Photopolymerization of 2-(dimethylaminoethyl)methacrylate induced by diacetoxyiodobenzene and bis(trifluoroacetoxy) iodobenzene

Summary The title hypervalent iodine compounds are efficient photoinitiators for the polymerization of 2-(dimethylaminoethyl)methacrylate. The polymer is formed in daylight but faster under UV irradiation, with high conversion; its molecular weight M_n is 9×10⁴ daltons. Copolymerization of this monomer with styrene occurs also under similar conditions at a high rate. A free radical mechanism is suggested for these polymerizations.     

Removal of total phenols from olive-mill wastewater using an agricultural by-product, olive pomace

The purpose of this study was to investigate the sorption of total phenols, which are contained in olive-mill wastewater (OMWW), on solid by-products of olive pomace processing mills. Preliminary batch experiments were conducted using three different types of olive pomace, dried olive pomace (OP-1), dried and solvent extracted olive pomace (OP-2) and dried, solvent extracted and incompletely combusted olive pomace (OP-3). According to the results, OP-3 showed high performance for total phenols sorption and stability. For sorbent concentration of 10 g L⁻¹ and sorbate concentration of 50 mg L⁻¹, more than 40% of initial total phenols concentration was removed. Sorption kinetics was well described by the pseudo-second order rate model (R² > 0.99). Total phenols removal efficiency was improved by increasing sorbent concentration and solution's pH or decreasing particle size of the sorbent material. The Langmuir and Freundlich isotherms sufficiently described OP-3 sorption capacity for the concentration range studied (50–500 mg L⁻¹). Fixed bed sorption experiments showed that lower flow rates and smaller particle size of sorbent resulted in longer column exhaustion time and higher initial removal efficiency. Experiments with thermally or chemically regenerated OP-3 showed that sorption capacity deteriorated after regeneration.     

基于单试验脑电图的n-back任务中的脑力负荷分类

近年来,脑力负荷估计已经经历了广泛的研究,因为监测认知负荷的能力能够防止认知超负荷并且改善工作场所安全。脑电图（EEG）信号已经被发现是一种客观和非侵入性的脑力负荷的测量方式。然而,作为实时脑力负荷监测和脑机接口研究的重要一步,基于单试验EEG数据的认知负荷的评估一直是一个重大的挑战。最近,许多高级的特征提取方法和机器学习算法已经被采用于基于EEG的脑力负荷评估中。在本研究中,使用在具有2个难度水平的n back任务的执行期间记录的EEG数据进行了单试验脑力负荷分类,测试了3种类型的特征提取的有效性（谱功率、离散小波变换和公共空间滤波）,并评估了4种分类算法的性能（支持向量机、K 近邻、随机森林和梯度推进分类器）。研究结果表明,公共空间滤波是性能最好的基于单试验的脑力负荷分类的特征提取方法,而且最佳性能可以通过将来自谱功率或离散小波变换的特征与来自公共空间滤波的特征相结合,并采用随机森林分类器来实现。这项研究可能对基于单试验脑电图数据的脑力负荷评估中的特征提取方法以及机器学习算法的选择提供一些有用的指导。     

Growth of conformal single-walled carbon nanotube films from Mo/Fe/Al2O3 deposited by electron beam evaporation

We discuss growth of high-quality carbon nanotube (CNT) films on bare and microstructured silicon substrates by atmospheric pressure thermal chemical vapor deposition (CVD), from a Mo/Fe/Al₂O₃ catalyst film deposited by entirely electron beam evaporation. High-density films having a tangled morphology and a Raman G/D ratio of at least 20 are grown over a temperature range of 750-900 °C. H₂ is necessary for CNT growth from this catalyst in a CH₄ environment, and at 875 °C the highest yield is obtained from a mixture of 10%/90% H₂/CH₄. We demonstrate for the first time that physical deposition of the catalyst film enables growth of uniform and conformal CNT films on a variety of silicon microstructures, including vertical sidewalls fabricated by reactive ion etching and angled surfaces fabricated by anisotropic wet etching. Our results confirm that adding Mo to Fe promotes high-yield SWNT growth in H₂/CH₄; however, Mo/Fe/Al₂O₃ gives poor-quality multi-walled CNTs (MWNTs) in H₂/C₂H₄. An exceptional yield of vertically-aligned MWNTs grows from only Fe/Al₂O₃ in H₂/C₂H₄. These results emphasize the synergy between the catalyst and gas activity in determining the morphology, yield, and quality of CNTs grown by CVD, and enable direct growth of CNT films in micromachined systems for a variety of applications.     

