522 research outputs found

    The impacts of production base relocation on port cluster competition: The case of the Pearl River Delta region

    Get PDF
    Due to increases in labor and operational costs within the Pearl River Delta (PRD) region, many manufacturing firms are relocating their plants to inland provinces in China. The existence of significant intra- and inter-port cluster competition means that this ongoing relocation process will not only affect the ports of Shenzhen and Hong Kong, but will also have an impact on ports in other clusters such as Shanghai in the Yangtze River Delta (YRD). Furthermore, since Hong Kong and Shenzhen share the same transportation corridor to inland China, the hinterland access condition is another concern to be examined. This paper employs an analytical economic model to investigate the implications of this process. With the model allowing for substitutable but differentiated services among the three competing ports, the finding in all cases shows that the process will harm the performance of the ports in PRD region, but will benefit the port YRD region. With respect to the impact of a change in hinterland access condition, the implications for Hong Kong are clear, but more complex for Shenzhen. This is because although it shares the same transport corridor to inland China with Hong Kong, it is also one of Hong Kong’s competitors. Since Hong Kong also benefits from the hinterland access and/or negative externality improvement, such effect may either benefit or lower performance of Shenzhen port. The analytical results suggest that a more competitive port of Hong Kong will be in a better position to cooperate with the neighboring port of Shenzhen, and that it is important for Hong Kong to improve its cross-border cargo flows

    Pembentukan cekung berkualiti tinggi menggunakan tempoh penganodan yang singkat bagi penghasilan AAO

    Get PDF
    Kualiti membran AAO yang disediakan melalui teknik penganodan dua peringkat adalah sangat dipengaruhi oleh pra-pembentukan cekung yang dihasilkan semasa penganodan pertama. Kajian ini dijalankan untuk menentukan tempoh penganodan yang optimum bagi menghasilkan cekung yang berkualiti. Penganodan dilakukan menggunakan larutan 0.3 M H2C2O4 sebagai elektrolit dengan beza keupayaan dan suhu masing-masing ditetapkan pada 40 V dan 18°C. Proses penganodan dilakukan sehingga 6 jam. Perubahan nilai arus sepanjang tempoh penganodan direkodkan. Selepas penyingkiran lapisan oksida, kualiti cekung yang terbentuk dikaji menggunakan FESEM. Mikrograf FESEM mengesahkan pembentukan cekung berstruktur heksagon adalah seragam. Selain memperbaiki keseragaman, pertambahan tempoh penganodan telah membentuk cekung yang lebih jelas, tersusun serta kecacatan yang minimum. Keputusan kajian mendapati bahawa tempoh optimum bagi mendapatkan cekung yang seragam dan sempurna adalah antara 4 dan 6 jam. Ini kerana pertambahan tempoh penganodan seterusnya akan menyebabkan keruntuhan dinding cekung yang akhirnya menjadi punca kepada pembentukan liang yang bersentuhan antara satu sama lain. Selain itu, mekanisma penghasilan bentuk cekung turut dibincangkan

    The effect of Al(NO3)3 concentration on the formation of AuNPs using low temperature hydrothermal reaction for memory application

    Get PDF
    Distribution of gold nanoparticles (AuNPs) on a substrate becomes crucial in nanotechnology applications. This work describes a route to fabricate AuNPs directly on silicon substrates by using an aluminum template in hydrothermal reaction at 80°C for 1 h. The effect of aluminum nitrate (Al(NO3)3) concentration in the hydrothermal bath was investigated. The properties of AuNPs were studied using field-emission scanning electron microscope (FESEM), x-ray diffractometer (XRD) and semiconductor characterization system (SCS). Two distinct sizes of AuNPs were observed by FESEM. XRD analysis proved the formation of AuNPs directly on the substrate. AuNPs were embedded between polymethylsilsesquioxane (PMSSQ) in order to investigate their effect on memory properties. The sample grown in 0.1 M Al(NO3)3 exhibited the largest hysteresis window (2.6 V) and the lowest Vth (2.2 V) to turn ‘ON’ the memory device. This indicated that good distribution of FCC structure AuNPs with 80±4 nm and 42±7 nm of large and small particles produced better charge storage capability. Charge transport mechanisms of AuNPs embedded in PMSSQ were explained in details whereby electrons from Si are transported across the barrier by thermionic effects via field-assisted lowering at the Si-PMSSQ interface with the combination of the Schottky and Poole Frenkel emission effect in Region 1. Trapped charge limited current (TCLC) and space charge limited current (SCLC) transport mechanism occurred in Region 2 and Region 3

