Is Environmental Tax Harmonization Desirable in Global Value Chains?

The spatial unbundling of parts production and assembly currently characterizes globalization, leading to the worldwide dispersion of pollution. We consider socially optimal (cooperative) environmental taxes in a two-country model of global value chains in which the location of both parts and assembly can differ. When unbundling costs are so high that parts and assembly must colocate in the pre-globalized world, pollution is spatially concentrated, and harmonizing environmental taxes maximizes global welfare. In contrast, with low unbundling costs triggering the dispersion of parts and thus pollution throughout the world as today, harmonization fails to maximize global welfare. Similar results hold when the two countries non-cooperatively choose their environmental taxes

Numerical Simulation on Jet Formation of Shaped Charge with Different Liner Materials

In this paper, the effect of liner material of the shaped charge on jet formation and its penetration capability is investigated by experimental and numerical methods. Liner materials investigated in this paper are copper, steel, and aluminium, respectively. Pulse X-ray photographic technology to shoot the formation of jet is employed to obtain the tip velocity and the diameter of jet. A two-dimensional multi-material code is designed to simulate the entire process from jet formation to penetrating a target. A markers on cell lines method is utilised to treat the multi-material interface. The results show that aluminium jet has the highest velocity with the poorest penetration capability. Copper jet has the strongest penetration capability with a velocity higher than that of steel jet, but lower than that of aluminium jet. The simulated results agree with the experimental results very well. It also indicates that the code developed can not only address large distortion problems but also track the variation of multi-material interfaces. It is favourable to simulate the explosive loading on thin-wall structure such as shaped charge. It is proved that authors’ method is feasible and reliable for optimising the structure of shaped charge jet to dramatically improve its tip velocity and penetration capability, and provides an important theoretic basis for designing high explosive anti-tank warhead.Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 279-286, DOI: http://dx.doi.org/10.14429/dsj.65.864

Integrated Microwave Resonator/antenna Structures for Sensor and Filter Applications

This dissertation presents design challenges and promising solutions for temperature and pressure sensors which are highly desirable for harsh-environment applications, such as turbine engines. To survive the harsh environment consisting of high temperatures above 1000°C, high pressures around 300 psi, and corrosive gases, the sensors are required to be robust both electrically and mechanically. In addition, wire connection of the sensors is a challenging packaging problem, which remains unresolved as of today. In this dissertation, robust ceramic sensors are demonstrated for both high temperature and pressure measurements. Also, the wireless sensors are achieved based on microwave resonators. Two types of temperature sensors are realized using integrated resonator/antennas and reflective patches, respectively. Both types of the sensors utilize alumina substrate which has a temperature-dependent dielectric constant. The temperature in the harsh environment is wirelessly detected by measuring the resonant frequency of the microwave resonator, which is dependent on the substrate permittivity. The integrated resonator/antenna structure minimizes the sensor dimension by adopting a seamless design between the resonator sensor and antenna. This integration technique can be also used to achieve an antenna array integrated with cavity filters. Alternatively, the aforementioned reflective patch sensor works simultaneously as a resonator sensor and a radiation element. Due to its planar structure, the reflective patch sensor is easy for design and fabrication. Both temperature sensors are measured above 1000°C. A pressure sensor is also demonstrated for high-temperature applications. Pressure is detected via the change in resonant frequency of an evanescent-mode resonator which corresponds to cavity deformation under gas pressure. A compact sensor size is achieved with a post loading the cavity resonator and a low-profile antenna connecting to the sensor. Polymer-Derived-Ceramic (PDC) is developed and used for the sensor fabrication. The pressure sensor is characterized under various pressures at high temperatures up to 800°C. In addition, to facilitate sensor characterizations, a robust antenna is developed in order to wirelessly interrogate the sensors. This specially-developed antenna is able to survive a record-setting temperature of 1300°C

Development of Creep Models for Glued Laminated Bamboo Using the Time-Temperature Superposition Principle

This paper describes the development of creep models for glued laminated bamboo (GLB)using the time-temperature superposition principle (TTSP). Creep (15 min) and recovery (45 min) data were obtained at constant temperature levels ranging from 25 to 65C. The moisture contents of specimens for testing were dry, 7% and 12%. The individual curve at each temperature was plotted against the log-time axis to obtain a master curve. A nonlinear regression analysis was used to estimate the model parameters. Then the individual temperature master curves were shifted again to a reference MC to construct an overall master curve using time-temperature-moisture principle. The relation of temperature and moisture shift factors loga (T, M) to temperature (T) and MC (M) was analyzed. The results show that the TTSP was successfully applied to GLB tested at different moisture contents