Influence of oestrus on the heat stability and other characteristics of milk from dairy goats

We examined the heat stability, somatic cell count (SCC), pH, fat, protein and lactose content of milk from goats during the oestrous period, in order to investigate evidence of possible oestrus effects on milk physical and chemical properties. Goats free from mammary infections were ranked on average SCC from three tests so that they could be stratified randomly in pairs to synchronized oestrus or left as unsynchronized non-oestrus controls. The synchronisation consisted of insertion of an intravaginal progesterone-releasing device for 17 d, and introduction of the bucks the day of the device removal (D0). The repeated measurements analysis of variance model included the fixed effects of the experimental group (oestrus or control) and day and the corresponding interaction and also the random effect of doe. Reduced milk-heat stability, increased SCC, increased protein content and reduced pH were found in the milk samples of the oestrus group on D1, 2 and 3. The fat and lactose content of the milk was not affected by oestrus. These data indicate that the milk of goats during the mating period has reduced heat stability and, therefore, that dilution into bulk tanks should be recommended to avoid clotting when milk is intended for high thermal treatment.     

Phenylpyrrole-resistance and aflatoxin production in Aspergillus parasiticus Speare

Mutants of Aspergillus parasiticus highly resistant to phenylpyrroles were isolated at a high mutation frequency, after UV-mutagenesis and selection on media containing fludioxonil. Studies on the effect of mutation(s) on the aflatoxin production resulted in the identification of two fludioxonil-resistant phenotypes: aflatoxigenic (FLD(afl)(+)) and non-aflatoxigenic (FLD(afl)(-)) mutant strains. Most of the FLD(afl)(+) mutant strains produced the aflatoxin B(1) at similar or even higher (up to 2.5-fold) concentrations than the wild-type parent strain on yeast extract sucrose medium. Interestingly, in most of these mutant strains the aflatoxigenic ability significantly increased (up to 4-fold) when the mutants were grown on fungicide-amended medium. However, a significant reduction in the aflatoxin production was observed in wheat grains by all FLD(afl)(+) mutant strains. Tests on the response of mutant strains to high osmotic pressure showed that most fludioxonil-resistant mutants were more sensitive to high osmolarity than the wild-type parent strain. Study of other fitness determining parameters showed that the mutation(s) for resistance to phenylpyrroles may or may not affect the mycelial growth rate, sporulation and conidial germination. However, in a number of aflatoxigenic-mutant strains these fitness parameters were unaffected or only slightly affected. Cross resistance studies with fungicides from different chemical groups showed that the mutation(s) for resistance to fludioxonil also highly reduced the sensitivity of mutant strains to the aromatic hydrocarbon and dicarboximide fungicides. No effect of phenylpyrroles resistance mutation(s) on fungitoxicity of triazoles, benzimidazoles, anilinopyrimidines, phenylpyridinamines, strobilurin-type fungicides and to the non site-specific inhibitors chlorothalonil and maneb was observed. The above mentioned data indicate, for the first time, the potential risk of increased aflatoxin contamination of agricultural products by the appearance and predominance of highly aflatoxigenic mutant strains of A. parasiticus resistant to aromatic hydrocarbon, dicarboximide and phenylpyrrole fungicides.     

