bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal design of sealing structure of vehicular radar case door
Authors: Zhang Jicheng , Hua Haitao
Published: February 2022

The quality of antenna array environment control technology directly affects the reliability and service life of vehicular radar. The structure design of case door sealing is an important part of the environmental control technology of vehicular radar. The stress distribution analysis of case door sealing structure of vehicular radar antenna is carried out in this paper. Maximum stress of double-peaked sealing ring and stress distribution and deformation of case door panel are investigated through finite element analysis based on ABAQUS. In order to increase the reliability of sealing structure, the section size of double-peaked sealing ring and the spacing length of fasteners are optimized by the way of co-simulation optimal design method using ISIGHT. Through radial basis function neural network surrogate model, which is built based on Latin hypercube sample algorithm, the sensitivity of each optimization variable is analyzed. Meanwhile the optimal section size of double-peaked sealing ring and spacing length are obtained through non-dominated sorting genetic algorithm.
Development and Application of High-gloss Injection Molding Technology
Authors: Zhu Junjie , Qiu Zhiwen , Huang Wenhan
Published: February 2022

High-gloss injection molding technology is a new green injection molding technology based on dynamic mold temperature control strategy. Compared with the traditional injection molding technology, this technology can obviously improve the surface quality of products, and obtain high quality products with high gloss and no weld line. This paper introduces the principle and technological characteristics of high-gloss injection molding, analyzes the key technology and development of high-gloss injection molding. The key technologies of high-gloss injection molding mainly include high-gloss molding material, high-gloss mold, mold temperature control system, etc. Finally, the existing problems of high-gloss injection molding technology are analyzed, and the breakthrough direction in the field of injection molding in the future is proposed.
Research on lateral control of autonomous vehicle based on driver steering model
Authors: Qiu Runqi , Xin Shangfeng
Published: February 2022

Path tracking is an important issue in autonomous driving research. In this paper, based on the vehicle two-degree-of-freedom linear dynamics model for path tracking, the study of vehicle path tracking is carried out by applying model predictive control. A linear state space model of the vehicle is established based on the linear two-degree-of-freedom dynamics model, which provides the basis for the path tracking research. Based on the established state space model and the model predictive control method, the path tracking control algorithm is established using the preview point of driver steering model instead of the prediction part in the traditional model predictive control algorithm, which reduces the complexity of the algorithm and greatly improves the real-time performance. Finally, the effectiveness of the algorithm is verified by the joint software simulation of CarSim and Simulink.
Design and control of optical steady image system of aerial camera
Authors: Di Zhimin , Zhong Xiangqiang , Fan Jingsong
Published: February 2022

In order to solve the problem of aerial photography imaging blur, an aerial camera optical image stabilization system is designed. Based on the principle of optical image stabilization, a forward image stabilization system of aerial camera was designed by analyzing the imaging blur of aerial camera. The equivalent resolution of the system is 500-1000 l p/mm, and the corresponding pixel size is 1-2 μm. Aiming at the optical image stabilization system to establish its PID and corresponding adaptive PID control model, establish its closed-loop system transfer function, and use MATLAB to simulate and analyze the control system. The results show that the whole image stabilization system becomes stable after 0.01s and can achieve the goal of image stabilization. It solves the problem of forward image motion of aerial camera, and greatly improves the imaging effect of aerial camera when it works.
Study on the Properties of Water Molecule at Different Temperatures
Authors: Li Yuanze
Published: February 2022

Using computers as tools to perform molecular dynamics simulations from a microscopic point of view to explain macroscopic physical phenomena has become mainstream. This article discussed the properties of water molecules at different temperatures from the perspective of molecular dynamics simulation. In terms of general physical properties, this article investigated the trend of water viscosity and thermal conductivity with temperature by collecting and comparing existing literature data. The conclusion is that the viscosity decreases with increasing temperature, and the thermal conductivity increases with increasing temperature. In terms of special properties, this article took the hydrogen bond of water as the research object, and made a comprehensive analysis from three aspects of hydrogen bond length, hydrogen bond angle, and the hydrogen bond coordination number, which includes data analysis of existing literature and molecular dynamics simulation analysis. The latter used “Moldy” to perform three molecular dynamics simulations on water molecules at different temperatures, and imported the simulation results into “Vmd” for visual analysis. The results were compared with the existing literature data, and the conclusions were almost the same. That is, as the temperature increases, the hydrogen bond length becomes slightly longer, the hydrogen bond angle becomes smaller, and the hydrogen bond coordination number becomes less.
Research on the Status of Two-dimensional Layout Circular Parts
Authors: Ji Jun , Xing Fei-Fei , Zhang Sai-Kun
Published: February 2022

This paper introduces the research background of the two-dimensional circular part layout problem, analyzes the complexity of the layout problem, studies the current research status of the circular part layout problem, and finally, lists the relationship between layout methods and layout schemes of the two-dimensional circular part layout problem.
Design and analysis of multi-channel signal acquisition circuit based on FPGA
Authors: Zhang Jian Yu , Na Jie Si , Guo Fu Chun , Jiao Yu Chen
Published: February 2022

