Diagnostic analysis of RO desalting treated waste water

Diagnostic analysis of reverse osmosis membranes that were fed with Western treatment plant (WTP) recycled water was investigated by both thermodynamic calculations and laboratory experiments in order to predict the feasibility of RO desalting for WTP. The thermodynamic calculations suggested that RO recoveries of 80–85% were feasible with careful control of feed water pH and the use of chemical additives such as antiscalants and chelating agents, it also predicted the major minerals of concern to be silica, calcium fluoride, calcium carbonate, and calcium phosphate. Following the thermodynamic simulations, diagnostic laboratory experiments were undertaken. The experiments showed that the major contributor to scale formation was indeed calcium phosphate and possibly another calcium based compound, which was strongly suspected to be calcium carbonate. Based on previously published literature that indicated anti-scalants did not substantially decrease the scaling effect of calcium phosphate and laboratory tests that indicated controlling the pH to 6.4 in the feed water dramatically reduced scaling formation, it was suggested that the feed water could be controlled by pH adjustments only. Inter-stage pH correction was suggested as an optional technique to enhance the overall water recovery to above 95%

The Epsilon Calculus and Herbrand Complexity

Hilbert's epsilon-calculus is based on an extension of the language of predicate logic by a term-forming operator $\epsilon_{x}$. Two fundamental results about the epsilon-calculus, the first and second epsilon theorem, play a role similar to that which the cut-elimination theorem plays in sequent calculus. In particular, Herbrand's Theorem is a consequence of the epsilon theorems. The paper investigates the epsilon theorems and the complexity of the elimination procedure underlying their proof, as well as the length of Herbrand disjunctions of existential theorems obtained by this elimination procedure.Comment: 23 p

Innovative Behavior of Destination Marketing Organizations

The role of destination marketing organizations changed considerably over the past few decades. Today, these organizations are not only marketers of a certain area, but are also required to constantly develop new tourism offerings to keep pace with fast changing consumer demands and a volatile economic environment. The purpose of this study was to identify if American destination marketing organizations collaborate with other organizations to develop new services and to identify drivers of collaboration for innovation. Furthermore, the authors evaluated the impact of organizational settings for innovation and partnerships development on organizations’ partnership-for-innovation behavior. It was found that top management support for partnerships as well as a long-term perspective towards partnerships is the foundation of partnerships that can lead to innovation. Several other organization settings (e.g. top management support for innovation) increase the likelihood of establishing such partnerships

Evolution of a Bridge Builder Outreach Activity

Many engineering outreach programs use building a bridge as a hands-on activity for multiple grade levels and audiences. South Dakota State University has used a bridge building activity, with slight modifications for grade level and time allowed, for over 10 years in outreach at schools and campus workshops. In recent years, it has been noted that the same level of students attending these outreach events are either performing the same or a similar activity at their school or another event outside of our outreach program which has adversely affected using this activity to stimulate interest in engineering. In the last two years, modifications have been made to create a bridge builder challenge that incorporates measurement, experimentation, simulation, design, and redesign for middle and high school students. Incorporation of design standards and performance as well as economic efficiency has been the key to linking science principles to engineering principles. Details of the activity and its implementation are discussed

Crystallization of classical multi-component plasmas

We develop a method for calculating the equilibrium properties of the liquid-solid phase transition in a classical, ideal, multi-component plasma. Our method is a semi-analytic calculation that relies on extending the accurate fitting formulae available for the one-, two-, and three-component plasmas to the case of a plasma with an arbitrary number of components. We compare our results to those of Horowitz, Berry, & Brown (Phys. Rev. E, 75, 066101, 2007), who use a molecular dynamics simulation to study the chemical properties of a 17-species mixture relevant to the ocean-crust boundary of an accreting neutron star, at the point where half the mixture has solidified. Given the same initial composition as Horowitz et al., we are able to reproduce to good accuracy both the liquid and solid compositions at the half-freezing point; we find abundances for most species within 10% of the simulation values. Our method allows the phase diagram of complex mixtures to be explored more thoroughly than possible with numerical simulations. We briefly discuss the implications for the nature of the liquid-solid boundary in accreting neutron stars.Comment: 14 pages, 5 figures, submitted to Phys. Rev.

Online Purchase of Travel Products

The Internet has become the primary channel for the purchase of travel-related products such as airline tickets and hotel reservations. This study examines the range and pattern of travel-related products purchased online by American travelers. The results indicate that American travelers can be classified into three travel product groups, ranging from the “Core Traveler” to “Complete Traveler.” Importantly, travelers in these three groups are significantly different in terms of demographic characteristics, information search behavior, and travel planning activities. These findings offer a number of important theoretical and practical implications for destination marketing