silicon modules. Study the contribution of five recycling technologies to the life cycle carbon emission reduction of two crystalline silicon modules, and the impact of the life cycle of 1MWP PERC P-type monocrystalline silicon and PERC P-type polycrystalline black silicon module systems on the environment. The results show that the carbon emissions of the two photovoltaic systems are concentrated in the production stage, and the carbon emissions of the crystalline silicon purification process are the highest, accounting for more than 41%. Through green low-carbon recycling technology to process waste photovoltaic modules to obtain glass, aluminum, silicon and other materials to achieve resource recycling, it can reduce the energy consumption of the module production process and life cycle carbon emissions. According to calculations, 1 MWp PERC P-type monocrystalline silicon system has 10% higher life cycle carbon emissions than PERC P-type polycrystalline black silicon system.
Comparisons of nitrogen and phosphorus removal efficiency in A2/O process, UCT process, MUCT process, enhanced phosphorus removal process and inverted A2/ O process based on GPS-X simulation
Authors: Lei Shuhan , Zhao Jianqiang , Xie Shuting , Zhao Junkai , Min Jia , Ma Xiaoqing , Yan Chunxiao
Published: February 2022

By using the GPS-X software, the enhanced phosphorus removal (EPR)process was simulated in this study. The comparisons among nitrogen and phosphorus removal efficiency of traditional A2/O process, University of Cape Town (UCT) process, Modified University of Cape Town (MUC) process and inverted A2/O process were conducted, in order to determine the best process under the same conditions of construction investment and running cost. The results showed that the simply reversed A2/O process exhibited poor total phosphorus (TP) removal efficiency under low carbon level. The effluent water qualities of the other three processes under low, medium and high levels of carbon source met the first B level criteria in Discharge Standard of Pollutants for Municipal Wastewater Plan (GB18918-2002) for China. The ranges of removal efficiencies of TP, TN, NH4
+-N and COD were 63.15% ∼ 94.91%, 55.38% ∼ 77.89%, 96.91% ∼ 97.70% and 90.89% ∼ 93.66%, respectively. Denitrifying phosphorus removal occurred in anoxic tank of EPR process. The phosphorus accumulation concentration was 6.91 mg/L, and the maximum phosphorus released in anaerobic tank was 24.01 mg/L, and the higher P release gave the EPR process a high P removal effiency. Except for the TN which met the first B level criteria (GB18918-2002), TP, NH4
+-N and COD met the first A level criteria GB18918-2002), above that, the process was feasible. Inverted A2/O process exhibited the highest nitrogen removal efficiency for its sufficient carbon source in anoxic tank.
The high-efficiency methods to identify lithology with well logging plates or a program
Authors: Wu Zhaohui
Published: February 2022

As traditional manual method to identify lithology of cored wells is laborious and lack of efficiency, two efficient methods are used this time. One method is the identification with well logging plates while another is a program. The critical values of 5 kinds of well loggings are found to be relatively stable through many trials, and some major steps should be taken before using the logs. First is to find standard rock types and their logging values. Rock types are more reliable after the observation under microscopes. The second step is to find out the logging data ranges of each rock type. The third step is to quantitatively identify rock types with the optimal critical values. In this process, the multi-array logs (M2Rn) is found to be the most effective log to distinguish mudstone and oil reservoir. Low density (DEN) value is effective to distinguish the lightest matter or pores. The other two well logs, i.e. AC and CNL, can be used to distinguish whether there is limy content. Wave impedance (PD=DEN/AC) log can be a supplementwhen that kind of data is available, and finally all lithology is identified after that. The result that calculated from well logs with a program is similar to litholgy of drilling cores. Through many trials and errors, it is finally found and proved to be a successful approach to automatically and efficiently distinguish rock types in the software of Direct and Petrel. This method is more efficient and easier to operate with a program when there are hundreds of wells, and it is a progem made that work possible. There is more widespread use in deep carbonate buried hill with this method, simply by changing the lithology codes and critical values in the program.
Multi-fidelity weight analyses for high aspect ratio strut-braced wings preliminary design
Authors: Delavenne M , Benard E , Defoort S , David C , Fabbiane N , Schotte J S , Arnoult G , Carrier G
Published: February 2022

