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.     

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.     

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 aqueous thermal polycondensation of asparagine and isoasparagine and the structure of polyaspartic acid

Summary Both asparagine and isoasparagine were converted into polyaspartic acids by refluxing the corresponding aqueous solutions at neutral pH in the presence of a salt. The properties of the resulting polyaspartic acids were studied. The dissociation behavior of the carboxyl groups in the polypeptides were studied by the potentiometric titration. The analysis of the titrational data was performed by a modified Speakman's method. The analysis show that both polyaspartic acids prepared from asparagine and isoasparagine have - and -aspartyl residues and the ratio of - and -aspartyl residues is 75 2585 15. A possible mechanism for the formation of - and -aspartyl residues in the polymer was discussed.     

Defensive steroids from a carrion beetle (Silpha novaboracensis)

Two novel steroids, 3,7-dihydroxy-14-pregn-4-en-15,20-dione (1) and 3,7, 20-trihydroxy-14-pregn-4-en-15-one (4), have been characterized from the rectal gland ofSilpha novaboracensis (Coleoptera: Silphidae). Judging from the function of comparable pregnanes in another species ofSilpha, the compounds may play an antipredator role.Paper No. 81 of the seriesDefense Mechanisms of Arthropods. Paper No. 80 is Eisner, T., Deyrup, M., Jacobs, R., and Meinwald, J.,J. Chem. Ecol. 12:1407–1415.     

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.     

Chemical detection of “self” and conspecifics by crayfish

Stimulus waters were used to examine behaviorally chemical communication in female crayfishProcambarus clarkii. Animals detected conspecifics. Response to stimulus water drawn from the animal's own tank, self water, mimicked either response to distilled water or response to water drawn from the tank of another animal. The response to self water depended on the relative concentration of substance(s) in self water stimuli to that of the same substance(s) in the test animal's tank.     

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.     

Comparative analysis of sex-pheromone-response antagonists in three races of European corn borer

Behavioral responses of males from three New York races of European corn borer,Ostrinia nubilalis (Hübner), to various suspected sexpheromone-response antagonists were investigated with a flight tunnel protocol. Males from a bivoltine (Z) race and from a univoltine (Z) race utilizing a natural pheromone blend of 982 (Z)-(E)-11-tetradecenyl acetates and males from a bivoltine (E) race utilizing a 199 (Z)-(E)-11-tetradecenyl acetate ratio were flown to their natural blends and to blends containing 1 % of one of the following additional compounds: Z9–12OAc,E9–12OAc,Z9–14OAc, andE9–14OAc. In each race, the added components lowered significantly the number of individuals completing the behavioral sequence. The only exception was bivoltineE males flown to a blend withE9–12OAc added. The number completing the sequence in this case was statistically not significantly lower than the number that completed the sequence to the standard blend. In all three races, theZ9–14OAc produced the most dramatic reduction in completed flights, and in the univoltineZ race, this added component was significantly more effective in reducing completed flights than any other added component. The response to the Z9–14OAc is understandable given recently published findings of an electrophysiological study of single sensilla in the European corn borer.     

Critical solution point and chain dimension of branched-polystyrene solutions

Summary Critical solution point and chain dimension were measured for branched polystyrene(BPS) in solution as a function of molecular weight(M) and compared with those for linear polystyrene(LPS). The critical concentration _c of BPS was quite different from that of LPS at a fixed M, but the same at a fixed overlap-concentration ^*, i.e., plots of _c vs. ^* fall on a single straight line for both BPS and LPS (gf_c ^*). Reduced critical temperature _c defined by gt_c=(–T_c)/ [T_c: critical temperature, : the -temperature] was related to _c as _{c c} ² for BPS, whereas _{c c} for LPS.     

Enhancement of βα-recrystallization in β-form isotactic polypropylene during heating after roll deformation

Summary -form isotactic polypropylene shows -recrystallization behavior (recrystallization from - to -form) during slow heating. This is enhanced by deformation. -form specimen with uniaxially oriented lamellae was deformed by rolling, and -recrystallization was studied by DSC and x-ray diffraction. The result showed that (1) — recrystallization is promoted with the degree of deformation. (2) Deformed specimen shows -recrystallization from considerably low temperature compared with the undeformed one. (3) The recrystallized -form is c-axis-oriented along the roll direction. From these results the -recrystallization mechanism was discussed in view of -nucleus formation by deformation.     

Quasi‐Homogeneous and Pseudospin Modes of Zirconium‐Wire Combustion in Air

A novel experimental technique is proposed for examining the transition mechanism from quasihomogeneous to heterogeneous combustion — burning of a variablepitch spring. Depending on the pitch of aircombustible zirconium springs, two combustion modes are possible. Quasihomogeneous (layerbylayer) combustion is observed in the case of smallpitch springs; as the spring pitch increases, quasihomogeneous combustion transforms into heterogeneous (pseudospin) combustion. Conditions for the occurrence of various combustion modes, depending on the spring diameter and pitch, are studied.     