Design of Secondary Settling Tanks Using a CFD Model

A computational fluid dynamics (CFD) model is presented and applied in the design of the secondary settling tanks of Psyttalia Wastewater Treatment Plant in Athens, Europe’s largest sewage treatment facility. The tanks are of the Gould Type II consisting of the following regions: an inlet-flocculation chamber with an inlet baffle, two zones of settling separated by an intermediate baffle, an outlet region, and a sludge collection region. The number of tanks and their dimensions were determined with an empirical design procedure. Then, theoretical considerations, information from similar existing tanks, and preliminary CFD calculations were combined to determine the dimensions of the main regions and the positions of the baffles. Finally, detailed CFD calculations were performed to examine the performance of the tanks for various design conditions. Computations showed that the flow in the inlet-flocculation region was completely mixed; while in the settling regions a “three-layer” structure with relatively constant layer heights was observed. CFD results were processed to determine parameters of practical interest, including the heights of the sludge blankets and the effluent suspended solids concentrations; these parameters were correlated satisfactorily with the Hazen number, which is used as a scaling parameter in primary settling tanks.     

Square‐root Nyquist FIR filter synthesis for QAM modems

An optimal joint method for digital FIR filters synthesis used in PSK and QAM modulators and demodulators is proposed. It is based on the criterion of demodulation energy loss minimization (bit‐error rate minimization). The analysis of energy loss of demodulation is developed and the objective function for energy loss minimization is obtained. The synthesis is carried out for fixed filter lengths, signal‐to‐noise ratio at the input of demodulator, carrier spacing between adjacent channels, and relative powers between considered and adjacent channels. This method does not require the introduction of any other weighting coefficients or functions for synthesis. Copyright © 2000 John Wiley & Sons, Ltd.     

High throughput cellular biosensor for the ultra-sensitive,ultra-rapid detection of aflatoxin M1

The aim of this study was the development of a rapid novel biosensor system based on the Bioelectric Recognition Assay (BERA) for the detection of aflatoxin M1 (AFM1). Membrane-engineering was achieved by electroinsertion of AFM1-homologous antibodies into the membrane of the cells. The sensor measured the electric response of cultured membrane-engineered fibroblast cells suspended in an alginate gel matrix due to the change of their membrane potential after the interaction of the analyte molecules with the antibodies. The BERA-based sensor was able to detect AFM1 rapidly (3min) at very low concentrations (5 pg/ml = 5 ppt), thus demonstrating a higher sensitivity than most currently available biosensor-based methods. In addition, the assay was quite selective against other aflatoxins, such as aflatoxin B1 and ochratoxin A. Furthermore, the assay system allowed for high throughput AFM1 analysis (160 individual tests/h), due to its multiple cell–electrode interface array. Although further research is required for the optimization of the assay, the elimination of possible matrix effects and its validation by assaying actual food samples, this novel biosensor offers new perspectives for ultra-rapid, ultra-sensitive and low-cost monitoring of mycotoxins in food commodities.     

Using Real Options Theory to Irrigation Dam Investment Analysis: An Application of Binomial Option Pricing Model

This paper demonstrates the utility of the real options approach to irrigation dam investment analysis. The main objective is to show how to calculate the option values of selected options that may be available to managers of irrigation dam investments. The paper provides an empirical application, which compares an irrigation dam investment using the static Net Present Value (NPV) model and the real options approach and shows how it can be adopted to model uncertainty and managerial flexibility in dam management. Four management options are used for the real options approach: an option to delay the investment, an option to enlarge the dam, an option to abandon the dam, and multiple options that evaluated all three options together. All options were evaluated using the binomial option pricing model, where water values are assumed to follow a multiplicative binomial process. The analysis show that although the traditional NPV approach accepted the investment as profitable the option approach provided better results showing that all three options were highly valuable if exercised. When real options are considered, the traditional NPV model for assessing the profitability of a dam investment may fail to provide an adequate decision-making framework because it does not properly value management’s ability to adjust to shocks in the economy, as well as risks and uncertainty.