Addition Of Various Types Research Articles

Combined effects of non-Newtonian rheology and fluid inertia forces on the non-linear transient behaviour in circular squeeze films

On the basis of the momentum integral method and the microcontinuum theory, the combined effects of total fluid inertia forces and non-Newtonian couple stresses on the non-linear squeeze film characteristics between parallel circular discs are presented. The squeeze-film lubrication equation is derived from the Stokes couple-stress motion equation retaining total fluid inertia terms to take into account the effects of non-Newtonian couple stresses resulting from the base oil blended with various types of additives, and the effects of local fluid inertia and convective fluid inertia. The non-linear motion equation for the squeezing disc is then numerically solved by using fourth-order Runge-Kutta method. Comparing with the Newtonian-lubricant inertialess case, the combined effects of fluid inertia forces and non-Newtonian couple stresses provide a significant increment in the response time of the squeeze film. The operating life of squeeze film discs are therefore lengthened, especially for larger couple stress parameters, Reynolds numbers and body inertia parameters. A design example is provided to facilitate the engineers assessing the extent to design the non-linear squeezing film discs considering the combined effects of total fluid inertia forces and non-Newtonian couple stresses.

Asymmetric catalysis for the construction of quaternary carbon centres: nucleophilic addition on ketones and ketimines

There is a growing need in organic synthesis for efficient methodologies for the asymmetric synthesis of quaternary carbon centres. One of the most attractive and straightforward methods focuses on the use of asymmetric catalysis for the addition of various types of nucleophiles on prochiral ketones and ketimines. A view of the literature from this growing area of research will be presented in this review, with an emphasis on the pioneer works and milestones brought by the main players in this field.

DNA and its cationic lipid complexes induce CpG motif‐dependent activation of murine dendritic cells

Unmethylated CpG motifs in bacterial DNA, but not in vertebrate DNA, are known to trigger an inflammatory response of antigen-presenting cells (APC). In this study, we investigated the cytokine release from murine dendritic cells (DC) by the addition of various types of DNA in the free or complexed form with cationic lipids. Naked plasmid DNA and Escherichia coli DNA with immunostimulatory unmethylated CpG motifs induced pro-inflammatory cytokine secretion from granulocyte-macrophage colony-stimulating factor (GM-CSF)-cultured bone marrow-derived DC and the DC cell-line, DC2.4 cells, though vertebrate calf thymus DNA (CT DNA) with less CpG motifs did not. These characteristics differed from mouse peritoneal resident macrophages that do not respond to any naked DNA. The amount of cytokines released from the DC was significantly increased by complex formation with cationic lipids when CpG-motif positive DNAs were used. Unlike murine macrophages or Flt-3 L cultured DC, GM-CSF DC did not release inflammatory cytokines in response to the addition of CT DNA/cationic lipid complex, suggesting that the activation is completely dependent on CpG motifs. Taken together, the results of the present study demonstrate that murine DC produce pro-inflammatory cytokines upon stimulation with CpG-containing DNAs and the responses are enhanced by cationic lipids. These results also suggest that DC are the major cells that respond to naked CpG DNA in vivo, although both DC and macrophages will release inflammatory cytokines after the administration of a DNA/cationic lipid complex.

Role of submicron residual fillers in improving optical reflectance of barrier rib glasses for plasma display panels

The improvement of optical reflectance of BaO–ZnO–B2O3–SiO2 (BZBS) glass by the addition of various types of micron-scale crystalline fillers (TiO2, SiO2, ZrO2, Al2O3, MgO, and cordierite) was investigated for application of the materials to barrier ribs of plasma display panels. The fillers were partially dissolved during sintering, yielding an increased local volume of the fillers in the submicron range, filler rearrangement along boundaries of sintered glass frits, and rather irregular and rugged filler shapes differing from the original morphologies. The measured optical reflectance of the various filler added specimens was within the 30–70% range, which was much higher than the predicted values (less than 10%) based on the rule of mixture of the refractive index. Here we report that the high reflectance of the barrier rib glass for plasma display panels is explained by light scattering by the increased submicron portion of the partially dissolved residual fillers, the size of which is similar to the visual spectrum range (0.4–0.7 μm). The order of reflectance improvement among different types of filler-embedded specimens was consistent with that of the degree of dispersion of the residual fillers in the glass matrix.