Antifungal polyoxygenated fatty acids fromAeollanthus parvifolius

Two polyoxygenated fatty acids with antifungal activity have been isolated from aerial parts ofAeollanthus parvifolius (Labiatae) using bioassay-guided isolation procedures. Spectroscopic analysis was used to identify the compounds as (Z)-4,9-diacetoxy-6,7-epoxy-5-hydroxy-8-oxododeca-2-enoic acid and (Z)-4,6,7,9-tetraacetoxy-5-hydroxy-8-oxododeca-2-enoic acid. Both of these compounds inhibited spore germination ofCladosporium cucumerinum. Minimum inhibitory doses were 1 µg and 5 µg, respectively, but only the former inhibited germination ofAspergillus niger at a dose of 5 µg. Neither compound exhibited antibacterial activity. (Z)-4,9-Diacetoxy-6,7-epoxy-5-hydroxy-8-oxododeca-2-enoic acid reduced the hyphal growth ofPythium ultimum. The mode of action was not resolved but did not involve either the disruption of the cell wall membrane or the inhibition of extracellular enzymes. Application of (Z)-4,6,7,9-tetraacetoxy-5-hydroxy-8-oxododeca-2-enoic acid to seedling plants did not give any protection against fungal attack, and indeed the compound appeared to be phytotoxic.     

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.     

Specific features of the phase transformations occurring during the sintering process of the beta-alumina based ceramics and their properties

Conclusions During the sintering process of beta-alumina obtained using the method of plasmochemical synthesis, the structural transformation occurs and it is accompanied by the separation of the excess Na₂O and the formation of an intergranular meltlike phase that is saturated with sodium and is characterized by high dielectric properties.The quantity of the meltlike phase and the magnitude of the /( + ) ratio determine the degree of stabilization (stability) and the final resistivity of the material and depend on the initial chemical composition and the heating rate maintained during the sintering process.It was shown that when the duration of residence of the material in the hot zone of the furnace is increased or when the specimens sintered maintaining high heating rates are subjected to additional heat treatment, one observes the occurrance of the reverse structural transformation that is characterized by an increase of the phase ratio /( + ) 1, a reduction in the quantity of the meltlike phase right up to its complete disappearance, and a decrease of the electrical resistivity of the material.In the materials having a large excess quantity of sodium oxide, the process of crystallization of the intergranular NaAlO₂ phase occurs simultaneously with the second phase transformation.The best ceramic and electrophysical parameters were obtained when sintering the material contained 7.9% Na₂O.Translated from Ogneupory, No. 3, pp. 13–18, March, 1990.     

Variable‐temperature IR spectroscopic studies of CO adsorbed on Na‐ZSM‐5 and Na‐Y zeolites

CO interacts with extraframework alkali metal cations (M⁺=) of zeolites to form both M⁺CO and M⁺OC species. By using variabletemperature FTIR spectroscopy, these Cbonded and Obonded species were found to be in a temperaturedependent equilibrium. For the same cation, the difference in interaction energy depends upon the zeolite framework. Thus, for the equilibrium process ZNa⁺=CO ZNa⁺OC, where Z represents the zeolite framework, H ⁰ was found to take the values 3.8 and 2.4 kJ mol^– for CO/NaZSM5 and CO/NaY, respectively. The Cbonded species show always the highest cation–CO interaction energy.     

Effect of high shear rate gradients on the gel particle content of viscose

Conclusions It has been found that a decrease in gel particle content takes place during the process of a short-term rheological treatment of a viscose in a high shear velocity gradient field.The advisability of carrying out the process of dissolving cellulose xanthate in apparatus having a rheological action has been demonstrated.Translated from Khimicheskie Volokna, No. 1, pp. 29–30, January–February, 1984.     

Recovery and recrystallization of electrodeposited bright copper coatings at room temperature. II. X-ray investigation of primary recrystallization

X-ray investigations of the recrystallization processes occurring at room temperature in electrodeposited bright copper coatings were carried outin situ. As a result of the orientation transformation of the growth texture with 311, 111 and 110 components, a recrystallization texture with 100, 110 and 111 components was obtained. It was established that one of the factors which influence the microhardness of copper coatings is the orientation distribution of crystallites.     

Cooperative inclusion of sodium 1-pyrenesulfonate by γ-cyclodextrin

Summary The interaction of -cyclodextrin(-CD) with sodium 1-pyrenesulfonate(PS) was studied spectrophotometrically. -CD was found to cause much larger decrease in the absorption maxima of PS than -CD. The fluorescence spectra of PS in the presence of -CD showed excimer emission, while those of PS with -CD showed only monomer emission, indicating that -CD forms 12 (-CDPS) complexes in which two PS molecules are included in the -CD cavity in a face-to-face fashion. The binding isotherm showed a sigmoidal curve. The association constants were estimated by computer simulation of the binding curve. The 12 (CDPS) complex was found to be much more stable (K=10⁶ M^–1) than the 11 complex (K=1 M^–1). At high concentration of -CD another -CD cooperates in binding two PS molecules, resulting in the formation of a 22 complex.     

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.