Phase inversions and properties of refractories in the system MgO-Al2O3-ZrO2

Conclusions In the compositions for the system MgOAl₂O₃ZrO₂=111 fired at 1750°, with the use of original components of different chemical activity, conditions are created for partial stabilization of the monoclinic zirconium dioxide on account of the magnesia which has not succeeded in reacting with the alumina, resulting in the formation of spinel.The presence in the fired products (together with monoclinic zirconia) of its cubic modification makes it actually possible to obtain thermal shock resistance and strong refractories on the basis of this system.The maximum quantity of stabilizing zirconium dioxide is present in the sinters in which we use chemically active ZrO₂ as the initial material obtained by the thermal decomposition of zirconium nitrate, and high-temperature fired magnesium oxides. The quantity of stabilized ZrO₂ in these sinters is about 70%.The quantity of stabilized zirconium dioxide in the compositions MgO-Al₂O₃-ZrO₂ depends on the activity of the alumina employed, as with the magnesium oxide, which is connected with the rate and temperature of formation of the magnesia spinel. The maximum quantity of cubic solid solutions is formed with the use of less active alumina.The technical properties of the products from firing these compositions are determined not only by their phase composition but also the distribution of the phases in the volume of the specimen.Translated from Ogneupory, No. 8, pp. 46–50, August, 1972.     

Supported and sulfided Pb-Mo oxides: Active and stable hydrotreatment catalysts

A newly developed PbMo/Al₂O₃ HDS catalyst shows activity and stability that are comparable to or better than the traditional CoMo/Al₂O₃. Activity is optimum when the atomic ratio PbMo is 16. At that ratio, the generated surface phase(s) display maximum degree of Mo coordinative unsaturation, as measured by low temperature oxygen chemisorption.     

Zirconium tetra-n-butylate modified with different organic acids: Hydrolysis and polymerization of the products

In this work; (a) complexation reaction of zirconium tetra-n-butylate, Zr(OBu ⁿ )₄, with MAc and different organic acids. (b) the hydrolysis reaction of modified Zr species, and (c) the polymerization reaction of complex products are studied. Zr(OBu ⁿ )₄ was reacted with different mole ratios of methacrylic acid (MAc) at room temperature and the maximum combination ratio was found to be 12 [Zr(OBu ⁿ )₄MAc] by FT IR. The modification of zirconium tetra-n-butylate with the acid mixtures [methacrylic acid-acetic acid (MeCOOH), methacrylic acid-propionic acid (EtCOOH), methacrylic acidbutyric acid (PrCOOH)] was made for a combination ratio of 111 [MAcRCOOHZr(OBu ⁿ )₄RMe. Et, Pr] and the products were characterized by¹H-NMR, FT-IR, and UV-spectroscopies. Following their synthesis, hydrolysis of the complexes with various amounts of water and polymerization with benzoyl peroxide were realized. The hydrolysis and polymerization products of the complexes were studied by Karl-Fischer Coulometric titration and thermal analysis respectively. Methyl-ethyl-ketone (MEK) and chloroform were chosen as solvents.     

31P and119Sn high resolution solid state CP/MAS NMR study of Al2O3-SnO2 systems

A series of Al₂O₃-SnO₂ catalysts with the mole ratio of Al₂O₃ to SnO₂ equal to 1:1, 1 0.5, 1 0.1, 1 0.05 and 1 0.01 were characterized by³¹P NMR of adsorbed trimethyl phosphine (TMP) and¹¹⁹Sn MAS NMR spectroscopy. It was found from³¹P NMR that no Brønsted acid sites exist in these samples. Pure SnO₂ shows two different types of Lewis acid sites; in the mixed oxide samples a Lewis peak characteristic of pure Al₂O₃ is always seen, together with either one or two other Lewis peaks, depending on the Sn concentration.¹¹⁹Sn CP/MAS NMR spectra of the highest Sn-content sample show one narrow line at –603 ppm superimposed on a very broad line, indicating a strong interaction between Al and Sn oxides.     

