An exact solution of linearized flow of an emitting, absorbing and scattering grey gas

The governing equations for the problem of linearized flow through a normal shock wave in an emitting, absorbing, and scattering grey gas are reduced to two linear coupled integro-differential equations. By separation of variables, these equations are further reduced to an integral equation similar to that which arises in neutron-transport theory. It is shown that this integral equation admits both regular (associated with discrete eigenfunctions) and singular (associated with continuum eigenfunctions) solutions to form a complete set. The exact closed-form solution is obtained by superposition of these eigen-functions. If the gas downstream of a strong shock is absorption–emission dominated, the discrete mode of the solution disappears downstream. The effects of isotropic scattering are discussed. Quantitative comparison between the numerical results based on the exact solution and on the differential approximation are presented

Technology Transfer, Foreign Direct Investment and International Trade

By developing a Ricardian trade model that features technology transfer via foreign direct investment (FDI), we show that technology transfer via multinational enterprises (MNEs) increases world output and trade in goods and services. When there are many goods a continuous reduction in the cost of technology transfer will cause increasingly more technologically advanced goods to go through the product cycle, i.e., goods initially produced in the advanced North are later produced in the backward South as a result of increased technology transfer via MNEs.

The Effects of Financial Crises on International Trade

This paper studies empirically the effects of financial crises on international trade. The major findings are that banking crises had a negative impact on imports but a positive impact on exports in the short term, whereas currency crises decreased imports in the short term and stimulated exports in the longer term.

The national security argument for protection of domestic industries

Tracing the origin of the national security argument for protection of domestic industries to Adam Smith, Alexander Hamilton, and Friedrich List, we study its post-GATT applications with reference to Article XXI of the WTO. We compare the use of tariff, production/input subsidy, and government procurement as alternative instruments of protection from the perspective of economic efficiency and study the disapproval of inward FDI to gain insights into the underlying national security concerns. The case studies of a) the US tariffs on aluminum and steel, b) German disapproval of the acquisition of a technology firm Leifeld Metal Spinning by a Chinese firm, and c) US’ all out global effort to cripple China’s telecom equipment giant Huawei are presented for illustration

Application of singular eigenfunction expansions to the propagation of periodic disturbances in a radiating grey gas

The effect of thermal radiation on the propagation of small disturbances generated by the harmonic oscillation of a planar wall, either in position or temperature or both, is considered. By separation of variables, it is shown that the governing linearized equations can be reduced to a homogeneous integral equation that admits both regular and singular solutions to form a complete set; thus, the problem can be solved by the application of singular eigenfunction expansions analogous to those used in neutron-transport theory. An exact closed form solution is obtained for disturbed quantities in the flow and radiation fields. The exact solution shows that the disturbances consist of a damped continuum mode with infinite wave speed in addition to two discrete modes with finite wave speed. One of the discrete modes represents the "modified classical" wave whereas the other discrete mode plus the continuum mode corresponds to the radiation-induced wave. For sufficiently small Bouguer numbers, the discrete mode of the radiation-induced wave disappears. The newly found continuum mode damps faster than the discrete mode. Consequently, only the discrete modes persist away from the boundary. The differential approximation is found to predict the modified classical wave accurately but predicts the radiation-induced wave only approximately. The implications as well as the accuracy of the differential approximation are discussed and compared

University education under COVID-19 : what to do beyond online classes?

For any organization Covid-19 presents a serious continuity problem. The attack of the novel coronavirus entails a shrinkage of the space of human face-to-face interactions and uncertainty of its duration and intensity. In this talk I shall briefly report how Lingnan University deals with the Covid-19 challenge by adjusting the mode of teaching and learning in response to changes in the epidemic’s impact on public health. While replicating the essential elements of regular classroom learning with online classes and offering hybrid learning when public health conditions permit are central to our effort, we face an even bigger challenge in providing required or highly recommended learning experiences outside the classroom. The latter include a) our co-curricular Integrated Learning Program (including hostel education) whose intended learning goal is whole-person development, b) community services, c) internships, and d) global experience. I look forward to learning about how other universities address these or other learning needs of their students under threat of the Covid-19 epidemic. Highlights: https://www.ln.edu.hk/global-higher-education-webinar-series/global04.htm