Improving the visual quality of commercial development at the rural–urban fringe

Rapid growth at the rural–urban fringe has resulted in increased commercial development along arterial roads connecting cities and the countryside. These developments, often termed “commercial strips” or “linear commercial complexes”, are characterized by a mix of many different types of businesses that often lack any separation from the road, spatial definition, or natural features such as trees. The result is too often an open, barren, confusing setting with little aesthetic appeal. Could a change in the design of the commercial setting or the addition of natural features improve the visual quality of the roadway at the rural–urban fringe? This study examines the extent to which local citizens prefer various development patterns for a roadway corridor at the fringe of a medium-sized community. Participants responded to a photo-questionnaire that included images of alternative design treatments for the roadside and written items dealing with visual quality. The results revealed moderate preference for the existing condition that showed a typical Midwestern US agricultural setting. The addition of various types of commercial development to the settings caused preference ratings to plummet. However, the addition of trees to the commercial development scenes increased preference ratings substantially. In fact, this low cost alteration in the design not only caused preference ratings to rebound, but actually exceed the ratings for the existing condition. Ratings were higher still for scenes in which trees were added to the existing condition. The findings suggest that nature plays an important role in the aesthetics of developed settings at the rural–urban fringe, and that trees in particular can be used to improve visual quality. This study has implications for the design of roadways and commercial developments at the fringe.

Investigation into the effectiveness of detergent—dispersant agents and additive packages

AbstractComparative tests of more than 15 detergents (calcium sulphonates and phenates) of different basicity and dispersants (succinimides) were carried out using laboratory test methods. The effectiveness of the detergent and dispersant action of the test additives, their thermal, hydrolytic, and colloidal stability, and their influence on the antioxidant properties of engine oils were evaluated. The results obtained showed that it is possible to differentiate additives of various types, and demonstrated the relative efficiency of additives belonging to the same class. The effectiveness of certain additive packages was evaluated using a new approach: in addition to the laboratory methods, the retention of the dispersing ability of additive packages was evaluated in previously oxidised additivated engine oils. This allowed the efficiency of engine oils of different categories to be characterised.

Immobilization of the heavy metals Cd, Cu and Pb in an acid soil amended with gypsum‐ and lime‐rich industrial by‐products

Summary In situ stabilization of heavy metals in contaminated soils by the addition of various types of soil amendment is an attractive technique for remediation. We investigated the potential of three industrial by‐products (phosphogypsum, red gypsum and dolomitic residue) for boosting the heavy metal sorption capacity of an acid soil (patents pending, Spanish applications no 200201704 and 200201375) by using sorption isotherm experiments. The three by‐products were found substantially to increase the retention of lead, cadmium and copper on the solid components of the soil. The increase in lead retention of the soil horizons upon the addition of both phosphogypsum and red gypsum was dominated by the formation of anglesite minerals. The dolomitic residue increased the metal retention capacity of the soil horizons through the precipitation of laurionite‐type minerals as well as cadmium and copper hydroxy‐chlorides. In addition to the batch sorption study, we used scanning electron microscopy to investigate the metal sorption processes in the soil by the effect of the treatments. Lead was frequently found to be linked to the edge charges of kaolinite minerals. The three metals were found to be associated with organic matter in the Ap horizon treated with the three by‐products. Finally, the three metals were found to be associated with undissolved dolomitic residue particles.

Improvement of permanent magnet machines performance by including magnetic shells into the rotor geometry

FEM modelling of PM motor was carried out to demonstrate the effects of the addition of various types of ferromagnetic tubes (shell) to a rotor of surface mount permanent magnet motor. An enhancement in magnet operating point towards the high field region is obtained. A shell made of amorphous ribbon offers optimum advantages.

Akzo Nobel Polymer Chemicals joins PolymerAdditives.com

This article looks at the underlying chemistry of various types of additives, and antimicrobial films, which potentially could be used by the food-packaging industry, and the associated research work which seeks to make this technology commercially usable.

