Determination of relative reactivity ratios (copolymerization parameters) for styrene and acrylamidostearic acid

Thesis (M.A.)--Boston UniversityAcrylamidosteric acid is both a monomer and (as its potassium salt) a soap. This problem was undertaken in order to establish fundamental copolymerization parameters for the system styrene, M1, and acrylamidostearic acid, M2. The propagation steps in the copolymerization of two monomers M1 and M2 are illustrated by the four equations: Equation: M1' + M1 ---> M1', Rate Constant: k11 Equation: M2' + M2 ---> M2', Rate Constant: k12 Equation: M2' + M2 ---> M2', Rate Constant: k22 Equation: M2' + M2 ---> M1', Rate Constant: k21 where M1' and M2' represent chain radicals having monomers M1 and M2 respectively, as their terminal, free-radical-bearing units. The fundamental parameters are defined as r1 = (k11/k12) and r2= (k22/k21). The polymerizations were run in tubes which had a side arm viscometer so that it was possible to determine whether any conversion had taken place during the experiment. After polymerization had produced evidence of some conversion (as indicated by the attached viscometer), the reaction tubes were cooled in a Dry Ice acetone bath. The contents of the tube were then subjected to a purifying procedure which for this system required that the mixture of monomer and polymer be precipitated four times from a dioxane solution by a four fold excess of ligroin. This procedure was deduced from preliminary solubility studies of monomer and polymer. The purifying procedure was tested by preparing synthetic mixtures of both monomers and polymers in proportions which amounted to a ten percent conversion of monomer to polymer. From the results of the test of the purification procedure a correction factor was calculated by which the experimentally determined values of the polymer composition were corrected. The calibration factors were determined by analyzing known mixtures of the two homopolymers. Five copolymerization runs were made in bulk at 65° with 0.5--0.6 mole percent initiator (dibenzoyl peroxide) to low conversion. The values for the relative reactivity ratios are as follows: r1 = 2.12, r2 = 0.36. These were determined by plotting the data according to the equations of Fineman and Ross: F(f-1)/f = r2*(F2/f)-r2 (f-1)/F= -r2*(f/F2) + r1 where F=F1/F2 (F1 and F2 are the initial mole fractions of monomers in the charge) f=f1/f2 (f1 and f2 are the mole fractions of the polymers). In order to visualize the accuracy of the results a theoretical curve of incremental polymer composition as a function of monomer composition was constructed using the above values of r1 and r2. The experimental points were then placed on the same curve. All the points fell close to the curve thus indicating acceptable results

Free field realizations of the Date-Jimbo-Kashiwara-Miwa algebra

We use the description of the universal central extension of the DJKM algebra $\mathfrak{sl}(2, R)$ where $R=\mathbb C[t,t^{-1},u\,|\,u^2=t^4-2ct^2+1 ]$ given in earlier work to construct realizations of the DJKM algebra in terms of sums of partial differential operators.Comment: arXiv admin note: substantial text overlap with arXiv:1303.697

Airborne lidar stratospheric ozone and aerosol investigations

The objectives are to study the distribution of ozone (O3) and aerosols across the polar regions during the winter and spring periods and to relate these observations to chemical and dynamical processes that can contribute to the chemical perturbation of the polar stratosphere and the possible destruction of O3. The distribution and characteristics of stratospheric aerosols and polar stratospheric clouds (PSCs) are required to understand heterogeneous chemical processes that can lead to O3 depletion, and observation of O3 variations are important in the direct detection of O3 depletion and in tracing atmospheric dynamics. An airborne Differential Absorption Lidar (DIAL) system is operated in a zenith mode from the NASA DC-8 aircraft to obtain data on the large scale spatial variability of O3, and aerosol/PSC's in the lower stratosphere from about 11 to 23 km for O3, and 11 to 28 km for aerosols. The variability of O3 and aerosols/PSCs is studied in relation to chemical processes that can produce O3 depletion and to dynamics in the lower stratosphere that transport gases and aerosols inside the vortex and in some cases, across the edge of the vortex

Proposals for Multiple Component Pricing in Midwest Federal Milk Marketing Orders

Agricultural and Food Policy, Demand and Price Analysis, Livestock Production/Industries,

Towards a software profession

An increasing number of programmers have attempted to change their image. They have made it plain that they wish not only to be taken seriously, but they also wish to be regarded as professionals. Many programmers now wish to referred to as software engineers. If programmers wish to be considered professionals in every sense of the word, two obstacles must be overcome: the inability to think of software as a product, and the idea that little or no skill is required to create and handle software throughout its life cycle. The steps to be taken toward professionalization are outlined along with recommendations

U.S. Imports of Concentrated Milk Proteins: What We Know and Don't Know?

International Relations/Trade, Livestock Production/Industries,

"A New Approach to Tax-Exempt Bonds, Infrastructure: Financing with the AGIS Bond"

The current system of tax-exempt bond financing is inefficient and inequitable because a large portion of the federal subsidy provided by the tax exemption does not reach state and local governments and accrues instead to the wealthiest investors. In addition, the current system excludes large institutional investors, both domestic and foreign, with their huge pools of capital, and it lacks the stable oversight characteristic of the taxable bond market. Regan and his associates have developed a new security concept to overcome these weaknesses. The American global infrastructure security (AGIS) bond has two components that are sold separately--tax exemption and income flow--creating a taxable bond for sale in the regular capital markets in addition to the tax exclusion benefit.

Lidar measurements from space for tropospheric chemistry investigations: Summary of workshop overview presentation

Over the past decade, NASA has played a lead role in defining the scientific objectives and technology requirements for spaceborne lidar investigations of the atmosphere. An assessment of the potential for conducting lidar measurements from space for investigations that pertain specifically to tropospheric chemistry is presented. A description of potential lidar measurement techniques is given, and the scientific requirements for tropospheric chemistry are reviewed. The current status of airborne lidar measurements of aerosols, O3, and H2O is discussed, and a brief description of the evolution of lidar technology to space is given. Also, the measurement of tropospheric gases with a spaceborne lidar system is evaluated for a wide range of gas species. From this general assessment, it appears feasible to measure aerosols, H2O, O3, NH3, CO, CH4, NO2, atmospheric pressure and temperature, and wind with a lidar from space provided that the appropriate laser and receiver technology is available. For the mid-1990's, it is expected that lidar technology will be available for the measurement of aerosols, H2O, and O3 from a space platform

Section 102: The California Make Allowance Issue

Agricultural and Food Policy, Livestock Production/Industries,