This paper designs and implements a real-time underwater acoustic signal acquisition system based on FPGA. The system can collect and transmit the noise generated by ships. It provides the basis and guarantees for the subsequent research and analysis of noise.
The reliability design of inspection device based on the obstacles and the derailment
Authors: Hu Chunhong , Li Juanjuan , Tian Yuan , Zhai Guorui
Published: February 2022

This paper introduces a kind of contact train obstacles and derailment detection device. It is composed of detection device and electric box. The energy produced by collision between obstacles and detection device and the train derailment is converted to electrical signal which can be measured, then it could control emergency braking. It can minimize the impact of foreign matter on vehicle safety or operation order after entering the vehicle limit. This system uses CPLD as the control core and adopts double redundancy design that improved the reliability of the device. It provides guarantee for train running safety and has good application prospect.
Design of Fully Intelligent Quality Error Prevention System for Tobacco Production Line Based on Configuration Software and PLC Program
Authors: Gu Yongqiang , Zhang Xi , Yang Huan , Zhang Jianlin
Published: February 2022

Aiming at the problems of wrong brand, mixed batch and wrong transmission of electronic parameter information in the production of cut tobacco of different brands in the tobacco industry, a fully intelligent quality error prevention system based on WinCC configuration software and PLC distributed control program is designed. The information of the production and manufacturing execution system in the general control room and the brand, batch and other information stored in the PLC of the bottom electric control cabinet is compared and verified instead of manual self-inspection. If the information is consistent, production is allowed. Otherwise, the equipment locks itself and sends alarm feedback. The design and application of the system realize the automatic error prevention of process equipment and the implementation accuracy of production control parameters, to ensure that the production process meets the requirements of process technology, effectively avoid major quality accidents, and finally guarantee the product quality.
Polyester fabric impregnated with carbon nanotubes directly to form a flexible heating fabric
Authors: Wei Xiru , Xiao Yuan
Published: February 2022

In order to solve the problems of complex fabrication process, poor flexibility and high cost of heating element in electric heating clothing, a method of preparing flexible heating fabric by directly impregnating polyester fabric with carbon nanotube was proposed. According to the process flow of preparing flexible heating fabric, the process conditions of uniform loading carbon nanotubes on polyester fabric were determined, the flexible heating fabric was prepared under different process conditions, and the surface microstructure of the flexible heating fabric was observed and its heating performance was tested. The results show that the pretreatment process can reduce the resistance value of the flexible heating fabric. When the concentration of carbon nanotubes is 6wt% and the content of waterborne polyurethane is 35g/L, the flexible heating fabric can be prepared. By observing the surface micro-topography, it can be seen that the surface of the prepared flexible heating fabric is smooth, and a uniform conductive layer of carbon nanotubes is formed on the fabric. A 5V DC voltage was applied to the prepared flexible heating fabric, and the highest heating temperature was 46.8°C within 62 seconds after the electricity was turned on, which realized rapid electric heating and uniform heating, laying a foundation for the subsequent development of heating clothing.
Design of a high-resolution Rayleigh-Taylor experiment with the Crystal Backlighter Imager on the National Ignition Facility
Authors: Angulo A.M. , Nagel S.R. , Huntington C.M. , Weber C. , Robey H.F. , Hall G.N. , Pickworth L. , Kuranz C.C.
Published: February 2022

The Rayleigh-Taylor (RT) instability affects a vast range of
High Energy Density (HED) length scales, spanning from supernova
explosions (1013 m) to inertial confinement fusion
(10-6 m). In inertial confinement fusion, the RT instability
is known to induce mixing or turbulent transition, which in turn
cools the hot spot and hinders ignition. The fine-scale features of
the RT instability, which are difficult to image in HED physics, may
help determine if the system is mixing or is transitioning to
turbulence. Earlier diagnostics lacked the spatial and temporal
resolution necessary to diagnose the dynamics that occur along the
RT structure. A recently developed diagnostic, the Crystal
Backlighter Imager (CBI), [1,2] can now
produce an x-ray radiograph capable of resolving the fine-scale
features expected in these RT unstable systems. This paper describes
an experimental design that adapts a well-characterized National
Ignition Facility (NIF) platform to accommodate the CBI
diagnostic. Simulations and synthetic radiographs highlight the
resolution capabilities of the CBI in comparison to previous
diagnostics. The improved resolution of the system can provide new
observations to study the RT instability's involvement in mixing and
the transition to turbulence in the HED regime.
Economic growth dominates rising potential flood risk in the Yangtze River and benefits of raising dikes from 1991 to 2015
Authors: Qi Wei , Feng Lian , Yang Hong , Liu Junguo , Zheng Yi , Shi Haiyun , Wang Lei , Chen Deliang
Published: February 2022

