Inhibition of the thermal polymerization of styrene

The purpose of this work is to study the rate of reaction and mechanism of various inhibitors in the thermal, uncatalyzed polymerization of styrene. Other attempts have been made to study the inhibitory process, the most recent making use of a dilatometer to measure volume changes during the course of polymerization. However, this method, and others, represents indirect means of study. The spectrophotometric method of study presented here, offers a simple and direct method for determining the rate of disappearance of an inhibitor in the inhibition process, and also affords a method calculating the rate constants for the initiation stage of polymerization. This method however, had its limitations. Only inhibitors which are colored in solution and which lose their color during the inhibition process, can be successfully studied, since all spectrophotometric measurements are made in the visible spectrum. Some of the family of compounds known as quinones come in this category. The method was tried unsuccessfully on a nitroso compound, p-nitrosodimethylainline. The work is divided into two main parts; one dealing with a study of p-benzoquinone, the other study of chloranil (tetrachloroquinone). Each study is further divided into spectrophotometric measurements and viscosity measurements. The purpose of the viscosity data is to correlate and validate the basic assumptions made

Of Persons and Property: The Politics of Legal Taxonomy

To talk of law without politics or history is nonsensical. All lawyers must concede that what they do takes place in historical circumstances and has political consequences. Every piece of law-making and law-application is a governmental act; it relies on political authority and claims binding force. Moreover, all legal activity occurs within a particular historical context; it is intended to respond to or influence a past, existing or anticipated state of affairs. This means that the study of law must concern itself with politics and history generally: it must not confine itself to only the politics and history of law. To do otherwise would be to distort and trivialise any understanding of law. Within such a broad political and historical appreciation, the focus of enquiry is not so much on \u27law\u27 as on \u27law-government\u27 because the idea of law without government is almost oxymoronic.1 Law is not only a symbol and act of power; it is also a major component of the social context in which those symbols and acts of power acquire meaning, significance and effect

Of Persons and Property: The Politics of Legal Taxonomy

To talk of law without politics or history is nonsensical. All lawyers must concede that what they do takes place in historical circumstances and has political consequences. Every piece of law-making and law-application is a governmental act, it relies on political authority and claims binding force. Moreover, all legal activity occurs within a particular historical context, it is intended to respond to or influence a past, existing or anticipated state of affairs. This means that the study of law must concern itself with politics and history generally: it must not confine itself to only the politics and history of law. To do otherwise would be to distort and trivialize any understanding of law. Within such a broad political and historical appreciation, the focus of inquiry is not so much on \u27law\u27 as on \u27law-government\u27 because the idea of law without government is almost oxymoronic. Law is not only a symbol and act of power, it is also a major component of the social context in which those symbols and acts of power acquire meaning, significance and effect

Of Persons and Property: The Politics of Legal Taxonomy

To talk of law without politics or history is nonsensical. All lawyers must concede that what they do takes place in historical circumstances and has political consequences. Every piece of law-making and law-application is a governmental act; it relies on political authority and claims binding force. Moreover, all legal activity occurs within a particular historical context; it is intended to respond to or influence a past, existing or anticipated state of affairs. This means that the study of law must concern itself with politics and history generally: it must not confine itself to only the politics and history of law. To do otherwise would be to distort and trivialise any understanding of law. Within such a broad political and historical appreciation, the focus of enquiry is not so much on \u27law\u27 as on \u27law-government\u27 because the idea of law without government is almost oxymoronic.1 Law is not only a symbol and act of power; it is also a major component of the social context in which those symbols and acts of power acquire meaning, significance and effect

Comparison of Scale Identification Methods in Mixture IRT Models

The effects of three scale identification constraints in mixture IRT models were studied. A simulation study found no constraint effect on the mixture Rasch and mixture 2PL models, but the item anchoring constraint was the only one that worked well on selecting correct model with the mixture 3PL model

Parameter Uncertainty in the Kalman--Bucy Filter

In standard treatments of stochastic filtering one first has to estimate the parameters of the model. Simply running the filter without considering the reliability of this estimate does not take into account this additional source of statistical uncertainty. We propose an approach to address this problem when working with the continuous time Kalman--Bucy filter, by making evaluations via a nonlinear expectation. We show how our approach may be reformulated as an optimal control problem, and proceed to analyze the corresponding value function. In particular we present a novel uniqueness result for the associated Hamilton--Jacobi--Bellman equation

Why Defining the Construct Matters: An Examination of Teacher Knowledge Using Different Lenses on One Assessment

What does it mean to align an assessment to the domain of interest? In this paper, we analyze teachers’ performance on the Learning Mathematics for Teaching assessment of Proportional Reasoning. Using a mixture Rasch model, we analyze their performance on the entire assessment, then on two different subsets of items from the original assessment. We consider the affordances of different conceptualizations of the domain and consider the implications of the domain definition on the claims we can make about teacher performance. We use a single assessment to illustrate the differences in results that can arise based on the ways in which the domain of interest is conceptualized. Suggestions for test development are provided