Thermogravimetric studies on the reduction of hematite ore fines by a surrounding layer of coal or char fines: Part 2. Non-isothermal kinetic studies

A kinetic study on the non-isothermal reduction of a column of iron ore fines by a surrounding layer of char fines is the main theme of this paper. A study on isothermal reduction by coal/char fines was described in Part 1 of this communication.In the present work the degree of reaction at a given instant has been described as in Part 1, i.e., as the ratio of weight loss at that instant to the maximum possible weight loss. Reduction experiments have been carried out on three different sample sizes. Samples of ~1 g were used in a thermogravimetric set-up and continuous measurements of weight loss analysed in terms of the degree of reaction. Some fixed time reduction experiments have been carried out on large (~15 g) samples where the reduced sample was chemically analysed for the degree of reduction. In addition, a thermal analyser was used to study reduction in a thoroughly mixed ore-char system (sample size, ~30 mg).It is shown that while the reaction in a mixed system is characterized by uniform internal reduction, reduction in an unmixed system is characterized by diffusion of gases through a porous product layer, the reaction being controlled by gasification of carbon.     

Non-cooperative competition among revenue maximizing service providers with demand learning

This paper recognizes that in many decision environments in which revenue optimization is attempted, an actual demand curve and its parameters are generally unobservable. Herein, we describe the dynamics of demand as a continuous time differential equation based on an evolutionary game theory perspective. We then observe realized sales data to obtain estimates of parameters that govern the evolution of demand; these are refined on a discrete time scale. The resulting model takes the form of a differential variational inequality. We present an algorithm based on a gap function for the differential variational inequality and report its numerical performance for an example revenue optimization problem.     

Thermogravimetric studies on the reduction of hematite ore fines by a surrounding layer of coal or char fines: Part 1. Isothermal kinetic studies

Although there is a good deal of literature on the reduction of iron oxide by carbonaceous materials, it mostly covers systems where the oxide and reductant are thoroughly mixed. The present work concerns a system where the oxide and the reductant are not mixed.The kinetics of isothermal reduction of a central column of ore fines by a surrounding layer of coal fines have been studied by thermogravimetry. The course of reaction has been expressed in terms of a “degree of reaction” (f) defined as weight loss measured at a given time (t) with respect to the maximum possible weight loss. The kinetic data expressed in terms of f have been analysed using a kinetic law appropriate for diffusion-controlled processes and apparent activation energies have been calculated for reduction by coal and char. The results have been interpreted to identify carbon gasification as the rate-controlling step.     

Amphiphilic Tobramycins with Immunomodulatory Properties

Amphiphilic aminoglycosides (AAGs) are an emerging source of antibacterials to combat infections caused by antibiotic‐resistant bacteria. Mode‐of‐action studies indicate that AAGs predominately target bacterial membranes, thereby leading to depolarization and increased permeability. To assess whether AAGs also induce host‐directed immunomodulatory responses, we determined the AAG‐dependent induction of cytokines in macrophages in the absence or presence of lipopolysaccharide (LPS). Our results show for the first time that AAGs can boost the innate immune response, specifically the recruitment of immune cells such as neutrophils required for the resolution of infections. Moreover, AAGs can selectively control inflammatory responses induced in the presence of endotoxins to prevent septic shock. In conclusion, our study demonstrates that AAGs possess multifunctional properties that combine direct antibacterial activity with host‐directed clearance effects reminiscent of those of host‐defense peptides.