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Drawn fibres of high-density polyethylene, and their crystalline residues obtained by nitric acid digestion of the amorphous phase, exhibit single- or double-peaked melting endotherms depending on the degree of crystallinity of the fibre, the draw ratio and, in the case of some of the crystalline residues, whether or not they have been melted once or twice. The melting behaviour of the drawn fibres and their crystalline residues has been accounted for in terms of the rupture of a fraction of the original lamellar structure and the growth of a new crystalline structure.

Gelation in reactions of Niax triols with hexamethylene and decamethylene di-isocyanates has been studied. The gel points occur at extents of reaction in excess of those predicted by Flory-Stockmayer theory. The excess, intramolecular reaction increases with dilution and with decreases in the molecular weights of the reactants. Kilb's theory of gelation does not explain the results, but a semi-quantitative explanation is found in terms of a combination of Frisch's and Kilb's theories. In this, λ, the intramolecular branching parameter of Frisch, is given by the equation λ = const .v − 3 2 ( OH 0 + NCO 0 ) −1 , with v the number of bonds in the smallest ring which can form.

The rate of sorption of an acid dye by a nylon fabric is strongly influenced by mass–transfer processes in the liquid phase, even at rates of flow far exceeding those to be expected in existing commercial dyeing equipment. It is suggested that concentration gradients exist in the solution within the yam elements of the fabric, and the individual fibres in the yarn elements are shown to differ in their accessibilities to dye; the yarn cross–sections are ‘ring–dyed’. In spite of these complexities the major features of the overall mass–transfer process are well represented by a simple model based on the concept of an equivalent diffusional boundary resistance to mass transfer. The numerical values obtained for δ are comparable with the yarn dimensions, which reflects the ‘coalescence’ of the individual boundary layers to form a region within the yarn elements in which dye transport by convective diffusion in the liquid phase limits the overall mass–transfer rates.

The injection process using calcium carbide based mixtures as a desulfurlzing agent is safe and economical.

The accelerated rate of diffusion of disperse dyes into synthetic fibers caused by various dyebath additives (“carriers”) has been correlated with their plasticizing action. The rate of change in length of Acrilan filaments with temperature under dyebath conditions enabled the effects of the carrier on the Tg of the filaments to be measured, and the results for different concentrations of carrier at one temperature could be superimposed on a common curve by employing suitable shift factors. The shift factors, as well as the variations of the diffusion coefficients of dyes with temperature and carrier concentration, both matched a WLF relationship, confirming that the dyeing process is controlled by the segmental mobility of the polymer. Indirect experimental evidence suggests that the same relation will describe the effect of carriers on the dyeing of poly(ethylene terephthalate) substrates with disperse dyes.

The equilibrium adsorption of a series of leuco vat dyes on cotton has been measured in various concentrations of sodium chloride and sodium hydroxide. From the results the thermodynamic affinities have been calculated. Deviations from theory are observed in so far as the affinities are not constant, but show a regular drift as the concentration of electrolyte is changed. This drift is more apparent when the added electrolyte is sodium chloride than when it is sodium hydroxide. Two explanations for these deviations from theory are proposed and discussed— either the theory is inadequate to account for the facts, or the leuco solutions of the dyes are not true solutions but are in fact aggregated.

Dyeing in excess of the amino content of the nylon can be obtained with dyes of the Carbolan type from solutions of pH 45. This is accompanied by some hydrolysis, but insufficient to account for the whole of the dye uptake, and it is suggested that dyeing is to a large extent due to non-ionic affinity of the dye anions. There is evidence that the dyes form micelles in solution and that this determines the maximum rate of dyeing.

This paper describes the methodology for a nutrient balance to evaluate the sources and distribution of nutrients in a small river basin. Loadings for total nitrogen and phosphorus are calculated from measured nutrient concentration and river discharge data. Using a special retrieval program and a data storage and processing system, loadings are accumulated over a given time period to allow for time of passage through the basin and seasonal changes in nutrient distribution. Nutrient balances are made with the accumulated loadings to obtain the relative contribution of each nutrient source and the retention of nutrients within the basin through sedimentation and aquatic growth. The methodology has been used to study nutrients in the Qu'Appelle River Basin, Saskatchewan, Canada.

