Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

The Influence of Climate Change and Variability on Aircraft Take-off and Landing Performance;a Case Study of the Abeid Amani Karume International Airport-Zanzibar

Climate change (CC) and variability have been world widely reported to pose number of risks in aviation industry including accidents, astray, and other operational difficulties. The impact of weather on landing and take-off performances has been several times experienced at Abeid Amani Karume International Airport (AAKIA);however, the influence of climate change and variability to the aircraft performance needs to be assessed. Thus, this study investigated the influence of climate change and variability on aircrafts take-off and landing performances. Specifically, the study investigated;i) the influence of climate change on Take-off Distance Required (TODR) and Maximum Take-off Mass (MTOM) for different types of aircraft;ii) the influence of climate variability to the aircraft landing performance on light, medium and heavy aircraft and lastly, iii) the study investigated the seasonal and annual variability on aircraft landing performance due to climate variability. The datasets used in this study include the eight years (2014-2021), aircraft operational records (diversion and missed approach events) and Aviation Routine Weather Reports (METAR) records which were utilized as the indicators for landing performance, the long-term (1990-2020) annual maximum temperatures (Tmax) which was used to determine the TODR and MTOM. Statistical tools including mean, percentage changes, correlations, regression, and the chi-square test were used for analysis and hypotheses testing. The results revealed that light and medium aircraft categories were significantly most affected on diversion events as compared to the heavy categories;however, for the missed approach events the impact was vice versa. Moreover, the seasonal and annual variability on diversion and missed approach events were significantly different (at p ≤ 0.001). As for the take-off performance, results show that the TODR and MTOM were significantly increasing and decreasing (at p ≤ 0.001), based on increasing air temperatures. Therefore, the study concludes that the changing climate has significantly affected aircraft by increasing the TODR and decreasing the MTOM, while the climate variability has significantly affected landing performance by influencing the diversion and missed approach events. Thus, the study recommends (i) further research works including the feasibility study on runway extension for the safety of future aircraft operations at the AAKIA and (ii) proper maintenance and improvement of the Instrumental Landing Systems (ILS) as an adaptation measures to the landing aircraft during bad weather events.

一种高性能CMOS电流模Winner-take-all电路

提出了一种新颖的CMOS电流模Winner-take-all(WTA)电路.该电路利用可再生比较器提高了电路的解析度和速度,没有使用电流镜,而是利用整流电路输出电流,从而改善了电路的精确度,不同于传统的树型WTA电路.还提出了一种新的并行N输入WTA结构.在TSMC 0.18μm CMOS工艺下设计了一个8输入WTA电路,并与已有的WTA电路进行了比较.仿真结果表明,该电路可以达到1nA的解析度和99.99%的精确度,同时面积小,功耗低,非常适合于各种嵌入式智能应用.

“have a V-inf”及“take a V-inf”结构的句法与语义分析

在英语语言中 ,人们可以说 :“Letmehaveatry !” ,却不可以说 :“Letmetakeatry !” ;可以说 :“Hetookalookatherphoto.”却不可以说 :“Hetookalistentotheradio.”有的语言学家认为这类结构是英语语言中的奇特现象 ;而另有一些学者又将其归属于习惯用法。然而 ,经对大量的英语语言事实进行观察和研究后 ,文章认为这类结构是有规律可循的 ,并从句法和语义的角度分析了这类结构的内部机制 ,深入浅出地阐述了这类结构的有关特性。

基于语料库的动词搭配习得研究——以动词‘Take’的惯用搭配为例

相关研究表明中国英语学习者英语习得的较大缺陷在于程式化语言的严重缺乏,从而大大影响了语言习得的效率。通过大型书面语料或是语料群之间的比较,发现母语使用者和中国英语学习者在动词惯用搭配使用上存在差别,从中国英语课堂教学和使用的教材上可以探讨存在差异的可能原因。语料比较发现:中国高级英语学习者在动词惯用搭配使用上与母语使用者没有显著差别,但课堂教学和教材在动词惯用搭配的出现频次上却存在严重不足。这一结果支持了深层次的词汇知识学习可能依靠通过大量阅读的附带习得,而不是完全依赖于有意识指导。

Analysis of the Heroine's Mental Growth in I'll Take You There

This thesis makes an analysis of the heroine's mental growth from the initial phase of the heroine's mental trauma to the struggling phase and to the mature phase. It analyzes the reasons and manifestations for her mental solitariness,expounds her confusion and struggling during her growth from the perspective of psychoanalysis and reveals her mental maturity in the end after a series of setbacks and conflicts during pursuit of affection,friendship and kinship. In some senses,the heroine's mental growth displayed in this thesis is the psychological portrayal of some contemporary college students,which has certain educational significance to the student readers especially those who possess the similar life experience and accesses them to have an incisive understanding of real life.

