Change in degree of polyamidation of polycaproamide during orientation stretch

Conclusions The effect of stretch ratio, the ratio of stretch ratios in the cold and hot zones, and of the relative viscosity of polycaproamide on the degree of its breakdown during stretching have been examined.The degree of breakdown decreases if the viscosity stays within the range 3.25–3.35, and the stretch ratio in the cold zone is the maximum possible.Translated from Khimicheskie Volokna, No. 5, pp. 26–27, September–October, 1983.     

Improving the proportioning of raw components of a glass mixture

Tensometric proportioners with discharge feeders with a principally new design are described. A partition separating the lower part of the proportioner into a chamber for rough discharge and a chamber for accurate filling makes it possible to realize discharge at two different rates with a specified accuracy using a single-rate drive.Translated from Steklo i Keramika, No. 3, pp. 7–9, March, 1996.Borsk Glass Plant Joint Stock Company; Stekloavtomatika BSPKTO Joint Stock Company.     

Deposition of nanocrystals on flat supports by spin-coating

Monodisperse particles can be evenly distributed over flat supports by spin-impregnation. In this way Cu precursors have been deposited onto Si wafers. The effects of the rotation frequency and the concentration of the impregnation solution have been investigated. The mean diameter of the deposited particles can be varied from several nanometers upto several micrometers as is shown by microscopy images. Spin-impregnation appears a useful tool to prepare well-defined flat model catalysts, which are readily accessible both to quantitative characterisation and to catalytic testing.     

Oviposition deterrent from eggs ofCallosobruchus maculatus: Spacing mechanism or artifact?

Females ofCallosobruchus maculatus (F.) avoid ovipositing on host seeds already bearing conspecific eggs, and thus distribute eggs evenly among seeds. This behavior was presumed to be mediated by an ether-soluble oviposition marker that is deposited with the egg and can be extracted from egg-laden artificial hosts (glass beads). Ablation experiments revealed that the true factors promoting an even dispersion of eggs were perceived by the maxillary and labial palpi. In contrast, receptors on the antennae were largely responsible for avoidance of seeds treated with oviposition marker. Taken together, these results suggest that a careful distinction should be drawn between factors that promote spacing of eggs under natural conditions and general oviposition deterrents that may be isolated from both sexes.     

Inter-versus intramolecular oligomerization of nitrile groups in polyacrylonitrile

Summary Experimental evidence is presented indicating that intermolecular oligomerization of CN groups (leading to crosslinked structures) takes place, and possibly has an even greater importance than the intramolecular reaction (leading to ladder polymer), at higher temperatures. The easy, quasi built-in crosslinking upon heat treatment is considered the most significant single feature with regard to making polyacrylonitrile and its copolymers unique among synthetic polymers as a carbon fiber precursor.     

Improving water-consumptive processes under conditions of operating viscose fibre manufacture

Conclusions The most water-consumptive technological processes in the basic and auxiliary works in the manufacture of viscose fibre have been identified.Results of realizing the developments of the Khimvolokno NPO and of the Ryazanskii Khimvolokno PO, aimed at reducing water usage and discharge of contaminants into wastewater have been presented.Translated from Khimicheskie Volokna, No. 6, pp. 22–23, November–December, 1984.     

Chemical effects in the assessment of phosphate rock residues extracted from multicomponent fertilisers

Methods of obtaining reactive phosphate rock residues from multicomponent phosphate fertilisers which contain soluble phosphorus components have been examined. Extraction using cold neutral ammonium citrate has been found to be more suitable than water, as chemical reactions appear to occur in water extraction solutions to modify the residue, and more impurity species such as calcium sulphate and iron and aluminium phosphates remain in the residues to complicate the process of obtaining reliable solubility figures.Deactivation of the phosphate rock residues (as measured by decreased 2% formic acid solubilities) was found to be due to reactions occurring during the maturing process, and was dependent on the phosphate rock used, with North Carolina phosphate rock-based residues significantly affected, but Arad-based residues almost unaffected. However, for neutral ammonium citrate extractions, only North Carolina-based residues produced solubility figures lower than the original phosphate rock. Some selectivity of reaction in single superphosphate-reactive phosphate rock mixtures was indicated which further complicated assessment of the deactivation effect; however such an effect appeared to be much less significant than previously suggested.     

