Ultrasound-assisted extraction (UAE), using petroleum ether as the solvent, was systematically applied to extract main macamides and macaenes from Maca hypocotyls. Extraction yield was related with four variables, including ratio of solution to solid, extraction temperature, extraction time, and extraction power. On the basis of response surface methodology (RSM), the optimal conditions were de...

The paper revisits the issue of necessary optimality conditions for infinite-horizon optimal control problems. It is proved that the normal form maximum principle holds with an explicitly specified adjoint variable if an appropriate relation between the discount rate, the growth rate of the solution and the growth rate of the objective function is satisfied. The main novelty is that the result ...

BACKGROUND Garlic oil which is the main active constituent of garlic has a wide range of pharmacological activities, and a broad antibacterial spectrum. It also has a strong anti-cancer activity, and can significantly inhibit a variety of tumors such as liver cancer, gastric cancer and colon cancer. The objective is to study the extraction process of garlic oil and its antibacterial effects. ...

Abstract The feature extraction of a point cloud fragment model is the basis splicing, which provides technical support for research on segmentation, and restoration surfaces. High-quality extraction, however, complicated process due to diversity surface information model. For this subject, high-efficient method was proposed address new extracting lines. First, projection distance calculated id...

The nonlinear model of economic growth involving production, technology stock and their rates is considered. Two trends growth and decline, in interaction between production and R&D investment are examined in the balance dynamics. The optimal control problem of R&D investment is studied for the balance dynamics and discounted utility function of consumption index. Pontryagin’s optimality princi...

We investigate how the relationship between economic growth and pollution is affected by the source of pollution: production or consumption. We are interested in polluting waste that cannot be naturally absorbed, but for which recycling efforts aim to avoid massive pollution accumulation with harmful consequences in the long run. We distinguish the cases where recycling efforts are capital-impr...

This paper studies the effects of effluent taxes on firms’ allocation of resources to cost-reducing and emission-reducing R&D, and on entrepreneurs’ decisions to develop new goods and enter the market. A tax set at an exogenous rate that does not depend on the state of technology reduces growth, the level of consumption of each good, and raises the number of firms. The induced increase in the v...