Choosing the Right Model

Building Agent-Based Models requires assumptions (as does building any model).The advantage of ABM is the assumptions can be realistic, rather than made in order to solve a calculus-based problem. But what does "realistic" mean? I shall outline the issues of verification of a model (is it working as the modeller wants?) and validation of a model (how close is the model behaviour to some measures of reality?), after talking about the general issue of choosing models.Australian Research Council DP0881799 IF Wilkinson, RE Marks and LC Young; Discipline of Marketing, The University of Sydney Business School; The University of Sydney Business School; Australia New Zealand Marketing Academy; School of Marketing, University of Western Sydney; Discipline of Marketing, The University of Western Australia Business Schoo

Biological Treatment of Hazardous Waste Sludges in Suspended Growth Systems for Removal of Benzo(a)pyrene and Other Polynuclear Aromatics.

The scope of this research project was to develop a bioremediation process for accelerated oxidation of bioresistant hazardous waste sludges in continuous flow sludge reactors. Benzo(a)pyrene (BaP) was selected as the target compound due its strong bioresistance, highly carcinogenic nature, extremely low aqueous solubility, and extremely low allowable release limits for land disposal. BaP is often a major hazardous organic component in many hazardous waste impoundments when source wastes have originated from either petroleum refining or associated petrochemical facilities. There is evidence that the biodegradation rate of high molecular weight polynuclear aromatic hydrocarbons (PNA\u27s) is the rate limiting step in liquid-solids contact systems in spite of the low solubilities of these compounds (Sherman et al., 1989). The biological half-lives reported in the technical journals for low concentrations of high molecular weight PNA\u27s typically varies from 1-3 years for land disposal, 1-3 days in static batch reactors, and 2-3 days in mixed batch reactors. There is virtually no published data for successful treatment of high concentrations of PNA\u27s in high-solids suspended growth reactors. The recalcitrance of the PNA\u27s is believed due to the lack of suitable co-substrates containing primary source carbon which would permit rapid acceleration of the biodegradation process and foster fortuitous transformation of BaP and other PNA\u27s. Bench-scale pulsed-flow continuous sludge reactors feeding petrochemical sludge containing 8,700-35,000 mg BaP/kg of dry feed solids averaged 90% w/w destruction at equilibrium conditions. The biological half-life of BaP varied from 0.8-1.4 days and demonstrated that an enhanced environment increased the destruction of BaP at rates up to 2.5 times faster than mixed batch reactors, and 300-1000 times faster than land treatment. Steady state models were developed which predicted total suspended solids, BaP substrate, and oil co-substrate concentrations. The rapid contact bioremediation process (RCBP) developed in this dissertation research, has demonstrated that destruction of the anthropogenic-source annual production and existing accumulations of bioresistant toxic hydrocarbons is a practical goal. This research describes how indigenous microbial consortia can adapt to new strategies for destruction of bioresistant compounds if the microbial environment is appropriately enhanced

