Ozonation Impact on Degradation and Toxicity of Non-Ionic Surfactants

Aqueous solutions of five selected non-ionic surfactants: Triton (i-octylphenolethoxylates), Tergitol (2,6,8-trimethyl-4-nonanoloxethylates), Symperonic (n-nonylphenol-oxethylates) and Brij (fatty alcohol ethoxylates) were investigated in this study. Using the bioluminescent bacteria Vibrio fischeri the toxicity of the surfactants solutions were determined. An attempt was made to relate rather low biodegradability of nonionic surfactant solutions measured by the BOD₅/COD ratio (ranging from 1 to 17%) to their toxicity. The ozonation process was carried out in a 1.5 dm³ stirred cell reactor equipped with two ozone detectors. The following parameters were analyzed: pH, COD, BOD₅, DOC, TOC, polarography as well as UV spectrum. The positive effect of ozonation, represented by decay of UV absorption, was visible in almost complete destruction of the surfactants, with exception of Triton X-705 (only 65% degradation after absorption of 2000 mgO₃/dm³). The most striking results were obtained in toxicity tests for ozonated solutions of the non-ionic surfactants – an increase of the bacterial growth inhibition (1.5 to 4 times increase in toxicity due to ozonation). The obtained results were discussed taking into account the literature and our own experimental data on mechanisms of ozonation and biodegradation of non-ionic surfactants of the Triton-type and similar chemical structures.     

Microstructure and Mechanical Properties of the Ductile Al–Ti–Mo–Nb–V Refractory High Entropy Alloys

Metallurgical and Materials Transactions A - A number of non-equimolar refractory high entropy alloys (RF HEAs) from the Al–Ti–Mo–Nb–V system are synthesized, with the...     

Realization and synthesis of reversible functions

Reversible circuits play an important role in quantum computing. This paper studies the realization problem of reversible circuits. For any n-bit reversible function, we present a constructive synthesis algorithm. Given any n-bit reversible function, there are N distinct input patterns different from their corresponding outputs, where N≤2ⁿ, and the other (2ⁿ−N) input patterns will be the same as their outputs. We show that this circuit can be synthesized by at most 2n⋅N ‘(n−1)’-CNOT gates and 4n²⋅N NOT gates. The time and space complexities of the algorithm are Ω(n⋅4ⁿ) and Ω(n⋅2ⁿ), respectively. The computational complexity of our synthesis algorithm is exponentially lower than that of breadth-first search based synthesis algorithms.     

Relationship of ergosterol content and fungal contamination and assessment of technological quality of malting barley preserved in a metal silo using the near-ambient method

Environmental microbiologists frequently use ergosterol, a fungal-specific membrane lipid, as an indicator of fungal infection in grain and other plant materials. Microbiological loading and technological quality of barley was determined directly after harvest, after post-harvest drying, and during storage. The conventional plate count method was used to measure fungal contamination (CFU). Ergosterol concentration (ERG) was determined by extraction, saponification and quantification using high-performance liquid chromatography (HPLC) with UV detection. The laboratory malting method was used to determine technological quality of the malt. Results showed a significant correlation between ERG and CFU (the coefficient of correlation was 0.92). Analyses also indicated that the high germinative energy and technological quality of the malt produced from dried barley was retained.     

Evolutionary Approach to Quantum and Reversible Circuits Synthesis

The paper discusses theevolutionary computation approach to theproblem of optimal synthesis of Quantum andReversible Logic circuits. Our approach usesstandard Genetic Algorithm (GA) and itsrelative power as compared to previousapproaches comes from the encoding and theformulation of the cost and fitness functionsfor quantum circuits synthesis. We analyze newoperators and their role in synthesis andoptimization processes. Cost and fitnessfunctions for Reversible Circuit synthesis areintroduced as well as local optimizingtransformations. It is also shown that ourapproach can be used alternatively forsynthesis of either reversible or quantumcircuits without a major change in thealgorithm. Results are illustrated onsynthesized Margolus, Toffoli, Fredkin andother gates and Entanglement Circuits. This isfor the first time that several variants ofthese gates have been automatically synthesizedfrom quantum primitives.     

