The effects of different manufacturing techniques on the availability of sulfate to pasture from mixtures of elemental sulfur with either triple superphosphate or partially acidulated reactive phosphate rock

Six different preparations of elemental sulfur incorporated into triple superphosphate and a single mixture of elemental sulfur with partially acidulated reactive phosphate rock were evaluated for the rate of release of sulfatesulfur to pasture at two sites.The method of preparing the mixtures affected the size of sulfur particles released on dispersion of fertilizer granules. The rates of release of sulfate from oxidation of the elemental sulfur was controlled by the fineness of the particles of elemental sulfur. For rapid release of sulfate by oxidation a mixture prepared by sintering elemental sulfur with mature triple superphosphate was the most effective. It contained sulfur particles of diameter less than 75 m. The mixtures which comprised synthetic blends of elemental sulfur of particle size less than 150 m or 150–250 m, each with mature triple superphosphate, released sulfate at a progressively slower rate than that with particles less than 75 m. However, both proved effective sulfur fertilizers releasing sulfate over a 1–2 year period. In contrast, mixtures prepared by adding molten elemental sulfur during the process of manufacturing triple superphosphate resulted in a coarser distribution of sulfur particles and a slow release of sulfate to plants.The incorporation of sulfur into a mixture with partially acidulated reactive phosphate rock was made via the dispersion of molten sulfur into phosphoric acid which was then used to partially acidulate phosphate rock. The resultant sulfur particles ranged from finely divided (e.g. 38% < 150 m) to moderately fine (81% < 500 m), and the release of sulfate was predictable based on the particle size distribution.Differences between the two experimental sites in uptake of plant sulphate reflected the different pastures grown. At the cool temperate coastal site a ryegrass/clover pasture rapidly took up sulfate as it was released into the topsoil. Inland, in the summer-dry environment, the uptake of released sulfate by the deep-rooted lucerne pasture was delayed for 12–18 months, indicating that the sulfate uptake increased after the nutrient had leached beyond the surface soil layer.     

Acceleration Ability and Heat of Explosive Decomposition of Aluminized Explosives

This paper studies the effect of aluminum particle size on the acceleration ability and heat of explosive decomposition of aluminized compositions containing HMX, nitroguanidine, and bis (2,2,2trinitroethyl) nitramine. The addition of Al increases the acceleration ability of the HEs. The replacement of Al with micronsize particles by an ultrafine powder with a particle size of 0.1 m does not lead to an additional increase in the acceleration ability. The effect of Al on the heat of explosive decomposition of the examined compositions is investigated.     

Fate of quinolizidine alkaloids through three trophic levels:Laburnum anagyroides (Leguminosae) and associated organisms

The quinolizidine alkaloids (QA) of golden rain,Laburnum anagyroides, and those of phytophagous insects associated with the plant, as well as of parasitoids of the latter, were analyzed by capillary GLC and GLC-MS. The alkaloid content in samples of vegetative plant parts was high at the beginning of the season, then decreased, while that of reproductive organs was high throughout flowering, pod formation, and maturation. The analyses showed that the QA of the plant passed through two higher trophic levels (herbivorous insects and their parasitoids) and that the alkaloid pattern changed little during the passage. The alkaloids were present in two phytophagous insect species associated with golden rain: the predispersal seed predator,Bruchidius villosus [5–13g/g fresh weight (fw)], andAphis cytisorum (182–1012g/g fw), an aphid that feeds on shoots, leaves, and inflorescences. Braconid and chalcidoid parasitoids emerging from the bruchid host also contained alkaloids (1.3–3g/g fw), as did three foraging ant species,Lasius niger, Formica rufibarbis, andF. cunicularia (45g/g fw), that visited the aphid colonies or honeydew-covered leaves of aphid-infested plants. The hypothesis that developing bruchid larvae and/or the plant manipulate QA supply to infested seeds was not supported, because QA content of leftover endosperm in seeds after bruchid development was similar to that of uninfested seeds. The frass of developing bruchid larvae was rich in QA (31g/ g dry weight). While aphids sequestered, the bruchid larvae took up and eliminated QA with the frass without chemical transformation.     