Preparation of nanosize Pt clusters using ion exchange of Pt(NH3) 4 2+ inside mesoporous channel of MCM-41

Mesoporous molecular sieve MCM-41 with a Si/Al ratio of 35 was obtained by hydrothermal synthesis using a gel mixture with a molar composition of 6 SiO₂0.1 Al₂O₃1 hexadecyltrimethylammonium chloride 0.25 dodecyltrimethylammonium bromide 0.25 tetrapropylammonium bromide0.15 (NH₄)₂O1.5 Na₂O300 H₂O. The MCM-41 sample was calcined in O₂ flow at 813 K and subsequently ion exchanged with Ca²⁺. A small Pt cluster has been supported on the MCM-41 sample following a procedure using ion exchange of Pt(NH₃) ₄ ²⁺ . The Pt(NH₃) ₄ ²⁺ ion supported on MCM-41 has been activated in O₂ flow at 593 K and subsequently reduced with Fh flow at 573 K, in the same way used for the preparation of a Pt cluster entrapped inside the supercage of zeolite NaY. The resulting Pt cluster supported on the MCM-41 shows hydrogen chemisorption oftotal two H atoms per Pt at 296 K (based on the total amount of Pt) and high catalytic activity for hydrogenolysis of ethane. The chemical shift in¹²⁹Xe NMR spectroscopy of adsorbed xenon indicates that the Pt cluster is located inside the mesoporous molecular sieve.     

A four-component pheromone blend for optimum attraction of redbacked cutworm males,Euxoa ochrogaster (Guenée)

Four acetates,Z-5-decenyl acetate,Z-5-,Z-7-, andZ-9-dodecenyl acetates, in microgram ratios of 120021 or 120062 were excellent, specific sex pheromone blends for capturing male redbacked cutworm moths in cone traps. Blends in ratios of 120021 and 220021 at 1000 g/ rubber septum dispenser remained highly effective for 6 weeks under field conditions. The essential minor components,Z-5-decenyl,Z-7-, andZ-9-dodecenyl acetates, became inhibitory at concentrations of about 10% in the blends, and this may be an important general phenomenon in lepidopteran pheromones. Blends involving a parapheromone,Z-5-undecenyl acetate, withZ-5-,Z-7-, andZ-9-dodecenyl acetate, in microgram ratios of 820021 or 2020062 were also excellent specific attractants for this species. TheZ-8-dodecenyl acetate had no obvious effect on the attraction of the redbacked cutworm males.     

Sex pheromone chemistry of the western spruce budwormChoristoneura occidentalis Free

SCOT capillary Chromatographic and SCOT capillary chromatographic-mass spectrometic analyses of gland washes and effluvia of virgin femaleChoristoneura occidentalis Free, have been conducted with both a diapausing and nondiapausing strain of this insect. The following compounds were identified in gland washes and effluvia in both strains:E andZ11–14Ald,E andZ11–14Ac,E andZ11–14OH and 14Ald, 14Ac, and 14OH. The average aldehyde: acetate: alcohol ratio found by analysis of single glands by virgin females (nondiapausing strain) was 170.73. Analysis of virgin female effluvia gave this ratio as 1038 (diapausing strain: %Z=8, 11, 15, respectively) and 1036 (nondiapausing strain: %Z=8, 11, 12, respectively). The saturated components were generally 1–2% of theE isomer in each case. Comparisons of EAG responses of bothC. occidentalis andC. fumiferana toE11–14Ald,E11–14Ac andE11–14OH were made. Correlations with both laboratory and field data previously published were also made betweenC. fumiferana andC. occidentalis.Lepidoptera: Tortricidae.     

Highly refractory' material based on magnesia spinel

Conclusions An increase in the content of commercial alumina in magnesite refractory body to a ratio of MgOAl₂O₃ =1.3, corresponds to an increase in the refractoriness-under-load and 4% compression, increases the spalling resistance with a certain reduction in refractoriness.Formation of spinel in bodies with a ratio of MgOAl₂O₃ from 31 to 13 occurs at 1600–1650°C.The refractory material KM-3 on the basis of magnesia-alumina spinel is suitable for making, by the semidry pressing method, saggers, rods, supports, and other components intended for firing ceramic and refractory articles at Temperatures up to 1950°C.Translated from Ogneupory, No. 7. pp. 58–60, July, 1966.     

