Conceptual Design and Comparative Study of Strut-Braced Wing and Twin-Fuselage Aircraft Configurations with Ultra-High Aspect Ratio Wings

Sustainable and fuel-efficient next-generation air transportation demands a step change in aircraft performance. The ultra-high aspect ratio wings (UHARW) configuration is one key enabling strategy for improving aircraft aerodynamic efficiency and reducing fuel consumption and emissions. Unconventional aircraft configurations and novel airframe technologies are required to address the large bending moment, and shear stresses in the UHARW structure. This paper considers two promising unconventional configurations suitable for adopting UHARW design, including strut-braced-wing (SBW) and twin-fuselage (TF), equipped with novel airframe technologies, i.e., active flow control, active load alleviation, and novel airframe structures and materials. Three typical missions, including short-range (SR), medium-range (MR), and long-range (LR), are considered for aircraft design. A conceptual design and performance analysis framework for the SBW and TF configurations with novel airframe technologies is developed in this paper by integrating and improving several methods and tools. According to the mission profile and top-level requirements proposed for each mission, an SBW and a TF configuration are designed for each class of aircraft. A comparative study is carried out to determine the best-in-class configuration of the corresponding mission. The results showed that the TF configuration has a better wing weight reduction effect than the SBW configuration, and the MR-TF and LR-TF aircraft have lower takeoff weight and fuel weight than the SBW aircraft for the same mission. However, due to the adjustment of the dimensions for the cabin arrangement of the SR-TF aircraft, the SBW configuration outperforms the TF configuration in this mission

Aerostructural optimization and comparative study of twin-fuselage and strut-braced-wing aircraft configurations

This is an accepted manuscript of an article published by American Institute of Aeronautics and Astronautics in Journal of Aircraft on 09/12/2023, available online: https://doi.org/10.2514/1.C037388 The accepted version of the publication may differ from the final published version.The ultrahigh-aspect-ratio wing (UHARW) concept is a promising configuration to achieve future sustainable aviation goals. Twin-fuselage (TF) and strut-braced-wing (SBW) configurations are characterized by smaller structural bending moments and shear forces in the wing and are promising concepts for realizing UHARW designs. This paper addresses the aerostructural optimization problem of TF and SBW configurations with UHARW by using a coupled adjoint aerostructural optimization tool, which is composed of a geometrically nonlinear structural solver and a quasi-three-dimensional natural laminar flow (NLF) aerodynamic solver. The optimization results show significant improvements in fuel efficiency and performance for the TF and SBW aircraft, with fuel mass reductions of 13 and 10%, respectively, compared to the corresponding baseline aircraft designed in the conceptual design phase. In comparison to the original reference aircraft A320neo, the optimized TF and SBW have 48 and 31% lower fuel weights, respectively. The NLF range of both upper and lower wing surfaces is expanded during optimization. The optimized SBW configuration has a wing aspect ratio of 26.01, while the optimized TF has a wing aspect ratio of 20.74, indicating that the SBW concept is more conducive to realizing UHARW design compared with the TF configuration studied in this work. The optimized TF aircraft has a lighter fuel weight and gross weight compared to the optimized SBW aircraft, which is because the TF aircraft has a lighter operational empty weight, including a lighter fuselage structural weight, landing gear weight, etc., whereas the top-level aircraft requirements are the same for both aircraft, including range, payload, and cruise Mach.Published onlin

(Li0.84Fe0.16)OHFe0.98Se superconductor: Ion-exchange synthesis of large single crystal and highly two-dimensional electron properties

A large and high-quality single crystal (Li0.84Fe0.16)OHFe0.98Se, the optimal superconductor of newly reported (Li1-xFex)OHFe1-ySe system, has been successfully synthesized via a hydrothermal ion-exchange technique. The superconducting transition temperature (Tc) of 42 K is determined by magnetic susceptibility and electric resistivity measurements, and the zero-temperature upper critical magnetic fields are evaluated as 79 and 313 Tesla for the field along the c-axis and the ab-plane, respectively. The ratio of out-of-plane to in-plane electric resistivity,\r{ho}c/\r{ho}ab, is found to increases with decreasing temperature and to reach a high value of 2500 at 50 K, with an evident kink occurring at a characteristic temperature T*=120 K. The negative in-plane Hall coefficient indicates that electron carriers dominate in the charge transport, and the hole contribution is significantly reduced as the temperature is lowered to approach T*. From T* down to Tc, we observe the linear temperature dependences of the in-plane electric resistivity and the magnetic susceptibility for the FeSe layers. Our findings thus reveal that the normal state of (Li0.84Fe0.16)OHFe0.98Se becomes highly two-dimensional and anomalous prior to the superconducting transition, providing a new insight into the mechanism of high-Tc superconductivity.Comment: 11 pages, 4 figures, supplementary information is not uploade

DeepSeek LLM: Scaling Open-Source Language Models with Longtermism

The rapid development of open-source large language models (LLMs) has been truly remarkable. However, the scaling law described in previous literature presents varying conclusions, which casts a dark cloud over scaling LLMs. We delve into the study of scaling laws and present our distinctive findings that facilitate scaling of large scale models in two commonly used open-source configurations, 7B and 67B. Guided by the scaling laws, we introduce DeepSeek LLM, a project dedicated to advancing open-source language models with a long-term perspective. To support the pre-training phase, we have developed a dataset that currently consists of 2 trillion tokens and is continuously expanding. We further conduct supervised fine-tuning (SFT) and Direct Preference Optimization (DPO) on DeepSeek LLM Base models, resulting in the creation of DeepSeek Chat models. Our evaluation results demonstrate that DeepSeek LLM 67B surpasses LLaMA-2 70B on various benchmarks, particularly in the domains of code, mathematics, and reasoning. Furthermore, open-ended evaluations reveal that DeepSeek LLM 67B Chat exhibits superior performance compared to GPT-3.5