A series of poly(ethylene adipates) with molecular weights between 1800 and 15 000 were prepared, and were extended by reaction with di-isocyanates. In one series of extended polymers the different polyesters were all extended with tolylene di-isocyanate whilst in a second series a polyester of molecular weight 3000 was extended with 4 different di-isocyanates. The glass transition temperatures and melting points of all polymers were studied. The variation of Tg of homopolymers with molecular weight was not adequately represented by the usual equations and it was concluded that the OH end groups are tied into the structure. On the other hand the variation of Tm with molecular weight obeyed the Flory equation and leads to a value for the heat of fusion similar to that obtained by Edgar and Ellery by the copolymer method. The observed values of Tg and Tm of the copolymers did not agree with values calculated by random copolymer theory. In the case of melting points it is likely that the discrepancy arose from the disparate nature of the ethylene adipate, crystallizable, units and the di-isocyanate, non-crystallizable, units; the latter distorted the structure so badly that a number of neighbouring crystallizable units were prevented from crystallizing.

Inadequacies are demonstrated in previous attempts to explain dyeing mechanisms on the assumption of polar forces between dye and fibre. The important part played by non-polar forces in adsorption phenomena generally is illustrated by examples. It is postulated that such forces are mainly responsible for dye-fibre attachment and that in aqueous solution they occur between hydrophobic surfaces. The relative importance of hydrophobic and hydrophilic properties in fibres is deduced from their moisture regain figures and is discussed in relation to fibre structure. The properties of dyes are then similarly considered. Thence the dyeing behaviour of each type of fibre is predicted from the postulate that dye substantivity is due to non-polar forces. It is concluded that this assumption is sufficient to explain the methods adopted for dyeing different fibres and that it eliminates anomalies incapable of explanation on the assumption that dye-fibre attachment is due to polar forces.

The losses of amino acids and related compounds have been studied during hemodialysis of patients with the Kiil dialyzer and the Dow Hollow Fiber Artificial Kidney (HFAK). There was a linear relations

Experiments were performed in order to verify the resettability of the hydrogen maser. The method consisted of measuring the output frequency of one maser against the hydrogen pressure. It was found that at a given tuning of the cavity no shift larger than 2.1 parts in 1013 was observed for a change of 4 to 1 in pressure. This experiment also showed that the pressure shift due to exchange collisions, predicted by Bender, could not be observed for the field-independent transition in the hydrogen maser. Two masers, having the same storage bulb design and the same wall coating, were tuned by this technique and were found to have a frequency difference of 7.6 parts in 1013. Experiments on the wall coating of the hydrogen maser storage bulb were made. Relaxation and decorrelation times of various materials were measured. The hyperfine splitting of the ground state of hydrogen measured against cesium is also given.

Assessing the activity of the thyroidal iodide pump by measuring the thyroid/serum radioiodide gradient (T/S), we found the stimulatory effect of TSH to have a latency of from about 8 hours to 12 hours or more. The longer latent periods were observed in rats whose initial T/S was relatively high. The rise in the T/S was preceded by a depression of this ratio, whether hypophysectomized, normal, or triiodothyronine (T3) treated rats were injected with TSH. This biphasic response was elicited with Armour TSH, lyophilized rat pituitary tissue and Bates' highly purified mouse tumor and bovine TSH preparations; it seems therefore reasonable to attribute it to TSH proper rather than some contaminant(s). The same kind of response was also observed in rats whose thyroids were purged of organic iodine with goitrogens and whose endogenous TSH output was subsequently inhibited by giving T3 along with the antithyroid drugs; this indicates that the initial depression of the T/S is not due to flooding of the thyroidal i...

