Film insert molding as a novel weld‐line inhibition and strengthening technique

Specimens with weld lines were produced via conventional and film insert molding techniques using two types of materials as the substrate resin, i.e. a polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) blend and glass fiber‐filled polycarbonate (PC‐gf). The formation and morphology of the weld line region was assessed with and without the presence of 0.5‐mm‐thick PC film inserts. The weld line formation and characteristics were found to be dependent on the extent of interaction between the injected resin and the mold surface or the film insert. Better interfacial interaction between the substrate and film led to the distortion of the weld line orientation, which significantly enhanced the mechanical properties of the weld line. The incorporation of glass fibers into the substrate resin would usually reduce the resistance of the weld line towards tensile, flexural and impact loadings. However, with the attachment of film inserts, the mechanical properties of the weld line region have significantly improved, even with the presence of rigid fibers. Upon examination of tensile and impact fracture surfaces of film insert specimens, a unique orientation of fibers across the weld line (parallel to the flow direction and perpendicular to the weld line) could be observed at regions directly under the film. The combination of favorable properties from the unique fiber orientation and distortion of the weld line, as well as the ability of the film to effectively dissipate forces towards a larger area, have synergistically contributed towards the mechanical property enhancement of the weld line region in film insert moldings. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Effect of Time-Dependent Humidity Profiles from Air to Superheated Steam on Drying of a Wetted Starch Sphere

The effects of air humidity when drying with superheated steam (SHS) were examined considering displacement by SHS. A wetted raw starch sphere (ball) was used as the model material. It was found that the humidity profile strongly affects the mass change and properties of the products. The material became porous when it was dried with pure SHS from start to finish, which differs both from products dried with high-humidity air alone, and from products dried with air followed by SHS within a few minutes. A prediction method for adiabatic saturation temperature over a wide range of humidity is also proposed.     

Analysis of stress intensity factor of a crack approaching welding bead

An analysis of the stress intensity factor is made for a crack approaching the welding line from the normal direction in an infinite plate.The equations proposed by one of the authors and others were employed in the analysis as the distribution function of the residual stress caused by welding. The effects of crack location and the length on the stress intensity factor were closely examined.For the constant crack length, the maximum stress intensity factor does not occur when the crack center coincides with the welding line, but does when the crack front approximately reaches the welding line.For a better understanding of the behavior of a crack approaching the weldment, analysis was also carried out for a crack with various lengths but constant eccentricity.

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Résumé On a procédé à une analyse du facteur d'intensité de contrainte qui correspond à une fissure qui se rapproche d'un dépôt de soudure normalement à la ligne de fusion et dans une tôle infinie.On a utilisé les équations élaborées par un des auteurs ainsi que par d'autres chercheurs pour décrire la distribution des contraintes résiduelles provoquées par le soudage. On a également examiné de près les effets sur le facteur d'intensité de contrainte de l'emplacement de la fissure et de sa longueur.A longueur de fissure constante, le facteur d'intensité de contrainte ne passe pas par sa valeur maximum lorsque le centre de la fissure coïncide avec l'axe de la soudure, mais bien lorsque l'extrémité de la fissure est sur le point d'atteindre cet axe.Pour mieux comprendre le comportement d'une fissure qui se rapproche d'une soudure, on a également analysé le cas de fissures de diverses longueurs, mais à excentricité constante.

     

Multiple myeloma developing myelodysplastic syndrome with thrombocytosis

A 64-year-old woman with multiple myeloma, IgG lambda type Durie-Salmon Stage II, was admitted because of gradually developing anemia and increased blasts with abnormal karyotype in her bone marrow after 10 years of treatment. The chromosomal analysis showed 44, XX, del(5q), del(7q), -9, add(12p), -21, typical of secondary MDS due to the cumulative alkylating agents. Thrombocytosis concomitantly occurred with emergence of chromosomal abnormality, but the serum interleukin 6 level was not elevated, which suggested that it was related to development of secondary MDS.     

