Review of natural fibre-reinforced hybrid composites

Natural fibre-reinforced hybrid composites which contain one or more types of natural reinforcement are gaining increasing research interest. This paper presents a review of natural fibre-reinforced hybrid composites. Both thermoplastic and thermoset composites reinforced by hybrid/synthetic fibres or hybrid/hybrid fibres are reviewed. The properties of natural fibres, the properties and processing of composites are summarised

Ameliorating Heat Transfer Performance of Absorber Tube for Single Axis Concentrators

AbstractSolar parabolic trough collectors are being widely used to exploit solar energy for both thermal and power generation applications. But, these systems require long arrays of reflective troughs with absorber tube running along the axis of parabolic dish. A successful attempt to reduce the length of arrays was accomplished by experimentally analysing the modifications done in absorber tube. Three out of four tubes were fabricated and they were employed to obtain the performance parameters through experimentation conducted at VIT University, Vellore, India. Distilled water was used as the working fluid. Maximum efficiency of 39.12% was acquired at 451.6 W/m2 of direct normal irradiance (DNI)for absorber tube with internal pin-fins and without glass tube (AFWGt) compared to 8.15% obtained at same value of DNI and other conditions for simple absorber tube without glass cover (AWGt). Cylindrical parabolic trough available at the university was utilized, providing the basis for designing and fabrication of the tubes. Plots for varying mass flow rate at interval of 10 minutes were made against instantaneous thermal efficiency and heat utilized, for direct normal irradiance vs. temperature difference across the tubes and instantaneous thermal efficiency. Through the experimentation conducted, better performance was procured compared to earlier works. Thus, the proposal infers that absorber tube with internal fins has good scope for its application, both domestically as well as industrially. It also calls for further research and development of proposed techniques so as to achieve better performance curves

Abstract P5-03-09: Ovarian Hormones Promote Mammary Carcinogenesis by Altering Growth Factor Receptor Signaling

Abstract Study of carcinogenesis in rat models plays an important role in understanding the nature of neoplastic transformation. Identification of biological, cellular and molecular alterations involved in the carcinogen induced preneoplastic transformation has vital importance in mammary cancer development. Copenhagen rats are resistant to the carcinogen, N-methyl-N-nitrosourea (MNU) induced mammary carcinogenesis. Our previous studies indicate that MNU induced preneoplastic lesions were promoted to mammary cancer by the hormones estrogen and progesterone. The purpose of this study is to delineate the molecular mechanisms of hormonal promotion of mammary carcinogenesis. Seven week old female Copenhagen rats were administered a single dose of 50 mg/kg body weight MNU intraperitoneally. Four weeks post carcinogen administration, rats were divided into 4 groups, 1) Control, 2) rats treated with 30 mg estradiol, 3) rats treated with 30 mg progesterone, 4) rats treated with 30 mg estradiol plus 30 mg of progesterone. Two weeks after the implantation rats were killed and mammary glands were excised and used for further experiments. Quantitative RT-PCR experiments showed up-regulation of growth factor receptors such as Igf-1r, Egfr and growth factor signaling members Grb2, Pi3k and Ras mRNA expression. Immuno histochemical studies showed strong staining to growth factor receptors and western blotting studies showed increased protein levels of growth factor receptors such as IGF-1R and EGFR and active form of proliferative signaling molecules Akt and SAPK/JNK were up-regulated in combination of estradiol and progesterone treated rats. Phosphorylated p38 was reduced in the combination of hormones treated rat preneoplastic lesions when compared to control. Combination of ovarian hormones treatment provided enhanced growth factor signaling environment and promoted the mammary lesions through activation of SAPK/JNK and growth factor signaling pathways. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-03-09.</jats:p

Influence of ceramic nanoparticles on fatigue life of Al 6061 prepared via ultrasonic aided rheo-squeeze casting process

The fatigue behaviour of Al 6061 along with its ceramic nanoparticles reinforced cermets fabricated through ultrasonic-aided rheo-squeeze casting technique are evaluated. The fatigue behaviour was studied under ambient and elevated temperature (250°C) conditions, and the effect of notches was also examined under same stress conditions. Al 6061 indicated service life of ~1.15 million cycles at low stress value which dropped to 15,470 cycles with increase in stress magnitude. Al cermet (ALST) shwocased enhanced = fatigue life up to ~35% for hybrid cermet with highest service life of 1.71 million cycles due to load transfer mechanism. In elevated temperature condition, life of Al 6061 dropped by 37%, whereas the reinforced cermets remained higher with ALST revealing high service life cycles. Further, notch indicated drop in fatigue life of Al and its cermets with cermets prevailing better than Al. The elevated temperature notch represented the lowest fatigue life owing to stress concentration as well as the coefficient of thermal expansion mismatch

Abstract P5-03-06: Progesterone Activates MAPK Pathway in Estrogen Induced Mammary Carcinogenesis

Abstract In women, breast cancer is the most prevailing endocrine-related malignancy. Epidemiological and experimental studies argue that estrogens are central to its etiology. Estrogen-induced carcinogenesis in ACI rats is highly relevant as a model for human breast cancer. These estrogen-induced cancers exhibit aneuploidy, as do invasive ductal mammary carcinomas in women. It has been demonstrated that ovary intact ACI rats given estrogen induced high incidence of mammary cancers while ovariectomized rats given the same dose of estrogen for the same length of time did not induce mammary cancers. Recently, we demonstrated that ovariectomized ACI rats given estrogen plus progesterone had a high incidence of mammary cancer. In this context, it is essential to understand the possible role of progesterone, if any, as the other main ovarian hormone in mammary carcinogenesis. Our goal was to determine the role of progesterone in mammary cancer development by using carcinogenesis induced solely by hormones in ACI rats. To achieve our goal, we designed the following experiment. Ovary intact and ovariectomized rats were used in this study. The groups (n=30) tested were as follows: 1) ovary intact control (no hormone treatment); 2) ovary intact rats given 30 mg estradiol; 3) ovary intact rats given 30 mg estradiol plus 30 mg mifepristone; 4) ovary intact rats given 30 mg progesterone; 5) ovariectomized control (no hormone treatment); 6) ovariectomized rats given 30 mg estrogen; and 7) ovariectomized rats given 30 mg estradiol plus 30 mg progesterone. Mammary glands were surgically excised and snap frozen in liquid nitrogen and stored at -80°C from a subset (n=4) of intact animals after four weeks of treatment and ovariectomized rats after twelve weeks of treatment. In rest of the animals mammary carcinogenesis was followed for nine months. As expected, estradiol induced mammary cancers in ovary intact rats and not in ovariectomized rats. Addition of progesterone to ovariectomized rats treated with estradiol induced high incidence of mammary cancer. Mifepristone treatment inhibited mammary carcinogenesis in ovary intact rats receiving estradiol. Pathway focused microarray analysis of mammary glands from the rats of different groups and treatment indicated alterations in apoptosis, MAPK and PI3K pathways. Estrogen plus progesterone treatment down regulated apoptotic genes such as Apaf1, Bad, Bax, Bid, Casp9 and up regulated Mapk3, Grb10, Itgb1, PrKca, Prkcz and Map4k1, Map2k1ip1, Mapk8ip2, Mapkapk5 in PI3K and MAPK pathways respectively when compared with estrogen alone treatment. We have observed differences both at transcriptional and translational levels. Our results clearly demonstrate the significance of progesterone in mammary carcinogenesis. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-03-06.</jats:p