In the wake of ”flygskam” movement that emerged in Sweden a couple of years ago many voices recently raised denounce the environmental footprint of aviation. Even if the real impact of the sector could appear rather limited the critics reveal the necessity to propose cleaner aircraft to both meet public expectations and environmental goals. Because the classical wing-tube configuration seems to have reached its limits, disruptive designs must be considered. Among the perspectives to reduce emissions, high-aspect ratio wings represent a promising path to be explored within the European CleanSky2 project U-HARWARD. Indeed, substantial diminution of induced drag are expected from those new configurations resulting in fewer fuel consumption. To achieve high-aspect ratio without compromising the structural weight strut can be introduced. They allow for an alleviation of the bending moment at the wing root and therefore lighter structures. However, the consideration of those new wing configuration at early design stages is not straightforward and new methods have to be introduced. In this paper, we present three different fidelity approaches to tackle with (ultra) high-aspect ratio strut-braced wings sizing and weight estimation in preliminary design context. Already existing analytical formulations for the wings are extended, intermediate fidelity aero-structural coupling has been developed and high-fidelity structural representation are considered. Depending on the maturity of the concept these methods could be used to explore the design space, to refine the optimum or to analyse the final concept. Validation with respect to reference configurations is provided. Then the methods are applied to the analysis of strut-braced wings.
Ground effect aerodynamics of twin fuselage aircraft
Authors: Chernousov V I , Krutov A A , Savin P V , Pigusov E A
Published: February 2022

The paper presents experimental study results of ground effect influence on the aerodynamic characteristics of the twin fuselage transport airplane in a low-speed wind tunnel. The aerodynamic configuration has the two fuselages distributed under high-wing, and a “TT”–shaped tail. The twin fuselage transport airplane model consists of two fuselages, wing, empennage and external tank. The analysis includes studying the ground effect on the longitudinal and lateral aerodynamic characteristics and horizontal tail effectiveness. The effect of installing an external cryogenic fuel tank under the wing between the fuselages of the model was considered too. The obtained data shows the typical behaviour of the aerodynamic characteristics near the ground plate for aircraft model with high-wing and high placed horizontal tail. Ground proximity significantly increases the maximum lift-to-drag ratio and slightly changes the longitudinal moment characteristics. Horizontal tail effectiveness is maintained for all tailplane angles near the ground plate. The longitudinal and lateral stability of the twin fuselage transport airplane model is maintained in all considered modes near the ground plate.
Managing Airport Capacity and Demand: An Economic Approach
Authors: Rodríguez-Sanz Álvaro , Andrada Luis Rubio
Published: February 2022

This paper reviews major research trends and opportunities in airport demand and capacity management from an economic perspective. Airport capacity constraints lead to operational congestion and delays, which have become major threats to the aviation industry. They impose large costs on airlines and their passengers. Uncertainty in demand or unexpected events can cause a mismatch between capacity and demand, resulting in either capacity over-supply, with a decrease in efficiency, or airport congestion over an extended period. Moreover, airport capacity is rather difficult to define due to its multi-faceted and dynamic nature, and it depends both on the available infrastructure and on operating procedures. The non-linear relationship between airport capacity and on-time performance offers guidelines for congestion mitigation through demand and capacity management. This paper explores and produces an in-depth understanding of the capacity and demand balance problem and provides a roadmap for including economic concepts when evaluating airport capacity expansions.
Highly iterative concept development for requirement-compliant air taxis
Authors: Schuh G. , Spangenberg M. , Meyer-Hollatz T.
Published: February 2022

The increasing demand for individual mobility worldwide is leading to the development of new forms of mobility. Individual air mobility (e.g., air taxis) could be one innovative approach to meet this increasing demand. To successfully realise such innovative approaches, interested companies must know the technical, economic, and ecological requirements of all relevant stakeholders and integrate them in their air taxi developments. Based on these diverse requirements, a resilient air taxi concept must first be created that describes the essential characteristics of future air taxis and enables a well-founded assessment. However, in practice, it is often difficult for companies to outline such a concept and then develop it consistently and highly iteratively. To face this challenge, a process has been set up which creates a deep link between the requirements and concept development phase to assure the development of requirement-compliant air taxis in an agile manner. The process is divided into two parts. The first part connects the market analysis, requirements definition and concept creation, thus linking the requirements and concept development phase. It is based on a double diamond model consisting of two phases. In contrast, the second part is focusing on the pre-development until the end of the concept development phase by adapting the SCRUM methodology to derive a sound air taxi concept. Both parts are executed in a highly iterative manner to reflect the significant amount of uncertainty at this early process stages.
Innovative liner concept using friction powder for increasing of broadband noise absorption. Applications for broadband noise absorption in fan duct
Authors: Sandu Constantin , Humbert Thomas , Auregan Yves , Deaconu Marius , Totu Andrei , Radu Andrei , Serbescu Horatiu , Tipa Traian
Published: February 2022