Antimony in lead-acid cells. III. Transport measurements

The mechanism of transport of Sb(V) in H₂SO₄ through 12 commercial separators was investigated. This was carried out by comparing the diffusion coefficient of Sb(V) with the electrical ionic conductivity which should be simply related if diffusion is the rate-controlling transport process. Rates increased as convective flow became dominant. Separators with pore diameters below 2 m and above 20 m showed transport rate control by diffusion and convective flow, respectively. Between 2 and 20 m both processes contributed significantly.     

The surface structure and composition of the low index single crystal faces of the ordered alloy Pt3Sn

The surface composition and structure of 111, 100, and 110 oriented single crystals of the ordered alloy Pt₃Sn (Ll₂ or Cu₃Au-type) were determined using the combination of low energy electron diffraction (LEED) and low energy ion scattering spectroscopy (LEISS). The clean annealed surfaces displayed LEED patterns and Sn/Pt LEISS intensity ratios consistent with the surface structures expected for bulk termination. In the case of the 100 and 110 crystals, preferential termination in the mixed (50% Sn) layer was indicated, suggesting this termination to be the consequence of a thermodynamic preference for tin to be at the surface.     

Dihydromatricariate-based triglycerides,glyceride ethers,and waxes in the australian soldier beetle,Chauliognathus lugubris (Coleoptera: Cantharidae)

The soldier beetleChauliognathus lugubris is shown to contain triglycerides and glyceride ethers of 8-dihydromatricaria acid, and waxes of the C₁₂ homolog, of this acid, as well as the previously reported free acid. The triglycerides contain one, two, or three dihydromatricariate moieties, with any remaining positions esterified with normal fatty acids. The glyceride ethers were monostearyl ethers of glycerol esterified with dihydromatricaria acid and oleic or linoleic acid. The waxes, which also include a dihydromatricaria chromophore in the alcohol moiety, occur only in the females and are present in paired accessory glands in the abdomen. The ethers are restricted to females and appear to be associated with developing eggs. The triglycerides are much more abundant in females than males. Triglycerides, glyceride ethers, and waxes represent about 95% of the dihydromatricariate moiety (average, ca. 590 g) in females with free acid the remainder; in males free acid is present to over 50% (ca. 22 g) and the remainder is triglyceride (ca. 15 g). Larvae contain mainly tridihydromatricariate-substituted triglyceride and a smaller quantity of the free acid.     

Fabrication and evaluation of 1 Ah silver/metal hydride cells

Silver/metal hydride (Ag/MH) cells of about 1 Ah capacity have been fabricated and their discharge characteristics at different rates of discharge, faradaic efficiency, cycle life and a.c. impedance have been evaluated. These cells comprise metal–hydride electrodes prepared by employing 60 m powder of an AB₂-Laves phase alloy of nominal composition Zr_0.5Ti_0.5V_0.6Cr_0.2Ni_1.2 with PTFE binder on a nickel-mesh substrate as the negative plates and commercial-grade silver electrodes as the positive plates. The cells are positive limited and exhibit two distinct voltage plateaus characteristic of two-step reduction of AgO to Ag during their low rates of discharge between C/20 and C/10. This feature is, however, absent when the cells are discharged at C/5 rate. On charging the cells to 100% of their capacity, the faradaic efficiency is found to be 100%. The impedance of the Ag/MH cell is essentially due to the impedance of the silver electrodes, since MH electrodes offer negligible impedance. The cells may be subjected to a large number of charge–discharge cycles with little deterioration.     

