Mechanistic force modeling for milling of unidirectional carbon fiber reinforced polymer laminates

Carbon fiber reinforced polymer (CFRP) usage in the aerospace industry has been steadily increasing due to its superior material properties such as high strength, low weight, high resistance to corrosion, and a low thermal expansion coefficient. In addition, CFRP parts are produced near-net-shape, a process that eliminates rough machining operations. However, machining operations such as drilling, side milling, and slotting are still necessary to give the CFRP parts their final shape. A majority of the studies on machining of CFRP laminates are on drilling. The number of studies on milling of CFRPs is quite limited. In this study, a mechanistic cutting force model for milling CFRPs is proposed based on experimentally collected cutting force data during slot milling of unidirectional CFRP laminates using two different polycrystalline diamond cutters. Cutting force coefficients in radial and tangential directions are calculated as a function of fiber cutting angle. The relationship is represented with simple sine functions. The mechanistic model is shown to be capable of predicting cutting forces during milling of multidirectional CFRP laminates. The experimental milling force measurements and predicted milling forces agree well with each other. Surface milling experiments were also conducted to investigate the relationship between milling forces and surface quality. Some suggestions on surface milling of CFRP laminates are given based on these observations. © 2012 Elsevier B.V. All rights reserved

Effects of butylated hydroxytoluene on blood liver enzymes and liver glutathione and glutathione-dependent enzymes in rats

This study was aimed to detect the effect of butylated hydroxytoluene (BHT) on the liver glutathione level and glutathione-dependent enzyme activities in female Wistar albino rats. BHT was adminis-tered by oral gavage at a dose of 250 mg/kg (Group I) and 500 mg/kg (Group II) for 28 days, 1000 mg/kg (Group III) and 1500 mg/kg (Group IV) for 4 days. The serum ALT, AST and LDH activities were measured on an autoanalyzer, and liver gluthathione (GSH), gluthathione peroxidase (GPx), gluthathione S-transferase (GST), and gluthathione reductase (GR) activities were analysed with commercial ELISA kits. The ALT activity was significantly higher in Groups III and IV (P<0.05 and P<0.001, respectively) compared to the control group. Blood AST and LDH activities were signifi-cantly increased in Group IV (P<0.05). The GSH, GPx, GST and GR in the liver tissue were deter-mined to be statistically low in Groups II, III and IV (P<0.001) in comparison with control group. In microscopic examination, BHT caused histopathological changes in the rat liver tissue in Groups II, III and IV depending on the dose and duration of exposure. It can be concluded that BHT plays a role in producing liver damage in rats with depressed hepatic antioxidant defense. The hepatotoxic re-sponse seemed to be dose- and time-dependent

Mass and angular momentum of asymptotically AdS or flat solutions in the topologically massive gravity

We study the conserved charges of supersymmetric solutions in the topologically massive gravity theory for both asymptotically flat and constant curvature geometries.Comment: REVTEX4, 8 pages, no figures, added 2 references and a few clarifying remark

Uncovering the Importance of Selenium in Muscle Disease

A connection between selenium bioavailability and development of muscular disorders both in humans and livestock has been established for a long time. With the development of genomics, the function of several selenoproteins was shown to be involved in muscle activity, including SELENON, which was linked to an inherited form of myopathy. Development of animal models has helped to dissect the physiological dysfunction due to mutation in the SELENON gene; however the molecular activity remains elusive and only recent analysis using both in vivo and in vitro experiment provided hints toward its function in oxidative stress defence and calcium transport control. This review sets out to summarise most recent findings for the importance of selenium in muscle function and the contribution of this information to the design of strategies to cure the diseases

Suborbital graphs for the group ?2

In this paper, we investigate suborbital graphs formed by the action of ?2 which is the group generated by the second powers of the elements of the modular group ? on Q. Firstly, conditions for being an edge, self-paired and paired graphs are provided, then we give necessary and sufficient conditions for the suborbital graphs to contain a circuit and to be a forest. Finally, we examine the connectivity of the subgraph Fu, N and show that it is connected if and only if N ? 2. © 2015, Hacettepe Journal of Mathematics and Statistics. All rights reserved

Effects of the Replacement of Soybean Meal with Pea as Dietary Protein Source on the Serum Protein Fractions of Broilers

ABSTRACT The aim of this study was to determine the effects of the replacement of different levels of protein derived from soybean meal with that from peas in broiler diets on serum protein fractions. A corn-soybean meal basal diet was formulated as the control diet (Control=C) (NRC, 1994), and then pea was added to the control diet to replace 20% (P20) or 40% (P40) of the crude protein of the control diet. The diets were randomly fed to 12 pens per treatment, each housing five birds, for 42 days. Blood samples were collected from 36 birds (3 birds x 4 pens x3 treatments) and the serum protein fractions were separated. Gamma-globulin percentage was higher in group P20 compared with C and P40 groups. Total protein, beta-globulin, and gamma-globulin concentrations were significantly higher in group P20 compared with those of both control and P40 group (p<0.05)

Prevalence of Traumatic Dental Injuries and Associated Factors Among 8 to 12-years-old Schoolchildren in Diyarbakir, Turkey

Background and objectives: This study aimed to assess the prevalence of traumatic injuries of the permanent incisors in public primary schoolchildren from 8 to 12 years old in South-Eastern Anatolia, Turkey. Additionally, the relationship between traumatic dental injuries, parents’ education level, family income, size of incisal overjet and the presence of anterior open bite were examined. Materials and Methods: Data were collected through oral examinations and structured interviews, and included socio-economic indicators. A total of 2907 children of both genders (1498 boys, 1409 girls) were included in the study. The response rate was 97%. Results: The prevalence of dental injuries was 4.6% (n = 135). The highest frequency of trauma in permanent teeth was observed at the age of 12 (8%). Boys experienced more dental injuries than girls, 5.9% and 3.3% (p = 0.001), respectively. The most commonly reported cause of injuries to the permanent incisors was falls (71.8%), followed by collision with objects or people (17.8%). Maxillary central incisors were the most affected by dental injuries (154, 84.6%). The most common crown fracture was in enamel only (67.58%) followed by crown fracture of enamel and dentin (22.52%). Conclusion: Socio-economic indicators and parents’ level of education were not statistically significantly associated with the occurrence of traumatic dental injuries. Factors associated with increased risk of dental injuries in permanent teeth were age, gender, having an incisal overjet greater than 5mm and anterior open bite.Keywords: Traumatic dental injury, permanent teeth, socio-economic indicators, overjet, anterior open bit