Effect of iron alloying in evolution of nanostructure and microstructural stability in nickel

Nanocrystalline materials show many interesting properties such as high strength and hardness due to nanosized grains and high density of interfaces. In this context, the present work reports the effect of Fe (iron) addition in Ni (nickel) on nanostructure retention during the annealing of Ni-Fe alloy (with 0, 18.5, 28.5 and 43 wt% Fe) at 450 °C for 16 h. Furthermore, effect of annealing on the deformation mechanism was investigated. The integral breadth method revealed the decrease in grain size with increase in wt% Fe in Ni. The strain rate sensitivity exponent which is a signature of operating deformation mechanism showed a higher value (0.10803) in case of Ni-18.5 wt% Fe during nanoindentation. However, Ni-0 wt% Fe, Ni-28.5 wt% Fe and Ni-43 wt% Fe were characterized by a relatively low strain rate sensitivity exponent (between 0.02069 and 0.10803). Results indicated the presence of Hall-Petch relationship up to 18.5 wt% Fe and inverse Hall-Petch relationship above 18.5 wt% Fe.     

Experimental and simulation study of magnetorheological miniature gear-profile polishing (MRMGPP) method using flow restrictor

Journal of Mechanical Science and Technology - In this article, a new flow restrictor is utilized in the magnetorheological miniature gear-profile polishing (MRMGPP) method to ensure a consistent...     

Environmental Phenol and Paraben Exposure Risks and Their Potential Influence on the Gene Expression Involved in the Prognosis of Prostate Cancer

Prostate cancer (PCa) is one of the leading malignant tumors in US men. The lack of understanding of the molecular pathology on the risk of food supply chain exposures of environmental phenol (EP) and paraben (PB) chemicals limits the prevention, diagnosis, and treatment options. This research aims to utilize a risk assessment approach to demonstrate the association of EP and PB exposures detected in the urine samples along with PCa in US men (NHANES data 2005–2015). Further, we employ integrated bioinformatics to examine how EP and PB exposure influences the molecular pathways associated with the progression of PCa. The odds ratio, multiple regression model, and Pearson coefficients were used to evaluate goodness-of-fit analyses. The results demonstrated associations of EPs, PBs, and their metabolites, qualitative and quantitative variables, with PCa. The genes responsive to EP and PB exposures were identified using the Comparative Toxicogenomic Database (CTD). DAVID.6.8, GO, and KEGG enrichment analyses were used to delineate their roles in prostate carcinogenesis. The plug-in CytoHubba and MCODE completed identification of the hub genes in Cytoscape software for their roles in the PCa prognosis. It was then validated by using the UALCAN database by evaluating the expression levels and predictive values of the identified hub genes in prostate cancer prognosis using TCGA data. We demonstrate a significant association of higher levels of EPs and PBs in the urine samples, categorical and numerical confounders, with self-reported PCa cases. The higher expression levels of the hub genes (BUB1B, TOP2A, UBE2C, RRM2, and CENPF) in the aggressive stages (Gleason score > 8) of PCa tissues indicate their potential role(s) in the carcinogenic pathways. Our results present an innovative approach to extrapolate and validate hub genes responsive to the EPs and PBs, which may contribute to the severity of the disease prognosis, especially in the older population of US men.     

Voltammetric determination of citric acid and quinine hydrochloride using polypyrrole–pentacyanonitrosylferrate/platinum electrode

Cyclic voltammetry was used to investigate the electrochemical behavior of citric acid (CA) and quinine hydrochloride (QH) at a polypyrrole-pentacyanoferrate/Platinum (PPY–PCNFe/Pt) electrode in aqueous medium. The analytical plots obtained were found to be linear in the concentration range between 1.0 and 9.0 mM for both the analyte solutions. The detection limits (3δ) were found to be 1.17 × 10^?4 M and 1.08 × 10^?5 M for CA and QH analyte solutions, respectively. It was further observed that the diffusion of ionic species into and out of the polymeric film made the PPY–PCNFe/Pt electrode highly electroactive thereby enabling it to efficiently detect the analyte solutions having concentration as low as 1 mM.     