Flooding in the Yangtze River Basin could severely damage socio-economic development, river ecosystems, food security, hydropower production and transportation in China. The Yangtze River Basin accounts for approximately 30% of China’s gross domestic product (GDP) and is an engine for the country’s rapid economic growth. One commonly held belief is that climate change has intensified extreme flood events, leading to increasing economic damage in the Yangtze River. Here, we quantitatively attributed economic exposure to climate change (i.e. climate-induced changes in weather-related events) and GDP growth, and assessed benefits, i.e. the reduction in economic exposure, from flood defence dikes of varying heights. To do this, we developed a framework by combing a large scale hydrological model, a hydraulic model, and long-term GDP data. We find that climate-induced changes in flood inundation area and resulted economic exposure were decreasing overall, whereas GDP growth drove the increases of potential economic exposure to floods. We also reveal that the basin average flood defence dikes should be at least approximately 3.5 m high to achieve an about ten-year average flood occurrence. Our results have significant policy and socioeconomic development implications.
An extreme event of enhanced Arctic Ocean export west of Greenland caused by the pronounced dynamic sea level drop in the North Atlantic subpolar gyre in the mid-to-late 2010s
Authors: Wang Qiang , Shu Qi , Danilov Sergey , Sidorenko Dmitry
Published: February 2022

The North Atlantic subpolar gyre influences the climate in many different ways. Here, we identified that it is also responsible for a recent extreme event of Arctic Ocean freshwater export west of Greenland. A shift in climate regimes occurred in the mid-2000s, with a significant negative trend in the dynamic sea level in the subpolar gyre since then. We found that the dynamic sea level drop induced a strong increase in freshwater export west of Greenland, in particular from 2015 to 2017, when the sea level was close to the minimum. Sea ice melting and atmospheric variability in the Arctic had only a small contribution to this event. As the exported water from the Arctic Ocean has low salinity and constituents of chemical tracers very different from those in the North Atlantic, such events might have impacts on the North Atlantic ecosystem and the climate as well. Our study suggests that such events might be predictable if the subpolar gyre sea level has certain predictability.
l
1 norm of coherence is not equal to its convex roof quantifier
Authors: Xu Jianwei
Published: February 2022

Since a rigorous framework for quantifying quantum coherence was established by Baumgratz et al (2014 Phys. Rev. Lett.
113 140401), many coherence measures have been found. For a given coherence measure C, extending the values of C on pure states to mixed states by the convex roof construction, we will get a valid coherence measure

C

¯

, we call

C

¯

the corresponding convex roof quantifier of C. Whether

C
=

C

¯

for a given coherence measure is an important question. In this work, we show that for the widely used coherence measure, l
1 norm of coherence

C

l

1

, it holds that

C

l

1

≠

C

l

1

¯

.
Exact crystalline solution for a one-dimensional few-boson system with point interaction
Authors: Tomchenko Maksim
Published: February 2022

We study the exact solutions for a one-dimensional system of N = 2; 3 spinless point bosons for zero boundary conditions. In this case, we are based on M Gaudin’s formulae obtained with the help of Bethe ansatz. We find the density profile ρ(x) and the nodal structure of a wave function for a set of the lowest states of the system for different values of the coupling constant γ ⩾ 0. The analysis shows that the ideal crystal corresponds to the quantum numbers (from Gaudin’s equations) n
1 = ⋯ = n

N
= N and to the coupling constant γ ≲ 1. We also find that the ground state (GS) of the system (n
1 = ⋯ = n

N
= 1) corresponds to a liquid for any γ and any N ≫ 1. In this case, the wave function of the GS is nodeless, and the wave function of the ideal crystal has nodes.
The utility of a standardised breath sampler in school age children within a real-world prospective study
Authors: Bhavra K K , Wilde M , Richardson M , Cordell R , Thomas P , Zhao B , Bryant L , Brightling C E , Ibrahim W , Salman D , Siddiqui S , Monks P , Gaillard E A
Published: February 2022