Attraction ofCacoecimorpha pronubana male moths to synthetic sex pheromone blends in the wind tunnel

Attraction ofCacoecimorpha pronubana male moths to blends of four sex pheromone components was studied in the wind tunnel.Z11–14Ac alone did not elicit upwind flight, admixture of 10%Z11–14OH or more led to successful attraction of males to the source. Attractivity of these binary blends was further enhanced by addition ofE11–14Ac orZ9–14Ac; the optimum was a blend ofZ11–14Ac,Z11–14OH,E11–14Ac, andZ9–14Ac at the proportion of 1003033. In ternary and quaternary blends, the effect ofZ11–14OH andE11–14Ac was strongest at 30% and 3%, respectively. By contrast,Z9–14Ac increased behavioral responses over a wide range.     

Dewatering deposits formed in purifying effluent from refractory factories by vacuum filtration

Conclusions The residue formed from effluent contaminated with chamotte dust, with coagulation and without coagulation, is thoroughly dewatered on vacuum equipment with concentrations of more than 700 kg/m³ of suspended particles in the residue.Residues obtained from effluent contaminated with mixtures of chamotte and clay dust in the ratio 41, 11, and 14 are dewatered less effectively than chamotte residues. The residue from a mixture of chamotte and clay 41 is dewatered with a minimum concentration of 809 kg/m³; the residue from the mixture of chamotte and clay 11 can be satisfactorily dewatered only with a high vacuum (640 mm Hg) and with a filter cycle time longer than that used in existing equipment. With a filter cycle of 30 min the thickness of the skin of uncoagulated residue was 13 mm. The coagulated residue from a mixture of clay and chamotte 11 even after 14 days holding had too low a concentration, and in practice cannot be dewatered on a vacuum filter. The residue from mixtures of 14 chamotte and clay is dewatered very ineffectively. The thickness of the cake with a filter cycle time of 20 min for uncoagulated residue was only 4 mm.Translated from Ogneupory, No. 6, pp. 17–20, June, 1970.     

Investigation of sex pheromone components of female asian corn borer,Ostrinia furnacalis (Hübner) (Lepidoptera: Pyralidae) in Taiwan

(E)-12-Tetradecenyl acetate (E12–14OAc), (Z)-12-tetradecenyl acetate (Z12–143nOAc), and tetradecanyl acetate (14OAc) were extracted and identified as major chemical components from female tips of the Asian corn borer,Ostrinia furnacalis (Hübner) (Lepidoptera: Pyralidae) in Taiwan, with a combined wash ratio of 483715 and an individual female ratio of 453916. The average amount ofE12-,Z12–14OAc and 14OAc in each female gland was 6.6±4.6, 5.8±3.5, and 2.4±1.7 ng/female, respectively. The mixture of these three synthetic chemicals not only gave strong activities in male antennae but also could catch significantly more males than virgin females in field-trapping tests. The field test also showed no significant difference in trapping ability among the three-component Taiwan formulations, the two-component Taiwan formulation (Z12–14OAc andZ1214OAc, 5347), and the Japan formulation (Z12–14 OAc andE 12–14OAc, 3:2).     

Field response ofDendroctonus brevicomis toexo-brevicomin,frontalin, and myrcene released at two proportions and three levels

Racemicezo-brevicomin, racemic frontalin, and myrcene were released at two proportions (51400 and 111), each at three levels (1 ×, 10 ×, and 100 ×) in a ponderosa pine forest in central California. The 51400 mix was based on an estimate of the relative amounts released from a ponderosa pine under attack by the western pine beetle,Dendroctonus brevicomis. MoreD. brevicomis were trapped at a source of the three compounds released at 51400 than were trapped at a source released at 111, at all three levels, but this difference was statistically significant only at the 1 × and 10 × levels. Sex ratio of trapped beetles and distribution of catch at the source of attractant and 5 m away apparently did not differ between relative release rates.Coleoptera: Scolytidae.Trade names are mentioned solely for information. No endorsement by the U.S. Department of Agriculture is implied.     

