Prediction of potential mushroom yield by visible and near-infrared spectroscopy using fresh phase II compost

Potential mushroom (Agaricus bisporus) yield of phase II compost is determined by interactions of key quality parameters including dry matter, nitrogen dry matter, ammonia, pH, conductivity, thermophilic microorganisms, C : N ratio, fiber fractions, ash, and certain minerals. This study was aimed at generating robust visible and near-infrared (Vis-NIR) calibrations for predicting potential yield, using spectra from fresh phase II compost. Four compost comparative trials were carried out during the winter and summer months of 2001-2003, under controlled experimental conditions employing six commercially prepared composts, with eight replicate (8 bag) plots per treatment (48 x 8 = 384). The substrates were prepared by windrow or bunker phase I, followed by phase II production. The fresh samples were scanned for Vis-NIR (400-2498 nm) spectra, averaged, transformed, and regressed against the recorded yield by employing a modified partial least squares algorithm. The best calibration model generated from the database explained 84% of yield variation within the data set with a standard error of calibration of 13.75 kg/tonne of fresh compost. The model was successfully tested for robustness with yield results obtained from a validation trial, carried out under similar experimental conditions in early 2004, and the standard error of prediction was 18.21 kg/tonne, which was slightly higher than the mean experimental error (17.94 kg/tonne) of the trial. The accuracy of the model is acceptable for estimating potential yield by classifying phase II substrate as poor (180-220 kg), medium (220-260 kg), and high (260-300 kg) yielding compost. The yield prediction model is being transferred to a new instrument based at Loughgall for routine evaluation of commercial phase II samples.     

Direct contact ultrasound assisted freezing of mushroom (Agaricus bisporus): Growth and size distribution of ice crystals

To reduce the size of ice crystals in mushroom (Agaricus bisporus) contact ultrasound (300 W, 20 kHz) was applied during freezing and frozen storage. Stereomicroscopy was used to observe the ice crystal morphology, and DSC and NMR spectroscopy were performed to evaluate the water states in the samples. Results indicated that ultrasound irradiation initiated the nucleation of ice and reduced the mean size of ice crystals during freezing and frozen storage, and therefore improved the frozen product quality compared to the control samples. Most of the ice crystals in the ultrasound assisted frozen (UAF) samples were in the size range of 0–80 microns while that for the control samples were in the size range of 50–180 microns. SEM photos also proved that due to the application of ultrasound, the sizes of the ice crystals was reduced. This micro-scale information on the documentation of ice crystals will assist in understanding the ice crystal growth phenomena in an ultrasound assisted freezing process.     

Biosorption of Cr (VI) from aqueous solutions by biomass of Agaricus bisporus

In this study, biosorption of Cr (VI) ion was investigated by using biomass of Agaricus bisporus (a species of mushroom) in a temperature and shaking speed controlled shaker. The effect of shaking speed, biomass concentration, initial metal ion concentration and initial pH on biosorption yield was determined and the fitness of biosorption data for Freundlich and Langmuir adsorption models was investigated. Optimum biosorption conditions were found to be pH 1, C0=50 mg/l, m=10 g/l, shaking speed=150 rpm, T=20 degrees C Cr (VI), respectively. It was found that biosorption of Cr (VI) ions onto biomass of A. bisporus was better suitable to Freundlich adsorption model than Langmuir adsorption model. The correlation coefficients for the second-order kinetic model obtained were found to be 0.999 for all concentrations. These indicate that the biosorption system studied belongs to the second-order kinetic model.     

Facile one-pot synthesis of near-infrared luminescent gold nanoparticles for sensing copper (II)

Novel near-infrared luminescent gold nanoparticles (NIRL-AuNPs) were synthesized by a simple, rapid and one-pot procedure. The driving force for the formation of these NIRL-AuNPs was attributed to the heat-assisted reduction of a gold(I)-thiol complex. These gold nanoparticles were characterized by TEM, DLS, FT-IR and XPS. Luminescence studies indicated that these NIRL-AuNPs exhibited strong emission with peak maximum at 810 nm, microsecond-range photoluminescence lifetime, large Stokes shifts (>400 nm) and stabilities towards photobleaching and chemical oxidation. The sensing application for Cu(2+) ions of these NIRL-AuNPs was demonstrated. These as-synthesized gold nanoparticles will provide a new NIRL nanomaterial for in vitro and in vivo applications.     

Preparation and photovoltaic properties of near-infrared absorbing manganese(II) phthalocyanine polymer films

2,9,16,23-Tetra-amino manganese(II) phthalocyanine (TAMnPc) was synthesized and characterized by mass spectrometry, infrared (IR) and electronic absorption spectrum. TAMnPc polymer films were prepared by spin-coating. The electronic absorption spectra of TAMnPc and its polymer films both exhibit an intense Q-band beyond 800 nm in the near-infrared region. The current-voltage characteristics of TAMnPc polymer films in the dark and under infrared irradiation were recorded. The electrical conductivity of films under infrared irradiation was obviously higher than that in the dark, indicating that TAMnPc has good photovoltaic response.     

