Removal of lindane using electrokinetic soil flushing coupled with air stripping

Journal of Applied Electrochemistry - This paper evaluates the remediation of soil spiked with lindane using a combined treatment consisting of electrokinetic soil flushing (EKSF) with air...     

Simulations of microfluidic droplet formation using the two-phase level set method

Microdroplet formation is an emerging area of research due to its wide-ranging applications within microfluidic based lab-on-a-chip devices. Our goal is to understand the dynamics of droplet formation in a microfluidic T-junction in order to optimize the operation of the microfluidic device. Understanding of this process forms the basis of many potential applications: synthesis of new materials, formulation of products in pharmaceutical, cosmetics and food industries. The two-phase level set method, which is ideally suited for tracking the interfaces between two immiscible fluids, has been used to perform numerical simulations of droplet formation in a T-junction. Numerical predictions compare well with experimental observations. The influence of parameters such as flow rate ratio, capillary number, viscosity ratio and the interfacial tension between the two immiscible fluids is known to affect the physical processes of droplet generation. In this study the effects of surface wettability, which can be controlled by altering the contact angle, are investigated systematically. As competitive wetting between liquids in a two-phase flow can give rise to erratic flow patterns, it is often desirable to minimize this phenomenon as it can lead to a disruption of the regular production of uniform droplets. The numerical simulations predicted that wettability effects on droplet length are more prominent when the viscosity ratio λ (the quotient of the viscosity of the dispersed phase with the viscosity of the continuous phase) is O(1), compared to the situation when λ is O(0.1). The droplet size becomes independent of contact angle in the superhydrophobic regime for all capillary numbers. At a given value of interfacial tension, the droplet length is greater when λ is O(1) compared to the case when λ is O(0.1). The increase in droplet length with interfacial tension, σ, is a function of with the coefficients of the regression curves depending on the viscosity ratio.     

Kinetics of Solid-State Reactions in Heterogeneous Catalysis from Time-Resolved X-Ray Absorption Spectroscopy

The potentials of X-ray absorption spectroscopy (XAS) (quantitative phase composition and average valence together with a short-range order structure analysis) combined with a time-resolution in the second range make time-resolved (TR-) XAS a powerful tool for investigating the reactivity of solids in catalysis and solid-state chemistry. General aspects of TR-XAS investigations are discussed (i.e., instrumentation, data analysis). In addition, some experiments illustrate how the kinetics of solid-state reactions in heterogeneous catalysis can be elucidated from TR-XAS studies.     

Toluenesulfonate-acyl esters of ethylene glycol and other 1,2-diols as industrial antioxidants with cupric ion

Ethylene glycol esters of soybean oil FA increased in viscosity much more slowly than methyl or glycerol esters when oxidized at 105°C in the presence of flowing air and colloidal copper. This increased stability was caused by a minor constituent of the ethylene glycol esters, which was shown by MS to be a mixed ethanediol fatty acylate p-toluenesulfonate (EFAT). The p-toluenesulfonate group came from the catalyst used in the formation of the ethylene glycol esters. EFAT was quantified by UV spectrometry, HPLC, or GC of the acyl group that it contains. EFAT could be synthesized in good yield by reacting ethylene glycol, a FA, and p-toluenesulfonic acid (TSA) in a 1∶1∶1 molar ratio using a benzene azeotrope to remove water of esterification. EFAT increased the time required for the polymerization of soybean oil by about 27 times but required concentrations of 2–5% by weight. EFAT made with a variety of FA were active in delaying viscosity increase. Ethyl and decyl p-toluenesulfonate were inactive. Replacing ethylene glycol by glycerol and 1,2-propylene glycol but not by 1,3-propylene glycol resulted in active EFAT. TSA itself delayed the polymerization of soybean oil, especially in the presence of free ethylene glycol and FA, but this probably was caused by formation of EFAT during the oxidation test. Colloidal copper could be replaced by cupric ion. EFAT-copper appeared to act as an antioxidant by destroying hydroperoxides without initiation of free radical chains.     

