Pitch-coke interactions

Penetration of molten pitch into a coke bed is correlated with thermodynamic properties of pitch and of pitch-coke interfaces, as well as with the rheology of the liquid. A review of the possible relation between the above properties and the molecular properties of the pitch is presented.     

Stage-Related Defense Response Induction in Tomato Plants by Nesidiocoris tenuis

The beneficial effects of direct predation by zoophytophagous biological control agents (BCAs), such as the mirid bug Nesidiocoris tenuis, are well-known. However, the benefits of zoophytophagous BCAs’ relation with host plants, via induction of plant defensive responses, have not been investigated until recently. To date, only the females of certain zoophytophagous BCAs have been demonstrated to induce defensive plant responses in tomato plants. The aim of this work was to determine whether nymphs, adult females, and adult males of N. tenuis are able to induce defense responses in tomato plants. Compared to undamaged tomato plants (i.e., not exposed to the mirid), plants on which young or mature nymphs, or adult males or females of N. tenuis fed and developed were less attractive to the whitefly Bemisia tabaci, but were more attractive to the parasitoid Encarsia formosa. Female-exposed plants were more repellent to B. tabaci and more attractive to E. formosa than were male-exposed plants. When comparing young- and mature-nymph-exposed plants, the same level of repellence was obtained for B. tabaci, but mature-nymph-exposed plants were more attractive to E. formosa. The repellent effect is attributed to the signaling pathway of abscisic acid, which is upregulated in N. tenuis-exposed plants, whereas the parasitoid attraction was attributed to the activation of the jasmonic acid signaling pathway. Our results demonstrate that all motile stages of N. tenuis can trigger defensive responses in tomato plants, although these responses may be slightly different depending on the stage considered.     

Effects of Speeds,Materials, and Tool Rake Angles on Metallic Particle Emission During Orthogonal Cutting

Dry high speed machining has been proposed as a viable and cost-effective process in metal cutting industries. However, it produces fine and ultra-fine metallic particles, also referred to as dust, which can be harmful to the machine-tool operator. The risk associated with exposure to metallic particles increases as the particle size decreases. For machining processes, little data exist on the size and distribution of dust generated during the shaping of materials. In order to reduce or eliminate the generation of these particles, it is necessary to understand how and under which conditions they are formed, as well as to be able to make predictions. In this study, the effects exerted by tool geometry, material, and machining parameters on dust emission were studied experimentally in order to understand the mechanisms of dust generation and to develop a predictive model. The particle sizes studied include the PM2.5 (particles with aerodynamique diameter below 2.5 μm) and a distribution of nanoparticles varying in size from 10 nm to 10 μm. Using dry machining and reducing the amount of dust generated should improve the air quality in machine shops in addition to helping protect the environment.     

Modeling of Particle Emission During Dry Orthogonal Cutting

Because of the risks associated with exposure to metallic particles, efforts are being put into controlling and reducing them during the metal working process. Recent studies by the authors involved in this project have presented the effects of cutting speeds, workpiece material, and tool geometry on particle emission during dry machining; the authors have also proposed a new parameter, named the dust unit (D _u), for use in evaluating the quantity of particle emissions relative to the quantity of chips produced during a machining operation. In this study, a model for predicting the particle emission (dust unit) during orthogonal turning is proposed. This model, which is based on the energy approach combined with the microfriction and the plastic deformation of the material, takes into account the tool geometry, the properties of the worked material, the cutting conditions, and the chip segmentation. The model is validated using experimental results obtained during the orthogonal turning of 6061-T6 aluminum alloy, AISI 1018, AISI 4140 steels, and grey cast iron. A good agreement was found with experimental results. This model can help in designing strategies for reducing particle emission during machining processes, at the source.     

Successful term pregnancy after Mustard operation for transposition of the great arteries

Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring.     

Acoustic emission and fracture of ductile materials

Acoustic emission, radius of the contraction zone on the side of the specimen and load-load point displacement were measured during fracture of single edge notched specimens containing fatigue cracks of different lengths. It was found that there exists a three-fold correlation between formation of a contraction zone, noticeable acoustic emission and deviation from linearity on the load-load point displacement curves. The stress intensity factor K was evaluated from the extent of contraction on the specimen surface and related to the acoustic emission total count. A correction for K was made to account for the considerable plasticity at the crack tip. Finally, a model for the formation and development of the plastic and contraction zones is formulated.     

Videotaped family interaction: Differences reflecting presence and type of child disturbance.

Analyzed behavior during videotaped family interaction in an unstructured situation (interpreted as interpersonally stressful). 20 families contained a disturbed child (aggressive, socially withdrawn, or distractible); 10 were normal control families. Repeated judgments were made on evaluative, directing, and activity dimensions. Analyses of covariance (covariate: amount of talking) showed significant differences between fathers but not mothers or children. Fathers of normal children were evaluatively neutral and nondirecting (suggesting low attempts to control others) and untalkative (suggesting social independence). Fathers of disturbed children showed controlling and/or dependent behavior: (a) fathers of distractible children were evaluatively extreme and talkative; (b) fathers of withdrawn children were neutral, nondirecting, and talkative; and (c) fathers of aggressive children were negatively extreme, directing, and untalkative. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Matrix microstructure effect on the abrasion wear resistance of high-chromium white cast iron

The two-body abrasion resistance of high-chromium white cast iron was investigated as a function of cast iron microstructure. Different microstructures were obtained by means of heat treatment. The chromium and carbon content were chosen in order to have different matrix microstructures (austenitic, martensitic and ferritic) with the same amount of eutectic carbide (M₇C₃). The results show that the cast iron with an austenitic matrix has the best wear resistance. The good wear resistance of this material is due to strong work hardening of the austenitic matrix resulting in a hardness which exceeds that of other structures. The effect of abrasive paper deterioration on abrasion has also been investigated.     

Characterization of tumor-associated neural cell adhesion molecule in human serum

In human serum, at least two molecular species of the neural cell adhesion molecule (NCAM) with molecular weights of 110,000-130,000 and 150,000-180,000, respectively, can be identified by Western blotting. Both are characterized by the absence of epitopes for monoclonal antibodies KD11 and MG5, which specifically recognize intracellular domains of the human NCAM transmembrane isoforms, NCAM-140 and NCAM-180. In contrast to the M(r) 110,000-130,000 molecule also detectable in serum samples from healthy blood donors, the M(r) 150,000-180,000 molecule appears to be tumor associated. The only difference between these two species is shown to be the presence of long chains of alpha-(2,8)-linked N-acetylneuraminic acids, which are characteristic for the so-called embryonic NCAM form. After treatment with endoneuraminidase N, the M(r) 150,000-180,000 molecule can no longer be discriminated from the M(r) 110,000-130,000 molecule in Western blotting as well as gel and anion exchange chromatography experiments. The experimental data clearly show that only the embryonic NCAM molecule carrying the poly-alpha-(2,8)-linked N-acetylneuraminic acid moiety can be regarded as a specific serum marker for small cell lung cancer.