Net shape formation of sub-micron alumina with reduced flaws by high-speed centrifugal compaction process

A new compacting method for powder materials is presented. High-Speed Centrifugal Compaction Process (HCP) utilizes centrifugal force of about 10,000 g for the compaction. HCP is suitable for net shape compaction of fine sub-micron and nano-powders. HCP possesses a unique compacting mechanism that is different from other colloidal processes including Pressure Casting (PC), and has a number of useful characteristics. HCP has a higher compacting speed than PC, wide applicability for net shape formation, as well as a defect removing function. Because of homogeneous and flawless green microstructure, HCP alumina shows superior sinterability and higher strength and hardness than most of other aluminas. This article is based on a presentation made in the symposium “The 3rd KIM-JIM Joint Symposium on Advanced Powder Materials“, held at Korea University, Seoul, Korea, October 26–27, 2001 under auspices of The Korean Institute of Metals and Materials and The Japan Institute of Metals.     

Evaluation of oxidative stability of canola oils by headspace analysis

Lipid oxidation is a major factor affecting flavor quality and shelf life of vegetable oils. Oxidative stability is therefore an important criterion by which oils are judged for usefulness in various food applications. In this study a method based on headspace analysis was developed to evaluate relative oxidative stability of canola oils. The method does not require the use of chemicals, involves minimal sample preparation, and can be performed on a relatively small sample size in comparison with traditional wet chemical methods. Canola oils freshly extracted in the laboratory from different seed samples were subjected to accelerated oxidation and analyzed for PV by standard methods and headspace volatiles by solid phase microextraction/GC-MS. Forward stepwise regression analysis of the data revealed a relationship between PV and headspace concentration of the volatile lipid oxidation products hexanal and trans,trans-2,4-heptadienal. The PV calculated using this formula correlated (R ²=0.73) with those measured by conventional methods. Presented in part at the 96th Annual Meeting of the AOCS, 1–4 May 2005, Salt Lake City, UT.     

The role of the surface free energy in the selection of a suitable excipient in the course of a wet-granulation method

Pellets containing metronidazole were produced in a centrifugal granulator, with hydroxypropylcellulose (Klucel LF®) as binding agent, and corn starch, microcrystalline cellulose (Vivapur 101®) and lactose as excipients. The wettability of the pharmaceutical powders was assessed by means of contact angle measurements, and the dispersive and polar surface energies were determined. The spreading coefficients, the work of adhesion and the work of cohesion were calculated and correlated with the pellet properties (friability, bulk and tapped density, and porosity). The aim was to investigate the role of the surface free energy of one- and two-component powder compositions in pellet production. The interactions between the particles were found to be connected with the measured pellet parameters. It was concluded that, in the course of the growth of the pellets, the particle sizes of the pharmaceutical powders and the interactions between them are important. If the work of cohesion of the binder is lower than the work of cohesion of the substrate and the work of adhesion, then the optimal amount of the binding agent is that which coats the particles uniformly in minimal quantity and in continuous layer.     

Impact of dietary n−3 FA deficiency on rat bone tissue FA composition

The effect of dietary n−3 FA deficiency on bone tissue FA composition was evaluated in growing rats. Two mixtures combining hydrogenated coconut oil with safflower oil served as the n−3-deficient dietary treatments and provided two levels of linoleic acid (LA). The n−3 treatments were formulated with added α-linolenic acid (LNA) from flaxseed oil (diet LNA) or LNA plus DHA, and both were balanced for LA. This study showed that bone is sensitive to changes in dietary n−3 FA and that DHA is more effective than LNA in maintaining DHA levels in these tissues.     

