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.     

Bending behavior of an electrically activated complex forming hydrogel

Summary The complex forming poly[(ethylene glycol-co-proplene glycol)-g-acrylamide]: polyacrylic acid interpenetrating polymer network hydrogel is able to bend under electric field stimuli. pH, ionic strength gradients and voltage can influence it's bending degree. So we may improve the sample' responsive speed through manipulating those factor in the further study in order to put it into the biomedical application.     

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.     

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.     

State and prospects of development of domestic equipment for manufacture of needle-punched,nonwoven materials from polymer melts

Conclusions Domestic equipment has been devised for the production of needle-punched nonwoven geotextile materials from second-grade polycaproamide or fibre-forming polypropylene.The geotextile materials produced are promising for use in construction of roads, foundations of buildings, in hydrotechnology, and in land reclamation.Promising trends in the development of equipment for preparing spun nonwoven materials have been noted (light-duty needle-punched or heat-bonded materials, bulky spun articles, etc.).Coworkers of the Kemerovskii and Kamenskii Khimvolokno IAs the Khimtekstil'mash SIA, the VNIISV, the GIPROtyumenneftegaz, the SoyuzdorNII, and the Plastpolimer SIA took part in this work.Translated from Khimicheskie Volokna, No. 4, pp. 8–10, July–August, 1989.     

The role of Ni2+ diffusion on the reducibility of NiO/MgO system: A combined TRP-XPS study

The progressive dissolution of nickel ions in the lattice of MgO matrix, promoted by the calcination temperature, has been monitored using XPS. The reducibility of Ni/MgO catalysts is affected by the modification of the surface chemical composition. TPR peaks have been correlated with several NiO forms. Both XPS and TPR results indicate a different behaviour pattern for the supported and physically mixed NiO/MgO systems, and this has been attributed to the different available contact area between NiO and MgO. The formation of both NiO rich and MgO rich NiO-MgO solid solutions, with the tendency to evolve towards the bulk solid solution, has been invoked to explain the substantial changes in the TPR pattern of the different air calcined systems.     

Formation of a phase structure of the “fibrils in matrix” type in a composite fibre based on high-density polyethylene and polyethylene terephthalate

Conclusions Regions of component ratio and conditions for obtaining a composite fibre of the fibrils in matrix type have been determined for the HDPE-PET system.At an HDPE-PET ratio of 60:40, phase inversion takes place and a structure of the interpenetration networks type is realized.Under identical fibre spinning conditions, the formation of a phase structure of the fibrils in matrix type can be regulated by varying the temperature.Translated from Khimicheskie Volokna, No. 4, pp. 38–40, July–August, 1987.     

New polymer syntheses

Summary Various poly(ether sulfide)s were prepared by polycon-densation of 4-mercaptophenol or silylated 4-mercaptophenol with 2,6-dichloropyridine or 3,6-dichloropyridazine. A two step and an one-pot procedure were compared. The poly-(ether-sulfide)s were characterized by elemental analyses, inherent viscosities, ¹³C-NMR spectroscopy, gel-permeation chromatography and DSC-measurements.     

Thermal stability of PP with acetylated sisal fiber: Romero García kinetic method

Summary This work deals the effect of acetylated and non-acetylated sisal fiber 011 thermal degradation of polypropylene. Applying the R-G method at constant conversion levels of 0.1, 0.3, 0.5, 0.7 and 0.9 to thermograms of the PP/untreated sisal fiber blend, E, values of 99, 213, 224, 187, and 145 kJ/mol were obtained, whereas they were 99, 299, 255, 205, 154 kJ/mol for the PP/treated sisal fiber blend. On the other hand, with the R-G method at constant temperature, activation energies within the range of 156-417 kJ/mol were obtained for the PP/treated sisal fiber blend and within the range of 126-344 kJ/mol for the PP/untreated sisal fiber blend. Additionally, the method establishes as dominant the following decomposition mechanisms: three-dimension limiting surface reaction between both phases, diffusion in two and three dimeiisions and first-order random nucleation and nuclei growth.     