Es wird eine Methode zum Nachweis und zur quantitativen Bestimmung gesattigter, mehrfach verzweigter Fettsauren (VFS) in tierischen und pflanzlichen Fetten beschrieben. Die Methode beruht auf der gas-chromatographischen Bestimmung der VFS-Methylester in den mit Harnstoff nicht addierenden Methylestern. Es wurden folgende Mengen an VFS in tierischen Fetten be-stimmt: Walol 15 000 ppm, Fischol 6000 ppm, Butterfett 4000 ppm, Rindertalg 2000 ppm und Schweineschmalz 110 ppm. In verschiedenen pflanzlichen Olen und Fetten wurden bis zu 200 ppm an VFS gefunden. Nicht nur Unterschiede im Gesamtgehalt an VFS, sondern auch in ihrer prozentualen Zusammensetzung und ihren Retentionsvolumina im Gas-Chromatogramm wurden gefunden. Diese Methode bietet deshalb eine Moglichkeit zur Identifizierung einiger tierischer Fette. Detection of Traces of Polybranched Fatty Acids in Fats A method for the detection and quantitative determination of saturated polybranched fatty acids in animal and vegetable fats is described. The method is based on gas-chromatographic determination of polybranched fatty acid methyl esters in the methyl esters which do not form urea adducts. The following amounts of polybranched fatty acids were determined in animal fats: whale oil 15 000 ppm., fish oil 6000 ppm., butter fat 4000 ppm., beef tallow 2000 ppm. and lard 110 ppm. In different vegetable oils and fats upto 200 ppm. of polybranched fatty acids were found. Not only the difference in total content of polybranched fatty acids but also differences in their percentage composition and retention volumes in gas-chromatograms were found. This method therefore offers the possibility of identification of some of the animal fats.

The melting characteristics of high-density polyethylene have been shown to be dependent on molecular weight and molecular weight distribution as well as on annealing and crystallizing history. The phenomenon of double melting endotherms is explained on the basis of a molecular weight fractionation process occurring during annealing and crystallization in which there is preferential crystallization of low or high molecular weight species according to the temperature. Reference is made to other polymers exhibiting similar behaviour.

The diffusion of acid dyes in nylon 6.6 film has been examined by the measurement of the concentration distribution through the film. For a series of films prepared by different methods, the shape of the distribution curve was independent of the history of the film. Dyes of different basicity have been shown to give approximately the same shape of curve, provided that the surface concentrations are the same. The variations of the concentration-distribution curve with salt concentration and pH are given. The results are explained in terms of the electrochemical potentials of the dyes.

The urine amino-nitrogen and creatinine excretion were studied in normal children and adults. From the results, the amino-nitrogen/creatinine ratio was calculated with special reference to the assumed constancy of creatinine excretion in urine of healthy subjects. The reviewed literature and the present results show that creatinine excretion varies in a wide range. The advantage of creatinine ratios as well as the validity of creatinine correction for incomplete urine collections are challenged.

The affinities of a series of anthraquinone and carbocyclic vat dyes have been determined. The attraction for the fibre appears to arise from two main causes- polar or hydrogen bonding and non-polar or van der Waals forces. The results are analysed in terms of these. It is found that, in a series of related compounds, a relationship exists between the affinity and the van der Waals forces as determined by the extinction coefficients of the dyes.

An apparatus and procedure to determine the amounts of sol and gel rubber in dried latex films and crude rubber have been described. It is shown that whereas plantation smoked sheet and crepe contain large and varying quantities of rubber soluble in petroleum ether, dried rubber films from latex are practically free from sol rubber when oxidation has been avoided. Latex increases in sol rubber content when subjected to various treatments permitting oxidation of the hydrocarbon. It appears from this work that the rubber in the form of latex is very susceptible to oxidation, which however involves only minute quantities of combined oxygen. When latex film rubber is subjected to creeping, it shows an increased content of sol rubber corresponding to that of crepe. A short milling of crepe was found to convert it completely into sol rubber. This confirms the gel-sol transformation mechanism of breakdown. Gel rubber from dried latex films is swelled to a maximum of 1500 to 7800 per cent but is not diss...

