Status Analysis and Trend Prediction for the Labor Costs of Chinese Construction Industry
Chinese huge low-cost labor force provided motive power for the development of construction industry in the past decades. However, Chinese labor costs soar quickly in recent years, which bring pressures to construction enterprises. In order to analyze the problems of rising labor costs of Chinese construction industry in depth, a questionnaire survey is conducted among construction workers and project managers. According to the result of the investigation and statistical data, the rising actuality and influence factors of labor costs in Chinese construction industry are analyzed comprehensively. Then the medium and long term prediction of labor cost is carried out by using GM (1, 1) grey model. The results show that the average pay of Chinese construction workers rose quickly over the past 5 years. Changes of supply–demand relation of labor force, soaring prices and the rapid economic development, and other aspects are the reasons causing the labor costs increase. The average daily pay of Chinese construction workers will keep rising in coming years, and will achieve 337 RMB yuan by 2020. The research results present valuable reference basis for construction enterprises to grasp the development trend of labor costs and takes steps to address the labor cost pressures.
Empirical Analysis on Contribution Rate of Human Capital in China's Construction Industry Based on DEA
In order to clarify the positive contributions of human capital to China's construction industry,this paper use the equivalent LP model of C~2R DEA.First,we processe related data by linear transformation,then use the input/output statistic data from 1995 to 2007,we measure the relative contribute rate of effective factors to China's construction industry in 2006 and 2007.We concluded that along with the intention of competition and transformation of economy development,human capital has become the first important factor in the economic development of China's construction industry.
Preparation of hydrophilic poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation
Abstract Hydrophilic microporous hollow fiber membranes were prepared via thermally induced phase separation (TIPS). Poly(vinyl butyral) (PVB) and three kinds of polyethylene glycols (PEG) with the molecular weight of 200, 400 and 600 were used as polymer and diluents. In all cases, liquid–liquid (L–L) phase separation occurred and asymmetric cellular structures with the smaller pores at the outer surface were obtained. The properties of membranes such as pore size, water permeability, solute rejection and intensity were investigated by changing molecular weight of PEG, concentration of PVB, composition of the bath and air gap distance. The smaller molecular weight of PEG, the more PEG in the bath and the shorter air gap distance resulted in the higher water permeability, the lower solute rejection property and the lower mechanical strength.