Adhesion of lacquer to phosphated steel — A shear test evaluation

Measurement of the adhesion toughness of a fast cure thermosetting powder coating used for corrosion protection of cold-rolled steel has been attempted in a shear test under uniform plane stress loading conditions at the interface. A specially designed test specimen preparation procedure (by direct crosslinking) and geometry (symmetrical) was developed to enable proper mechanical behaviour under shear initiation of fracture and uniform plane stress loading in the significant section of the specimen — the interface. The shear test was designed to measure the nominal and the net ultimate shear stress values (USS)_n and (USS)_net' as well as the critical stress intensity factor (SIF) of interfaces. From experimentally measured critical load at which the adhesion failed, the ultimate shear stress values (USS_net N mm^–2) were calculated and used as a quantitative information of the bond toughness along the interfaces. The experimental results with a range of specimens revealed that the test can, indeed, discern subtle variations influencing adhesion such as type of cold-rolled steel, an iron phosphate pretreatment before coating or variation in stoving temperatures. Fractographic analysis of shear failed specimens on mating surfaces revealed generation of a microcrack network in most of the fracture pattern tested, indicating fracture mechanism transitions characteristic of pure shear for both iron phosphated free cold-rolled steel-lacquer (SL) as well as for iron phosphated cold-rolled steel-lacquer (SPL) specimens. The fractographs, however, indicate fracture propagation more difficult for SPL specimens and comparatively smooth fracture surface for SL specimens, obviously affected by variations in their respective interface structure and morphology. This behaviour correlates well with measurements of (USS)_net in test.     

Formation of nitrogen-containing oligomers by methylglyoxal and amines in simulated evaporating cloud droplets

Reactions of methylglyoxal with amino acids, methylamine, and ammonium sulfate can take place in aqueous aerosol and evaporating cloud droplets. These processes are simulated by drying droplets and bulk solutions of these compounds (at low millimolar and 1 M concentrations, respectively) and analyzing the residuals by scanning mobility particle sizing, nuclear magnetic resonance, aerosol mass spectrometry (AMS), and electrospray ionization MS. The results are consistent with imine (but not diimine) formation on a time scale of seconds, followed by the formation of nitrogen-containing oligomers, methylimidazole, and dimethylimidazole products on a time scale of minutes to hours. Measured elemental ratios are consistent with imidazoles and oligomers being major reaction products, while effective aerosol densities suggest extensive reactions take place within minutes. These reactions may be a source of the light-absorbing, nitrogen-containing oligomers observed in urban and biomass-burning aerosol particles.     

A Unitary Analysis of some Voltage and Current Mode Linear Circuits

This paper presents a systematic and unitary analysis of a large class of current and voltage mode circuits based on a series-shunt-like configuration. Four possible OA types are considered for the basic amplifier. The amplifiers have voltage and current input signals and voltage and current outputs. The analysis method is based on the separation of the circuit signal graph in two different paths, one that controls the gain and the other that controls the bandwidth.     

Feeling the Squeeze: Nonmarket Institutional Pressures and Firm Nonmarket Strategies

This study investigates the drivers of pressures from various institutions in the nonmarket environment and the responses of MNEs to these pressures in a host country. By taking a broad institutional perspective, this study pairs and integrates the economic perspective of new institutionalism and the sociological perspective of neo institutionalism with the corporate political strategy perspective. This research provides a systematic review of the drivers underlying pressures from various types of nonmarket institutions that explain the preference of firms to use a transactional or relational strategy to deal with these pressures. The evidence is based on research involving MNEs in the Netherlands. The nonmarket institutions that exert the greatest pressures at the national level pushing MNEs to use transactional more than relational strategies and tactics are regulatory and standards agencies. The pressures of political institutions, interest groups, and the media, in contrast, trigger MNEs to employ relational rather than transactional strategies and tactics.     

The (Non)Violent World of YouTube: Content Trends in Web Video

In this content analysis, we examined violence in Web‐based entertainment. YouTube videos (N = 2,520) were collected in 3 different categories: most viewed, top rated, and random, with additional comparisons between amateur and professional content. Frequencies of violent acts and the context of violence (e.g., characteristics of perpetrator and victim, justification, consequences) were compared both between these categories of YouTube videos and with existing research on television violence. The results showed far less violence as a percentage of programming on YouTube than there is on television. Moreover, the violence that was present showed more realistic consequences and more negative context than television violence. Post hoc comparisons illustrated several differences in the presentation of violence between make and category of video.     

Synthesis and properties of phthalocyanine zinc(II) complexes replaced with oxygen and sulfur linked adamantane moieties

Novel, zinc (II) phthalocyanines substituted with 2-adamantanol and 1-adamantanethiol moieties were prepared from the corresponding phthalonitriles employing commercially available 3- and 4-nitrophthalonitrile as the starting material. The Q-band of tetra-α-substituted phthalocyanines occurred at longer wavelengths than those of the corresponding, tetra-β-substituted phthalocyanines. Substituents at the β position increased Φ_F values; all phthalocyanines studied displayed excellent singlet oxygen generations ability, with α-substituted dyes showing higher Φ_Δ values than their β-isomers. The dyes exhibited good photo-stability, with α-substituted phthalocyanines proving to be of higher stability than the corresponding β-isomers.     

Effects of cotton leaf surface alkalinity on feeding ofSpodoptera littoralis larvae

The high leaf surface pH in cotton (Gossypium hirsutum) var. Acala SJ2 was bioassayed againstSpodoptera littoralis larvae. Weight gain and leaf consumption of the larvae feeding on leaves devoid of alkalinity, due to daily washing, were recorded. Untreated cotton, with a leaf surface pH of 9.5–10.0 was used as control. The gland exudates contained potassium and magnesium cations, and the gland surface and intergland leaf areas were rich in calcium and phosphorus and low in K or Mg. The role of this plant antibiosis in the insect-host-plant relationship is discussed.Contribution No. 1885-E 1986 series, from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel.     

The impact of particle-bound cadmium on bioavailability and bioaccumulation: A pragmatic approach

Studying the bioavailability of sediment-bound contaminants is complicated by many reasons, such as the variable composition of the particles, their temporal variations, the low levels of contaminant concentrations, their partitioning between diverse aqueous and particulate phases, and the variety of uptake routes that may involved with the biota. Therefore, simple and innovative methodologies should be tested as analogues for natural sediments. Among them, a diverse selection of artificial particles with well-defined surface properties, in the presence and absence of commercially available humic acids, has been proposed and used to investigate the bioavailability of several organic pollutants. For this work, this model was applied to investigate the uptake and accumulation of cadmium by the freshwater oligochaete Lumbriculus variegatus. The results showed that the uptake of the metal depended on the free dissolved Cd(II) species, while the contribution from the particles was negligible. Thus, the extent of cadmium bioaccumulated from each test system could be predicted as a function of the rate of absorption of the free dissolved Cd(II) species. These species were calculated either from the particle-water partition coefficients, or by using the MINEQL+ computer program. In general, the estimated accumulation levels were in good agreement with the experimental results.