Clinical assessment of children with asthma is problematic, and non-invasive biomarkers are needed urgently. Monitoring exhaled volatile organic compounds (VOCs) is an attractive alternative to invasive tests (blood and sputum) and may be used as frequently as required. Standardised reproducible breath-sampling is essential for exhaled-VOC analysis, and although the ReCIVA (Owlstone Medical Limited) breath-sampler was designed to satisfy this requirement, paediatric use was not in the original design brief. The efficacy of the ReCIVA at sampling breath from children has been studied, and 90 breath-samples from 64 children (5–15 years) with, and without asthma (controls), were collected with two different ReCIVA units. Seventy samples (77.8%) contained the specified 1 l of sampled-breath. Median sampling times were longer in children with acute asthma (770.2 s, range: 532.2–900.1 s) compared to stable asthma (690.6 s, range: 477.5–900.1 s; p = 0.01). The ReCIVA successfully detected operational faults, in 21 samples. A leak, caused by a poor fit of the face mask seal was the most common (15); the others were USB communication-faults (5); and, a single instance of a file-creation error. Paediatric breath-profiles were reliably monitored, however synchronisation of sampling to breathing-phases was sometimes lost, causing some breaths not to be sampled, and some to be sampled continuously. This occurred in 60 (66.7%) of the samples and was a source of variability. Importantly, multi-variate modelling of untargeted VOC analysis indicated the absence of significant batch effects for eight operational variables. The ReCIVA appears suitable for paediatric breath-sampling. Post-processing of breath-sample meta-data is recommended to assess the quality of sample-acquisition. Further, future studies should explore the effect of pump-synchronisation faults on recovered VOC profiles, and mask sizes to fit all ages will reduce the potential for leaks and importantly, provide higher levels of comfort to children with asthma.
Hybrid solar fish dryers as a solution for improving the quality of fisheries products to support green technology during the pandemic COVID-19
Authors: Risa M , Irawan A , Pratomo A , Khalid A , Fauzi Y R
Published: February 2022

The fishing communities in Sungai Rasau village, South Kalimantan, Indonesia, have several joint business groups that mostly process their fish catch into salted fish products and shrimp paste for sale in the market. The fish drying technique still uses traditional methods that rely on sunny weather, this is not effective because the weather is difficult to predict due to climate change globally. This means that high rainfall affects fish drying production activities. If left unchecked, this certainly results in a decrease in the quantity and quality of salted fish production and affects their income and welfare. To maintain and improve the quality of raw materials for fisheries production, the solution is the use of appropriate technology, namely making salted fish processing equipment or dryers that are energy efficient and not influenced by weather factors such as rain. Using this tool can improve the quality and quantity of production. The form of activity methods carried out includes (1) coordination with related parties to foster local fishing groups; (2) identifying problems and determining solutions; (3) solar fish dryer design; (4) making efficient technology fish dryers that effectively and efficiently utilize solar energy. At the time of implementation of the dryer, the measurement of water content using TDS obtained results that the water content of mackerel has been reduced to about 10%
Effect of time and temperature on vitamin c contents and antioxidant activity in the hot water extraction of melinjo peels
Authors: Apriliyanti MW , Ardiyansyah M , Febrianti W , Arum P , Jayus  , Sjaifullah A
Published: February 2022

Melinjo peel contains ascorbic acid, tocopherol, polyphenols and has the potential as a xanthine oxidase inhibitor. Melinjo peel also has the potential as an antioxidant naturally good for the body. The purpose of this studies to determine effect of variation of time and temperature extractions on antioxidant activity and vitamin C of melinjo peel. This study used a completely randomized design with two factors. firstly, 75 and 100°C for temperature and then secondary factors is different extraction times are 30, 45, and 60 minutes. The highest value of vitamin C content is 313,30 mg/L at 100°C for 60 minutes. Although, the highest value was 30,89% at 100oC for 30 minutes. Consequently, the best treatments at 100 °C and 30 minutes would be appropriate extraction operating conditions.
Increasing maize yield and farming benefit through integrated plant management in Madura Island East Java
Authors: Handayati W , Latifah E , Sugiono  , Subagio H , Sihombing D , Fitria R U
Published: February 2022

Maize is one of the primary plant cultivations on Madura Island and is usually cultivated by farmers with traditional technology and using open-pollinated local varieties. According to this condition, an experiment and a demo plot for local farmers were conducted in Larangan Slampar village Tlanakan District Pamekasan Regency. The experiment was arranged in randomized block design. The treatment was integrated plant management (IPM) using HJ21 and Bima14 hybrid and as control was conventional technology applying local Madura variety. The analyzed data indicated that IPM technology could increase plant yield and farming benefits. The highest harvest yield was shown by IPM1 with Bima 14 variety up to 6.35 ton ha-1, meanwhile existing technology (local Madura variety) only 1.22 ton ha-1 or the productivity was increased up to 422,40 %. The results of the farming analysis showed that benefit with IPM1 reached Rp 15,520,500 and B/C ratio 1,35; while existing technology only Rp 2,168,000 and B/C ratio of 0.55.
Determinants and strategies of social forestry development for integrated coffee agribusiness in the foot of mount Argopuro area, Jember regency
Authors: Djamali R A , Cahyaningrum D T , Putra D E
Published: February 2022

