The dissolution kinetics of pandermite and hydroboracite, present in an Iranian borate ore, in sulfuric acid has been comparatively studied. The effect of particle size, temperature, and acid concentration on their dissolution rate was investigated. Dissolution rates of both minerals increased by reducing the particle size and by raising the temperature. Although, an increase in the acid concen...

A segregated model was proposed to investigate the inherent relationships between growth, substrate consumption, cell differentiation and product formation in a Bacillus subtilis fermentation producing heterologous amylase in a 22-l bioreactor. The segregated model includes three distinguishable cell states and the transition from vegetative phase to sporangium and finally to mature spore. An a...

An extensive investigation was carried out to describe the kinetics of cell growth, substrate consumption, and product formation in the batch fermentation using starch as substrate. Evaluation of intrinsic kinetic parameters was carried out using a best-fit unstructured model. A nonlinear regression technique was applied for computational purpose. The Andrew’s model showed a comparatively bette...

Direct fermentation of 226 white rose tapioca stem to ethanol by Fusarium oxysporum was studied in a batch reactor. Fermentation of ethanol can be achieved by sequential pretreatment using dilute acid and dilute alkali solutions using 100 mesh tapioca stem particles. The quantitative effects of substrate concentration, pH and temperature on ethanol concentration were optimized using a full fact...

Abstract T he return of capital is fundamental to the intertemporal allocation of resources by changing the consumption behavior and capital accumulation over time. Taxation on return of capital increases the marginal product of capital, meaning that capital stock is lower than when capital is not taxed, which results decreased growth and welfare in steady state. This pape...

In this paper, a nonlinear mathematical model is proposed and analyzed to study the effect of an intermediate toxic product on the growth of plant biomass. It is assumed that the toxicant uptaken by plant biomass interacts with water (sap) present in it and forms an intermediate product, which then affects the biomass. To model the phenomena, it is further assumed that the intermediate product ...

despite the existence of vigorous theoretical basis lor cooperatives little attention has been paid to it in iran. at the same time, little use has been made of the quantitative models for analyzing the efiects and impacts of cooprative activities in economic literature. in this study, followed by a review of literature on cooperaion theory, a simple quantitative model was examined. this model ...

In light of the pressing need for development of parameterizations of gravity current entrainment in ocean general circulation models, the behavior of turbulent gravity currents in the presence of ambient stratification is studied via numerical simulation, for cases in which equilibrated product water masses are formed. The main objective is to explore how the ambient stratification impacts ent...

Vertical roller mills (VRMs) are well-established grinding equipment for various tasks in the coal and cement industry. There are few studies on simulation of VRMs. In this research work, application of perfect mixing model for simulation of a VRM in a cement grinding plant was investigated. Two sampling surveys were carried out on the VRM circuit. The samples and data from the first survey wer...

abstract t he return of capital is fundamental to the intertemporal allocation of resources by changing the consumption behavior and capital accumulation over time. taxation on return of capital increases the marginal product of capital, meaning that capital stock is lower than when capital is not taxed, which results decreased growth and welfare in steady state. this paper studies the impact o...