Performance and impedance studies of thin,porous molybdenum and tungsten electrodes for the alkali metal thermoelectric converter

Columnar, porous, magnetron-sputtered molybdenum and tungsten films show optinum performance as AMTEC electrodes at thicknesses less than 1.0 m when used with molybdenum or nickel current collector grids. Power densities of 0.40 W cm^–2 for 0.5 m molybdenum films at 1200 K and 0.35 W cm^–2 for 0.5 m tungsten films at 1180 K were obtained at electrode maturity after 40–90 h. Sheet resistances of magnetron sputter deposited films on sodium beta-alumina solid electrolyte (BASE) substrates were found to increase very steeply as thickness is decreased below about 0.3–0.4 m. The a.c. impedance data for these electrodes have been interpreted in terms of contributions from the bulk BASE and the porous electrode/BASE interface. Voltage profiles of operating electrodes show that the total electrode area, of electrodes with thickness <2.0 m, is not utilized efficiently unless a fairly fine (1×1mm) current collector grid is employed.     

Feeding and Growth of Plutella xylostella and Spodoptera eridania on Brassica juncea with Varying Glucosinolate Concentrations and Myrosinase Activities

We measured feeding behavior, feeding damage, and larval growth of the crucifer specialist, Plutella xylostella and the generalist, Spodoptera eridania, on the cotyledons of 14 homozygous lines of Brassica juncea differing in myrosinase activity and glucosinolate profiles. The proportion of time feeding and area damaged by P. xylostella were lower on lines with high myrosinase activities [0.49–0.73 nmol glucose released/mg tissue(fresh weight, FW)/min] than on lines with low myrosinase activities [0.20–0.31 nmol glucose released/mg tissue(FW)/min]. In contrast, the proportion of time feeding and area damaged by S. eridania were not related to myrosinase activity, but were lower on cotyledons of lines with high glucosinolate concentrations [6.8–21.3 g/g(FW)] than on lines with low glucosinolate concentrations [0.09–0.61 g/g(FW)]. Relative growth rates (RGR) of both insect species were lower on lines with high glucosinolate concentrations, but were not related to myrosinase activity in the lines. In toxicity experiments that used artificial diets, allyl isothiocyanate, but not allyl glucosinolate, was lethally toxic to neonate P. xylostella (LC₅₀s of 1.54 mol/g, and 100 mol/g, respectively), whereas isothiocyanate and the glucosinolate were lethally toxic to neonate S. eridania (LC₅₀s of 3.42 and 6.73 mol/g, respectively). We interpret these results to indicate that myrosinase activity might be more important for plant defense against specialist insects that have adaptations to intact glucosinolates, but less important for defense against generalists, which are susceptible to the intact glucosinolates.     

The cause of residual capacity in nickel oxyhydroxide electrodes

Chemical analysis, X-ray diffraction and linear sweep voltammetry have been used to examine the cause of the secondary discharge plateau associated with the inefficient reduction of sintered plate NiOOH electrodes. The techniques confirm the presence of-Ni(OH)₂,-NiOOH and-NiOOH in electrodes after failure at high rates. No evidence was obtained in support of the plateau arising from a new intrinsically less active compound. In disagreement with previous claims the-phase formed on overcharging was found to discharge as efficiently as the-phase. Inefficient discharge is considered to be caused by an insulating barrier layer of-Ni(OH)₂ between the charged active material and the current collector. The complex non-linear current-potential behaviour, exhibited by the secondary discharge plateau near –200 mV, is considered to be caused by the removal of Ni³⁺ or Ni³⁺ defects from the electronically conducting Ni(OH)₂ prior to returning it to the poorly conducting divalent state.     