Die Hypervitaminose A der Ratten kann durch Thyroxin verhutet und geheilt werden. Bei der experimentellen Thyreotoxikose konnte durch Vitamin A wieder normales Wachstum erreicht werden. Dabei reicherten sich Carotin und Vitamin A wieder in der Leber an. Die antagonistische Wirkung des Vitamin A ermoglichte aber nicht die gleichzeitige Speicherung von Fett und Glykogen in der Leber. In den vorliegenden Versuchen wirkte auch Fett in Form von Erd nusol heilend auf die Thyreotoxikose. Die Leber zeigte auch hier eine Wiedereinlagerung von Carotin und Vitarmin A in der Leber, nicht ebar eine solche von Fett und Glykogen.

An apparatus and procedure to determine the amounts of sol and gel rubber in dried latex films and crude rubber have been described. It is shown that whereas plantation smoked sheet and crepe contain large and varying quantities of rubber soluble in petroleum ether, dried rubber films from latex are practically free from sol rubber when oxidation has been avoided. Latex increases in sol rubber content when subjected to various treatments permitting oxidation of the hydrocarbon. It appears from this work that the rubber in the form of latex is very susceptible to oxidation, which however involves only minute quantities of combined oxygen. When latex film rubber is subjected to creeping, it shows an increased content of sol rubber corresponding to that of crepe. A short milling of crepe was found to convert it completely into sol rubber. This confirms the gel-sol transformation mechanism of breakdown. Gel rubber from dried latex films is swelled to a maximum of 1500 to 7800 per cent but is not dissolved when placed in benzene, chloroform, carbon tetra-chloride or carbon disulfide and allowed to stand for several days. Gel rubber becomes soluble and therefore diffusible in these solvents as a result of oxidation. It was found that dried latex film and various types of crude rubber swelled to a maximum of 1000 to 2400 per cent in petroleum ether and that this swelling was not proportional to the sol content. This investigation strengthens the belief that sol rubber is an oxidation product of gel rubber. The formula for sol rubber is suggested as (C5H8)nO2, and a relationship between the molecular weight and the oxygen content is postulated on the basis that oxygen acts as a molecular splitting agent for both gel and sol.

Rate-of-dyeing curves have been measured for nylon dyed under very acid conditions (pH ca. 1.5). The curve falls into two parts; in the initial stages the uptake is rapid, and this is followed by a slow increase in dye concentration which does not reach a maximum. By stripping the dye from the fibre and redyeing under conditions of high pH, the number of free amine ends has been estimated. From the results it has been shown that during the second part of the rate-of-dyeing curves hydrolysis occurs, giving an increased number of amine groups. The amount of dye taken up at the low pH values is, how- ever, far in excess of that required to saturate the amine group and must be accounted for by “amide group” dyeing. Viscosities have also been used to confirm the hydrolysis. The picture of the dyeing process at low pH is, therefore, initial absorption of dye on to sites provided by the peptide groups either as the free dye acid or by absorption of the hydrogen ions in the dyebath followed by the dye anion. Simultaneous with the absorption is a slow but definite hydrolysis of the nylon molecules with consequent degradation of the fibre.

Recently published work on the uptake of acid dyes by nylon is discussed. The concept of anion activity gradient as the driving force for diffusion of dyes in nylon is applied to the uptake of mixtures of acid dyes and the problem of compatibility. It is shown that the properties of single acid dyes in finite dyebaths may be represented by “compatibility indices” and that incompatibility is entirely determined by liquor ratio.