Strength level of high-strength complex fibre from stiff-chain polymers

The discrete strength levels for ultrahigh-modulus Terlon, Armos, and SVM fibre were found. Small-angle x-ray scattering and the calculation procedure known as the method of tangents were used to estimate the radii of submicrocracks. The limiting and actual values of the average strength levels of these types of fibre were calculated for two characteristic radii of inertia R₁ and R₂. The agreement of the results with the published data confirms the accuracy of the method of tangents.Ukrainian Scientific-Research Institute of Fibre, Kiev. Translated from Khimicheskie Volokna, No. 6, pp. 33–35, November–December, 1992.     

Functional type separation of oligocarbonates by liquid chromatography under critical conditions

Summary The separation of linear oligocarbonates has been carried out by the type of functionality, namely the number and nature of terminal chloroanhydride and hydroxyl groups. The analysis was performed with the aid of a novel variant of HPLC — separation in a critical region (SCR), on the boundary of the exclusion and adsorption separation modes. The SCR method is characterised by practically complete disappearance of separation by molecular masses (sizes) while chromatograms obtained in the critical region give information only on the types of functionality of oligomers under study. The critical point for the oligocarbonates has been found on silicas Silasorb 600 and Lichrosphere Si 500 in a binary solvent carbon tetrachloride-chloroform. An effect of pore size on the retention volumes of macromolecules of different functionality under critical conditions is discussed.     

Dynamics and self-organization of catalytic systems

The kinetics of a catalytic reaction is frequently formulated in terms of simple concepts of the Langmuir type. Apart from limitations arising from the non-uniformity of the catalyst's surface and from the coverage dependence of the rate constants, several other complications may come into play. These may arise on the quantum level where energy flow between the various degrees of freedom may cause failure of simple transition state theory, as well as on the continuum level where formulation of rate equations in terms of coupled non-linear differential equations may give rise to a rich scenario of spatio-temporal self-organization, including kinetic oscillations, chaos, and formation of concentration patterns. Several of these phenomena are illustrated by selected examples.     

Processing of boron-nitrogen preceramic polymers

A number of new oligomeric and polymeric reagents rich in boron and nitrogen have recently been derived by several research groups. These reagents offer potential for the formation of boron nitride (BN) as controlled morphology powders as well as nonpowder forms. Specifically, it has been found that a family of 3-point and 2-point poly(borazinylamine) reagents may be processed by techniques used in organic polymer chemistry, with subsequent formation of BN ceramic fibers, coatings, xerogels, aerogels, and aerosols.     

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.     

A study of carbon deposition on catalysts during the partial oxidation of methane to synthesis gas

The deposition of carbon on catalysts during the partial oxidation of methane to synthesis gas has been investigated and it has been found that the relative rate of carbon deposition follows the order Ni>Pd>Rh>Ir. Methane decomposition was found to be the principal route for carbon formation over a supported nickel catalyst, and electron micrographs showed that both whisker and encapsulate forms of carbon are present on the catalyst. Negligible carbon deposition occurred on iridium catalysts, even after 200 h.     

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.     

Characteristics of Heterophase Radical Graft Polymerization of Methyl Methacrylate on Polymer Fibres

Graft copolymers with graft PMMA were synthesized using the Cu²⁺—H₂O₂ redox system. The conditions for obtaining graft PCA—PMMA and HC-PMMA of 40–60 composite composition with grafting efficiency at the 85% level are found. The effect of the polymer matrix on the kinetic and thermodynamic properties of graft polymerization of MMA is revealed. Possible schemes of the reactions of graft polymerization of MMA to polycaproamide and hydrated cellulose are proposed based on quantum chemical calculations of the enthalpy of formation of the graft copolymers.The research was conducted under MNTPP Project No. 203 Chemical Engineering (Section 2 General Chemical Engineering) in the scientific-industrial program Higher-Education Research on Priority Directions in Science and Engineering.__________Translated from Khimicheskie Volokna, No. 1) pp. 19–23, January–February, 2005.     

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.     

The supracaudal scent gland of the red foxVulpes vulpes

The supracaudal gland of the red fox consists of both tubular apocrine sweat glands and massively developed sebaceous glands. The gland is characterized by a high level of histochemically demonstrable hydroxysteroid dehydrogenase activity (particularly -3 HSD) and by the presence of naturally fluorescent photolabile sebum constituents. Evidence suggests that these components may be carotenoid. Results are presented in the context of histological observations and are discussed in relation to scent production.     

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.