Calorimetric evaluation of nonequilibrium state in as-melt spun Al-1.72 and Al-3.12 At. Pct Cu Alloys and Al-6.74, Al-8.48, and Al-11.97 At. Pct Si alloys

Formerly Graduate Student, Graduate School of Engineering, Osaka University, Suita Osaka 565, Japan     

Exon structure and flanking intronic sequences of the human RET proto-oncogene

Using a PCR strategy based on an initial set of 15 couples of primers designed from the known cDNA sequence, we identified 18 introns in the human RET proto-oncogene and sequenced the corresponding 5' and 3' exon-intron junctions. This approach was successful in locating all the introns contained in fragments short enough to be amplified by PCR. Thus 19 exons were identified which, together with the previously reported exon subjected to alternative splicing, brings the total number of RET exons to 20. This information is relevant for the screening of recently reported missense mutations of RET which cause Multiple Endocrine Neoplasia 2A (MEN2A) and for the search of additional point mutations of the same gene which might cause two other neural crest disorders, MEN2B and Hirschsprung disease, mapping in the same region as MEN2A.     

FATIGUE STRENGTH OF NON-LOAD-CARRYING FILLET WELDED JOINTS: EFFECTS OF WELD RESIDUAL STRESSES AND STRESS CONCENTRATION

The fatigue strength of non-load-carrying fillet welded joints of KE36(TMCP) steel was studied. Both residual stress measurements and fatigue tests were carried out, with the plate thickness, the plate width and the heat input being varied. Specimens given a Post Weld Heat Treatment (PWHT) were also prepared. The plate width had no effect on the fatigue strength, because it hardly affected the transverse residual stresses at the weld toe. However, the heat input influenced the transverse residual stress distribution, and a significant difference in fatigue strength due to the heat input was observed, especially when N≥ 10⁶ cycles. It was also found that PWHT removed almost all the residual stresses at the weld toe, improving the fatigue strength drastically. In this study, the values of stress concentration factor K₂ were estimated by Machida's method and it was concluded that the thickness effect resulted from a combination of both stress concentration and residual stresses with the contribution of the latter being particularly significant for N≥ 10⁶ cycles.     

Corticosteroid induction of threat-induced behavioral inhibition in preweanling rats.

Termination of ongoing behavior and assumption of defensive postures when threatened are adaptive characteristics of vertebrates. Altricial rat pups develop these characteristics by 14 days of age. At this time, pups inhibit their ultrasonic vocalizations and freeze when threatened. This emergence of behavioral inhibition is impaired when rats are adrenalectomized (ADX) at 10 days of age. That is, 14-day-old ADX pups exhibit deficits in freezing and continue to emit ultrasounds when confronted by an adult male rat. Studies also showed that removal of adrenal hormones does not potentiate vocalizations or render pups incapable of reducing their ultrasounds. More important, 3.0 mg/kg of corticosterone (CORT), but not lower doses, administered daily to ADX pups restored freezing, with lesser effects on ultrasound inhibition. Disrupting the developmental action of endogenous CORT appears to impair the ontogenic expression of behavioral inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cytokine regulation of cell-to-cell interactions in lymphokine-activated killer cell cytotoxicity in vitro

The permanent pancreas carcinoma cell line, PCI-24, was developed in order to analyse cytokine regulation on pancreas carcinoma and lymphokine-activated killer (LAK) cell interaction. PCI cells expressed ICAM-1 and HLA-ABC, but not HLA-DR antigens. PCI cells showed augmented ICAM-1 and HLA-ABC expression when incubated with interferon gamma (IFN gamma) and tumour necrosis factor alpha. A similar but weak augmentary effect on the HLA-ABC and ICAM-1 surface expression was seen with interleukin-1 beta treatment. Natural attachment of LAK to PCI cells was augmented by recombinant IFN gamma in close association with ICAM-1 up-regulation on PCI cells. In addition, natural attachment was significantly inhibited by anti-LFA-1 and anti-ICAM-1 antibody treatments. Cytotoxicity of the LAK cells against PCI cells was also significantly inhibited with the same treatment. Thus, the attachment of LAK cells to PCI cells through LFA-1/ICAM-1 molecules appeared to be essential for the cytotoxicity for PCI cells. Pretreatment of PCI cells, but not of LAK cells, with IFN gamma or other cytokines resulted in a decrease of susceptibility for LAK cell cytotoxicity. The decreased susceptibility inversely correlated with HLA-ABC expression on the PCI cells. The collective evidence indicates that, although LAK cell attachment to pancreas carcinoma cells through the LFA-1/ICAM-1 molecule is augmented by IFN gamma, IFN gamma treatment of pancreas carcinoma cells reduces LAK cell cytotoxicity possibly through an increase in HLA-ABC or a regulation of molecules closely associated to HLA-ABC expression.