Visible and near-infrared spectroscopy as a technique for screening the inorganic arsenic content in the red crayfish (procambarus clarkii Girard)

The potential of near-infrared spectroscopy (NIRS) for screening the inorganic arsenic (i-As) content in the red crayfish (Procambarus clarkii Girard 1852) was assessed. Sixty-two samples belonging to this species were freeze-dried and scanned by NIRS. The i-As contents of the samples were obtained by acid digestion-solvent extraction followed by hydride generation atomic absorption spectrometry and were regressed against different spectral transformations by modified partial least-squares (MPLS) regression. Second derivative transformation equations of the raw optical data, previously standardized by applying standard normal variate and de-trending algorithms, resulted in a coefficient of determination in the cross-validation (1-VR) of 0.84, indicative of equations of good quantitative information. The standard error of cross-validation to standard deviation ratio, shown by the second derivative equation, was similar to those obtained for other trace metal calibrations reported in NIRS reflectance. Spectral information related to chromophores and lipids of the red crayfish tissues, and also the plant matter contained in their stomachs, were the main organic components used by MPLS for modeling the selected prediction equation. This pioneering use of NIRS to predict the i-As content in red crayfish represents an important savings in time and cost of analysis.     

Enrichment/separation of cadmium(II) and lead(II) in environmental samples by solid phase extraction

A preconcentration/separation procedure is presented for the solid phase extraction of trace cadmium and lead ions as their 1-(2-pyridylazo) 2-naphthol (PAN) chelates in environmental samples on Chromosorb-106 resin, prior to cadmium and lead determinations by atomic absorption spectrometry. The preconcentration procedure was optimized by using model solutions containing cadmium and lead ions. The influences of pH of the model solutions, amounts of PAN, eluent type and volume etc. were investigated. Also the effects of the matrix constituents of the samples were also examined. Separation of cadmium and lead from real samples was achieved quantitatively. The procedure presented was checked with the analysis of microwave-digested standard reference materials (IAEA-336 Lichen and SRM 1515 Apple leaves). The preconcentration procedure was applied for the lead and cadmium contents of the natural water samples, some salts with satisfactory results (recoveries >95%, relative standard deviations <8%).     

Chitosan selectivity for removing cadmium (II), copper (II), and lead (II) from aqueous phase: pH and organic matter effect

The aim of this study was to investigate the selectivity of chitosan for cadmium, copper and lead in the presence and absence of natural organic matter (NOM) in different pH solutions. Adsorption isotherms of one and three adsorbates at initial concentration of 5-100mg/L were carried out in batch reactors at pH 4, 5, or 7 and 25 degrees C in reactive and clarified water. The chitosan employed had a MW of 107.8 x 10(3)g/mol and degree of acetylation (DA) of 33.7%. The chitosan adsorption capacity at pH 4 in reactive water was 0.036, 0.016, 0.010mmol/g for Pb(2+), Cd(2+), and Cu(2+), respectively, and it decreased for Pb(2+) and Cd(2+) in clarified water. Conversely, experiments carried out in clarified water showed that the cadmium adsorption capacity of chitosan was enhanced about three times by the presence of NOM at pH 7: an adsorption mechanism was proposed. Furthermore, it was found that the biosorbent selectivity, in both reactive and clarified water at pH 4, was as follows Cu(2+)>Cd(2+)>Pb(2+). Finally, the preliminary desorption experiments of Cd(2+) conducted at pH 2 and 3 reported 68 and 44.8% of metal desorbed, which indicated that the adsorption mechanism occurred by electrostatic interactions and covalent bonds.     

Investigation of Cs(I) and Sr(II) removal using nanoporous bentonite

ABSTRACT

Bentonites are types of clays made up the dominant constituent of montmorillonite. Four types of nano-porous and nano-structured commercial bentonite clays were studied in detail for their physicochemical and mineralogical properties vs. Cs and Sr adsorption. The instrumental analyses to study samples were X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET) surface area measurements, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetry (TG). The XRF and peaks of XRD patterns at 2θ?=?8, 19.9, 35, 55, and 62 clearly indicated that the main component of the bentonite samples was montmorillonite. The BET analysis showed that B1 has the highest specific surface area among the other samples which its single and multiple point BET surface area were equal to 84.85 and 85.94?m²?g^?1, respectively. These values represents the amount of montmorillonite and adsorption capacity of samples. The physicochemical, structural and morphological characteristics of different samples were investigated through instrumental analysis. The results of separation processes of Cs(I) and Sr(II) showed 59.75 and 45.5% adsorption capacities for B3 and B2 which were the highest values among the others. The results lead to the conclusion that samples B3 had a good adsorption capacity to remove Cs(I) and Sr(II).     

