Development and Evaluation of a Chase View for UAV Operations in Cluttered Environments

Civilian applications for UAVs will bring these vehicles into low flying areas cluttered with obstacles such as building, trees, power lines, and more importantly civilians. The high accident rate of UAVs means that civilian use will come at a huge risk unless we design systems and protocols that can prevent UAV accidents, better train operators and augment pilot performance. This paper presents two methods for generating a chase view to the pilot for UAV operations in cluttered environments. The chase view gives the operator a virtual view from behind the UAV during flight. This is done by generating a virtual representation of the vehicle and surrounding environment while integrating it with the real-time onboard camera images. Method I presents a real-time mapping approach toward generating the surrounding environment and Method II uses a prior model of the operating environment. Experimental results are presented from tests where subjects flew in a H0 scale environment using a 6 DOF gantry system. Results showed that the chase view improved UAV operator performance over using the traditional onboard camera view.     

NL—Ni—Co—Mn—Al合金吸氢动力学

应用特制双层水恒温反应器和动力学机理函数计算机拟合的方法，在３０３—３４３Ｋ温度范围内研究了ＭＬ—Ｎｉ—Ｃｏ—Ｍｎ—Ａｌ五元系和ＭＬ—Ｎｉ—Ｃｏ—Ｍｎ—Ａｌ—Ｃｕ六元系（ＭＬ为富镧混合稀土金属）在α＋β相区恒温吸氢动力学．研究结果表明，五元系贮氢合金吸氢初期受化学反应控速，后期受氢在合金氢化物中的扩散控速，动力学规律不受氢初压的影响．由于Ｃｕ的加入，六元系贮氢合金吸氢机制初期转变为β相形核长大控速，后期仍为氢在合金氢化物中的扩散控速．     

ML－Ni－Co－Mn一Al合金吸氢动力学

应用特制双层水恒温反应器和动力学机理函数计算机拟合的方法，在３０３—３４３Ｋ温度范围内研究了ＭＬ—Ｎｉ—Ｃｏ—Ｍｎ—Ａｌ五元系和ＭＬ—Ｎｉ—Ｃｏ—Ｍｎ—Ａｌ—Ｃｕ六元系（ＭＬ为富镧混合稀土金属）在α＋β相区恒温吸氢动力学．研究结果表明，五元系贮氢合金吸氢初期受化学反应控速，后期受氢在合金氢化物中的扩散控速，动力学规律不受氢初压的影响．由于Ｃｕ的加入，六元系贮氢合金吸氢机制初期转变为β相形核长大控速，后期仍为氢在合金氢化物中的扩散控速．     

Spray drying of red (Hylocereus polyrhizus) and white (Hylocereus undatus) dragon fruit juices: physicochemical and antioxidant properties of the powder

This study aims to investigate physical stability and antioxidant properties of spray‐dried red (Hylocereus polyrhizus) and white (Hylocereus undatus) dragon fruit powder upon storage at various relative humidity (RH). Inlet air temperatures of 120 °C (red dragon fruit) and 110 °C (white dragon fruit) as well as maltodextrin concentration of 30% (w/v) were selected as the spray drying conditions as powder was obtained at these minimum conditions. The powder was ranging from 3 to 7 μm in particle size with spherical morphology. The powder had lower antioxidant content and antioxidant activities compared with the control before spray drying. Storage of powder at 43%, 54% or 75% RH at 25 °C for 25 days resulted in structural changes correlating to the depression of glass transition temperatures (T_g) to below storage temperature. At 33% RH, no visible structural changes were observed. Antioxidant properties of the powder remained unchanged after 25 days' storage at the studied RHs.     

Rhodium catalyzed hydroformylation of kaurane derivatives: A route to new diterpenes with potential bioactivity

Kaurenic and grandiflorenic acids are naturally occurring diterpenes whose biological activity has been described. Both acids contain an exocyclic methylenic double bond that allows further functionalization on their structure. In an attempt to expand the number of derivatives of these two natural products, we have undertaken a study on the hydroformylation of the methyl esters of the two acids and the trimethylsilyl ether of kaurenol. These substrates have been hydroformylated by using unmodified Rh catalysts, as well as Rh/PPh₃ and Rh/tris-(o-t-butylphenyl)phosphite catalytic systems at 100 °C and 20 bar of CO/H₂ (1:1). For the three substrates, the two Rh catalysts modified with P-donor ligands, produced high conversions and chemo- and regioselectivities in the diastereoisomeric pair of linear aldehydes. In all cases, the stereoselectivity observed is strongly dependent of the system used, being the most diastereoselective the least hindered unmodified Rh/CO catalyst. A correlation between the higher diastereoselectivity and the faster β-elimination of the metal-alkyl intermediate observed in the unmodified system is discussed.     

A systematic review of China’s belt and road initiative: implications for global supply chain management

China’s Belt and Road Initiative (BRI) is one of the world’s largest infrastructure projects, with its potential political and economic impact being widely discussed since its inception in 2013. Yet the phenomenon has received only limited attention in the Supply Chain Management (SCM) literature. In response, we first conduct a broad systematic review of the literature to assess how China’s BRI is portrayed. Using this as a backdrop, we then distil the likely impact of the BRI on location decisions and supply chain flows. Finally, in a broader discussion of the SCM literature, we explore the implications of the BRI for future research in four key areas: supply chain configuration, supply chain resilience, sustainable SCM, and cross border SCM. While these areas are not new, the BRI presents a unique context that can be used to enhance theory and understanding in each area. The BRI reduces time distance independent of geographical distance by diverting supply chain flows from established routes to new routes via far less accessible regions. This introduces new risks and sustainability issues that call for multi-criteria decision support systems. Another important issue is the adoption and diffusion of the BRI since this will ultimately determine project success.     

A review of coordination studies in the context of supply chain dynamics

Supply chain management is and has been a popular research topic in recent years. Among the reported studies, coordination is an important ingredient to improve the performance of supply chains subject to the presence of system dynamics. This paper sets out to review some recent supply chain studies in the last decades that are related to coordination among supply chain members regarding supply chain dynamics. Focus is put on inventory management problems. More than a hundred research papers are reviewed and they are broadly categorised into analytical approaches and simulations approaches. They are further divided into sub-categorises. Observations of each category are summarised in this paper so that characteristics of each of which could be comprehended. In addition, the concluding section reveals some insights that could be considered for future research regarding coordination in supply chains and supply chain systems dynamics.     

A hierarchical fuzzy TOPSIS approach to assess improvement areas when implementing green supply chain initiatives

Implementing green supply chain management (GSCM) initiatives can generate more business opportunities for firms. It also requires changes in firms’ operational capabilities and resources that may have an adverse effect on firms’ operations performance. In order to achieve sustainable economic and environmental performance, it is essential for companies to evaluate different green initiatives and assess improvement areas when implementing green initiatives. This study proposes a fuzzy hierarchical TOPSIS approach to support such an assessment. It enables decision makers to better understand the complete evaluation process and provide a more accurate, effective and systematic decision support tool. An illustrative case is presented to help researchers and practitioners understand the importance of developing an appropriate organisation strategy in implementing green practices.