Effect of the particle size on the activity of MoO x C y catalysts for the isomerization of heptane

Molybdenum trioxide samples having apparent particle sizes (APS) of 5 and 20 .m were partially reduced under flow of a mixture of H₂/n-heptane during 4 h. X-ray diffraction and Raman spectroscopy showed the typical structural transformation of MoO₃ into MoO_xC_y and MoO₂. These structural changes occur preferentially on the {0k0} planes. After the reduction treatment the resulting materials, having surface areas of 23 and 53 m²/g, were evaluated in the isomerization of n-heptane at 643 K and 18.5 bar. The catalyst with an APS of 20 .m showed a maximum conversion around 70%, while for the catalyst with an APS of 5 .m the maximum conversion was 34%. The lower activity of the 5 .m MoO_xC_y catalyst seems to be related to a faster rate of formation of oxygen vacancies and rearrangement of the lattice into a more stable and less active structure in the case of small-size particles, due to a higher concentration of terminal Mo=O bonds along the a- and b-axes, which facilitate the electrophilic attack by hydrogen on the (010) plane.     

Depolarization of the hydrogen evolution reaction on cadmium electrodes in alkaline media

Depolarization of the hydrogen evolution reaction on high purity polycrystalline cadmium electrodes in alkaline media (12pH14 and 5T55°C) produced by cathodization in the range of potential comprised between the Cd/Cd(OH)₂ electrode potential and the net HER potential under solution stirring conditions has been studied. The depolarization effect depends on the perturbing potential programme and it is little affected by the alkaline cation in solution. Results are discussed in terms of three concurrent reactions, namely the electrochemical formation of Cd(OH)₂ and soluble Cd(OH) ₃ ^– , the HER and the electrocrystallization of cadmium renewing the fresh active sites for the HER, SEM micrographs of activated cadmium electrodes reveal a heterogeneous surface topography of the new cadmium layers.     

Mechanical Sensitivity and Detonation Parameters of Aluminized Explosives

Experiments were performed to study the effect of the species particle size and structure of aluminized mixture samples on the sensitivity and detonation parameters of HMX, nitroguanidine, bis(2,2,2trinitroethyl)nitramine, and their mixtures with an Al powder with a mean particle size of 0.1 – 150 m. The addition of ultrafine Al to HMX and bis (2,2,2trinitroethyl)nitramine substantially increases the sensitivity to mechanical effects and decreases the detonation velocity. In compositions with nitroguanidine, the detonation velocity practically does not vary. For nitroguanidine, the width of the chemicalreaction zone and Chapman–Jouguet parameters were determined by recording the detonationpressure profiles. The pressure profiles for bis(2,2,2trinitroethyl)nitramine show that detonation decomposition can occur in two stages. A twopeak detonationwave structure was detected for mixtures of HMX with Al. Temperature measurements indicate that Al interacts with detonation products in the immediate proximity to the front. The highest temperature was recorded for compositions containing ultrafine aluminum and an aluminum dust.     

Defense Secretion of Prorhinotermes simplex: Toxicity to Insecticide Susceptible and Resistant House Fly

(E)-1-Nitropentadec-1-ene (NPE), the main component of the defense secretion of Prorhinotermes simplex soldiers, is toxic to both insecticide-susceptible (S) as well as to insecticide-resistant (R) strains of the house fly, Musca domestica. The LD₅₀ is 11.7 g/female fly for the S strain and 9.7 g for the R strain. The same efficacy of NPE on R and S strains indicates a different mechanism of action compared to conventional chlorinated, organophosphorus, and pyrethroid insecticides. Termite nestmates are protected against NPE by a specific detoxification mechanism. 1-Nitropentadecane, the detoxification product of NPE is nearly nontoxic to house flies, and doses up to 160 g/fly caused only very low mortality.     

Effect of Volatile Constituents from <Emphasis Type="Italic">Securidaca</Emphasis><Emphasis Type="Italic">Longepedunculata</Emphasis> on Insect pests Of Stored Grain