1. Evaporated latex films and Bolivian fine para contain a chloroform-soluble fraction of about 62 per cent, whereas the soluble portion of crepe and smoked sheets is about 86 per cent. The average molecular weight of these sols, which contain the low polymers and “resin”, range from about 130,000 to 180,000, the more soluble type having the lower value. 2. Diffusion and precipitation methods were employed to fractionate R. C. M. A. crepe, and the following data indicate the approximate composition and molecular weight range of the soluble hydrocarbon fractions separated: 3. The chloroform-insoluble portion of crepe contains a nonlinear type of hydrocarbon, judged by x-ray and viscosity studies. These methods show that the chloroform-insoluble portion of ammonia-preserved latex films contain extremely high-molecular rubber hydrocarbon which is easily oriented to give the regular x-ray crystalline pattern for rubber. 4. Freshly tapped latex contains a large proportion of petroleum-ether-soluble fraction, which becomes insoluble in this solvent on standing in the presence of ammonia. Ammonia-preserved latex films are soluble in chloroform or in hexane containing alcohol-acetone or acetic acid; this insolubility is thus an association effect, which is overcome by the addition of a polar solvent. 5. Viscosity studies on fractions of balata and gutta-percha show that their hydrocarbons have an average molecular weight of about 42,000 and cover a narrow polymeric range.

Durch thermodilatometrische und DTA-Untersuchungen wurde das thermische Verhalten von C-Typ-PrO1.50, A-Typ-PrO1.50 und PrO1.833 im Temperaturintervall von Raumtemperatur bis 1200 °C in Luft und Wasserstoff-Atmosphare untersucht. Die Temperatur des Phasenuberganges C-PrO1.50 → A-PrO1.50 wurde zu 790±10 °C gefunden. C-PrO1.50 ist nur unterhalb der Umwandlungstemperatur bestandig, A-PrO1.50 im gesamten untersuchten Temperaturbereich. PrO1.833 geht oberhalb von 400 °C, in Luft erhitzt, uber mehrere definierte oxidische Zwischenphasen in A-PrO1.50 uber.

IT HAS been demonstrated that hypothalamic-adenohypophyseal regulatory mechanisms maintain the production and release of thyroid hormone within euthyroid limits (1, 2). Previous observations from this laboratory have indicated that without exogenous thyroid or iodide intake the protein-bound iodine in healthy adults remains relatively constant (3). Granting adequate analytic precision, such constancy is compatible with, but does not necessarily support, the existence of a “feed-back” mechanism activated by changes in the plasma level of thyroid products. Introduction of exogenous thyroid products into such a system should provide evidence, however, concerning the presence and the efficiency of such adaptive responses. This report describes the effects of thyroid feeding on serum protein-bound iodine levels and other pertinent indices in euthyroid adult males. PROCEDURES Desiccated thyroid of the same lot number1 was administered in amounts ranging between 1 and 6 grains per day to 9 presumably healthy adu...

1. The cryoscopic method is not satisfactory for polystyrenes containing more than twelve styrene units in the chain on account of the failure of their solutions to obey Raoult's law. 2. The present work has established a new Kcm value of 0.45×104 for benzene solutions of polystyrene to be used in the equation: A Kcm value of 0.6×104 has been similarly established for benzene solutions of polyindene. 3. Increased confidence in the viscosity-molecular weight procedure is derived from the data presented for the new Kcm equivalent covering a wide range of different polymers.

Equilibration of radioiodide between thyroid and blood was studied in rats fed propylthiouracil with or without subsequent acute administration of thiocjanate, stable iodide or perchlorate. The results were analyzed in terms of Wollman and Reed's open two-compartment model of the thyroidal iodide pump. All three anions examined were found to inhibit thyroidal radioiodide collection predominantly through lowering of the unidirectional clearance of plasma radioiodide by the thyroid, and to a lesser extent by enhancing the exit rate constant of thyroidal radioiodide. These observations are scrutinized for information regarding the anatomical site of the thyroidal iodide pump.