LMDH “Rengganis” Pakis Village, District, Jember Regency has received the Recognition and the Forestry Partnership (“KULIN-KK”) from the Ministry of Environment and Forestry, covering an area of ± 1,032.19 hectares. The forest land is cultivated by 536 families by planting robusta coffee. The research objective is to describe the determinants and strategies for developing an integrated coffee agribusiness area through the social forestry program. The methodology used is descriptive exploratory with an expert system approach. The analysis technique used is cognitive mapping analysis and hierarchy process analysis. Conclusions: (a) Five priority factors are the main determinants of coffee agribusiness development in social forestry programs, namely: legal certainty in forest use, dynamics and cooperation in forest village farme business groups, downstream processing of smallholder coffee products, shortening the trade system chain, support for facilities and infrastructure from the government; (b) Strategy for developing an integrated coffee agribusiness area based on priorities, namely (1) Objectives: developing an integrated coffee agribusiness area in a forest village; (2) Stakeholders, namely: forest farmers/members of LMDH, LMDH Management, LMDH Business Unit, Perhutani, Government, (2) Integrated Coffee Agribusiness Area Development Program: social engineering to increase cooperation in forest village farmer groups, engineering technology to increase coffee productivity, engineering technology downstream processing ofpeople’s coffee, economic engineering to design an efficient coffee marketing chain, development of integrated agro-tourism based on agribusiness and processing of products from social forestry programs, namely coffee and durian commodities.
Improvement of primary frequency modulation test method of renewable energy stations in North-west Power Grid
Authors: Bao Sijia , Li Chong , Qin Xiaodi , Liu Xin , Xu Haichao
Published: February 2022

In recent years, with the rapid development of renewable energy power generation, the operation and structure of the power grid are becoming more and more complex, the difficulty of power balance and frequency regulation is increasing. North-west Power Grid took the lead in carrying out renewable energy frequency modulation function transformation and performance test technology research in 2016, and developed a primary frequency modulation function test method for renewable energy stations in the North-west transmission-end large power grid. In this paper, by calculating and analyzing the response data of some renewable energy stations when Yindong HVDC is blocked, combined with the fast frequency response performance test results of a renewable energy station, this paper analyzes the shortcomings of the current fast frequency response function test methods of the renewable energy stations of the North-west Power Grid, and put forward suggestions for improvement to provide technical support for the promotion of the primary frequency modulation function of renewable energy stations in the northwest transmission power grid.
Integrated reservoir evaluation and simulation study for gas injection: a field case study
Authors: Yue Wenting , Yilin Wang John
Published: February 2022

The objective of this study was to better understand the target oil reservoir through ensemble Kalman filter-based production data analysis, and to optimize the enhanced oil recovery strategy of the reservoir. We first improved our understandings of the heterogeneous properties by combining single-well reservoir simulation model with Ensemble Kalman Filter (EnKF) method. The reservoir properties along with other available in-formation in the geological and simulation models such as production history and well logs were then integrated in one simulation model. We carried out parametric studies to investigate the influence of four production parameters. We also developed the optimized EOR strategy of the target field based on the ultimate oil recovery and economics. Compared with traditional production data analysis methods, the EnKF-assisted production data analysis model from this study proves to improve the reservoir characterization in an accurate and practical manner. The work improved the understandings of Smackover formation and similar analogous fields. The strategic evaluation of in the study, together with the EnKF-assisted PDA model can facilitate the readers in making informed decisions for successful EOR development of their mature fields.
Study of fine structures for the two-phase flow control in the PEMFC channel
Authors: Gao Qian , Yuan Shu , Zuo Tao , Hou Junbo
Published: February 2022

The flow field design is an important approach to improve water management in exchange membrane fuel cells (PEMFCs), so it has always been a hot topic of research. We find that adding fine structures in the channel can change the two-phase flow behavior, which may improve the distribution of liquid water and promote water removal. In our research, four types of fine structures in the channel are investigated: continuous grooves, continuous bosses, intermittent grooves and intermittent bosses. The results show that the continuous grooves guide the water flow along the sidewall and the intermittent grooves create a disturbance to the airflow. Accordingly, liquid water has a faster discharge rate in the channel with continuous grooves and a more uniform distribution in the channel with intermittent grooves, which contribute to the water management in the channel. The boss structures should be avoided because they occupy much flow space and the liquid water near the bosses is difficult to remove. This work provides a new idea of channel design and confirms the effectiveness of the fine structure in water management. In the future, we will conduct further research on the shape and size of fine structures to achieve greater improvements in the water management capabilities of the flow channel.
Developing a new transportation container for irradiation source
Authors: Zhuang Dajie , Li Guoqiang , Wang Renze , Sun Hongchao , Liu Hongyan
Published: February 2022

China Institute for Radiation Protection (CIRP) was commissioned the work of developing FCTC10 container. FCTC10 container is designed to transport 60Co special form radioactive sources used in irradiation industry. With a loading of 6.7×1015 Bq, the package is a Type B(U). The dynamic finite element analyses were performed. The structural integrity of the transport package was evaluated considering the hypothetical accident condition conditions include 9 m free drop on rigid surface (drop I). we considered several candidate drop postures, including top over-the-corner drop, side drop and top drop, which are known to cause the most severe damages to the packages of cylindrical shape in most cases. It is shown that the posture of top over-the-corner for 9 m free drop is the most damaging posture, and the posture is chosen as the best experiment program in the following physical experiment of real package. And also the simulation results of deformation of a whole or a part of the package play a guiding role in the optimal design and experiment of container.
A review about microwave regeneration technology of waste activated carbon
Authors: Yang Dong , Du Xin
Published: February 2022