Soil Apparent Electrical Conductivity (EC<Subscript>a</Subscript>) as a Means of Monitoring Changesin Soil Inorganic N on Heterogeneous Morainic Soils in SE Norway During Two Growing Seasons

An efficient method to monitor changes in soil inorganic N content during crop growth would be a useful means to guide N fertilization to ensure high yields and low N losses to the environment. In this study, soil apparent electrical conductivity (EC_a) measured by the widely used conductivity meter EM38 was tested as an indirect measurement of available N in spring barley during two cropping seasons at two sites with morainic loam in SE Norway. The experiment was constructed to maximize soil variation. In spite of the ȁ8noiseȁ9 caused by the soil heterogeneity, concentrations of inorganic N (cN_inorg) or NO₃-N were most strongly correlated with EC_a in both years and at both locations (with one exception). The measurements of EC_a reflected well the temporal variation in inorganic N content (N_inorg), and a ranking of the treatments based on EC_a fitted very well with a ranking based on N_inorg at the first three sampling times after fertilizing. The best subset of sensor variables (i.e. variables which can be measured ȁ8on-the-goȁ9 by sensor techniques in the field) described 27–69% (average 47%) of the variation in topsoil cN_inorg. When expanding the regression models to include pH as well, the degree of explanation increased significantly. In conclusion, the method of using EC_a appears to be quite robust in terms of detecting relative differences in cN_inorg, whereas a determination of absolute levels of cN_inorg with the method is unreliable.     

Effect of processing on sphingolipid content in soybean products

Soybeans are believed to be a rich source of sphingolipids, a class of polar lipids that has received attention for their possible cancer-inhibiting activities. The effect of processing on the sphingolipid content of various soybean products has not been determined. Glucosylceramide (GlcCer), the major sphingolipid type in soybeans, was measured in several processed soybean products to illustrate which product(s) GlcCer is partitioned into during processing and where it is lost. Whole soybeans were processed into full-fat flakes, from which crude oil was extracted. Crude oil was refined by conventional methods, and defatted soy flakes were further processed into alcohol-washed and acid-washed soy protein concentrates (SPC) and soy protein isolates (SPI) by laboratory-scale methods that simulated industrial practices. GlcCer was isolated from the samples by solvent extraction, solvent partition, and TLC and was quantified by HPLC. GlcCer remained mostly within the defatted soy flakes (91%) rather than in the oil (9%) after oil extraction. Only 52, 42, and 26% of GlcCer from defatted soy flakes was recovered in the acid-washed SPC, alcohol-washed SPC, and SPI products, respectively. All protein products had a similar GlcCer concentration of about 281 nmol/g (dry wt basis). The minor quantity of GlcCer in the crude oil was almost completely removed by water degumming.     

Physical properties of oleochemical carbonates

Carbonates are a class of compounds that have recently found increasing interest in commercial applications owing to their physical properties and relatively straightforward synthesis. In this work, physical and fuel properties of five straight-chain C_17–39 and three branched C_17–33 oleochemical carbonates were investigated. These properties included cetane number (CN), low-temperature properties, (kinematic) viscosity, lubricity, and surface tension. The carbonates studied had CN ranging from 47 to 107 depending on carbon chain length and branching. For the same number of carbons, the CN of carbonates were lower than those of FA alkyl esters owing to interruption of the CH₂ chain by the carbonate moiety. Kinematic viscosities at 40°C ranged from 4.9 to 22.6 mm²/s whereas m.p. ranged from +3 to below −50°C depending on the carbonate structure. High-frequency reciprocating rig testing showed the neat carbonates to have acceptable lubricity that improved as chain length increased. Finally, the carbonate's ability to influence cold-flow properties in biodiesel (methyl soyate) and lubricity in low-lubricity ultra-low sulfur diesel were examined. The carbonates studied did not significantly affect cold flow or lubricity properties at concentrations up to 10,000 ppm (1 wt%). The properties of the carbonates resemble those of fatty alkyl esters with similar trends resulting from compound structure.     

