A som study of DC-PBH laser catastrophic failures

OBIC and PL imaging modes of a SOM have been successfully applied to the failure analysis of catastrophically degraded DC-PBH lasers. High lateral resolution, variable in-depth penetration and selective excitation are the most interesting features. A degradation mechanism has been found due to the development of leakage paths in the confining junctions.     

An empirical equation of state for gases

A simple pressure-explicit empirical equation of state for gases is presented which contains five constants in addition to the gas constant. It has been applied to carbon dioxide, hydrogen and nitrogen. The equation gives good accuracy (with maximum errors slightly higher than 1%) for densities up to critical and for temperatures from slightly above critical up to very high values. Below critical temperature it can still be applied with reasonable accuracy to the vapor. Thermodynamic functions (internal energy, enthalpy and entropy) derived from this equation show simple form and satisfactory accuracy over a wide range of temperature and density.     

Design of power‐blocks for medium‐scale supercritical carbon dioxide plants

For power production, the emerging technologies of supercritical carbon dioxide (S‐CO₂) cycles show potential advantages if compared to conventional plants. The current bottleneck in exploiting such cycles is the development of novel components such as turbomachines and heat‐exchangers. This paper focuses on the layout arrangement and machinery design of a novel power‐block for a 10 to 15 MW supercritical carbon dioxide plant. The applied design procedure involves 0D and 1D models implemented using an in‐house Fortran code, and 3D computational fluid dynamics ( CFD) analyses using ANSYS‐CFX. Novel configurations of the power block were designed, starting with the same primary thermal source. At nominal conditions, expected overall output powers from 13.2 to 16.2 MW were found. Finally, some qualitative considerations were included in the discussion to compare the analysed arrangements.     

Evaluation of Cu, Mn, and Se in Vegetables Using Ultrasonic Extraction and GFAAS Quantification

This paper proposes a method for the determination of copper, manganese, and selenium in vegetables of conventional and organic farming in the state of S?o Paulo/Brazil using ultrasonic extraction of analytes and subsequent quantification by graphite furnace atomic absorption spectrometry (GFAAS). Using 0.10 mol L⁻¹ of hydrochloric acid as the extracting solution, the following optimal extraction conditions were established: sample mass of 100 mg, sample grain size of <60 μm, sonication time of five cycles of 40 s, and sonication power of 136 W. The analytes were determined by GFAAS, applying drying temperatures of 90 °C to 250 °C, pyrolysis temperature of 1,300 °C, atomization temperature of 2,300 °C, and cleaning temperature of 2,800 °C. Palladium nitrate was co-injected with the samples as a chemical modifier and tungsten as a permanent modifier. The accuracy and precision of the proposed extraction method were evaluated based on a certified standard, RM 8433 Corn Bran (NIST RM 8433). The results obtained by the ultrasonic extraction method were equivalent to those obtained by the method of acid mineralization of samples in a microwave oven. However, the proposed methodology reduces the analytical time considerably, favoring the analytical speed. Moreover, the quantity of residues generated and discharged into the environment is also considerably lower.     

Engineered organic/inorganic hybrids for superhydrophobic coatings by wet and vapour procedures

Siloxane/oxide hybrids have attracted growing attention thanks to their ability to modulate the surface energy, wettability, or self-lubricity of a material. Here, we compare two functionalisation procedures (chemical vapour deposition and wet impregnation) on substrate films composed by preformed oxide particles. Three kinds of particles, characterised by different natures (SiO₂ and TiO₂) and average particle size, were studied to highlight possible effects related to the chemical and morphological state of the substrate surface. Morphological characterisations were carried out using dynamic light scattering and scanning electron microscopy, while the structure of the hydrophobing layer was studied by combining Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance. The degree of functionalisation and the features of the siloxane layer vary significantly among the adopted oxides and functionalisation methods. The wettability features of the different hybrids closely mirror the results of the spectroscopic characterisations, giving rise to either Lotus leaf or patch-wise hydrophobic systems depending on the adopted conditions.     

Proteomic analysis of water soluble and myofibrillar protein changes occurring in dry-cured hams

The myofibrillar fraction of raw ham muscles and dry-cured hams with different ripening times was extracted in denaturing and reducing conditions and subjected to two-dimensional gel electrophoresis. The two-dimensional maps gave overall pictures of the already noted progressive disappearance of actin, tropomyosin and myosin light chains during ripening. In addition, two fragments from Myosin Heavy Chain proteolysis, marked as myosin chain fragments MCF1 and MCF2, were identified by immunodetection and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Furthermore, a new form of actin on two-dimensional gel was identified by MALDI-TOF peptide mapping. In 12-month-old dry-cured ham, most myofibrillar proteins were completely hydrolyzed. At this stage of ripening, in fact, in some Parma and S. Daniele dry-cured ham samples, myosin heavy chain fragments and other unidentified neo-formed spots were found. Some of the sarcoplasmic proteins in water extracts from pork meat markedly decreased in amount or disappeared totally, during ripening. Surprisingly, two-dimensional gel electrophoresis maps of the water soluble protein fraction from dry-cured ham showed the presence of two spots identified as tropomyosin α- and β-chain. This result suggests that some of the saline soluble myofibrillar proteins can disappear from this fraction because of salt solubilization and not due to complete enzyme action. Two-dimensional gel electrophoresis (2-DGE) has proved a powerful tool to evaluate the enzymatic susceptibility of meat proteins and the evolution of protein map fragmentation throughout ripening process as well as a means of obtaining a standard fingerprinting map characterizing the final product.