Tribological performance of thin organic permanent coatings deposited on 55%Al–Zn coated steel — influence of coating composition and thickness on friction and wear

Dry lubricants are today increasingly being used in various types of sheet metal forming operations. Among these, permanent coatings, based on organic resins are the only lubricants which have the potential to increase the formability without additional lubrication, serve as temporary corrosion protection during transportation and, finally, serve as a pre-treatment before subsequent painting. In the present study, the influence of coating composition and thickness on the friction and wear behaviour of different thin organic permanent coatings deposited on 55%Al–Zn coated steel sheet have been evaluated by various types of laboratory tests. Surface profilometry, scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and time-of-flight secondary ion mass spectrometry (ToF–SIMS) were used in order to characterise and model the tribological behaviour of the coatings. The results obtained show that the tribological properties of thin organic permanent coatings are strongly influenced by the coating thickness. In order to reduce problems associated with high friction and galling, the coating must be deposited with a uniform thickness, i.e. uncoated regions must be avoided. Furthermore, the addition of various types of additives can be used in order to further improve the tribological performance of these types of coatings.

Antimicrobial food packaging materials

This article looks at the underlying chemistry of various types of additives, and antimicrobial films, which potentially could be used by the food-packaging industry, and the associated research work which seeks to make this technology commercially usable.

Influence of phase transformation on the permanent-magnetic properties of Fe–Pt based alloys

We have studied the effect of the atomic disorder–order transformation on remanence enhancement and coercivity in Fe–Pt-based materials by isothermal annealing at temperatures well below the transformation point. We also investigated the effect of the annealing temperature and the effect of various types of additives. The relative amount of the low-temperature hard-magnetic face-centered-tetragonal (FCT) phase precipitated in the high-temperature magnetically soft face-centered-cubic (FCC) phase was determined by means of X-ray diffraction. As a function of annealing time and annealing temperature, particle size and relative amount of the FCT phase increased at the cost of the FCC phase. These changes were followed by means of magnetic measurements. We observed a continuous increase in coercivity with increasing annealing time, eventually reaching a maximum. The Kneller–Hawig model was used to explain the occurrence of remanence enhancement and the continuously changing degree of exchange coupling between the magnetically soft and hard phase. The suitability of Fe–Pt based alloys in dental applications is discussed.

A strategy to solve environmental concerns caused by poultry production

Poultry manure and litter have the potential to be either land resources or pollutants of surface and ground water as well as giving rise to unpleasant odours. Provided proper attention is paid to nutrient management, they can be used as fertilisers, soil amendments and feed ingredients. Furthermore, the contents of nitrogen, phosphorus and other minerals in poultry manure and litter can be reduced by paying careful attention to diet composition – for example, by applying the concept of ideal protein, supplementation with synthetic amino acids, the addition of various types of enzymes including phytase, the lowering of the protein and phosphorus contents and the use of highly available sources of supplementary phosphorus and vitamin D. Good nutrient management also depends on obtaining representative samples of feed, manure, litter, water and soil from each handling system and having these analysed on a regular basis in a reliable laboratory. This not only ensures that proper quantities of nutrients are added to the native soil on which the crops that are ultimately to be used as feed sources are to be grown, but also means that lower amounts of nitrogen, phosphorus and other elements are present in the feed. One outcome of the latter effect is that the poultry manure and litter excreted contains fewer potential pollutants and reduces the criticism levelled at the poultry industry that it runs roughshod over environmental concerns. It would be beneficial if all of these analytical procedures were handled in one laboratory specialising in animal agriculture with specialists advising farmers on how best to apply the analytical data.

Phase Transition in Linear and Cross-Linked Poly(N-Isopropylacrylamide) in Water: Effect of Various Types of Additives

The conformational status of a macromolecule in solution is dictated primarily by two forces: polymer-solvent interaction and polymer-polymer interaction. In a good solvent, the former predominates...