Activated carbon (AC) can concentrate and transfer pollutants using its own adsorption capacity. Waste AC is a kind of solid waste, its adsorption capacity of pollutants is greatly reduced after adsorption saturation. If handled improperly, it will cause secondary pollution to the environment. Therefore, it is necessary to regenerate the waste AC to restore its adsorption performance and reduce environmental pollution and resource waste. Microwave regeneration technology is of great research value because of its low energy consumption, time saving and high efficiency. Based on the characteristics of microwave heating and regeneration mechanism, this paper summarizes the advantages of microwave regeneration compared with conventional heating regeneration, and the application status of microwave technology in the regeneration of waste AC was reviewed. The influence of different types of pollutants adsorbed by AC, the change of control conditions for microwave regeneration of AC and the characteristics of AC itself on microwave regeneration were briefly described. And the development direction of microwave regeneration of AC in the future is also prospected.
Safety verification tests of low and intermediate level radioactive solid waste drum
Authors: Sun Shutang , Hong Zhe , Zhuang Dajie , Sun Hongchao , Yan Feng , Wang Xuexin , Chen Lei
Published: February 2022

Steel drums or boxes are used to transport, store, and dispose of low- and intermediate-level waste. According to relevant standards, before the solid waste container design is finalized, a series of type tests should be performed, including leakage test, water spray test, stacking test, penetration test, free-drop test, etc. This article focuses on the acceptance test and test methods for the LID- II b type waste drum finalization test. The tests in accordance with the standard requirements are the first time reported in China. It found the inherent design defects, and had high guiding significance to improve design and test verification operation.
Benchmark of different aerodynamic solvers on wing aero-propulsive interactions
Authors: Ciliberti Danilo , Benard Emmanuel , Nicolosi Fabrizio
Published: February 2022

Distributed electric propulsion is a fertile research topic aiming to increase the wing aerodynamic efficiency by distributing the thrust over the wing span. The blowing due to distributed propulsors shall increase the wing lift coefficient for a given planform area and flight speed. This should bring several advantages as wing area, drag, and structural weight reduction, which in turn reduce fuel consumption, allowing airplanes to fly more efficiently. However, there are no consolidated preliminary design methods to size a distributed propulsion system. Numerical analysis is then performed at early stage, where many design variables have not been fixed yet. Therefore, the design space is vast and exploring all the possible combinations is unfeasible. For instance, low-fidelity methods (VLM, panel codes) have a low computational time, but usually they do not account for flow separation and hence they are unable to predict the wing maximum lift. Conversely, high-fidelity codes (CFD) provide more realistic results, but a single drag polar sweep can last days. This work provides a benchmark of different aerodynamic solvers for a typical regional turboprop wing with flaps and distributed propulsion, to better understand the limits of each software in the prediction of aero-propulsive effects.
Design challenges of cryogenic regional turboprop aerodynamic layout
Authors: Chernavskih Yu N , Chernousov V I , Krutov A A , Perchenkov E S , Pigusov E A
Published: February 2022

This paper is discussed the results of study on aerodynamic layout of the cryogenic regional turboprop with a low level of environmental impact. The use of cryogenic fuel (liquid hydrogen, liquefied natural gas) in aircraft will radically reduce harmful emissions into the atmosphere, as well as reduce fuel consumption. But the introduction of cryogenic fuel on transport category aircraft requires solving the problems of its storage on board. A modification of a regional twin-engine turboprop for operation on cryogenic fuel is considered. The problems and features of the placement of the fuel tank for cryogenic fuel are shown. The results of experimental studies of the aerodynamics of an aircraft model with a cryogenic tank and the results of the calculation of flight performance with various types of fuel are presented.
Dynamic sector characterisation model with the application of machine learning techniques
Authors: Pérez Moreno F , Gómez Comendador V F , Jurado R Delgado-Aguilera , Suárez M Zamarreño , Janisch D , Arnaldo Valdés R M
Published: February 2022

The ATC service has the objective of controlling airspace operations safely and efficiently. This control is becoming more and more difficult due to the increasing complexity of airspace. With the objective of collaborating and facilitating the provision of the control service, FLUJOS project aims to develop a methodology to characterise ATC sectors according to their complexity. This paper shows the first results obtained in this project. A methodology is proposed that first performs a statistical analysis of the data present in the flight plans of individual aircraft. The statistical analysis will be used to estimate the impact of air traffic flows. With this, the complexity of ATC sectors will finally be determined. In addition, a machine learning tool will be added to develop a dynamic methodology. After evaluating the methodology with data from Spanish airspace in 2019, it can be said that the results obtained are logical from an operational point of view, and that they allow a fairly accurate classification of the sectors based on their complexity. However, the proposed methodology is still a preliminary version, so more work will have to be done to add variables to achieve the objective of obtaining an even more accurate and realistic classification.
Machine Learning classification techniques applied to static air traffic conflict detection
Authors: Pérez-Castán Javier A. , Pérez-Sanz L. , Bowen-Varela J. , Serrano-Mira L. , Radisic Tomislav , Feuerle Thomas
Published: February 2022