结合Winner-Take-All的足球机器人控制策略研究

在足球机器人运动过程中,足球机器人处于一个实时对抗的复杂环境中,这就需要机器人有较高的实时运动过程应对能力。需要对每个关键时刻,例如:多机器人抢球过程、单机器人控球过程等,做出合理的应对措施。许多策略的研究都只注重单机器人控球过程的路径规划,没有考虑到多机器人竞争的过程,导致足球机器人整个运动过程中的一些关键步骤的缺失,丧失了完整性,忽略了实时的对抗性。拟采用新的策略解决上述问题:第一步是将采用WTA(Winner Take All)竞争模型去有效的解决多机器人竞争问题;第二步将采用一种改进的APF(Artificial Potential Field)路径规划法来进行避障。解决了传统APF算法的弊端,提高了效率。通过仿真实验,验证了理论的正确性,也验证了所提理论的科学性和实用性,为以后在其他科学领域的实践奠定了基础。

Capture Performance of A Multi-Freedom Wave Energy Converter with Different Power Take-off Systems

Among the wave energy converters (WECs), oscillating buoy is a promising type for wave energy development in offshore area. Conventional single-freedom oscillating buoy WECs with linear power take-off (PTO) system are less efficient under off-resonance conditions and have a narrow power capture bandwidth. Thus, a multi-freedom WEC with a nonlinear PTO system is proposed. This study examines a multi-freedom WEC with 3 degrees of freedom: surge, heave and pitch. Three different PTO systems (velocity-square, snap through, and constant PTO systems) and a traditional linear PTO system are applied to the WEC. A time-domain model is established using linear potential theory and Cummins equation. The kinematic equation is numerically calculated with the fourth-order Runge–Kutta method. The optimal average output power of the PTO systems in all degrees of freedom are obtained and compared. Other parameters of snap through PTO are also discussed in detail. Results show that according to the power capture performance, the order of the PTO systems from the best to worst is snap through PTO, constant PTO, linear PTO and velocity-square PTO. The resonant frequency of the WEC can be adjusted to the incident wave frequency by choosing specific parameters of the snap through PTO. Adding more DOFs can make the WEC get a better power performance in more wave frequencies. Both the above two methods can raise the WEC’s power capture performance significantly.

A Synchronous Electronic Let-off and Take-up Device

A synchronous electronic let-off and take-up device isdesigned.The device is controlled by a single-chipcomputer and driven by two step motors.It has somefunctions such as keeping the warp tension constant dur-ing the weaving instant,releasing the warp tension whenloom is stopping and straining warp when loom is start-ing.By means of these functions,the stop mark of thewoven fabrics is eliminated.In addition,this device canapply to weaving variant-pick-density fabrics.

Problems and Barriers Impeding the Implementation of MagLev Assisted Aircraft Take-Off and Landing Concept

Nowadays, the success of the new technology development and deployment process depends not only on technical, technological solutions, but also on solving the non-technological problems and crossing the societal and psychological barriers. A large international European projects, GABRIEL1 had developed a maglev assisted aircraft take-off and landing, that was applied to conceptual design of aircraft and required on-board and ground systems, had analysed all impacts (effects of concept deployment on effectiveness, safety, security, noise, emissions) and had demonstrated the safe applicability by concept validation. The applied methodology, used methods and the results of the Gabriel projects had been described and discussed by 55 project deliverables. This paper has a special goal: investigating the problems and barriers of possible implementing of the radically new technology, aircraft MagLev assisted take-off and landing. The study was started by identification and classification of the problems and barriers. After it, the problems were systematically analysed by use of special methodology containing the understanding (description) of the problems, investigation of the possible solutions and discussing their applicability (mainly by use of the Gabriel project results). The paper has three major sections: 1) description of the Gabriel concept and project results, 2) introducing some related thoughts on general aspects of new technology developments, and 3) discussion on the problems and their solutions. The major classes of the problems are the 1) technical, technological problems as developing a radically new solution, landing the undercarriage-less aircraft on the magnetic tracks, 2) stakeholders’ problems as decision makers kicking against supporting the developments of so radically new technologies and 3) society barriers like society worrying on and fear of future passengers on flying by aircraft have not conventional undercarriage systems. The paper will show that these problems have safe and cost-effective solutions.