On the promotional effect of Sn in Co–Sn/Al2O3 catalyst for NO selective reduction

NO reduction with propylene over Co/Al₂O₃ and Co–Sn/Al₂O₃ catalysts has been investigated. For the Co/Al₂O₃ catalyst, a calcination temperature exceeding 800°C led to a decrease of NO conversion. Calcination of the Co/Al₂O₃ catalyst at 1000°C resulted in the formation of -Al₂O₃ and Co₃O₄. The presence of 20% water vapor showed a significant shift for the maximum NO reduction temperature from 450 to 600°C over Co/Al₂O₃. It has been found that modification of 6 wt% Co/Al₂O₃ with 2 wt% Sn significantly enhanced the catalyst thermal stability and improved the inhibitory effect of water on NO conversion and reaction temperature. The promotional effect of Sn on the catalyst thermal stability was attributed to the suppression of the phase transformation from highly dispersed Co²⁺ species on -Al₂O₃ to -Al₂O₃ and Co₃O₄. The smaller influence of water vapor on NO reduction conversion and temperature over Co–Sn/Al₂O₃, compared to Co/Al₂O₃, was attributed to the dispersion effect of Sn species on Co²⁺ species as well as the involvement of Sn species in NO reduction at a relatively lower temperature. The synergetic effect between the octahedral Co²⁺ species and -alumina plays a significant role in the catalysis of NO selective reduction by C₃H₆.     

Crystal structure and size distribution of Pt-Cu-Fe alloy clusters supported on carbon black

Carbon supported alloy electrocatalysts based on Pt, Cu and Fe (atomic ratios PtCuFe=211 and 611) are prepared at various alloying temperatures and are characterized by XRD and TEM techniques. Powder XRD analyses show that Pt₆CuFe clusters form a face-centered cubic structure (AuCu₃ type), while Pt₂CuFe clusters form an ordered alloy with a facecentered tetragonal structure (AuCu type) at higher temperature than 700C. Transmission electron micrographs reveal that the size of metal clusters increases gradually and size distribution becomes broader, as alloying temperature increases from 500 to 1100C.     

Blackheaded fireworm: Laboratory and field studies of its sex pheromone

Electroantennogram (EAG) responses of maleRhopobota naevana (Hübner), the blackheaded fireworm, to all of the monoene straightchain 12- and 14-carbon alcohols and acetates implicated (Z)-11-tetradecenl-1-ol (Z11–14OH) and its acetate (Z11–14Ac) as sex pheromone components.Z11–14Ac produced the strongest EAG response of all compounds tested. Gas chromatography-mass spectrometry (GC-MS) analysis of extract of female sex pheromone glands (SPG) confirmed the presence ofZ11–14OH (125 pg/female) andZ11–14Ac (600 pg/female) (all other monoenes had different retention times). In field tests, traps baited withZ11–14OH alone captured males, but traps baited withZ11–14Ac alone did not. Traps baited with a combination ofZ11–14OH andZ11–14Ac in various ratios did not produce better trap catches thanZ11–14OH alone. (Z)-9-Dodecen-1-ol acetate (Z9–12Ac), reported by others to be a field attractant, did not produce trap catch in our tests, but in combination withZ11–14 OH (982 in septa corresponding to 95:5 in vapor,Z11–14OH toZ9–12AC) produced a sevenfold increase in catch overZ11–14OH alone. IfZ9–12AC had been present in extract of SPG at 2–5% ofZ11–14OH, it would not have been detected in our GC-MS experiment. Rhopobota naevana (Hübner) Lepidoptera: Tortricidae: Olethreutinae.     

