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Voluntary employee turnover can cause organ­izations to lose profits and competitiveness. Unexpected employee turnover may also result in project delay and reduction in project quality. It is important to control employee turnover rate and maintain good employees within an organization. This paper investigates the major causes of voluntary employee turnover in engineer­ing industries. Australia, Mainland China, and Taiwan were selected for the investigation. Questionnaires were administered, and structured interviews were conducted. Power spectrum was used for the analysis. It was found that “Good physical working environment”, “Receiving advanced training”, and “Short travel distance between home and work” are the major job-related ideal factors for the Australian, Mainland China, and Taiwan respondents, respectively. However, “Far distance between work and home” and “Dislike the colleague relationships” are found as the major factors for leaving jobs for the Australian/ Taiwan and Mainland China respondents, respectively. Recommendations to improve and to control employee turnover rate are also discussed.

The Vietnamese government has advocated developing an export-based economy. In fact, the Prime Minister issued Decision No. 2471/QD-TTg dated December 28, 2011, approving the strategy of import and export of goods for the period 2011 to 2020, with a vision to 2030 formulating policies on development of logistics services, credit, and investment to develop export production, and customs clearance places for import and export goods. That fact prompted us to conduct the research investigating the impact of export support policies on export performance of firms locating in Ho Chi Minh City. The combination of qualitative and quantitative research method was applied. The netnography method and in-depth interview were used to explore support policies influencing export performance, and found Tax Incentives, Credit Incentives, Trade Promotion Support, and Custom Procedures Reform are four policies significantly explaining firms' export performance. To measure the impact of these policies on export performance, we surveyed 141 firms in HCMC. The quantitative study confirmed that four policies impact positively significantly on export performance. The best explanatory factor is Trade Promotion Support, the second is Customs Procedure Reforms, followed by Tax Incentives. Credit incentives have the lowest effect on export performance. The findings asserted the positive effectiveness of policies promoting export performance implementing in Vietnam, and provided empirical evidence to support institutional theory. [ABSTRACT FROM AUTHOR]

In the current age of enhanced environmental awareness, transformation to sustainable management in the construction sector is needed. China currently produces the largest amount of construction and demolition (C&D) waste around the world, but the average recovery rate of the waste was only about 5% in 2017. In order to investigate problems in current C&D waste management in China, a cross-national comparative analysis is conducted among China and seven selected countries (Japan, South Korea, Germany, Italy, Austria, the Netherlands and the United Kingdom), to compare legal texts of national policies and laws which relate to C&D waste management and are currently being used. Through the comparison, problems in management of C&D waste in China are investigated. The problems could be concluded to: (a) inadequate guidance on recycling, (b) lack of market incentives in utilising recycled materials, (c) incomplete knowledge of stakeholders' responsibilities, (d) lack of penalty for other stakeholders, and (e) inefficient supervision system. By understanding these problems, this paper further provides recommendations to enhance the performance of C&D waste management in China. [ABSTRACT FROM AUTHOR]

Carbon-conditioning or chemical permeation methods can provide excellent microstructural improvements to recycled concrete and brick aggregate; however, the applications have their limitations. Further, recycled brick aggregate cannot be effectively carbon-conditioned with conventional methods as it contains only trace amounts of reactive materials. It is therefore a necessity to use hybrid methods involving dual technologies combining carbon-conditioning and chemical permeation for its improvement. This paper is focused on developing a novel hybrid method for improving the microstructural properties of recycled concrete aggregate and recycled brick aggregate for concrete usage. This study conducts particle density, water absorption and crushing value tests to measure the physical improvements achieved with the novel hybrid method, and utilises a variety of chemicals and a reaction chamber for carbon-conditioning for aggregate treatment. The study evinces that both the recycled concrete aggregate and recycled brick aggregate experienced significant improvements, with 10 mm and 20 mm recycled concrete aggregate and 10 mm recycled brick aggregate exceeding the density of virgin aggregate. Magnesium hydroxide plus carbon dioxide (Mg(OH)2 (s) + CO2 (g)) treatment for recycled concrete aggregate and calcium hydroxide plus magnesium hydroxide plus carbon dioxide (Ca(OH)2 (s) + Mg(OH)2 (s) + 2CO2 (g)) treatment for recycled brick aggregate can be considered as potential candidates for optimal hybrid treatment methods. [ABSTRACT FROM AUTHOR]

Photo‐catalysis by small‐molecules is often limited by catalyst degradation and low electron‐transfer efficiency. Herein we report a stable N‐phenyl‐phenothiazine (PTH)‐derived porous coordination cage (PCC) as a highly efficient photocatalyst. By the incorporation of the photocatalytic PTH moiety into a PCC, aggregation‐induced quenching (AIQ) was shown to be reduced. An improvement in catalyst stability was discovered, ascribed to the synergistic effects of the PTH moieties. The catalyst, operating through a photolytic single‐electron transfer, was utilized for photo‐catalyzed dehalogenation and borylation. Evaluation of the catalytic mechanism in the borylation reaction showed that the improved performance results from the more efficient formation of the electron donor‐acceptor (EDA) complex with the cage. This discovery provides a potential strategy to improve the photophysical properties and stabilities of small‐molecule organic photocatalysts via supramolecular chemistry. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are hybrid materials known for their nanoscale pores, which give them high surface areas but generally lead to poor electrical conductivity. Recently, MOFs with high electrical conductivity were established as promising materials for a variety of applications in energy storage and catalysis. Many recent reports investigating the fundamentals of charge transport in these materials focus on the role of the organic ligands. Less consideration, however, is given to the metal ion forming the MOF, which is almost exclusively a late first‐row transition metal. Here, we report a moderately conductive porous MOF based on trivalent gallium and 2,3,6,7,10,11‐hexahydroxytriphenylene. Gallium, a metal that has not been featured in electrically conductive MOFs so far, has a closed‐shell electronic configuration and is present in its trivalent state—in contrast to most conductive MOFs, which are formed by open‐shell, divalent transition metals. Our material, made without using any harmful solvents, displays conductivities on the level of 3 mS/cm and a surface area of 196 m2/g, comparable to transition metal analogs. [ABSTRACT FROM AUTHOR]

In this article, a radio-frequency (RF) power-amplifier (PA) system configuration for the on-board energy conversion is proposed for unmanned aerial vehicle base station's (UAV-BS's) battery charging. First, the PA system utilizes the internal RF source for energy conversion so that perpetual battery charging is possible without external power sources. Therefore, a continuous battery charging of the UAV-BS is possible while providing wireless network coverage by hovering over the target location. In addition, the proposed PA system offers a higher RF power control resolution than the existing PA works, which is desirable for precise power control of the UAV-BS. The objective of simultaneous RF power control and battery charging by the PA system is achieved by activating one Wilkinson power divider (WPD) with a specific power splitting ratio in the power divider bank. The simulations show that the dynamic activation of ten distinct unequal split WPDs of the proposed PA system improves the RF power control resolution by $157$ and $396{\,}\%$ compared to the existing PAs. Additionally, the simulations show that the PA's power added efficiency fluctuation is reduced by $54$ and $82{\,}\%$ compared to the existing PAs. In addition, it will be shown that the proposed on-board battery charging increases the hovering time by $7.4{\,}\%$. Furthermore, an energy-efficiency optimization framework for UAV-BS's is proposed considering real-world communication system's hardware imperfections, and the proposed result suggests that UAV-BS's flight time may decrease by $50{\,}\%$ depending upon the type of UAV-BS RF components. [ABSTRACT FROM AUTHOR]