Studies in 2-Naphthol Derivatives

This thesis consists of two sections. The first section deals with the sodium hydroxide induced rearrangement of l-methyl-2-bromo-3H-naphtho (2,1-b) pyran-3-one. This reaction had already been studied by Dey and Lakshminarayanan, who identified the products as 2-(2-hydroxynaphth-l-yl) propanal and 1-methylnaphtho (2,1-b) furan-2-carboxylic acid: The naphthylpropanal would be a useful starting material for the synthesis of l-alkyl-2-naphthols, so we attempted to repeat this rearrangement. When the Indians' conditions were followed, no clean and tractable products resulted. Air oxidation and dehydration of the initial products seemed to occur. The reaction and work-up were therefore performed under nitrogen and acidification of the reaction mixture was done with carbon dioxide. Under these conditions, two products were isolated. The main product (78%) is 1-(2-hydroxynaphth-1-yl) propan-2-one. The minor product (7%) is 2-methylnaphtho (2,1-b) furan-1-carboxylic acid: These structure assignments are supported by elemental analyses, full spectral data and chemical transformations on both products. A critical review of Dey's published evidence suggests that he had isolated the same products as we did, but assigned an erroneous structure to each as a result of inadequate spectral evidence, uncritical interpretation of chemical evidence and over-reliance on analogies. Mechanisms for the displacement of halides from sp2 hybridised carbons, in a-halolactones and in related systems is reviewed in the Introduction. From this large group of reactions, only the formation of Feist's acid from 2-bromo-4,6-dimethy 1-5-ethoxycarbonylpyrone seems to bear any similarity to the aryl shift wo observe with the methylbromonaphthopyran. The unique occurrence of this rearrangement in this compound is rationalised in terms of the steric congestion due to the methyl group in this particular bromopyrone. The second section deals with synthesis and epoxidation of various 2(1H) naphthalenones. 1-Hydroxy-1-isopropyl-2(1H) naphthalenone has been reported to give on treatment with Na2CO3/H2O2 in aqueous ethanol only one epoxide (90% yield) with the epoxide oxygen on the opposite face (trans) to the hydroxyl group. The same author also reported the 1-acetoxyl analogue to yield the trans epoxide exclusively. There are relatively few such cases of stereospecific epoxidation of dissymmetric enones in the literature and the factors controlling which face of the enone is epoxidised are not all understood. Leppards epoxidations were repeated and the reported results confirmed, save that the 1-acetoxyl compound underwent substantial hydrolysis of the acetoxyl group (only 36% of a single acetoxy-epoxide was isolated). In order to explore the structural requirements for this steric control a range of 2(1H) naphthalenones with different alkyl and oxygen-containing functions on C was made. In addition to the two compounds already mentioned, 2(1H) naphthalenones bearing the following pairs of substituents on C were successfully synthesised: methyl and hydroxyl; methyl and acetoxyl; methyl and methoxyl; ethyl and acetoxyl; isopropyl and trimethylsilyloxyl. Attempts to synthesise and isolate the compound bearing isopropyl and methoxyl on C by alkylation of the 1-hydroxyl compound were unsuccessful. Epoxidation with alkaline hydrogen peroxide of 1-acetoxy-1-methyl-2(lH) naphthalenone and 1-isopropyl-1-trimethylsilyloxy-2(1H) naphthalenone led to the complete hydrolysis of the acetoxyl and trimethylsilyloxyl groups respectively. The epoxide isolated in both cases was the same as that from 1-hydroxy-1-alkyl-2(1H) naphthalenone. Epoxidation of 1-hydroxy-1-methy1-2(1H) naphthalenone and of 1-methoxy-1-methyl-2 (1H) naphthalenone gave one simple epoxide in each case (assumed trans). The 1-hydroxy-1-methyl compound also gave a material which seemed to be a dimer of the simple epoxide. Although in all cases studied only one stereoisomer was formed in the epoxidations it was difficult to prove its stereochemistry. 13C and lanthanide shifts of 1H NMR spectra were studied but no conclusions could be drawn from them about the stereochemistry of the epoxides. The Introduction consists of a selected survey of published examples of epoxidations and related processes in which stereoselective product formation took place. In some cases this outcome might have been anticipated, and in others not. A critical examination of the explanations given does not appear to reveal any underlying unity of cause

Dispossessed Again: Paiute Land Allotments in the Mono Basin, 1907-1929

Like most California Indians, the Kutzadikaa people in the Mono Basin on the east side of the Sierra Nevada Mountains were dispossessed of their land in the second half of the nineteenth century. However, they were not then removed to a reservation. They were left landless with no rights to reclaim their land until the Dawes Act (1887) made land allotments to non-reservation Indians possible. This article explores the history of land allotments in the Mono Basin, and places that story into the broader context of U.S. assimilationist policies but more importantly into the context of local history. Kutzadikaa (later called Piute or Paiute) had to maneuver the land and water bureaucracies of the U. S. federal and California state governments, as well as the larger winds of capitalist development in an arid environment that commercialized land and water rights. Those Paiuteswho received allotments worked hard to farm and ranch them, but within a decade of receiving their allotment they faced pressures to sell their them to Euro-American landowners who had come to monopolize land and water rights in the Mono Basi

Sheep Replace Pronghorn: An Environmental History of the Mono Basin

This article examines the ways in which the hunting-gathering people of the Mono Basin lived before their way of life and environment was overturned by the nineteenth-century arrival of Euro-American settlers with vastly different ways of interacting with the environment. And it tracks some of these alterations by tracking when and how sheep replaced pronghorns

Mr. Clover Goes to Washington: Land, Water, and Fraud in the Mono Basin, 1910-1945

The water woes of the Mono Basin of the Eastern Sierra region of California did not begin when Los Angeles\u27 Department of Water and Power began to purchase water rights there in the early twentieth century. Robert Marks argues persuasively that James B. Clover\u27s water schemes predated, and in a sense, opened the way for Los Angeles later to tap Sierran snowmelt and funnel it down to Southern California