Robert A. Pittman

3-amino-1-propanol as a complexing agent in the determination of total gossypol

SummaryA method is proposed for the determination of total gossypol in cottonseed meals, crude oils, and soapstocks based on a rapid extraction of gossypol by neutralized 3-amino-1-propanol in dimethylformamide to form a stable complex, followed by colorimetric analysis of an aliquot of the extract by means of an aniline reaction. A determination can be completed in about 2 hrs. and with minor modification in 1 hr. compared to about 7 hrs. for current methods. Results obtained by the proposed procedure on meals, oils, and soapstocks are in essential agreement with those found by use of other accepted methods. Desirable features, such as stability of reagents and extracts and a high degree of reproducibility, suggest that the procedure will satisfy the requirements for a rapid and simplified method for the analysis of all cottonseed products for total gossypol.

The Changes in Fiber-Number Length Distribution Under Various Breakage Models

Two basic models for the breakage of uniform rods or fibers are discussed—the lost ends in which one of the pieces of each broken rod is discarded from the system and the saved ends under which all fragments are retained. Random breakage is considered as a process with an input length distribution F(x), a breakage function π( x), and an output distribution G(x). General solutions are given so that, from any two functions, the third may be obtained. Cases under which departures from random breakage occur are discussed, and a solution is given for each. Simplifications of the general solutions are show n for the two important cases of breakage independent of and proportional to length, i.e., π( x) = α and #( x) = βx, respectively. Practical application to the length distributions of cotton fibers which had been subjected to varying degrees of damage are given.

Breakage Models and Measuring Techniques for Fiber. Weight-Length Distributions

Previously developed number-frequency equations are translated into their weight- frequency counterparts. A solution is developed for the problem of fiber-length distri bution to be expected when a sliver or similar textile structure, with straight fibers, is cut systematically. A double-clamping technique is described which permits the determina tion of the weight-frequency distribution and weight-mean length of the fiber population in the sliver, with the same assumption that the fibers are straight and parallel to the structure axis. It is shown that, if the fibers are not straight and parallel, the same technique measures the projection of the fibers along the structure axis. Simple methods for measuring the projected length are described and data are represented showing the change in projected length as a typical cotton proceeds from card sliver through roving. The basic mathematical equations for the Lindsley combing ratio are derived, and it is shown that a modification of the Lindsley technique can also yield the projected mean length.

Methods for the determination of cyclopropenoid fatty acids V. A spectrophotometric method for cottonseed oils based upon the Halphen-test reaction

A spectrophotometric method of analysis for the quantitative estimation of cyclopropenoid fatty acids in cottonseed oil based upon the Halphen-test reaction has been described. Various parameters involved in the reaction have been investigated and two pigment fractions responsible for the characteristic Halphen-test cherry-red color have been isolated. The method is applicable to relatively small amts of sample material. The average deviation from the actual cyclopropenoid acid contents as determined by the stepwise HBr titration method was less than ±0.02% in both the refined and crude oil series.

Random-Fiber Breakage Models

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Wide-line NMR spectra of some saturated and unsaturated long chain fatty acids

Wide-line NMR spectra were obtained on a series of homologous normal long chain fatty acids: decanoic, lauric, myristic, palmitic, stearic and behenic as well as three isostructural unsaturated acids: elaidic,trans-5-eicosenoic and brassidic. Also included are NMR spectra of metastable forms of both the saturated and unsaturated acids. NMR parameters are correlated with carbon chain length, crystal long spacing and density. Polymorphic forms are distinguished on the basis of line width and second moment differences.

A Technique for the Characterization of Sorption States in Water—Cellulose Systems by Wide Line NMR

A technique is described by which the protons in water–cellulose sorption systems may be assigned to four categories. The protons are quantitatively divided into water- and cellulose-associated protons and these categories are further subdivided into interchanging and non-interchanging species. The relationships are derived on the assumption that the line narrowing observed in the NMR spectrum of celluloses on the addition of moisture is due to the rapid interchange of some of the water and cellulose protons (or their spins). The experiments were carried out at water–cellulose concentrations of about 7% on a variety of cellulose samples differing in supramolecular structure as characterized by crystalline fraction and lattice type. Data are presented which indicate that the larger the proportion of water protons involved in the interchange process, the larger the spin–spin relaxation time of those water protons not involved in the interchange. It is concluded that linewidth of the narrow component of the water–cellulose NMR signal is not related to sorption processes as simply as previously suggested.

Rating Fabric Luster: A Statistical Evaluation of Panelists and Reflectance Data

, other set consisting of twenty ’white cotton fabrics processed under known laboratory conditions to provide a wide range of luster, were used in a statistical evaluation of fabric luster. The method of paired comparisons was used for presentation of ten fabrics to a panel for ranking according to luster. The coefficient of consistence of each panelist and coefficients of agreement among panelists were calculated. The coefficient of consistence for the same set of paired fabrics was calculated from measured reflectance data. The second set of fabrics was ranked according to decreasing luster by a second group of six consistent panelists and by the instrument. The total numerical rankings of the six panelists for each fabric were used as the consensus ranking Y. Relationships between Y and the instrument values were calculated by use of the correlation coefficients between Y. and the gloss (primarily specular) reflectance X1 and between Y and the diffuse reflectance X2. Possible curvilinearity and joint effects of X1 and X2 were also considered. The gloss component of reflected light was apparently the primary gauge of panelists in ranking luster of fabrics, as the diffuse component of reflected light did not contribute significantly to correlation between panelist rankings and instrument rankings based on gloss as the independent varialbe.

Methods for the determination of cyclopropenoid fatty acids. VII. The dilution-HBr-titration technique as a general method

The stepwise HBr titration method for the cyclopropenoid analysis of cottonseed oils is subject to serious inaccuracies when applied to samples containing higher cyclopropenoid concentrations, particularly if they contain appreciable amounts of alumina-adsorbable materials. A modification of the method is described which eliminates these sources of error. Its validity has been established by the analysis of a wide range of synthetic compositions including compositions containing massive amounts of interfering HBr-reactive substances and other alumina-adsorbable materials. The method with further modification can be used to analyze glycerides with the same high degree of accuracy.

Obtaining Fiber Length Measurements From a Fibrogram

a new instrument results in a claim that the measure results in a number mean length and its coefficient of variation (number basis) by an outlined procedure, and (2) a discussion and statement of Hertel’s approach to the same problem ~3~ and a claim of its inapplicabilitv. No comment will be made at this time on the validity of analysis ~8~ of Hertel’s work (3~. However, introduction of still another measure into the already rather chaotic area of cotton fiber-length statistics deserves a more careful analysis. A fundamental error in ~8) is that their Equation 21 and the following statement &dquo;’I’herefore, it follows that the mean fiber length is twice the area under the fibrogram plus m,&dquo; should refer to the mean fiber length by weight rather than,