Mineralogy of air-pollution-control residues from a secondary lead smelter: environmental implications

The mineralogy and solubility of air-pollution-control (APC) residues from a secondary lead (Pb) smelter have been studied on samples from the Príbram smelter, Czech Republic, recycling car batteries, with the emphasis on their potential environmental effect. The presence of dominant anglesite (PbSO4) and laurionite (Pb(OH)Cl) was observed in a sintered residue from after-burning chambers (800-1000 degrees C). In contrast, low-temperature Pb-bearing phases, such as KCl x 2PbCl2 and caracolite (Na3Pb2(SO4)3Cl), were detected in the major APC residue from bag-type fabric filters. Metallic elements, zinc (Zn), cadmium (Cd), and tin (Sn) were found homogeneously distributed within this residue. The formation of anglesite, cotunnite (PbCl2), (Zn,Cd)2SnO4, and (Sb,As)2O3 was observed during the sintering of this APC residue at 500 degrees C in a rotary furnace. The 168 h leaching test on filter residue, representing the fraction that may escape the flue gas treatment system, indicated rapid release of Pb and other contaminants. Caracolite and KCl x 2PbCl2 are significantly dissolved, and anglesite and cotunnite form the alteration products, as was confirmed by mineralogical analysis and PHREEQC-2 modeling. The observed Pb-bearing chlorides have significantly higher solubility than anglesite and, following emission from the smelter stack, can readily dissolve, transferring Pb into the environmental milieu (soils, water, inhabited areas).     

Redox processes in pressurised smoked salmon studied by resonance Raman spectroscopy

Non-thermal food preservation technology is based on the application of high pressures up to 600 MPa. Here we report a resonance Raman (RR) spectroscopic analysis of smoked salmon meat after high pressure processing. High quality spectra, which can be obtained even from packed salmon without spectral interference of the packing foil, allow determining pressure-dependent irreversible changes of the main RR-active components of salmon meat, astaxanthin and myoglobin/haemoglobin. High pressure-treatment causes a decrease of the relative RR intensities of astaxanthin as probed with 514 nm excitation which is in line with a slight attenuation of the originally intense red colour of the salmon meat. 413-nm excited RR spectra indicate a heterogeneous broadening of astaxanthin bands accompanied by the formation of deoxy-myoglobin or deoxy-haemoglobin. The results suggest that pressure-treatment facilitates the oxidative degradation of astaxanthin coupled to the reduction of metmyoglobin (methaemoglobin).     

Bandwidth limits of luminescent solar concentrators as detectors in free-space optical communication systems

Luminescent solar concentrators(LSCs)have recently emerged as a promising receiver technology in free-space optical communications due to their inherent ability to collect light from a wide field-of-view and concentrate it into small areas,thus leading to high optical gains.Several high-speed communication systems integrating LSCs in their detector blocks have already been demonstrated,with the majority of efforts so far being devoted to maximising the received optical power and the system's field-of-view.However,LSCs may pose a severe bottleneck on the bandwidth of such communication channels due to the comparably slow timescale of the fluorescence events involved,a situation further aggravated by the inherent reabsorption in these systems,and yet,an in-depth study into such dynamic effects remains absent in the field.To fill this gap,we have developed a comprehensive analytical solution that delineates the fundamental bandwidth limits of LSCs as optical detectors in arbitrary free-space optical links,and establishes their equivalence with simple RC low-pass electrical circuits.Furthermore,we demonstrate a time-domain Monte Carlo simulation platform,an indispensable tool in the multiparameter optimisation of LSC-based receiver systems.Our work offers vital insight into LSC system dynamic behaviour and paves the way to evaluate the technology for a wide range of applications,including visible light communications,high-speed video recording,and real-time biological imaging,to name a few.     

