Publication year: 2012
Source: Resources, Conservation and Recycling, Volume 58, January 2012, Pages 1-7

Sappinandana Akamphon, Sittha Sukkasi, Yuttanant Boonyongmaneerat

To improve sustainability in a hot-dip galvanized coating industry, a series of galvanizing techniques have been developed. Here, a relatively novel galvanizing technique developed to reduce zinc consumption and enhance steel's corrosion protection is investigated in relation to the conventional galvanizing technique. A process-based cost modeling (PBCM) is employed to analyze the process's cost effectiveness and to determine the influence of the cost drivers, including part surface area, coating thickness, and raw materials’ costs. The new process, which involves the use of either electrodeposition or electroless-deposition technique, is found economically attractive if the electrodeposition technique is integrated and the pre-coating layer remains thin. The electroless-deposition integrated process shows promise as zinc and nickel prices increase. Cost reduction of the galvanizing process with pre-coating layers is achieved mainly through reduction of zinc consumption and exclusion of the fluxing step.

Highlights

â–º We analyze economic viability of innovative galvanizing process for reduction of zinc consumption, using process-based cost model. â–º The new galvanizing process allows reduction of zinc consumption by 74% while providing enhanced corrosion protection. â–º When thickness of pre-coat is controlled below a few micrometers, the new process is economically feasible regardless of zinc price. â–º The new process involving electrodeposition is more economically feasible than that with electroless deposition.

Publication year: 2011
Source: Biophysical Chemistry, Available online 10 November 2011

Laurence A. Belfiore, Michael L. Floren, Carol J. Belfiore

This research contribution addresses electric-field stimulation of intra-tissue mass transfer and cell proliferation in viscoelastic biomaterials. The unsteady state reaction–diffusion equation is solved according to the von Kármán-Pohlhausen integral method of boundary layer analysis when nutrient consumption and tissue regeneration occur in response to harmonic electric potential differences across a parallel-plate capacitor in adielectric-sandwichconfiguration. The partial differential mass balance with diffusion and electro-kinetic consumption contains the Damköhler (Λ) and Deborah (De) numbers. Zero-field and electric-field-sensitive Damköhler numbers affect nutrient boundary layer growth. Diagonal elements of the 2nd-rank diffusion tensor are enhanced in the presence of weak electric fields, in agreement with the formalism of equilibrium and nonequilibrium thermodynamics. Induced dipole polarization density within viscoelastic biomaterials is calculated via the real and imaginary components of the complex dielectric constant, according to the Debye equation, to quantify electro-kinetic stimulation. Rates of nutrient consumption under zero-field conditions are described by third-order kinetics that include local mass densities of nutrients, oxygen, and attached cells. Thinner nutrient boundary layers are stabilized at shorter dimensionless diffusion times when the zero-field intra-tissue Damköhler number increases above its initial-condition-sensitive critical value [i.e., {Λzero-field}critical ≥ 53, see Eq. (23)], such that the biomaterial core is starved of essential ingredients required for successful proliferation. When tissue regeneration occurs above the critical electric-field-sensitive intra-tissue Damköhler number, the electro-kinetic contribution to nutrient consumption cannot be neglected. The critical electric-field-sensitive intra-tissue Damköhler number is proportional to the Deborah number.

Schematic representation of cylindrical biomaterials in a dielectric-sandwich configuration subjected to harmonic electric potential differences across the capacitor plates, with radial diffusion of nutrients inward to support cell proliferation and sustainability.

Highlights

► reaction–diffusion equation is analyzed in electric-field-stimulated porous biomaterials ► critical intra-tissue Damköhler number is quantified in the presence of an electric potential ► Damköhler and Deborah numbers quantify electric-field-stimulated chemical kinetics ► mass transfer boundary layer thickness depends on the Damköhler and Deborah numbers

This study examines the relationship between corporate social responsibility and financial performance by analyzing the intra-industry wealth impact of additions and deletions to the Domini Social 400 index. Results from the event study analysis indicate that additions to the index generate a positive share price response for the announcement firm and a negative response by rival firms. The opposite reaction is observed for index deletions. Additionally, the share price response is more pronounced for informationally opaque industries. Our study highlights the importance of external monitoring agencies in providing meaningful information that helps resolve investor uncertainty regarding the quality of a firm's relationships with its primary stakeholders. Copyright © 2011 John Wiley & Sons, Ltd.