Vapor growth of CdSe:Cr and CdS:Cr single crystals for mid-infrared lasers

Single crystals of CdSe:Cr and CdS:Cr with the doping level up to 10¹⁹ cm⁻³ were grown by a vapor phase contact-free technique. An efficient room-temperature pulsed and continuous wave (CW) lasing with the CdSe:Cr crystal was achieved. First a pulsed lasing with the CdS:Cr crystal was also demonstrated. The slope efficiency on the absorbed energy was as high as 46.5% for Cr²⁺:CdSe and 39% for Cr²⁺:CdS lasers. Using an intra-cavity prism, the Cr²⁺:CdSe laser wavelength was continuously tuned from 2.26 to 3.61 μm while the Cr²⁺:CdS laser from 2.2 to 3.3 μm. For the laser wavelength, the crystal passive loss coefficient was estimated to be smaller than 0.045 cm⁻¹ for CdSe:Cr crystals and 0.039 cm⁻¹ for CdS:Cr crystals. For the Cr²⁺:CdSe laser, the CW output power up to 1.07 W was achieved.     

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.     

Identification of ubiquitin in bovine milk and its growth inhibitory effects on human cancer cell lines

Bovine milk is associated with improved health and reduced risk of several diseases, among them cancer. Milk is a complex mixture of known and unknown components. The components and the mechanisms that contribute to the cancer-preventive effects are largely unknown. We set out to find new peptides in milk and identified ubiquitin (Ub) using matrix-assisted laser desorption ionization-time of flight mass spectrometry and Western blot. Using quantitative Western blot, we estimated the Ub concentration to be about 0.003 μmol/L in milk. We then decided to investigate the effect of treating human colon cancer CaCo-2 cells with Ub, using higher concentrations than in milk. CaCo-2 cells treated with 0.02 to 2.0 μmol/L Ub showed significantly decreased proliferation compared with untreated control cells. A higher growth inhibitory effect than in CaCo-2 cells was found in the neuroblastoma cell line SH-SY5Y treated with 0.02 to 0.2 μmol/L Ub. A bromodeoxyuridine DNA flow cytometric method was used to study cell cycle kinetics in Ub-treated CaCo-2 cells. The data point toward a prolongation of the G₁ phase. The levels of several cell cycle regulatory proteins were affected. Our data point to Ub possibly being one of the components in milk reducing the risk of cancer.     

A new approach for multiple attribute group decision making with interval-valued intuitionistic fuzzy information

This paper proposes a novel method for multiple attribute group decision making (MAGDM) with interval-valued intuitionistic fuzzy information. The interval-valued intuitionistic fuzzy numbers of each expert preference matrix are first mapped into two dimensions. Thus, the values of each membership degree and non-membership degree are considered as points in the two-dimensional representation. Moreover, the distance between the points represents the variance among the different experts preferences. The preference points of the same character are considered as a point set. We employ the plant growth simulation algorithm (PGSA) to calculate the optimal rally points of every point set, the sum of whose Euclidean distances to other given points is minimal, and these optimal rally points reflect the preferences of the entire expert group. These points are used to establish an expert preference aggregation matrix. Suitable points from the matrix are chosen to constitute an ideal point matrix, a projection method is employed to calculate the sum of its Euclidean distance to the expert preference aggregation matrix, and the score of each alternative is evaluated. Finally, the overall ranking of alternatives is obtained. In addition, this study develops a process to evaluate the pros and cons of different aggregation methods. Two typical examples are presented to illustrate the feasibility and effectiveness of the proposed approach.     

Growth kinetics and lipid production using Chlorella vulgaris in a circulating loop photobioreactor

BACKGROUND: Compared with agriculture, microalgae culture promises to be a novel way of producing lipids for both food consumption and transportation fuel (biodiesel) purposes while using a minimal amount of land area. A circulating loop photobioreactor has been used to study the growth kinetics and lipid yield of Chlorella vulgaris growing on carbon dioxide as the sole source of carbon. RESULTS: Because of high photosynthetic active radiation (PAR) fluxes, C. vulgaris was observed to grow in exponential mode. The highest growth rate achieved was 0.049 h^?1 at the optimum growth conditions of 71.8 mW L^?1 PAR density, 10% CO₂ (v/v) in air and with an applied 8 h dark phase. The microalgae was observed to grow in a Monod fashion with a PAR density saturation coefficient of 2.8 mW L^?1. Light intensity showed the potential to significantly increase lipid yield, which reached a maximum of 30% (by mass) of cell dry weight. CONCLUSION: The circulating loop photobioreactor is a low‐cost bioreactor technology capable of culturing photosynthetic microalgae at high PAR densities and with uniform mixing and lighting. C. vulgaris is able to grow exponentially in this bioreactor and produce lipids at concentrations up to 30% by cell dry weight. Copyright © 2011 Society of Chemical Industry     