This article evaluates Machine Learning (ML) classification techniques applied to air-traffic conflict detection. The methodology develops a static approach in which the conflict prediction is performed when an aircraft pierces into the airspace. Conflict detection does not evaluate separation infringements but a Situation of Interest (SI). An aircraft pair constitutes a SI when it is expected to get with a horizontal separation between both aircraft closer than 10 Nautical Miles (NM) and a vertical separation closer than 1000 feet (ft). Therefore, the ML predictor classifies aircraft pairs between SI or No SI pairs. Air traffic information is extracted from The OpenSky Network that provides ADS-B trajectories. ADS-B trajectories do not offer enough SI samples to be evaluated. Hence, the authors performed simulations varying the entry time of the trajectories to the airspace within the same time period. The methodology was applied to a portion of Switzerland airspace, and simulations reached a 5% rate of SI samples. Cost-sensitive techniques were used to handle the strong imbalance of the database. Two experiments were performed: the Pure model considered the whole database, and the Hybrid model considered aircraft pairs that intersect horizontally closer than 20 NM and vertically lower than 1000 ft. The Hybrid model provided the best results achieving 72% recall, representing the success rate of Missed alerts and 82% accuracy, which means the whole predictions’ success rate.
Implementation of genetic algorithms for supersonic airfoil optimization
Authors: Michelotti A , Cavini A , Giacopino R , Misino F , Piottoli L
Published: February 2022

This paper describes the exploitation of Genetic Algorithms for the selection and optimization of supersonic airfoils. The main objective of the optimization is to ensure the possibility to reach the maximum efficiency at a given lift coefficient. The surrogate model presented in this paper implements the shock-expansion theory, and the optimization problem is constrained with respect to three design variables, since Bézier curves are used for the parameterization of the Diamond-Shaped and the 40-elements Double Circular Arc airfoil geometries. The airfoils were optimized for three different Mach numbers and two different lift coefficients. A thickness-constrained optimization has been run to evaluate the possibility to obtain a specific lift coefficient at a given Mach number and to understand how this parameter influences the optimized airfoil shape performance in terms of efficiency and the range of feasible angles-of-attack. An off-design evaluation is also presented, allowing for a comparison of the optimized geometries in terms of versatility. High fidelity models were validated with RAE 2822 airfoil using STAR CCM+, and they were compared to the surrogated model to ensure higher quality in the results. In conclusion, the Genetics Algorithms optimization coupled with the shock-expansion theory model results to be a fast and valuable solution to select and optimize airfoil solutions. The application of this approach has shown that a 20% reduction in airfoil thickness leads to a 25% efficiency improvement, while widening the range of viable angles of attack.
Reduction of the environmental impact of aviation via optimisation of aircraft size/range and flight network
Authors: Rötger T , Casas G , Çelikel A , Dörries H , Lim L , Owen B , van Velzen A , Linke F , Lührs B , Lutz M , Radhakrishnan K
Published: February 2022

REIVON is a Clean Sky 2 Technology Evaluator project that investigates to what extent CO2 emissions of global aviation can be reduced via optimisation of aircraft size/range and flight network. Three alternative global flight networks are created, considering (1) splitting long-haul flights into shorter legs (intermediate stop operations, ISO), (2) reducing frequency to the necessary minimum on busy routes using larger aircraft, and (3) a combination of 1 and 2. In all cases, the use of aircraft optimised for specific combinations of range and seating capacity not existing today will be considered. For the first time, REIVON will carry out a holistic analysis of the impact of an optimised flight network on global air transport system stakeholders, such as passengers, aircraft manufacturers, airlines and airports, and of potential measures to support the implementation of such an alternative network.
Far-field pressure measurements of elliptic jets discharged close to a wing
Authors: Proença A. R. , Lawrence J. L. T.
Published: February 2022

This paper presents a preliminary experimental investigation into the acoustics of two elliptical jet nozzles installed close to a wing model. Acoustic pressure data is obtained for a range of observer polar angles mounted in the far field of the jets. Three nominal jet Mach numbers, namely 0.4, 0.6 and 0.8 are studied. Results suggest that the elliptic jets surveyed provide a noise reduction of the jet-surface installation noise source. The noise reduction is maximum in the forward arc and in the order of 1 dB for the fully-corrected overall sound pressure level data. Additionally, the noise benefit exists only when the minor axis of the elliptical nozzle is mounted parallel to the wing trailing edge. It is hypothesised that the reduction in the jet plume cross-section width limits the scattering of the near pressure field by the wing trailing edge to a lower frequency range. The jet mixing noise source, however, is seen to increase with decreasing nozzle exit-plane aspect ratio. The three jet velocities surveyed suggest the consistency of the key results discussed in the paper. Investigation of the jet turbulent flow structures and jet near pressure field is under way.
Performance evaluation of jet fuel production by hydrothermal liquefaction in Europe
Authors: Penke C , Özal G , Bellot F , Moser L , Batteiger V
Published: February 2022