Electrical conductivity modeling of carbon black/polycarbonate,carbon nanotube/polycarbonate,and exfoliated graphite nanoplatelet/polycarbonate composites

Adding conductive carbon fillers to electrically insulating thermoplastic polymers increases the resulting composite's electrical conductivity, which would enable them to be used in electrostatic dissipative and semiconductive applications. In this study, varying amounts of carbon black (CB: 2 to 10 wt %), multiwalled carbon nanotubes (CNT: 0.5 to 8 wt %), or exfoliated graphite nanoplatelets (GNP: 2 to 15 wt %) were added to polycarbonate (PC) and the resulting composites were tested for electrical conductivity (EC = 1/electrical resistivity). The percolation threshold was ～ 1.2 vol % CNT, ～ 2.4 vol % CB, and ～ 4.6 vol % GNP. In addition, three EC models (Mamunya, additive, and general effective media) were developed for the CB/PC, CNT/PC, and GNP/PC composites. The general effective media (GEM) model showed the best agreement with the experimental results over the entire range of filler concentrations (above and below the percolation threshold) for all three composite systems. In addition, the GEM model can be easily adapted for composites containing combinations of different conductive fillers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mineral Oil Hydrocarbons (MOSH/MOAH) in Edible Oils and Possible Minimization by Deodorization Through the Example of Cocoa Butter

Mineral oil hydrocarbons (MOH) are present in many fats and oils as well as foods prepared thereof. A survey of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) in different types of vegetable fats and oils is reported. Contents of MOSH/MOAH were quantified using liquid chromatography online‐coupled to gas chromatography with flame‐ionization detection (LC‐GC‐FID). Cocoa butter (n = 142) showed levels from <LOQ (2.5 mg kg^?1) to 162 mg kg^?1 ΣMOSH (sum of C10–C50) and <LOQ to 55 mg kg^?1 ΣMOAH, in palm oil (n = 21) ΣMOSH were quantified from <LOQ to 124 mg kg^?1 and ΣMOAH from <LOQ to 39 mg kg^?1. Sunflower oil showed lower levels: ΣMOSH were determined in the range of <LOQ to 17 mg kg^?1 and MOAH were not observed at all. A possible influence of deodorization and a subsequent minimization of MOSH/MOAH was investigated. Systematic model‐experiments were performed on laboratory scale using spiked cocoa butter. Significant minimization of volatile MOH subfractions ≤C24 were observed at a deodorization temperature of 210 °C. Deodorization can be considered as an important processing step to reduce or even remove volatile MOSH/MOAH ≤C24. Practical Applications: Regardless of their possible entry routes into the food chain, volatile fractions of MOSH/MOAH can be removed by deodorizing vegetable fats and oils. This model‐study identifies the temperatures of deodorization that provide a significant improvement toward minimization of undesired MOSH/MOAH.     

Genomic Instability Is an Early Event in Aluminium-Induced Tumorigenesis

Genomic instability is generally considered as a hallmark of tumorigenesis and a prerequisite condition for malignant transformation. Aluminium salts are suspected environmental carcinogens that transform mammary epithelial cells in vitro through unknown mechanisms. We report here that long-term culture in the presence of aluminium chloride (AlCl₃) enables HC11 normal mouse mammary epithelial cells to form tumours and metastases when injected into the syngeneic and immunocompetent BALB/cByJ strain. We demonstrate that AlCl₃ rapidly increases chromosomal structural abnormalities in mammary epithelial cells, while we failed to detect direct modulation of specific mRNA pathways. Our observations provide evidence that clastogenic activity—a well-recognized inducer of genomic instability—might account in part for the transforming abilities of aluminium in mammary epithelial cells.     

Investigations on Selectivity of Gas-Liquid Reactions in Capillaries

Biocatalysis offers a broad spectrum of possible ecological and economic advantages over conventional chemical catalysis processes, e.g., lower energy consumption and high enantio selectivity. The focus of this work is on gas-liquid reactions. These are of great importance in the chemical and biochemical industry and subject of current research since they are often limited by mass transfer or show low selectivity. Different suitable biocatalytically gas-liquid reaction systems were tested in capillary reactor designs in order to obtain information about the interaction between reaction and fluid mechanics. Furthermore, an optical measuring method was established. The experiments were performed in batch mode in a glass beaker with a flow cuvette for UV/Vis measurement of product concentration.     

Entwicklung eines Transformationsmodells – Modularisierung schrittweise gedacht

For some years now, the process industry has been meeting the challenges of the markets with modular production and logistics concepts. This article presents this development process in the form of a four-stage transformation model. It is shown that the path towards modular production environments can be taken step by step. The motto is “evolution instead of revolution”. First, an overview of the state of the art of modularized production and logistics systems is given. Based on this, the article describes and classifies the four different stages of modularization.