Digital image analysis of hydrodynamics two-dimensional bubbling fluidized beds

A new method of digital image analysis has been developed to study the hydrodynamics of two-dimensional bubbling fluidized beds with a digital video camera. The method comprises simultaneous of the size and velocity of gas bubbles, and the axial and radial distribution of bubble voidage. It provides a better estimation of the visible bubble flow than from local probe methods. Also a good estimation of the throughflow can be gotten, which is of great importance for combustor applications.Parallel to the approach of Darton et al. (Transactions of the Institution Chemical Engineering 55 (1977) 274) for three-dimensional fluidized beds, an equation for the bubble diameter of two-dimensional beds is developed,

     

The Application of Mealworm (Tenebrio molitor) Oil in Cosmetic Formulations

The depletion of natural resources, the increasing use of valuable land surface for human activities, and the generation of waste are detrimental to the planet. Sustainable alternatives to guarantee a sufficient supply of food, feed, and biomaterials are needed. Insects may hold an interesting position in a circular economy to tackle contemporary societal challenges. Using insects for food, feed, biomaterial production, and to valorize side-streams, have gained increased interest. Mealworms are amenable to large-scale farming. Herein, the potential of mealworm oil for implementation in a cosmetic hand cream is evaluated. It is shown that mealworms are rich in oil (≈30% of the dry weight), and the oil can be extracted using hexane or ethyl acetate as a solvent. The euthanization step of mealworms has profound effect on the free fatty acid content. The fatty acid profile indicates a large proportion of unsaturated fatty acids, which is promising for use in cosmetic applications. In a proof of concept, the mealworm oil is implemented in a hand cream and compared to hand cream containing macadamia nut oil. No differences in odor and aspect/stability are observed, but mealworm creams are slightly less white color. Mealworm oil is suitable for cosmetics applications. Practical applications: Several insect species can be sustainably reared on low-value organic side-streams, requiring only small amounts of land-surface, less water, and producing less greenhouse gases. In addition, they have short life cycles and can be reared continuously and locally. This implies that insects are an interesting source of biological materials including proteins and oils. Insect oils, including oil of mealworms, have interesting fatty acid profiles that make them amenable to replace oils of vegetable origin for applications within cosmetics. The results indicate that mealworm oil can be a novel, sustainable ingredient for use in the cosmetics industry.     

Synthesis and magnetorheological characteristics of ribbon‐like,polypyrrole‐coated carbonyl iron suspensions under oscillatory shear

One of the crucial problems of classical magnetorheological (MR) fluids is their high rate of sedimentation. This disadvantage may be substantially eliminated using core‐shell particles. The aim of this study is to prepare spherical carbonyl iron (CI) particles coated with conducing polymer polypyrrole (PPy) with ribbon‐like morphology. Scanning electron microscopy proved the formation of the ribbon‐like layer onto CI particles while Fourier transform infrared spectroscopy confirmed the chemical structure of PPy. The magnetic properties observed via vibrating sample magnetometer showed decreased magnetization saturation of core‐shell‐structured particles due to the existence of non‐magnetic surface layer. MR measurements performed under oscillatory shear flow as a function of the applied magnetic flux density, temperature, and particle concentration showed that core‐shell particle‐based MR suspension exhibits sufficient MR performance for practical applications. Moreover, the suspension stability is promoted significantly when core‐shell particles are used as a dispersed phase. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mixture Rules for Critical Shear Values of Extruded Linear PE/Branched PE Blends

Oscillatory flow and elastic turbulence belong to the types of flow instabilities frequently encountered during extrusion of polymer melts. The onset of these defects corresponds to the flow conditions when the critical shear stresses or the critical shear rates are attained. The critical values of shear stresses and shear rates were experimentally determined for linear polyethylene/branched polyethylene blends (IPE/bPE) that were prepared with various weight ratios. Consequently, mixture rules of the logarithmic type are proposed. These rules relate the critical value of shear stress (shear rate) of blend to the critical values of shear stresses (shear rates) of the individual pure components, weight fractions, and interaction parameters. There is a good agreement between the proposed mixture rules and experimentally determined critical values.     

Introducing Glycolinkers for the Functionalization of Cytotoxic Drugs and Applications in Antibody–Drug Conjugation Chemistry

Antibody–drug conjugates (ADCs) are promising alternatives to naked antibodies for selective drug‐delivery applications and treatment of diseases such as cancer. Construction of ADCs relies upon site‐selective, efficient and mild conjugation technologies. The choice of a chemical linker is especially important, as it affects the overall properties of the ADC. We envisioned that hydrophilic bifunctional chemical linkers based on carbohydrates would be a useful class of derivatization agents for the construction of linker–drug conjugates and ADCs. Herein we describe the synthesis of carbohydrate‐based derivatization agents, glycolinker–drug conjugates featuring the tubulin inhibitor monomethyl auristatin E and an ADC based on an anti‐EGFR antibody. In addition, an initial in vitro cytotoxicity evaluation of the individual components and the ADC is provided against EGFR‐positive cancer cells.