Application of Ozone in Textile Wastewater Treatment

Textile wastewaters are known to be highly resistant to biodegradation under both natural and wastewater treatment plant conditions. However, ozonation can be used to increase the biodegradability of the biologically resistant compounds. The combined method of ozonation and subsequent biodegradation of both synthetic and real textile wastes was explored in laboratory-scale studies. Two kinds of industrial wastes were simulated for effluents from dyehouse and washing machines. Upon determining the ozonation conditions of synthetic wastes, the real industrial wastes were investigated. The real textile wastewater was taken from textile factories, located in ód? , Poland, from subsequent stages of textile processing; dyeing, washing, rinsing and from an equalizer tank. Ozonation was carried out in a lab-scale bubble column sparged reactor, while the biological degradation proceeded in a trickle bed biofilter.     

A High-Frequency Field-Programmable Analog Array (FPAA) Part 1: Design

The design of a high-frequency field-programmable analog array (FPAA) is presented. The FPAA is based on a regular pattern of cells interconnected locally for high frequency performance. No switches of any kind are used in the signal path of a cell: programming of the functions, parameters, and interconnections is achieved solely by modifying cells' bias conditions digitally. Limited global signal interconnections are also available for those application circuits which cannot be mapped onto locally-only interconnected structure. Key circuits of the FPAA have been fabricated in a CPI transistor-array bipolar technology.     

Investigation of structural order and morphology of MCM-41 mesoporous silica using an experimental design methodology

A 2⁴ factorial experiment program was carried out to study the main and interaction effects of four factors (mixture CTMABr/SiO₂, H₂O/SiO₂, and EthAc/SiO₂, and reaction time) on pore ordering, hexagonal unit cell parameter a₀, and morphology of MCM-41. The MCM-41 was synthesized from a sodium silicate solution using cetyltrimethylammonium bromide (CTMABr) surfactant and ethyl acetate (EthAc) pH modifier. None of the factors acted independently to determine pore ordering, in contrast to earlier limited literature data, which suggested a higher CTMABr/SiO₂ disturbs the assembly of the MCM-41 structure. However, there is no contradiction between these results considering that the poorly ordered product was obtained previously from a reaction mixture with the higher EthAc/SiO₂ and lower H₂O/SiO₂, which are shown to hinder pore ordering. A combination of these factors, resulting in a higher concentration of acetic acid (hydrolysis of EthAc), and thus, in a lower mixture alkalinity, implies that the pH affects pore ordering in MCM-41. This is consistent with extensive literature data on this mesoporous material. A small (up to ∼5%) variation of a₀ due to the reaction composition and time variation was insignificant compared to the reported doubling of a₀ caused by the effects of varying the surfactant alkyl chain length, addition of swelling organic compounds, or hydrothermal restructuring. Particle morphology (hexagonal platelets, gyroids, and crescent-like or worm-shaped particles) depended on the combination of mixture CTMABr/SiO₂, H₂O/SiO₂, and EthAc/SiO₂. This is consistent with the literature evidence that morphogenesis of hexagonally ordered silica is a complex phenomenon involving a variety of reaction variables.     

Guest editorial

This issue contains papers presented at the 7th International Conference on Electrical and Related Properties of Organic Solids (ERPOS-7). It is a companion issue to Vol. 6. No. 5/6 which contained the bulk of the papers. Unfortunately, not all of the papers could be published in one special issue. © 1997 John Wiley & Sons, Ltd.     

Non-contact electrostatic flow probes for measuring the flow rate and charge in the two-phase gas-solids flows

The paper presents mathematical models of a measuring system for real-time monitoring the net electric charge, the mass flow rate or concentration of charged particles, and the mean flow velocity of the particles in a pipe. The main problem lies in proper defining and establishing the unambiguous relationships between the electric parameters of a measuring system, which uses a probe, sensor or transducer based on electrostatic induction. Such devices are non-contact, non-obstructive ones and are intended for the two-phase flow metering of charged solids in pipelines. The probe's output potential (voltage) is derived as a function of an equivalent point charge representing the net charge of a charged particle column within the probe's sensing zone and flowing in a real pipe as well as a function of the net charge of this column and its dynamic space density. The relationships are established for the above three forms of charge travelling rectilinearly along or parallel to the probe's geometrical axis in a laminar or fully developed turbulent flow. The models presented here show a useful, helpful approach to the modelling of non-contact, non-intrusive measuring systems based on electrostatic induction. The substantial role the capacitance of the electrostatic flow probe itself and the whole measuring system plays in the physical process of electrostatic induction of charge and in the mathematical modelling of the probe and system is interpreted. The capacitance influence on the system bandwidth is also discussed.