一种改进的winner-take-all模型及在图像中的应用

作为一种广泛存在于各个领域的竞争现象,关于赢者通吃(winner-take-all)的大部分研究太复杂以至于难以很好地理解该现象。为了用简单的方式解释winner-take-all现象,提出了一个改进的winner-take-all模型,由离散时间差分方程表示,该模型的状态空间是一个矩阵并且模型具有多范数可选性,对应的初始输入矩阵中具有最大输入值的元素最终获胜。对提出模型的收敛性和稳定性进行了严格的理论分析,并将该赢者通吃模型应用于图像处理的实验中,分别比较了单层和多层赢家通吃模型的效率。实验正确地生成了winner-take-all现象,表现了多层winner-take-all图像处理的高性能,理论和实验都验证了所提出模型的正确性和有效性。

英语动词take与名词的搭配

take是个非常活跃的动词,它与各类名词连用构成意义各异的短语、成语、俗语或俚语。本文对take与名词的搭配能力、构成形式和表达语义等方面进行探讨。

Measurement and Analysis of a Take-down Mechanism of Eccentric Links

In this paper the rule of take-down speed variationthrough a mechanism of eccentric links is analysed.Us-ing telemetric technique,the authors dynamicly mea-sured take-down speed and tension of this mechanism.The curve diagram of the take-down speed is experi-mentally obtained.Results of theoretical analysis and ex-perimental measurement show that take-down tensionof this kind of mechanism is more even than that of theoblique rings in model Z214 interlock machine and it isdeeply affected by many factors which include the instal-lation of the conic gear,horizontality of the take-downroller,gaps between hinge joint points of the wholemechanism and so on.

Research of Power Take-off System for “Sharp Eagle Ⅱ” Wave Energy Converter

The " Sharp Eagle” device is a wave energy converter of a hinged double floating body. The wave-absorbing floating body hinges on the semi-submerged floating body structure. Under the action of wave, the wave-absorbing floating body rotates around the hinge point, and the wave energy can be converted into kinetic energy. In this paper, the power take-off system of " Sharp Eagle Ⅱ” wave energy converter (the second generation of " Sharp Eagle”) was studied, which adopts the hydraulic type power take-off system. The 0-1 power generation mode was applied in this system to make the " Sharp Eagle Ⅱ” operate under various wave conditions. The principle of power generation was introduced in detail, and the power take-off system was simulated. Three groups of different movement period inputs were used to simulate three kinds of wave conditions, and the simulation results were obtained under three different working conditions. In addition, the prototype of " Sharp Eagle Ⅱ” wave energy converter was tested on land and in real sea conditions. The experimental data have been collected, and the experimental data and simulation results were compared and validated. This work has laid a foundation for the design and application of the following " Sharp Eagle” series of devices.

A Simple Approach Assessing the Vegetable Content of Asian Takeout Meals with Nutrition Education Potential

A demand for convenient eating options has led to an increase in foods eaten away from home, and consumers are looking for healthy options when they eat out. Increasing vegetable consumption is a key public health nutrition prior-ity. Although Asian menu items are considered a healthy option, there is little information about their relative health-fulness. This study aims to pilot a simple method for measuring the vegetable content of popular Asian dishes for use in nutrition education. Thirty vegetable containing take-out dishes from three Asian restaurants (Chinese, Thai and Singaporean) in Perth, Western Australia were photographed and weighted with, and without the vegetables. Standard 75 gram vegetable servings per dish and the average vegetable content between cuisines were compared. The mean vegetables servings per dish was 1.8 (0.25 to 5.5) with no statistical difference between cuisines (p > 0.05). The variety and amount of vegetables in individual dishes varied within each cuisine. Vegetarian dishes had the highest vegetable content and noodle and rice dishes the lowest (0.23 - 0.75 servings/dish). Digital imagery clearly, simply and quickly displayed the vegetable content of Asian dishes. The Asian take-out dishes were low in vegetables. Nutrition educators should encourage Asian food businesses to increase the vegetable content of their menus and advise customers to choose at least one vegetarian dish.

