Fundamental optical spectra of ferroelectric NaNO<Subscript>2</Subscript>

Polarized spectra of complete complexes for fundamental optical functions of the NaNO₂ ferroelectric at 77K in the region of 4–24 eV for E ‖ a, E ‖ b, and E ‖ c are calculated. For the first time, integral polarized curves of dielectric permeability and specific volumetric losses of electrons are factorized into elementary transverse and longitudinal components of transfer bands and their main parameters are determined. For the calculations, the experimental reflection spectra, methods of Kramer-Kronig, and joint Argand diagrams are used. On the basis of theoretical calculations for the zones and dielectric permeability, a scheme of the nature and localization of the obtained bands for the components of separation of ?₂ is proposed in accordance with the model of interband transitions.     

Efficient centrifugal recovery of Bacillus thuringiensis biopesticides from fermented wastewater and wastewater sludge

Studies were conducted on harvesting of Bacillus thuringiensis (Bt)-based biopesticides from fermented broths of starch industry wastewater (SIW), wastewater sludge (raw and hydrolyzed-NH and TH, respectively) and semi-synthetic soyameal to enhance entomotoxicity (Tx) by centrifugation. Pertinent factors influencing Tx, solids concentration, pH, temperature and centrifugal force were investigated. The centrifugate solids concentration beyond 100 g/l did not enhance Tx, instead caused pellet formation. Centrifugation efficiency (Tx recovery) was higher at pH 4, and temperature 20 degrees C for starch wastewater (98%), wastewater sludge (98% and 97.8% for non-hydrolyzed and hydrolyzed, respectively) and soya broth (83%). For maximum Tx recovery (SIW-95%; NH-90%; TH-98% and soya-78%), the centrifugal force and time required was 48,000 g and 30 min, respectively. Losses in recovery efficiency were lower for SIW and wastewater sludge in comparison to soya on adopting commercially recommended centrifugal force of 9000 g. The settling velocity computations for different fermented broths enabled calculation of Sigma factor for continuous commercial centrifuge of a given capacity and hence simulation of power requirements. It was established that power requirements for a given Tx recovery efficiency were highest for conventional medium (soya) in comparison to other waste-based fermented broths.     

Reliability-based bridge assessment using risk-ranking decision analysis

Information about present and anticipated bridge reliabilities can be used in conjunction with decision models to provide a rational decision-making tool for the assessment of bridges and other structural systems. The present paper presents a broad overview of reliability-based assessment methods and will then focus on decision-making applications using updated time-dependent estimates of bridge reliabilities considering a risk-ranking decision analysis. A practical application of reliability-based safety assessment is illustrated herein which relates the effects of bridge age, current and future (increasing) traffic volume and loads, and deterioration on the reliability and safety of ageing RC bridges.     

Thinking about Antarctic Heritage: kaleidoscopes and filters

The preliminary results of a project that is currently investigating the nature and range of meanings of Antarctic heritage are explored. The project involves two visits to Scott Base, and the subjects of the qualitative research are the members of the New Zealand Antarctic community. Work so far suggests that different meanings do exist, and a four-fold typology of meanings is suggested which needs to be considered in decisions affecting the future of Antarctica.     

In situ kinetics study of the formation of organic nanoparticles by fluorescence lifetime imaging microscopy (FLIM) along a microfluidic device

In this study, a three-dimensional hydrodynamic focusing microfluidic method is presented that allows full control of the nano-precipitation process of adamantyl mesityl BODIPY (4,4-difluoro-3,5-di-(adamantyl)-8-mesityl-4-bora-3a,4a-diaza-s-indacene) (Adambodipy). The precipitation is achieved by combining a central Adambodipy organic flow with a mixture of water and a cationic surfactant, creating a non-solvent precipitation method. The flow and mixing were simulated using COMSOL Multiphysics^® 3.4. A good agreement between theory and experiment was obtained for the flow velocity, concentration fields and the subsequent precipitation kinetics. Fluorescence lifetime imaging was used to visualize the precipitation domains following the changes in fluorescence lifetime. The lifetime decreases from 6.1 ns for the molecules down to 0.9 ns for nanoparticles. A principal components analysis of the successive fluorescence decay curves showed that the process could be adequately modeled using three components, which can be attributed to monomers (single molecule), clusters (nuclei) and nanoparticles.     

Model for thermodynamic point identification in laser cutting

In recent years, laser cutting has been introduced and developed to such an extent that it is now thought to be one of the leading and indispensable manufacturing tools. At the present time, dross‐free and accurately‐cut parts are basically regarded as the major targets to aim for, because the costs and efforts associated with dross removal by postprocessing cut parts are considerable. Therefore, control of dross formation during laser cutting is an important factor in maintaining edge quality. The initial aim of this paper is to describe the importance of physico‐mechanical material properties that need to be taken into account in modeling of laser material processing in order to control melting of the material.     

Chemical reactivity of mineral aggregates in aqueous solution: relationship with bitumen emulsion breaking

This paper reports a study on chemical reactivity of gneiss, diorite and limestone aggregates in aqueous solution. The originality of this study is that it extended to very short times (less than 1440 min). Rise in pH tests was implemented and dissolution kinetics was analysed. The results showed that calcium was the major element released by the aggregates. It has also been found that dissolution had an influence on the final morphology of aggregates. Polyamine emulsifier adsorption onto aggregates has been assessed using electrophoresis. Finally, the rise in pH and electrophoretic tests were compared to the breaking test traditionally performed to characterise bitumen emulsions. It was found that breaking values were controlled by both the surface area and the surface charge of the particles. Results may be correlated to polyamine adsorption on aggregates. Adsorption seemed to be efficient for gneiss and diorite: at pH 2, their charge turned from slightly negative to highly positive. At this pH value, limestone particles were dissolved and polyamine adsorption must be less efficient than with gneiss and diorite, for which the emulsion breaking was facilitated by the high attraction of particles for the emulsifier, due to their negative surface charge.     

Coexistence of Superconductivity and Antiferromagnetism in Heavy-Fermion Intermetallic Compound CeRhIn5

An interference of heavy-fermion superconductivity (SC) and antiferromagnetism (AFM) has been studied in the framework of the periodic Anderson model with the superexchange interaction between localized electrons. It has been shown that pressure-induced energy change of the localized states leads to modifying antiferromagnetic and superconducting order parameters. Conditions have been found for the coexistence of SC and AFM in the model. Theoretical results of the pressure effects on the ground state character of the heavy-fermion systems are in good agreement with experimental data for a rare-earth intermetallic compound CeRhIn₅. The divergence of the effective electron mass produced by suppressing the long-range antiferromagnetic order has also been analyzed in the same framework.