A number n is said to be economical if the prime power factori-sation of n can be written with no more digits than n itself. We show that under a plausible hypothesis, related to the twin prime conjecture, there are arbitrarily long sequences of consecutive economial numbers, and exhibit such a sequence of length 9.

Ibuprofen (I) is the most widely used non-steroidal anti-inflammatory drugs (NSAIDs) has been synthesized in recent years. NSAIDs are the first choice of drugs that are normally used for the treatment of pain and inflammation. There are many methods for synthesizing of I but each one has some difficulties as raw materials preparation, reaction conditions and etc. In an effort to establish modif...

Optimization based control aims at maximizing the economical performance of a plant in a transient environment employing nonlinear models. Model quality is crucial for achieving good economical performance. The models have to represent plant behavior with sufficient detail, but the computational complexity must be limited to facilitate real-time optimization on a time horizon oriented at the do...

Recent developments and analysis do prove that any waste management system that does not consider the social aspect does not have a high chance of success. In such cases the decision making process focuses upon technical characteristics, economical aspects and legal compliance. However, public participation in all stages of waste management, from informal status until the acceptance, including ...

Biomass pyrolysis is one of the beneficial sources production sustainable bio-oil. Currently, marketable bio-oil plants are scarce because complex operations and lower profits. Therefore, it necessary to comprehend relationship between technological parameters economic practicality. This review outlines technical economical routine produce bio-oils from various biomass by fast pyrolysis. Explic...