A multivariate causality test of carbon dioxide emissions,energy consumption and economic growth in China

This paper uses multivariate co-integration Granger causality tests to investigate the correlations between carbon dioxide emissions, energy consumption and economic growth in China. Some researchers have argued that the adoption of a reduction in carbon dioxide emissions and energy consumption as a long term policy goal will result in a closed-form relationship, to the detriment of the economy. Therefore, a perspective that can make allowances for the fact that the exclusive pursuit of economic growth will increase energy consumption and CO₂ emissions is required; to the extent that such growth will have adverse effects with regard to global climate change.     

Antioxidant and antihypertensive hydrolysates obtained from by-products of cannery sardine and brewing industries

Hydrolysates with antioxidant and antihypertensive activities were obtained from sarcoplasmic proteins of canned sardine by-product and proteases extracted from Brewer’s spent yeast. Using response surface methodology, hydrolysis time and temperature were selected to achieve the maximum bioactivity. Hydrolysates produced using the substrate/enzyme ratio 1:0.27 (mg/U), 7 h and 50ºC, presenting an angiotensin I-converting enzyme-inhibitory activity of 164 µg protein/mL and an antioxidant activity of 293 μM TE/mL. Experimental results agreed with predicted values within a 95% confidence interval. Within this work the simultaneous valorisation of two agro-industrial by-products was successfully achieved.     

An investigation of fatigue failure prediction of adhesively bonded metal/metal joints

A fracture mechanics-based model for fatigue failure prediction of adhesive joints has been applied in this work. The model is based on the integration of the kinetic law of evolution of defects originated at stress concentrations within the joint. Final failure can be either brittle (fracture toughness-driven) or ductile (tensile/shear strength-driven) depending on the adhesive. The model has been validated against experiments conducted on single-lap shear joints bonded with a structural adhesive. Three different kinds of adhesives, namely a modified methacrylate, a one-part epoxy and a two-part epoxy supplied by Henkel, have been considered and three different overlap lengths have been tested. Fracture toughness and fatigue crack growth properties of the adhesives have been determined with mode I tests. The number of cycles to failure has been successfully predicted in several cases. It is interesting to notice that in the case of joints loaded at the same average shear stress, the shorter the joint, the longer the duration. This fact is also captured by the model.     

Mesoflowers: A new class of highly efficient surface-enhanced Raman active and infrared-absorbing materials

A method for the synthesis of a new class of anisotropic mesostructured gold material, which we call “mesoflowers”, is demonstrated. The mesoflowers, unsymmetrical at the single particle level, resemble several natural objects and are made up of a large number of stems with unusual pentagonal symmetry. The mesostructured material has a high degree of structural purity with star-shaped, nano-structured stems. The mesoflowers were obtained in high yield, without any contaminating structures and their size could be tuned from nano- to meso-dimensions. The dependence of various properties of the mesoflowers on their conditions of formation was studied. The near-infrared-infrared (NIR-IR) absorption exhibited by the mesoflowers has been used for the development of infrared filters. Using a prototypical device, we demonstrated the utility of the gold mesoflowers in reducing the temperature rise in an enclosure exposed to daylight in peak summer. These structures showed a high degree of surface-enhanced Raman scattering (SERS) activity compared to spherical analogues. SERS-based imaging of a single mesoflower is demonstrated. The high SERS activity and NIR-IR absorption property open up a number of exciting applications in diverse areas. Electronic Supplementary Material  Supplementary material is available in the online version of this article at http://dx.doi.org/ and is accessible free of charge.     

Crack growth retardation following the application of an overload cycle using a strip-yield model

Experiments have shown that the application of an overload cycle can act to retard crack growth and even potentially lead to crack arrest. This paper describes a new method for investigating fatigue crack growth after the application of an overload cycle under plane stress conditions. The developed method is based on the concept of plasticity-induced crack closure and utilises the distributed dislocation technique and a modified strip-yield model. The present results are compared to previous experimental data for several materials. A good agreement is found, with the predictions showing the same trends in the various stages of post-overload crack growth.