Molybdansaure bzw. Molybdanoxid-Hydrate sind nicht durch Ansauern beliebiger Alkalimolybdat-Losungen zu erhalten, sondern offenbar nur aus Natriummolybdat-Losungen bei Raumtemperatur bis maximal 70°C. In allen ubrigen Fallen erhalt man der Molybdansaure chemische sehr ahnliche Alkalipolymolybdate („Molybdan-;C-Phasen”) sehr geringen Alkaligehaltes, wobei die Polymolybdate des Ammoniums, Kaliums und Natriums im gleichen Gittertypus (bcc) kristallisieren. Praparationsbedingungen, thermischer Abbau und d-Werte dieser Verbindungen sowie von MoO3 · H2O (weis) werden mitgeteilt. By acidification of solutions of alkali molybdates alkali polymolybdates with very low content of alkali are precipitated. These polymolybdates are quite similar to molybdic acids resp. molybdic oxide hydrates. The polymolybdates (so called “molybdic-C-phases”) of ammonium, potassium, and sodium have the same type of crystal lattices (bcc). The conditions of preparation, the thermal decomposition and d-values of X-ray diagrams of these compounds are communicated and compared to those of MoO3 · H2O (white).

Meetings of the Leeds Junior Section, held in the Department of Colour Chemistry and Dyeing, University of Leeds, on 11 November 1969, Mr K. R. F. Cockett in the chair; and of the Manchester Region, held at the Literary and Philosophical Society, Manchester, on 20 November 1969, Mr H. R. Hadfield in the chair Films of methoxymethylnylon 6.6 have been inserted into a stream of dye-liquor. The rates of dyeing of an acid dye at different points down the film were measured. Under some conditions of dyeing, the rate was shown to be controlled by the diffusion in the liquid phase. Values of the thickness of the diffusional boundary layer were calculated from the flux and shown to agree with theory. Modifications of the dyeing conditions, e.g. by increasing the pH or lowering thedyebath concentration, reduced the diffusion coefficient of the dye in the film, and the rate of dyeing became dependent on diffusion both in the film and in the liquid.

An ion-exelusion column chromatographic procedure has been described that accomplishes the separation of isoniazid and its metabolites into completely ionized, slightly ionized and neutral derivatives. By applying specific colorimetric and enzymatic techniques to the column fractions, it was possible to measure isoniazid, isoniazid hydrazones of pyruvic acid and α-ketoglutaric acid, acetyl isoniazid and isonicotinic acid derivatives in urine of human subjects ingesting isoniazid. Isonicotinic acid derivatives were separated via an ion-exchange column chromatographic system. This technique combined with colorimetric procedures demonstrated that isonicotinic acid and isonicotinyl glycine were the only derivatives contributing to the isonicotinic acid fraction of isoniazid metabolites. The glucose hydrazone of isoniazid, diisonicotinyl hydrazine, isonicotinic acid amide, N-methyl isonicotinic acid and isonicotinic acid N-oxide were not detected as urinary metabolites of isoniazid in man.

Sorption isotherms have been determined for five basic dyes on films prepared from an acrylic polymer. The results can be explained by an ion-exchange mechanism over 80% of the concentration range, or by a simple ion-distribution mechanism over the whole of the range. Addition of sodium ions reduces the dye uptake in accordance with the suggested mechanism. Isotherms of a dye mixture have shown that competition occurs, and the ‘ion selectivity’ constants calculated from these results agree well with those derived using the dyes singly.

An examination of the exact solutions that are available for problems in convective diffusion, i. e. diffusion to the surface of an object of simple geometrical shape immersed in a steadily flowing solution of uniform concentration, has shown that the major concentration changes produced in the solution, as a consequence of the absorption of the solute by the solid object, are located in a thin layer of liquid close to the surface of the object. This layer of liquid is known as the diffusional boundary layer and it is quite distinct from the hydrodynamic boundary layer. In principle, the thickness of this diffusional boundary layer can be calculated and it is across this layer that all the resistance to the passage of the solute from the solution to the solid object is located. The effect of stirring on the rate of dyeing arises primarily from the effect of the stirring on the thickness of the diffusional boundary layer. A simple theoretical treatment is given which reveals some of the important factors that influence the effect of the rate of flow on the rate of dyeing. This simple treatment is shown to agree with experiment.