The EU Horizon 2020 project HyFlexFuel successfully demonstrated hydrothermal liquefaction (HTL) fuel production chains from different feedstock types to upgraded kerosene products. Now the question arises which commercial scale HTL system design is associated with the lowest environmental impact and production costs. The contribution addresses this research question by establishing a comprehensive process model for different feedstock types (sewage sludge, straw, miscanthus and microalgae) based on experimental biocrude production and upgrading campaigns in pilot and laboratory scale. This model enables evaluating different process configurations and serves as basis for subsequent system analyses by applying techno-economic and life cycle analyses (TEA and LCA). Upgraded biocrude using sewage sludge, representing a waste stream in wastewater management, can be produced at near-competitive price levels. Compared to conventional jet fuel production, greenhouse gases are reduced significantly. However, sewage sludge is a limited resource and only limited amounts of jet fuel could be substituted. Lignocellulosic feedstock such as straw or miscanthus are available in larger quantities and provide the opportunity to produce large amounts of sustainable aviation fuels at moderate costs.
Application of Probabilistic principles to Set-Based Design for the optimisation of a hybrid-electric propulsion system
Authors: Spinelli Andrea , Anderson Luchien , Enalou Hossein Balaghi , Zaghari Bahareh , Kipouros Timoleon , Laskaridis Panagiotis
Published: February 2022

Current research in hybrid-electric aircraft propulsion has outlined the increased complexity in design when compared with traditional propulsion. However, current design methodologies rely on aircraft-level analysis and do not include the consideration of the impact of new technologies and their uncertainty. This can be a key factor for the development of future hybrid-electric propulsion systems. In this paper, we present a methodology for exploring the design space using the principles of Set-Based Design, which incorporates probabilistic assessment of requirements and multidisciplinary optimisation with uncertainty. The framework can explore every design parameter combination using a provided performance model of the system under design and evaluate the probability of satisfying a minimum required figure of merit. This process allows to quickly discard configurations incapable of meeting the goals of the optimiser. A multidisciplinary optimiser then is used to obtain the best points in each surviving configuration, together with their uncertainty. This information is used to discard undesirable configurations and build a set of Pareto optimal solutions. We demonstrate an early implementation of the framework for the design of a parallel hybrid-electric propulsion system for a regional aircraft of 50 seats. We achieve a considerable reduction to the required function evaluations and optimisation run time by avoiding the ineffective areas of the design space but at the same time maintaining the optimality potential of the selected sets of design solutions.
Design of near-zero emission aircraft based on refined aerodynamic model and structural analysis
Authors: Memmolo V , Orefice F , Nicolosi F , Ricci F.
Published: February 2022

During recent years, aircraft manufacturers focused their attention on environmentally friendly and aerodynamically efficient aircraft concepts that could allow a radical reduction of emissions. The use of hybrid-electric powertrain is one of the most effective ways to design near-zero emission aircraft. These aircraft are highly performing and sophisticated. Hence, the design process must be extremely accurate and should make use of multidisciplinary design optimization. It is indeed crucial to establish both aerodynamic and structural models to simulate the aircraft performance and design required according to top level aircraft requirements. Despite the largely discussed literature about preliminary design of such an unconventional aircraft, there is still a lack of reliable weight estimation approaches, simulation-based mission analysis and optimization tools. In order to step towards higher technological readiness levels, the purpose of this paper is to describe and apply a design platform for conventional, turboelectric, hybrid-electric and full-electric aircraft, integrating aero-propulsive interactions, accurate power system modelling and medium-fidelity structural weight estimation. In particular, the comprehensive structural analysis of the aircraft wing opportunely designed according to certification specification and equipped with different powertrain architectures shows that it is worth looking into structural dynamics from preliminary design to estimate aircraft weight properly. Meanwhile, the mission analysis reveals performance benefits by implementing distributed engines all over the wingspan.
First Principle Model of an Electric ECS Pack
Authors: Eschenbacher P W , Zimmer D , Weber N
Published: February 2022

Fully electric environmental control systems for aircraft are designed but currently rarely implemented. Simulation models of such systems in the early design phase have shown a lot of challenges: high electric power demand, complex architecture, difficult design of control strategies and difficult sizing.

In order to explore what performance figures are physically possible, a first principle model has been developed on the basis of purely thermodynamic considerations. Similar to a Carnot thermal engine, which tells what efficiency is reachable, the first principle model of an ECS can serve as a reference system which tells the minimum amount of electric power needed to fulfil the thermal requirements. Different to a specific technical design, this allows for more general conclusions.