This paper presents research related influence of friction powders on enlarging the absorption band of acoustic liners used for reduction of tonal noise in fan duct of aero-engine. Kundt tube measurements done at COMOTI using fine powders (granules) made of various light-weight materials placed in the honeycomb cells of SDOF liners have shown a considerable broadening of the absorbed band of frequencies without a significant decreasing of absorption at the resonance frequency. Although the phenomenon is generally present for any type of powder, it was observed that for some powders the absorption is higher than for others. On the other hand, it was observed that the effect of the filling percentage of the cavity is important. Then, experiments done at the grazing flow facility of CNRS-Le Mans University have shown that the phenomenon is also present for high acoustic incident levels (up to 140dB) and M=0.13 while it still depends by the nature of powder material. The best results were obtained for the cork powder when the honeycomb is filled with powder at 66% of its height. For this material, the broadening of the transmission loss well was maximum. This phenomenon could be explained by the apparition of friction between powder granules which are taking place at very low scale consuming the noise power on a broader range of frequencies. It is supposed that the friction between the particles of powder have major influence because the best noise absorption was obtained for powders with a large distribution of particles’ dimensions while for particles with a small dimensional distribution (expanded polyester balls, for example) the transmission well broadening was smaller. The friction powders technology is simple and can be easily adapted to existing acoustic liner technologies with small manufacturing costs. This feature is conferred by the fact that powders can be easily poured in the honeycombs at the required height. The friction powder technology can be applied not only for the fan duct. In future, it could also be applied for reduction of jet noise reflected by pressure side of wing and for cabin noise reduction.
Prediction of Fan Tone Radiation Scattered By A Cylindrical Fuselage
Authors: Rouvas D-M. , McAlpine A.
Published: February 2022

A theoretical prediction method of the scattering of fan tone radiation from a turbofan inlet duct by the airframe fuselage is presented. The fan tone noise is modelled by an acoustic disc source that represents the sound field at the inlet duct termination. Adjacent to the source is a cylindrical fuselage that scatters the fan tone radiation. The prediction method is valid for upstream sound radiation. The acoustic pressure on the cylindrical fuselage is affected by refraction of the sound as it propagates through the fuselage boundary layer. This effect known as boundary layer shielding is more prominent forward of the turbofan, since the fan tone noise radiated from the inlet duct is propagating upstream. An asymptotic approach is used to model sound propagation through a boundary layer which is modelled by a thin linear shear velocity profile. Consequently the scattered pressure field can be computed very quickly, thus providing a fast and efficient prediction method. Although a realistic fuselage turbulent boundary layer does not resemble a linear shear layer, it is shown that the effect of acoustic shielding by a turbulent boundary layer can be modelled by taking a liner shear profile with a shape factor that matches the shape factor for a realistic turbulent profile.
The impact of propulsive architecture on the design of a 19-passenger hybrid-electric aircraft
Authors: Nasoulis Christos P. , Protopapadakis Georgios , Gkoutzamanis Vasilis G. , Kalfas Anestis I.
Published: February 2022

The electrification of aircraft is an on-going endeavor, currently examined intensively in the general aviation class. However, for the commuter class, the proper selection of the hybrid-electric propulsive architecture is instrumental, to fully exploit the electrification benefit. Within this work, a comparison of two 19-seater aircraft with different hybrid-electric propulsive components is made, using an in-house aircraft conceptual design tool. The first aircraft is based on a twin-turboprop parallel-hybrid configuration that cruises at low Mach number speeds and altitude. On the other hand, the second aircraft variant is based on a tri-fan series/parallel-hybrid configuration with an aft Boundary Layer Ingestion system that operates at both higher altitude and Mach numbers. A design space exploration is performed where different degrees of hybridization and batteries specific energy are considered, to define the technological requirements for each architecture. The evaluation of the propulsive architectures is based on block fuel reduction, overall mission duration, direct operating costs and total environmental impact. The results aim to quantify the benefits of each configuration and determine the one with the closest entry into service. Finally, it is observed that the overall environmental impact reduces by 26 % and 17 % for the turboprop and turbofan variants respectively.
Design of Hybrid-Electric Small Air Transports
Authors: Orefice F. , Marciello V. , Nicolosi F. , Zhang Q. , Wortmann G. , Menu J. , Cusati V.
Published: February 2022

The potential benefits of hybrid-electric or full-electric propulsion have led to the proliferation of many concepts over the past decade. The lack of conceptual design methods capable of grasping the effects of the new propulsive technologies is often due to the absence of industrial data supporting the research. In the present work, two objectives are pursued. On the one hand, the introduction of semi-empirical methods for weight estimation based on the data provided by the industrial partners of the ELICA CS2 project. On the other hand, the establishment of generative engineering as a conceptual design tool for propulsive system architecting and fault tolerance analysis. The applications of the proposed conceptual design methods deal with two different years of entrance in service.
Towards simulation of disassembly of bonded composite parts using the laser shock technique
Authors: Kormpos P , Tserpes K , Floros G
Published: February 2022