    The Effect of Sodium on the Catalytic Activity of ZnO-Al2O3/ZSM-5 and SnO-Al2O3/ZSM-5 for the Transesterification of Vegetable Oil with Methanol

    Get PDF
    In order to elucidate the effect of sodium on the activity of ZSM-5 supported metal oxides catalysts (ZnO-Al2O3/ZSM-5 and SnO-Al2O3/ZSM-5) for the transesterification of soybean oil with methanol, ZSM-5 supported metal oxides were prepared with and without sodium hydroxide by impregnation. The metal compositions of the ZSM-5 supported metal oxide catalysts and the metal concentrations dissolved from the catalysts to the methylester phase were measured by SEM-EDS and inductive coupled plasma spectroscopy, respectively. The catalytic activity of ZnO-Al2O3/ZSM-5 and SnO-Al2O3/ZSM-5 containing sodium did not originate from surface metal oxides sites, but from surface sodium sites or dissolved sodium leached from the catalyst surface

    Port Investments on Coastal and Marine Disasters Prevention: An Economic and Policy Investigation

    Get PDF
    Located along shorelines, seaports are highly vulnerable to coastal and marine natural disasters. Damage caused by disasters can be prevented or alleviated if sufficient investments are made in a timely manner. However, despite a wide range of investment options and well-developed engineering expertise, port investment on disaster prevention remains a challenging task involving great complexities. This paper develops an integrated economic model for the analysis of disaster-prevention investments at a “landlord” port. It simultaneously considers the uncertainty of disaster occurrence and associated return of prevention investments, the information accumulation and related investment timing, and the spillovers (externalities) of investment among stakeholders. Our analysis shows that the timing of port investments depends on the probability of disasters. Immediate investment is optimal for disasters with very high probability, while investment should be postponed if such a probability is very low. Optimal timing for cases of intermediate probability cannot be determined analytically, as it is influenced by other factors such as discount rate, information accumulation and efficiency of investments. Positive externalities between a port and its tenants lead to under-investment, which can be corrected by coordination between stakeholders. However, since there are risks of “over-investment” due to uncertainty, government intervention is only optimal with a good understanding of disaster probability distribution

    Effects of Preparative Parameters on the Structure and Performance of Ca-La Metal Oxide Catalysts for Oil Transesterification

    Get PDF
    The effects of preparative parameters on the surface basicity, composition, and transesterification activities of several Ca-La metal oxide catalysts were investigated. Four different preparation methods: ammonia-ethanol-carbon dioxide precipitation, physical mixing, impregnation, and co-precipitation, were studied. It was found that the ammonia-ethanol-carbon dioxide precipitation method resulted in the highest BET specific surface area, base strength and base site concentration. Moreover, catalyst surface composition and basicity are a function of calcination temperature, precipitants, pH, and molar ratio of Ca to La in precursor solution, and storage conditions. XRD, XPS, basicity and BET tests revealed that catalyst structure and dispersion of Ca species strongly influenced the catalyst activity. High surface concentration of Ca species, strong base strength and high concentration of base sites, and high specific surface area are characteristics of an active transesterification catalyst

    Op‐Ed Writing Assignment in Supply Chain Management Courses

    Get PDF
    Newspaper op‐eds, dedicated to commentary essays from outside of a newspaper, function as a platform for the public to exchange opinions. We designed an op‐ed writing assignment as part of a semester‐long course project in global supply chain management (SCM). Student teams conducted research on a SCM topic, presented their findings in the classroom, and wrote an op‐ed for submission to a local or regional newspaper. This teaching brief describes the implementation of this assignment at a northeast U.S. university. The goals of this assignment were: (1) to educate students on how to write an op‐ed and (2) to educate students on how to publish their opinion articles. Insights on the benefits and challenges that students experienced from completing the op‐ed assignment are discussed. A description of a case‐based version of the op‐ed writing assignment used in a Canadian university is also provided

    Low threshold linear cavity mode-locked fiber laser using microfiber-based carbon nanotube saturable absorber

    Get PDF
    In this work, we demonstrate a linear cavity mode-locked erbium-doped fiber laser in C-band wavelength region. The passive mode-locking is achieved using a microfiber-based carbon nanotube saturable absorber. The carbon nanotube saturable absorber has low saturation fluence of 0.98 µJ/cm2. Together with the linear cavity architecture, the fiber laser starts to produce soliton pulses at low pump power of 22.6 mW. The proposed fiber laser generates fundamental soliton pulses with a center wavelength, pulse width, and repetition rate of 1557.1 nm, 820 fs, and 5.41 MHz, respectively. This mode-locked laser scheme presents a viable option in the development of low threshold ultrashort pulse system for deployment as a seed laser
    corecore