Household Disposal and Recycling of Medication in Saudi Arabia: A Call for Introducing Drug Take-Back Programs

Background: Inappropriate disposal practices of medicinal products by households can harm nature. Alternatively, passing unused medications to friends and family members can have undesirable consequences as the quality of the product is in question. Objective: To investigate the disposal and recycling practices of medicinal products by households in Saudi Arabia. Methods: A cross-sectional questionnaire designed to investigate disposal and recycling practices aimed at households in Saudi Arabia. Phone interviews were conducted with healthcare providers from hospitals and community pharmacies as well as medical charity representatives. A thorough search (Jun-September 2020) for disposal and recycling policies was performed on the Saudi Food and Drug Authority (SFDA) and the Ministry of Health websites. Results: More than 900 participants were included in this study. Approximately 40% of respondents claimed to follow the SFDA recommendations for the disposal of unwanted medications in the wastebasket, whilst ≥6% preferred disposal via the toilet. On the other hand, 10% and 5% of households donated their unwanted over-the-counter and prescription-only medication products, respectively, to a person in need, without referring to healthcare professionals. Interviews with healthcare providers and medical charities revealed no drug take-back programs were currently available for households. The SFDA website provides a brief guide on the disposal of unwanted or expired medication. Conclusions: The absence of a clear drug disposal policy for households has created a gap allowing incorrect disposal practices that may lead to harming patients and/or the environment. The launching of drug take-back programs may lead to the provision of a clear consensus of governing bodies and healthcare providers on patient guidance for a safe drug disposal policy.

Reliability of the Estimation of the Take of Split Thickness Graft by the Observation Method

Introduction: Split thickness skin grafts are frequently employed to provide biological cover for extensive wounds. The take of the skin graft is traditionally estimated by observation and recorded as a percentage. The intent of this study was to ascertain the reliability of the observation method in comparison with the Image J digital programme. Materials and Methods: The study was a longitudinal study conducted on the wards of the National Reconstructive Plastic Surgery and Burns Centre (NRPSBC) at the Korle Bu Teaching Hospital (KBTH) on patients who were admitted during the period of the study with wounds who received split skin grafts. Image J®, an image analysis program, was employed in the calculation of the take of the grafts. These were compared to values obtained by estimation by observation. Results: There was no statistically significant difference between the estimation of graft take, made by observation and using Image J® digital programme. Conclusion: The estimation of graft take by observation is an acceptable practice.

Design of Low-Voltage, Low-Power FGMOS Based Voltage Buffer, Analog Inverter and Winner-Take-All Analog Signal Processing Circuits

This paper proposes novel floating-gate MOSFET (FGMOS) based Voltage Buffer, Analog Inverter and Winner-Take-All (WTA) circuits. The proposed circuits have low power dissipation. All proposed circuits are simulated using SPICE in 180 nm CMOS technology with supply voltages of ±1.25 V. The simulation results demonstrate increase in input range for FGMOS based voltage buffer and analog inverter and maximum power dissipation of 0.5 mW, 1.9 mW and 0.429 mW for FGMOS based voltage buffer, analog inverter and WTA circuits, respectively. The proposed circuits are intended to find applications in low voltage, low power consumer electronics.

Biomechanical and dynamic mechanism of locust take-off

The biomimetic locust robot hopping vehicle has promising applications in planet exploration and reconnaissance. This paper explores the bionic dynamics model of locust jumping by using high-speed video and force analysis. This paper applies hybrid rigid-flexible mechanisms to bionic locust hopping and studies its dynamics with emphasis laid on the relationship between force and jumping performance. The hybrid rigid-flexible model is introduced in the analysis of locust mechanism to address the principles of dynamics that govern locust joints and mechanisms during energy storage and take-off. The dynamic response of the biomimetic mechanism is studied by considering the flexibility according to the locust jumping dynamics mechanism.A multi-rigid-body dynamics model of locust jumping is established and analyzed based on Lagrange method; elastic knee and tarsus mechanisms that were proposed in previous works are analyzed alongside the original bionic joint configurations and their machinery principles. This work offers primary theories for take-off dynamics and establishes a theoretical basis for future studies and engineering applications.

Design of A Hydraulic Power Take-off System for the Wave Energy Device with An Inverse Pendulum

This paper describes a dual-stroke acting hydraulic power take-off(PTO)system employed in the wave energy converter(WEC)with an inverse pendulum.The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth,fast rotation of an electrical generator.The design of the hydraulic PTO system and its control are critical to maximize the generated power.A time domain simulation study and the laboratory experiment of the full-scale beach test are presented.The results of the simulation and laboratory experiments including their comparison at full-scale are also presented,which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.