Chemical modification of copoly(methylsilylene/1,4-phenylene) by Pt-catalyzed hydrosilation reactions with functionally substituted alkenes

Copoly(methyl-3-biphenoxypropylsilylene 1,4-phenylene), copoly(methyl-3-cyanopropylsilylene 1,4-phenylene), copoly(methyl-3-ethoxypropylsilylene 1,4-phenylene), copoly(methyl-3-phenoxypropylsilylene 1,4-phenylene), and copoly(methyl-4,7,10,13-tetraoxatetradecanylsilylene 1,4-phenylene) have been prepared by platinum-catalyzed hydrosilation graft reactions between poly (methylsilylene 1,4-phenylene) and appropriate functionally substituted alkenes. These polymers have been characterized by¹H,¹³C, and²⁹Si NMR as well as by FT-IR and UV-vis spectroscopy. The molecular weight distribution of these polymers has been determined by gel permeation chromatography (GPC), and their glass transition temperatures (T _e) by DSC.     

Porous mullite ceramics through diphasic gels of large boehmite and small silica particles

Mullite formation process has been studied in stoichiometric mullite (3Al₂O₃·2SiO₂) diphasic gel containing large boehmite (1 m) and small silica (10 nm) particles. It has been found that initial mullitization did not take place inside the silica phase (cristobalite), but took place in the defect -alumina phase. -alumina was stabilized by silica when the temperature was below 1350°C. At temperatures above 1350°C, mullite crystallized directly. It was suggested that silica diffused into the pores (<1.8 nm) of -alumina and prevented the collapse of -alumina pore structure. On the other hand, when silica was not present, the pore structure of -alumina collapsed and -alumina crystallized at 1100°C. Porous mullite ceramics were obtained by using special diphasic gels containing large boehmite and small silica particles.     

Combustion and the transition to detonation in a gas mixture in a closed space

The possibility of going from deflagration to detonation in mixtures of CH₄+2(O₂+N₂) and 2H₂+O₂ ±N₂ (03.76) was investigated experimentally in a space enclosed by various combinations of three thin-walled metal concentric turbulator-sphere (diameters in a ratio 124) with large numbers of openings (permeability 0.1–0.4). Transition from deflagration to detonation was observed for 1 in the first mixture and for 3.2 in the second.Balashikha. Translated from Fizika Goreniya i Vzryva, Vol. 29, No. 3, pp. 171–174, May–June, 1993.     

Adsorption of carbon monoxide on Ni/Ti and Ni/TiO2 surfaces preparedin situ in the electron spectrometer: A combined UPS-XPS study

Adsorption of CO on a clean Ti surface is partly associative at 80 K with a 1 -4 separation of 4.2 eV, becoming dissociative at 130 K. On Ni- covered Ti surfaces, however, associative adsorption (4-1, 3.3 eV) occurs at 80 K and partial dissociation, around 200 K. TiO₂ is reduced more effectively on annealing, when it is covered with Ni. On the surfaces of Ni deposited on TiO₂, there is only dissociative adsorption, unlike on Ni/Al₂O₃ and Ni/TiO₂ (non-annealed) surfaces.Contribution No. 565 from the Solid State and Structural Chemistry Unit.     

Trail-following responses of the Argentine ant,Iridomyrmex humilis (Mayr), to a synthetic trail pheromone component and analogs

Behavioral evidence indicates that (Z)-9-hexadecenal (Z9-16ALD) is a trail pheromone component ofIridomyrmex humilis, and that the true trail pheromone may be multicomponent. Trail-following responses ofI. humilis workers to several concentrations of syntheticZ9-16ALD, a constituent of the Pavan's gland, were found to be comparable to responses to gaster extract trails containing ca. 100 times lessZ9-16ALD. Of the five aldehyde analogs tested, only (Z)-7-hexadecenal (Z7-16ALD) elicited significant trail-following. However, following responses to severalZ9-16ALD-Z7-16ALD combinations were lower than responses toZ9-16ALD alone. Trails on filter paper of biologically relevant concentrations ofZ9-16ALD lose activity within 2 hr in the laboratory. The release rate ofZ9-16ALD measured from filter paper trails was 0.25 ± 0.10 pg/cm-sec. This was used to estimate the trail-following threshold for this compound of Argentine ant workers.