Study on China's timber resource shortage and import structure:natural forest protection program outlook,1998 to 2008

The state of China's ecological environment has improved to some extent since the Chinese government initiated the Natural Forest Protection Program (NFPP) in 1998. The logging prohibition and limitation policies adopted by the NFPP, however, have reduced domestic timber supply. Together with the thriving economy, decreasing domestic timer supply continues to widen the gap between supply and demand. Importation is considered to be the primary solution to this issue, making China the world's largest timber importer. China's major timber suppliers are Russia, Malaysia, Papua New Guinea, New Zealand, and Gabon, among which Russia accounts for more than 61 percent of China's total timber imports. The relatively cheaper conifers imported from Russia account for more than 60 percent of all imported timber, with volumes continually increasing because of the rapid pace at which China has been implementing its infrastructure projects. In addition, as living standards continue to improve, requirements for home decor and furniture also grow, further increasing the demand for tropical to temperate timber. In the long term, imports will remain the main solution to the insufficient domestic timber supply in China.NFPP; timber resource shortage; timber import structure

Knowledge-Aided STAP Using Low Rank and Geometry Properties

This paper presents knowledge-aided space-time adaptive processing (KA-STAP) algorithms that exploit the low-rank dominant clutter and the array geometry properties (LRGP) for airborne radar applications. The core idea is to exploit the fact that the clutter subspace is only determined by the space-time steering vectors, {red}{where the Gram-Schmidt orthogonalization approach is employed to compute the clutter subspace. Specifically, for a side-looking uniformly spaced linear array, the} algorithm firstly selects a group of linearly independent space-time steering vectors using LRGP that can represent the clutter subspace. By performing the Gram-Schmidt orthogonalization procedure, the orthogonal bases of the clutter subspace are obtained, followed by two approaches to compute the STAP filter weights. To overcome the performance degradation caused by the non-ideal effects, a KA-STAP algorithm that combines the covariance matrix taper (CMT) is proposed. For practical applications, a reduced-dimension version of the proposed KA-STAP algorithm is also developed. The simulation results illustrate the effectiveness of our proposed algorithms, and show that the proposed algorithms converge rapidly and provide a SINR improvement over existing methods when using a very small number of snapshots.Comment: 16 figures, 12 pages. IEEE Transactions on Aerospace and Electronic Systems, 201

Finite Element Investigation on Load Carrying Capacity of Corroded RC Beam Based on Bond-Slip

The finite element (FE) investigation on the load carrying capacity of corroded RC beam is carried out based on the bond-slip between the steel bars and concrete. In the numerical simulation, several FE models of RC simply supported beam with different corrosion ratios were built using ANSYS. In these FE models, element of Solid65 was used to simulate concrete, element of Link8 was used for bars and element of Combin39 was adopted to simulate the bond and bond-slip between bars and concrete. The effect of corrosion ratio on bonding force between bars and concrete was simulated by adjusting the parameter of Combin39. Besides, the reduction of bars section area and decrease of bars yielding stress were also considered for calculating the load carrying capacity of corroded RC beam with different corrosion ratios. The results show that as the corrosion ratio increases the stiffness of corroded beam would decrease, slip between bars and concrete would be larger and ductile failure of RC beam would turn to brittle failure. The load carrying capacity of corroded RC beam would obviously deteriorate and descending speed is the fastest when the corrosion rate falls in the range of 4%-7%

Broadband negative refraction in stacked fishnet metamaterial

We demonstrate a scheme to utilize the stacked fishnet metamaterial for all-angle negative refraction and subwavelength imaging within a wide frequency range starting from zero frequency. The theoretical predictions are verified by the finite-difference-in-time-domain (FDTD) numerical simulations. The phenomena come from the negative evanescent coupling between the adjacent slab waveguides through the breathing air holes perforated on metal layers.Comment: 8 pages, 4 figure

Technology In The Classroom Versus Sustainability

The use of technology in universities and colleges is an issue of interest and speculation. One issue related to technology use in the classroom is sustainability of resources that support the technology. This paper explores faculty perceptions about technology use and sustainability in an east coast university. This university has initiated a new program that has been charged with the objective of creating and maintaining a sustainability program. The program is still being developed, but a few of the key goals are to look at recycling campus-wide, printing costs in the computer labs and library, and exploring what the faculty perceptions are about using technology in the classroom. This paper focuses on the last goal; and in order to explore this objective, a survey was administered to the Schools of Business, Health Professions, Arts & Sciences and the Library. The research question addressed in this paper is the relationship between the use of technology in the classroom and the course discipline of the faculty teaching the class. The faculty participants in the survey included four of its academic schools - Business, Health Professions, Arts & Sciences, and the Library. Consequently, there are four different faculty affiliations based on their school. The research questions related to school assignments presented in this paper: · Are there significant differences in the use of technology based on the school in which the faculty member is associated? · Do technology-driven programs in the schools of business and library science tend to perceive the use of technology in the classroom differently than other schools? · Are differences in the school of affiliation reflected in faculty views of importance of technology to the learning process? · Are differences in the school of affiliation reflected in faculty perceptions in the use of technology devices, including the desktop computers, iPad/Tablets, Laptops, Smartphones, or E-Readers? · Do faculty affiliations with schools impact their view of the importance moving toward the use of electronic documents? · Do faculty affiliations impact whether technology devices are viewed as distractions? · Are sustainability enthusiasts also technology enthusiasts

The Effect of Off-Farm Employment on Forestland Transfers in China : A Simultaneous-Equation Tobit Model Estimation

China's new round tenure reform has devolved collective forests to individuals on an egalitarian basis. To balance the equity-efficiency dilemma, forestland transfers are highly advocated by policymakers. However, the forestland rental market is still inactive after the reform. To examine the role of off-farm employment in forestland transfers, a simultaneous Tobit system of equations was employed to account for the endogeneity, interdependency, and censoring issues. Accordingly, the Nelson-Olson two-stage procedure, embedded with a multivariate Tobit estimator, was applied to a nationally representative dataset. The estimation results showed that off-farm employment plays a significantly negative role in forestland rent-in, at the 5% risk level. However, off-farm activities had no significant effect on forestland rent-out. Considering China's specific situation, a reasonable explanation is that households hold forestland as a crucial means of social security against the risk of unemployment. In both rent-in and rent-out equations, high transaction costs are one of the main obstacles impeding forestland transfer. A remarkable finding was that forestland transactions occurred with a statistically significant factor equalization effect, which would be helpful to adjust the mismatched labor-land ratio and improve the land-use efficiency.Peer reviewe