Influence of additives on the formation of unsaturated PCAs produced during durable‐press curing with citric acid

To impart durable‐press properties to cellulosic material, the fabrics have been treated with a finishing bath containing a polycarboxylic acid in combination with an appropriate catalyst. When citric acid (CA) was applied as crosslinking agent discoloration of the fabric was observed. Special additives were included into the formulation to improve the whiteness index. Isocratic HPLC was used to identify and quantify the unsaturated polycarboxylic acids that are produced during the curing process of CA‐treated cotton fabrics. The influence of different catalysts (sodium hypophosphite, sodium dihydrogen phosphate, disodium hydrogen phosphate, tetrasodium pyrophosphate, trisodium phosphate) and of various types of additives, such as triethanol amine (TEA), W,/V,bis(hydroxy‐ethyljglycine (BICINE), boric acid and polyethylene glycol 200 (PEG 200), on the content of CA and the amount of unsaturated PCAs in the wash liquor and on the fabric has been investigated. A significant reduction of the unsaturated polycarboxylic acids was observed when an additive was incorporated into the pad bath.

Controlled release of U-86983 from double-layer biodegradable matrices: effect of additives on release mechanism and kinetics

Effects of additives on the drug release kinetics from biodegradable matrices is an important determinant in designing a drug delivery system. These experiments introduced the influence of an array of additives on the drug release from double-layered poly(lactic-co-glycolic acid) (PLGA) matrices. Various additives such as l-tartaric acid dimethyl ester (DMT), Pluronic® F127 (F127); 2-hydroxypropyl derivative of β-cyclodextrin (HPB), methyl derivative of β-cyclodextrin (MMB) and Beeswax (Wax), differing in molecular size, hydrophilicity and steric configuration were selected for this study. An antiproliferative 2-aminochromone, U-86983 (U-86, Pharmacia and Upjohn), was used as a model agent because of our interest in investigating local drug delivery systems for the inhibition of restenosis. The in vitro release of U-86 from PLGA matrices without additive showed a typical biphasic release kinetics, i.e. a slow diffusion release (Phase I) followed by a fast erosion-mediated release (Phase II). The water-soluble additives in PLGA matrices changed the biphasic release pattern to a near monophasic profile by increasing the release rate of the Phase I. Increasing the ratio of additives to PLGA in matrices causes a significant increase in the U-86 release rates. The high molecular weight water-soluble additive, Pluronic® F127, resulted in a matrix showing perfect zero-order release kinetics. The water-soluble cyclodextrin derivative, HPB, gave the highest release rate among all the matrices formulated. A hydrophobic additive, Beeswax, however showed biphasic release kinetics comparable to PLGA control matrices, but delayed the onset of the Phase II by 4 days. The U-86 release profiles were in good agreement with the mass loss profiles of these matrices except for the matrices with F127 and HPB additives. The morphologic evaluation of matrices using scanning electron microscopy indicates that the water-soluble additives are leachable and thus generate a highly porous structure in the matrices. The matrix pore configuration (e.g. interconnected or closed) created with different additives determined the mechanism of drug release kinetics from the various matrix formulations. In conclusion, the feasibility of modulating release rates and kinetics of an agent from PLGA monolithic matrices by utilizing various types of additives is demonstrated. Water-solubility, molecular size and steric configuration of the additives are the important determinants in generating various types of pore structures in polymer matrix which in turn affect the release mechanism and release kinetics.

Influence of additives on the growth morphology of γ-aminobutyric acid

Specific growth rates of the two main faces (120) and (001) of single γ-aminobutyric (GABA) crystals are measured in a cell under a laminar flow of supersaturated solution within a narrow temperature interval. In the non-diffusion-controlled region with respect to fluid velocity, the effect of supersaturation (σ) on face growth rates, Vhkl, fits the BCF model; furthermore, the crossing of the two curves V120(σ) and V001(σ) gives rise to morphological changes. Crystal growth studies in the presence of various types of additives show the pronounced influence of positively charged species, such as Cr3+ and dodecyltrimethylammonium ions, on the relative growth rate V120V001. This phenomenon is well explained by strong cation adsorption on the (001) face exposing the carboxylic groups of GABA zwitterions.