Securidaca longepedunculata Fers (Polygalaceae) is commonly used as a traditional medicine in many parts of Africa as well as against a number of invertebrate pests, including insects infesting stored grain. The present study showed that S. longepedunculata root powder, its methanol extract, and the main volatile component, methyl salicylate, exhibit repellent and toxic properties to Sitophilus zeamais adults. Adult S. zeamais that were given a choice between untreated maize and maize treated with root powder, extract, or synthetic methyl salicylate in a four-way choice olfactometer significantly preferred the control maize. Methyl salicylate vapor also had a dose-dependant fumigant effect against S. zeamais, Rhyzopertha dominica, and Prostephanus truncates, with a LD₁₀₀ achieved with a 60 l dose in a 1-l container against all three insect species after 24 hr of exposure. Probit analyses estimated LD₅₀ values between 34 and 36 l (95% CI) for all insect species. Furthermore, prolonged exposure for 6 days showed that lower amounts (30 l) of methyl salicylate vapor were able to induce 100% adult mortality of the three insect species. The implications are discussed in the context of improving stored product pest control by small-scale subsistence farmers in Africa.     

A Study and Comparison of the Properties of Bauxite Treated by Dry and Wet Grinding Techniques

The kinetics of dry and wet grinding of a sintered bauxite treated using a ball mill is studied. By the dry grinding technique, a dispersity characterized by a median particle diameter of about 17 m and average surface particle diameter of about 5 m can be reached. By the wet grinding technique, a higher degree of dispersion of the material is reached (of median diameter less than 3 m), with a certain amount of nanoparticles produced.     

Crosslinked particles of poly[n-(1-phenylethyl)acrylamide]: Preparation and application as chromatographic stationary phases

Crosslinked particles of poly [N-(1-phenylethyl)acrylamidel have been successfully prepared by suspension polymerization of N-(1-phenylethyl) acrylamide and ethylene dimethacrylate in water using poly(vinyl alcohol) as dispersant. The particle morphology is investigated by optical microscope and scanning electron microscope (SEM). The pressure resistance of the crosslinked particles, evaluated after packing as stationary phases of high-performance liquid chromatography (HPLC), increases from 7 to 20 kg/cm² as the mole percent of ethylene dimethacrylate increases from 10% to 30%. The particles were sieved into four sieve fractions, i.e. 37–63 m, 63–88 m, 88–105 m, and 105–149 m, and packed into HPLC columns, respectively. The chromatographic performances of these columns have been investigated in HPLC system thoroughly, using benzene as solute and mixtures ofn-hexane and 2-propanol as eluents. The crosslinked particles show potential application as stationary phases for HPLC.     

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.     

Effect of juvenile hormone analog,fenoxycarb, on pheromone production byIps paraconfusus (Coleoptera: Scolytidae)

Topical application of the juvenile hormone analog, fenoxycarb, in acetone induced newly emerged male California five-spined ips,Ips paraconfusus Lanier, to become attractive to females, as measured by positive responses to male abdominal extracts in a laboratory bioassay. Two pheromones, ipsdienol and ipsenol, were detected by gas chromatography in the abdominal extracts of fenoxycarb-treated males. Pheromone production was minimal at a dose of 0.1 g/insect of fenoxycarb, maximal at 10 g, and was reduced to unmeasurable amounts at a dose of 100 g. In comparison, peak production of pheromones was induced at a dose of 0.1 g/insect of natural juvenile hormone (JH III). Treatment with 10 g of fenoxycarb resulted in the occurrence of pheromones 12 hr after exposure, maximal pheromone content between 16 and 20 hr, and undetectable amounts after 36 hr. The demonstration that fenoxycarb is an active juvenile hormone analog for a bark beetle suggests that it may have practical utility in managing these insects.     

A Technology for Preparing Sintered Ceramics Based on Bauxite HCBS

A technology for preparing high-density (with zero open porosity) ceramics molded by casting from bauxite highly concentrated ceramic binding suspensions (HCBS) has been developed (90% Al₂O₃). The precursor HCBS feature a high dispersity (percentage of particles < 2 m across in excess of 40%; median particle diameter, < 5 m; d _max = 10 – 20 m), a high solid-phase concentration (C _V 0.65), and a high fluidity. A material with zero open porosity is obtained by sintering at 1400 – 1450°C and its potential use for making grinding bodies is considered.