Effect of silica doping on the densification and grain growth in zinc oxide

The ability of silica (SiO₂) in controlling the densification and grain growth behavior of nano crystalline zinc oxide (ZnO) has been systematically studied. It has been observed that SiO₂ acts as a sintering inhibitor in the ZnO–SiO₂ system up to 4 wt.% limiting value beyond which densification behavior of the system remains almost unchanged, especially above 1100 °C. The addition of SiO₂ to ZnO retards grain growth which in turn results a finer ultimate grain size as compared to the undoped ZnO. However, stabilization in grain size occurs at ≥4 wt.% SiO₂ addition. It has been observed that SiO₂ incorporation changes the grain growth mechanism up to 4 wt.% addition, beyond which no remarkable changes was noticed. The grain growth (n) shows distinctly different slopes as a function of sintering time for the SiO₂ doped ZnO systems than undoped ZnO. The different slopes tend to indicate that different diffusion mechanisms and probably the formation of a secondary phase (Zn–Si–O) at the grain boundary control the densification and grain growth. The thermal expansion coefficient of the system has been found to decrease substantially beyond 4 wt.% SiO₂ addition to ZnO.     

Spectral characteristics of a binary dye-mixture laser

We have investigated laser action in a binary mixture of dyes, Rh-6G and DCM, resulting in tunable laser emission over an extended frequency region. The two dyes absorb the same pump radiation but fluoresce over frequency ranges that are shifted with respect to each other, thereby resulting in extended tunability. Following a time-dependent analysis of a rate-equation model that describe the operation of such a laser, theoretical estimates for optimum dye concentrations and the corresponding extension of the laser tuning range have been obtained.     

The VVERs at KudanKulam

A Nuclear Power Project is being set-up at KudanKulam in the state of Tamil Nadu, India in collaboration with the Russian Federation. The project comprises of two units each of 1000 MWe VVER type reactor. The design of the plant and supply of all the major equipment is in the scope of the Russian Federation while development of infrastructure and project construction is in Indian scope of works. The VVER (Version V-412) reactor that is under construction at KudanKulam site is an advanced PWR, which incorporates all the features of a modern PWR as per the current Russian, Western and IAEA standards. The KudanKulam site in the southern Indian state of Tamil Nadu was one among the several sites evaluated by the Site Selection Committee, which cleared KudanKulam site for setting up an installed capacity up to 6000 MWe. The design, construction and operation of the plant meets the regulatory and licensing requirements of Russian regulatory body “RTN” as also India's Atomic Energy Regulatory Board. The supply of the equipment from the Russian Federation is on schedule and the project construction work by various Indian agencies is also ahead of schedule. The two units of KudanKulam Nuclear Power Project (KKNPP) are scheduled to achieve first criticality in the year 2007–2008. The paper discusses various design features, project construction and management aspects.     

Anthelmintic treatment improves the hemoglobin and serum ferritin concentrations of Tanzanian schoolchildren

To investigate the relationships between helminth infections and iron status among school-aged children, 1,115 Tanzanian children in grades 2 through 5 were randomly assigned to treatment or control groups. The children in the treatment group were screened for infection with Schistosoma haematobium and hookworm at baseline, 3 months, and 15 months; infected children were given albendazole against hookworm and praziquantel against schistosomiasis. The control group received a placebo and did not undergo parasitological screening until 15 months after the baseline. Hematological variables were compared between the treatment and control groups. The main results were, first, that the hemoglobin concentration significantly improved after treatment for hookworm (p < .001) by 9.3 g/L in children treated for hookworm only and by 8.8 g/L in children treated for hookworm and schistosomiasis. The ferritin concentration also improved in children treated for schistosomiasis (p = .001) or hookworm (p = .019). Second, a longitudinal analysis of the data from the children in the control group showed that hookworm and schistosomiasis loads were negatively associated with hemoglobin and ferritin concentrations. Moreover, ferritin concentrations increased as C-reactive protein levels increased. Overall, the results showed that anthelmintic treatment is a useful tool for reducing anemia in areas with high hookworm and schistosomiasis endemicity. The empirical relationship between ferritin and C-reactive protein indicated that simple procedures for adjusting cutoff points for the use of ferritin as an indicator of low iron stores were unlikely to be useful in this population.     

Hydrodynamically and chemically induced in situ kaolin particle release from porous media an experimental study

Contaminant transport in the subsurface is decidedly influenced by the presence of colloids that are clay type particles, like kaolinite. To understand the contaminant associated colloid transport, one needs to know how release of these colloidal particles in in situ condition is affected by change in geochemical condition. In this work an attempt has been made to experimentally study the effect of different parameters like flowrate, void fraction, ionic strength, and pH on release of kaolin particle from the porous bed of kaolin–sand mixture. It was observed that there exists a critical velocity at 0.017 cm/s for the release of kaolin, and plugging of these released particles was significant in the bed. This plugging was explained by size exclusion and agglomeration of particles. It was also observed that with increase of pH and decrease of ionic strength kaolin release increases.