The energy required to crush rocks is proportional to the amount of new surface area that is created; hence, a very important percentage of the energy consumed to produce construction aggregates is spent in producing non-commercial fines. Data gathered during visits to quarries, an extensive survey and laboratory experiments are used to explore the role of mineralogy and fracture mode in fines ...

Differential evolution (DE) has become a popular and promising technique in the recent decade. There are many successful applications implemented DE in scientific and engineering fields. However, we rarely found it applying to the field of highly constrained aggregate production planning (APP) problems. Besides, in the course of solving the APP problem, we discover that the most often used DE s...

We consider the problem of dynamically allocating scarce resources to multiple projects in a project-oriented production system such as a naval shipyard. We formulate axioms governing the relationship between resource allocations and work progress of aggregate project activities, from which a model of project execution is derived. This model is more accurate than models which represent aggregat...

Expression of recombinant proteins in Escherichia coli (E. coli) remains the most popular and cost-effective method for producing proteins in basic research and for pharmaceutical applications. Despite accumulating experience and methodologies developed over the years, production of recombinant proteins prone to aggregate in E. coli-based systems poses a major challenge in most research applica...

We study the celebrated Phelps-Koopmans theorem in environments with nonconvex production technologies. We argue that a robust failure of the theorem occurs in such environments. Specifically, we prove that the Phelps-Koopmans theorem must fail whenever the net output of the aggregate production function f (x), given by f (x) − x, is increasing in any region between the golden rule and the maxi...

Previous research has demonstrated that the production of information services can be characterized at the aggregate economy-wide level by the Cobb-Douglas production function. However, the underlying production process at the firm level has not yet been ascertained. The objective of this paper is to determine the form of the production process for information systems services at the firm level...

considering the importance of increase in production and supply of agricultural products in iranian economic development, this study was carried out to investigate the impact of factors influencing the acreage (as a proxy for planned production and supply) of five important crops , namely wheat, barley, potatoes, sunflower and cotton. the seemingly unrelated regression estimation (sure) was use...