Fireclay deposits in Kimovsk Coalfields

Conclusions The Kimovsk clays occurring in alternation with coal seams as well as the underclays are suitable for the production of grade B and to a certain extent of grade A chamotte.As a result of considerable losses on ignition only part of these clays is added to the bond in preparing mixtures for grade B refractories.In order to increase the homogeneity of refractories, employ local Kimovsk clays and more rationally possibly launch grade A production on their basis, it is necessary to forego the use of Suvorovsk and Latnaya clays and plan necessary to forego the use of Suvorovsk and Latnaya clays and plan selective mining at the Kimovsk coal fields.The planning of simultaneous but separate fireclay and coal mining at Kimovsk Coal fields is an urgent problem that calls for an expeditious solution.     

Convective Regime of Filtration Combustion of Energetic Materials in a Cocurrent Flow of Their Combustion Products

The convective regime of filtration combustion of energetic materials in a cocurrent flow of their combustion products is studied using a model with extremely simplified kinetics and heat transfer, which shows instability of the process. It is shown that the more accurate twotemperature model describes a steadystate regime. In this regime, the gas temperature on the hot boundary of the heating zone is well below the combustion temperature, and the solidphase temperature is well below the temperature proposed in recent studies on this topic. It is pointed out that the twotemperature approach is unjustified and intragranular nonisothermicity must be taken into account for convective regimes. It is shown that the threetemperature model, which takes into account this effect, does not give a stable steadystate solution.     

Interactions between pheromone traps with different strength lures for the pine beauty moth,Panolis flammea (Lepidoptera: Noctuidae)

Catches of malePanolis flammea in traps baited with lures containing 25 g of sex attractant are enhanced when in the proximity of traps baited with 125-g lures. The degree of enhancement is increased as the intertrap distance is decreased, and when the low-dose trap is upwind of the high-dose one. The patterns of alteration in trap catch suggest that moths initially attracted by one lure may divert into other traps, which may be either upwind of the original trap (overshooting), or downwind (undershooting). Overshooting can result in up to fivefold increases in catch and may provide a useful method for estimating the attractant zone of particular lure/trap combinations.     

Evolution of weak shock waves in dense media

Relations describing the evolution of a weak shock wave (SW) in a dense medium with account of its attenuation and spreading are derived. The evolution is presented as a result of superposition of two processes: propagation of a stepped weak shock wave and pursuit of the shock by a rarefaction wave.Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 139–143, March–April, 1995.     

Comparative study of diluent effects on the glass transition of polyvinylchloride and phenolphthalein

Summary Some binary polymer-diluent systems, previously studied by the Authors (SCANDOLA et al., 1982), showed an unusual T_g-concentration dependence. In order to investigate the relevance of the polymeric nature of the high-T_g component in determining this anomaly, two series of mixtures having the same diluent (di-n-Butylphthalate or Tricresylphosphate) and, as the high-T_g component, either a polymer (PVC) or a low-molecular weight substance (Phenolphthalein), have been examined. A discontinuity is found, as expected, in the polymeric systems PVC-di-n-Butylphthalate andPVC-Tricresylphosphate, as well as in Phenolphthalein-di-n-Butylphthalate mixtures where, however, the deviations from the calculated T_g-composition curve are much less marked. It is concluded that the presence of a polymer is not a necessary requirement for the occurrence of the above mentioned anomaly.     

Effect of grain size on the synthesis of active alumina from gibbsite by flash calcination and rehydration

Two series of alumina have been prepared by flash calcination (FCAL) and subsequent rehydration of coarse (> 50 m) and fine grain size gibbsite (< 50 m). The initial grain size of the gibbsite was found to determine the degree of amorphization, water content, rehydration ability, composition and pore structure of FCAL products. Active alumina materials having pore structure parameters similar to those of commercial alumina adsorbents and catalyst supports were obtained by FCAL and subsequent rehydration of fine grain size gibbsite.     

The “deer lactone”

Urine of the black-tailed deer is the source of the deer lactone, which is deposited on the tarsal gland tufts by rub-urination. The enantiomer composition of the lactone from the urine of the female is 89(R)-(–)/11(S)-(+). Responses by deer were strongest toward the synthetic racemic lactone in the social test and toward the natural lactone in the choice test. In both tests, the (–)- lactone released slightly stronger responses than its enantiomer.Odocoileus hemionus columbianus.     