BIOFUMIGANT COMPOUNDS RELEASED BY FIELD PENNYCRESS (<Emphasis Type="Italic">Thlaspi arvense</Emphasis>) SEEDMEAL

Defatted field pennycress (Thlaspi arvense L.) seedmeal was found to completely inhibit seedling germination/emergence when added to a sandy loam soil containing wheat (Triticum aestivum L.) and arugula [Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell.] seeds at levels of 1.0% w/w or higher. Covering the pots with Petri dishes containing the soil-seedmeal mixture decreased germination of both species at the lowest application rate (0.5% w/w), suggesting that the some of the phytotoxins were volatile. CH₂Cl₂, MeOH, and water extracts of the wetted seedmeal were bioassayed against wheat and sicklepod (Senna obtusifolia (L.) H. S. Irwin & Barneby) radicle elongation. Only the CH₂Cl₂ extract was strongly inhibitory to both species. Fractionation of the CH₂Cl₂ extract yielded two major phytotoxins, identified by gas chromatography–mass spectrometry and NMR as 2-propen-1-yl (allyl) isothiocyanate (AITC) and allyl thiocyanate (ATC), which constituted 80.9 and 18.8%, respectively, of the active fraction. When seeds of wheat, arugula and sicklepod were exposed to volatilized AITC and ATC, germination of all three species was completely inhibited by both compounds at concentrations of 5 ppm or less. In field studies, where seedmeal was applied at 0.50, 1.25, and 2.50 kg/m² and tarped with black plastic mulch, all of the treatments significantly reduced dry weight of bioassay plants compared to the tarped control, with the highest seedmeal rate decreasing dry matter to less than 10% of the control 30 d after seedmeal application. Field pennycress seedmeal appears to offer excellent potential as a biofumigant for high-value horticultural crops for both conventional and organic growers.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Nitrogen dynamics during till and no-till pasture restoration sequences in Rondônia,Brazil

The clearing of tropical rain forest in the Amazon basin has created large areas of cattle pasture that are now declining in productivity. Practices adopted by ranchers to restore productivity to degraded pastures have the potential to alter soil N availability and gaseous N losses from soils. We examined how soil inorganic N pools, net N mineralization and net nitrification rates, nitrification potential and NO and N₂O emissions from soils of a degraded pasture responded to the following restoration treatments: (1) soil tillage followed by replanting of grass and fertilization, (2) no-till application of non-selective herbicide, planting of rice, harvest followed by no-till replanting of grass and fertilization, and (3) the same no-till sequence with soybeans instead of rice. Tillage increased soil NH₄⁺ and NO₃^? pools but NH₄⁺ and NO₃^? pools remained relatively constant in the control and no-till treatments. Cumulative rates of net N mineralization and net nitrification during the first 6 months after treatment varied widely but were hightest in the tilled treatment. Emissions of NO and N₂O fluxes increased with tillage and with N fertilization. There were no clear relationships among rates of N fertilizer application, net N mineralization, net nitrification, NO, N₂O and total N oxide emissions. Our results indicate that pasture restoration sequences involving tilling and fertilizing will increase emissions of N oxides, but the magnitude of the increase is likely to differ based on timing of fertilizer application relative to the presence of plants and the magnitude of plant N demand. Emissions of N oxides appear to be decreased by the use of restoration sequences that minimize reductions in pasture grass cover.     

Continuous production of structured phospholipids in a packed bed reactor with lipase from <Emphasis Type="Italic">Thermomyces lanuginosa</Emphasis>

The possibilities of producing structured phospholipids between soybean phospholipids and caprylic acid by lipase-catalyzed acidolysis were examined in continuous packedbed enzyme reactors. Acidolysis reactions were performed in both a solvent system and a solvent-free system with the commercially immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) as catalyst. In the packed bed reactors, different parameters for the lipase-catalyzed acidolysis were elucidated, such as solvent ratio (solvent system), temperature, substrate ratio, residence time, water content, and operation stability. The water content was observed to be very crucial for the acidolysis reaction in packed bed reactors. If no water was added to the substrate during reactions under the solvent-free system, very low incorporation corporation of caprylic acid was observed. In both solvent and solvent-free systems, acyl incorporation was favored by a high substrate ratio between acyl donor and phospholipids, a longer residence time, and a higher reaction temperature. Under certain conditions, the incorporation of around 30% caprylic acid can be obtained in continuous operation with hexane as the solvent. Presented at the 95th American Oil Chemists' Society Annual Meeting and Expo in Cincinnati, Ohio, May 10, 2004.