The effects of polystyrene microplastics on human intestinal cells health and function

Recent studies have shown that microplastics (MP) have been detected in drinking water and drinking water resources. Their presence has raised significant public health concerns since oral exposure to MP may be more common than expected, yet our understanding of the potential adversarial effects of ingested MP is far from complete. While in vivo experiments have shown clues of weight loss, reduced feeding behaviour, and change of gene expression associated with glucose/lipid metabolism, direct evidence of digested MPs affecting nutrient uptake at the cellular level remains scant. In addition, previous research mostly used pristine MPs and cancer cell models, neglecting the biotransformation of MPs in the digestive system and the dissimilar metabolism of normal cells. Therefore, this study aims to perform a comprehensive evaluation of the effects of polystyrene MPs on human and cancer intestine cells. It is hypothesized that MPs may negatively impact cellular health and functions such as nutrient uptake. Polystyrene MPs of 0.1, 1 and 10 μm was used as the model MPs in our studies. To better appreciate the bio-accessibility of MPs, an in vitro digestive method was developed to simulate the physiological digestion process as the MPs passage through the gastrointestinal tract (GIT). Our study revealed several major findings. First, it was found that the digested MPs (D-MPs) underwent considerable biotransformation such as the formation of protein corona and larger hydrodynamic size as compared to the undigested pristine MPs. Correspondingly, using particokinetics analysis, D-MPs was found to sediment much faster (the deposited fraction of 0.1 μm and 1 μm D-MPs was 6.7 and 1.2-fold of P-MPs after 48 h, respectively). Amongst the different types and sizes of MPs screened, the 0.1 μm D-MPs displayed higher tendency to form agglomerates than 1 μm D-MPs. Furthermore, several in vitro comparative studies were also performed to examine the MPs' acute and sub-chronic biological effects using the NCM460 (normal) and Caco-2 (cancer) cells. Our findings revealed a complex interplay between the physiochemical properties of MPs and pathological states of the cells in determining the biological outcomes.Master of Engineerin

Next steps in aerostructural design of ultra-high aspect ratio wings

This paper presents the authors’ research work on the aerostructural design of Ultra-High Aspect-ratio Wings (UHARW). Firstly, aircraft configurations suitable for UHARW, especially unconventional configurations, are introduced and discussed. Then the aircraft conceptual design and analysis framework developed for the unconventional UHARW aircraft is described. The UHARW of the conceptually designed Strut-Braced Wing (SBW) and twin-fuselage aircraft are further investigated by employing a series of nonlinear aerostructural optimization methods, including the influences of aileron design and flutter constraint on the ultra-high aspect-ratio SBW design

Comprehensive approach for aerostructural optimisation of ultra-high aspect ratio wings

This paper presents a comprehensive study on the aerostructural design of Strut-braced Wing (SBW) aircraft featuring Ultra-High Aspect Ratio Wings (UHARW). A medium-fidelity, coupled adjoint aerostructural optimisation method was introduced and applied to investigate various aspects of SBW aircraft optimisation. The research encompasses a series of studies that consider geometric nonlinearities, flow transition, aileron effectiveness and flutter constraints, specifically focusing on medium-range SBW aircraft. The paper presents the optimisation results and provides preliminary insights into the aerostructural characteristics of SBW aircraft featuring UHARW designs

The Substitution Effect of Chinese Anti-Corruption “Alcohol Ban”

Over the past decade, China has intensified its anti-corruption efforts. On 21 December 2012, “Alcohol Consumption Prohibition at Military Functions” was announced, which made the consumption of high-end Chinese Baijiu decline. We apply principal-agent theory to analyze the potential substitution effect, and then, we apply the difference in difference model and event study method to test the substitution effect between Baijiu and foreign alcohol by using macro- and micro-data. The results indicate that, in response to the “Alcohol Ban”, the Chinese consume more imported wine and more expensive foreign spirits. What is more, the CARs of high-end alcohol companies listed on the U.S. stock market significantly increase. We conclude that there exist substitution effects after the “Alcohol Ban”, which is necessary for the government to comprehensively investigate when formulating policies, because it may partially weaken the effectiveness of the policy

The Substitution Effect of Chinese Anti-Corruption “Alcohol Ban”

Over the past decade, China has intensified its anti-corruption efforts. On 21 December 2012, “Alcohol Consumption Prohibition at Military Functions” was announced, which made the consumption of high-end Chinese Baijiu decline. We apply principal-agent theory to analyze the potential substitution effect, and then, we apply the difference in difference model and event study method to test the substitution effect between Baijiu and foreign alcohol by using macro- and micro-data. The results indicate that, in response to the “Alcohol Ban”, the Chinese consume more imported wine and more expensive foreign spirits. What is more, the CARs of high-end alcohol companies listed on the U.S. stock market significantly increase. We conclude that there exist substitution effects after the “Alcohol Ban”, which is necessary for the government to comprehensively investigate when formulating policies, because it may partially weaken the effectiveness of the policy