Prediction of Reverse Relaxation and Deformation—Recovery Processes in Synthetic Fibres

Use of force and geometric deformation variants of the nonlinear-hereditary viscoelasticity equation for prediction of complex processes by calculation is examined on the example of deformation-recovery and reverse relaxation processes in Lavsan synthetic fibres. A comparison of the calculated and measured values allows recommending the method of calculated prediction in which an elementary function — the normalized arctangent of the logarithm of the reduced time serves as the normalized relaxation or creep function.     

Sex pheromone of aPlanotortrix excessana sibling species and reinvestigation of related species

The sex pheromone of aPlanotortrix excessana sibling species was investigated. Females were found to produce eight potential pheromone components: dodecyl acetate, tetradecyl acetate (14OAc). (Z)-5-tetradecenyl acetate (Z5-14OAc), (Z)-7-tetradecenyl acetate (Z7-14OAc), (Z)-9-tetradecenyl acetate, hexadecyl acetate, (Z)-7-hexadecenyl acetate, and (Z)-9-hexadecenyl acetate. When these compounds were bioassayed using field-trapping and wind-tunnel techniques, only 14OAc,Z5-14OAc, andZ7-14OAc were found to be behaviorally active. The sex pheromone glands of females of other species including,Planotortrix MBS,Planotortrix M,P. notophaea, Ctenopseustis servana, and aC. obliquana sibling species, were also found to containZ5-14OAc orZ7-14OAc, singly or in combination. In the case ofPlanotortrix M, the addition ofZ7-14OAc to the previously identified sex pheromone blend ofZ5-14OAc and 14OAc was found to increase trap captures of male moths of this species. Thus in these New Zealand species (and in some Australian species),Z5-14OAc andZ7-14OAc appear to be utilized in combination in pheromonal communication just as (Z)-11-tetradecenyl acetate and (E)-11-tetradecenyl acetate are used by many species of Holarctic Tortricidae in the tribe Archipini.Lepidoptera: Tortricidae: Tortricinae.     

Molecular mechanics studies of model polysilanes

A molecular mechanics study of a homologous series of di-substituted polysilane model compounds investigates the effect ofn-alkyl side-chain substituent length on overall polymer conformation. Using the recently released MM3 program to probe backbone and side-chain energetics, the results suggest that an off-trans (160°) backbone structure is optimal in both longer-side chain (i.e., di-n-hexyl) and shorter-side chain (di-ethyl) polysilanes. Also a chair-like conformation for side-chain dihedral angles is preferred.This paper is from the Second International Topical Workshop, Advances in Silicon-Based Polymer Science.     

Amination of dimethyl ether on zeolite catalysts. 2. Acidic properties of the used T-zeolites and their influence on the catalytic reaction

Freshly prepared and used H/Na, K-T-zeolite catalysts for the conversion of dimethyl ether and ammonia to the three methylamines have been characterized by temperature-programmed desorption of ammonia and IR spectroscopy. Activity and selectivity depend on the nature and number of the acid sites. With time on-stream, deep alterations in the catalyst behaviour have been observed. The activity of the catalyst is decreased by blocking of active sites 5–10 h: furthermore, during an initial period hydrocarbons were formed almost exclusively on strong-acid sites. A second period is characterized by an increased shape selectivity observed in the distribution of the methylamines. The amination will proceed probably on left weak-acid sites and on the outer surface in a third period, however, without shape selectivity due to the progressive blocking of the inner catalyst surface.     

Rate of radical polymerization of N,N-dimethylaminoethyl methacrylate in cyclohexane

Summary Anions of propene, isobutylene and cycloheptatriene have been prepared using Lochmann's Base. Star polymers in the form of one arm star, two arm star and three arm star polymers of styrene have been synthesized from the allyl anion (2), 2-methylenepropylenyl dianion (4) and the cycloheptatrienyl trianion (6) respectively, with acid end groups by quenching the living polymers with carbon dioxide. The number average molecular weight has been determined by stoichiometry, HPSEC and end group analysis by titration.     

The problem of utilizing secondary polymeric resources in the manufacture of man-made fibres

Conclusions The possibility of developing waste-free manufacturing based on silk and acetate textile yarn using the wastes from these plants to modify nitron fibre has been demonstrated.Checking the results of experimental and laboratory tests and introducing them into manufacturing require the development of a pilot-plant unit in the Porduction Association Navoiazot.Translated from Khimicheskie Volokna, No. 3, pp. 35–36, May–June, 1986.