Spent clay as an additive for roofing and waterproofing materials

Petroleum asphalts are widely used in the production of roofing, waterproofing, sealing, anticorrosion, and other materials. Among their shortcomings, which carry over into materials based on petroleum asphalts, is poor freeze resistance, the end result being a shorter life of the coating. Various types of additives may be used to broaden the temperature range for the use of asphalt coatings.

Anionic Polymerization of (Meth)acrylic Monomers. 22. Anionic Polymerization of tert-Butyl Methacrylate in Toluene/THF Mixtures: A Preliminary Approach to the Role of Solvation/Ligation Equilibria

Although the anionic polymerization of tert-butyl methacrylate (tBMA) induces a narrow and unimodal molecular weight distribution (MWD) when performed in either pure THF or pure toluene at -78 o C in the presence of a lithium counterion, that in THF/toluene mixtures, keeping other conditions unchanged, surprisingly gives rise to broad bi- and even multimodal MWD's. Moreover, with increasing polymerization temperature from -78 to 0 o C, that multimodal MWD gets narrower, atypical of termination reactions, and indeed at 0 o C, a very narrow unimodal MWD is again obtained. These results have been satisfactorily interpreted in terms of a multiple solvation equilibria mechanism: there coexist several types of THF-solvated and nonsolvated active species and the exchange among them is slow at -78 o C but fast at 0 o C compared to the monomer propagation rate, thus resulting in a multimodal MWD in the former case and a narrow one in the latter. Furthermore, this solvation mechanism also dominates the stereoregulation of the tBuMA polymerization in mixed solvent. It has indeed been demonstrated that addition of various types of ligands, i.e., lithium chloride (LiCl) and lithium tert-butoxide (LiOtBu) (both μ-ligands), 12-crown-4 (12CE4) and cryptand 211 (K211) (both α-chelating ligands), and lithium 2-(2-methoxyethoxy)ethoxide (LiOE 2 M) (a μ/ dual type of ligand), affects the tBMA anionic polymerization in a way which can be accounted for by these so-called solvation/ligation multiple equilibria among THF-nonsolvated, THF-solvated, and ligated ion pairs. Once again, the fact that, in comparison with 12CE4 and LiOtBu, such ligands as LiOE 2 M, K211, and LiCl can effectively promote a much narrower MWD is nicely related to their high propensity to coordinate with a lithium ester enolate and at the same time to either promote a fast-exchanging ligation equilibrium or form a single type of active complex, in good agreement with the NMR investigation of corresponding model systems as previously reported by us

ワラ類の化学パルプ化 （ＩＩ） 稲ワラ・ソーダ蒸解黒液リグニンから分散剤の調製

Soda lignin from rice straw was sulfomethylated, and the dispersion ability of sulfomethylated lignin was compared with that of commercial softwood lignosulfonate. The results are summarized as follows : (1) Black liquor from soda cooking of rice straw was adjusted to pH 8.2 with aq. sulfurous acid. Same mole of formaldehyde as sodium sulfite formed in black liquor was added, and then dissolved lignin was directly sulfomethylated (SML I). Sulfomethylated black liquor was separated by gel filtration method (SML II : 0.18 S/C6-C3).(2) SML I shows the similar standard dispersion number (SDN), regardless of max. temperature of soda cooking and reaction time of sulfomethylation.SDN of sulfomethylated liquor including SWL I, however, is inferior to that of lignosulfonate. This may be due to the low content of sulfonic acid group and low purity of SML I. In order to utilize straw soda lignin as dispersant, it is necessary to isolate soda lignin from black liquor and to sulfomethylate the isolated soda lignin.(3) The setting time of mortar with SML II show the relatively similar results to that of commercial lignosulfonate. SML I, however, requires a long period of the setting time. The utilization of SML I as the dispersant is impractical in mortar manufacture.(4) The dispersion effect with SML II was compared by the use of various types of additives. Among seventeen additives tested here, citric acid, gluconic acid, glucuronic acid and K, H-glucarate show the excellent SDN. Very high SDN shown by K, H-glucarate is worth noting.