In this work, a model for simulating the laser shock-based disassembly of composite components is developed using the LS-DYNA explicit code. The laser shock technique has been used in the past for the non-destructive testing of adhesive bonds, but with appropriate adjustments it is possible to create a localized tensile stress that is high enough for adhesive failure to occur, making it suitable for use in the disassembly of bonded parts. In this first attempt, we focus on the development of a multiple loading instances simulation process, aiming to completely debond two carbon fiber reinforced plastic (CFRP) plates. The process of laser shock for disassembly requires an increased number of loading instances in order to cover the full bonded area. That, in addition to the short time duration in which the phenomena are evolved, poses a serious challenge for the numerical simulations, and thus a reliable procedure must be defined in terms of functionality and computational cost. Indeed, an iterative method, where the deformed model is used as input in subsequent simulations is evaluated, optimized and compared with a more traditional single model simulation.
InnEO’Space PhD: Preparing Young Researchers for a successful career on Earth Observation applications
Authors: Mothe Josiane , Bayer Aurelie , Castello Valentina , Ciaccio Valentina , Frate Fabio Del , Santis Davide De , Ivanovici Mihai , Kerisel Anne Lehuerou , Necşoi Daniela , Ndong Aude Nzeh , Neptune Nathalie , Perier-Camby Maude , Recchioni Marco , Ullah Zia , Voinea Mihaela
Published: February 2022

InnEO’Space PhD project is preparing young researchers for a successful career by developing modernised and transferable PhD courses and learning resources based on innovation skills and employers’ needs as well as in-depth knowledge of high stakes and approaches of Earth Observation in many application domains. The mains objectives of Inn’EO Space PhD are to enhance and develop researchers’ innovation-oriented mind-sets and skills through Earth Observation, raise awareness about employment opportunities in academia and industry among researchers and scientists, tackle future skills mismatches and create new synergies between PhD students and researchers and potential employers. The first action has been to develop the InnEOStartech where the program was set for European PhD students with the aim of developing their taste for entrepreneurship spirit through idea of founding a company or designing an application. The second action has been to develop a summer school that delivered both technical skills and soft skills, thus providing all the ingredients for an innovation-oriented mindset. From these activities we shall develop a series of SPOCs (Small Private Online Courses) that will be made available to the community for further dissemination and exploitation.
New Intelligent Semi-Products based on Recycled Carbon Fibres
Authors: Faure Alexandre , Mantaux Olivier , Gillet Arnaud , Cazaurang Gilles
Published: February 2022

The carbon fibre recycling industry is not yet able to operate at full capacity. This lack of potential is a repercussion of a low demand for recycled carbon fibres (rCF) to manufacture new composite materials. As a matter of fact, few semi-products containing recycled carbon fibres are available on the market. Moreover, rCF semi-products available do not allow to manufacture high performances composite parts. The MANIFICA project, based on highly realigned carbon fibres after steam thermolysis, aims at producing new semi-products from recycled carbon fibres for high performance composites. In this article we introduce the I2M/Université de Bordeaux re-alignment process producing continuous tapes made of highly aligned long discontinuous fibres. These tapes are then used to manufacture new intelligent rCF semi-products. In the first part, the mechanical properties of rCF composites based on different semi-products are compared. In the second part, several semi products based on realigned fibres tapes are presented. This work demonstrates that high performance products can be targeted with recycled carbon fibres, thanks to the development of these intelligent semi-products.
ECO-CLIP: circular economy from factory waste material towards aircraft structural components
Authors: Travieso-Puente R , Martín-Pérez C , González-Castro N , Rodríguez-Senín E , Vidal-Navarro J , Vicente-Guerrero G , Veldman S L
Published: February 2022

This paper discusses the development of short fibre frame clips and system brackets made from recycling CF/LMPAEK factory waste composites employing two technologies (injection molding and 3D-printing). The project will develop and validate fused deposition modeling (FDM) as cost-efficient process to manufacture system brackets using the novel formulation of recycled composite as raw material. Energy directors development for ultrasonic welding is presented for successful joining of the clips to the fuselage, avoiding fasteners. The manufactured parts will be assembled into the lower half of the multifunctional fuselage demonstrator. The results were developed within ECO-CLIP project, which aims to: (1) assess technical aspects of material recyclability and (2) assess the economic and environmental validity of the technology.