Synthesis and properties of a copper(I) cobalt(II) double sulfite

The Pourbaix diagrams of the Cu–H₂SO₄–H₂O and Co–H₂SO₄–H₂O systems have been refined and the stability regions of sulfite phases in the diagrams have been identified. Phase diagrams of copper(I) copper( II) and copper(I) cobalt(II) double sulfites have been mapped out. The double sulfites Cu₂SO₃ · СuSO₃ and Cu₂SO₃ · СoSO₃ have been isolated from an aqueous solution saturated with sulfur dioxide. We have obtained electron paramagnetic resonance spectra of the double sulfite Cu₂SO₃ · СoSO₃ and characterized it by X-ray diffraction, IR spectroscopy, particle size analysis, and thermogravimetry. A foundation has been laid for the thermodynamic prediction of the synthesis of the Cu₂SO₃ · MSO₃ (M = Cu, Co) double sulfites.     

Preparation and XPS studies of macromolecule mixed-valent Cu(I, II) and Fe(II, III) complexes

A new macromolecule ligand and its mixed-valent Cu(I, II) and Fe(II, III) complexes have been prepared by using ethylenediamine as core and maleic anhydride as branched units and characterized by UV-vis, FT-IR, thermal analysis and X-ray photoelectron spectroscopy (XPS). The data obtained from these studies suggested that the coordinate bonds of N-->M, Cl-->M, Ph-OH-->M and H(2)O-->M have been formed and possible binding models are proposed for these complexes. The thermal analysis (TG-DTG) reveals that these complexes possess thermal stable property below 800 degrees C.     

Use of artificial neural networks in near-infrared reflectance spectroscopy calibrations for predicting the inclusion percentages of wheat and sunflower meal in compound feedingstuffs

The use of near-infrared reflectance spectroscopy (NIRS) calibrations to predict the ingredient composition in compound feeds (i.e., inclusion percentage of each ingredient) is a complex task, regarding both the nature of the parameters to be predicted, since they are not well-defined chemical entities, and the heterogeneousness of the matrices/formulas in which each ingredient participates. The present paper evaluates the use of nonlinear regression methods, such as artificial neural networks (ANN), for developing NIRS calibrations to predict these parameters. Two of the most representative ingredients in the Spanish compound feed formulations (wheat and sunflower meal) were selected for evaluating ANN possibilities, using a large spectral library comprising a total of 7523 commercial compound feed samples; 7423 were used as training set and 100 as validation set. Three general models of networks were studied: multilayer perceptron with back-propagation training (BP), multilayer perceptron with Levenberg-Maquartd training (LM), and radial basis function nets (RBF); moreover, in accordance with a factorial design, more complex architectures were evaluated gradually, changing the number of hidden layers and hidden neurons, for the determination of the optimal network topology. For both ingredients, the best results were obtained using ANN with BP training, showing prediction error values (SEP) of 2.72% and 0.66% for wheat and sunflower meal, respectively. These SEP values showed a significant improvement (19%-49% for sunflower meal and wheat, respectively) in comparison with those obtained using calibrations developed with linear methods.     

Cystine-modified biomass for Cd(II) and Pb(II) biosorption

The surface of dried biomass of baker's yeast was modified by crosslinking cystine with glutaraldehyde. X-ray photoelectron spectroscopy and microscope were used to characterize the modified biomass. The adsorption capacity of the modified biomass for Cd(2+) and Pb(2+) showed an increase compared with the pristine biomass due to the presence of cystine on the biomass surface. Experimental data showed that the adsorption of the two metal ions increased with time until equilibrium was achieved. The adsorption capacities for Cd(2+) and Pb(2+) were 11.63 and 45.87 mg g(-1), respectively, which were determined from the Langmuir isotherm. The loaded biosorbent was regenerated using HCl solution and could be used repeatedly at six times with little loss of uptake capacity. FTIR spectroscopy revealed that carboxyl, amide, and hydroxyl groups on the biomass surface were involved in the adsorption of Cd(2+) and Pb(2+).     

信号相位匹配算法的语音降噪及性能评估

针对信号相位匹配算法能够在信号估计中准确提取信号频率成分的优点,将三子阵信号相位匹配算法应用于提取强背景噪声中的语音信号,同时提出了基于平均段内功率谱密度距离的语音质量客观评价方法,将主观平均意见分（MOS）、信噪比和平均分段功率谱密度距离作为指标,分别对三子阵信号相位匹配法、谱减法和最小均方误差估计法这三种算法的处理结果进行客观评价并对算法的降噪性能做了对比。仿真结果表明,三子阵相位匹配算法能够达到强背景噪声环境下语音降噪的目的;同时基于平均段内功率谱密度距离的语音质量客观评价结果与主观评价结果相符合,该评价方法具有一定的可行性。     

Removal of Zn(II), Cu(II), Ni(II), Ag(I) and Cr(VI) present in aqueous solutions by aluminium electrocoagulation

The performance of an electrocoagulation system with aluminium electrodes for removing heavy metal ions (Zn2+, Cu2+, Ni2+, Ag+, Cr2O7(2-)) on laboratory scale was studied systematically. Several parameters - such as initial metal concentration, numbers of metals present, charge loading and current density - and their influence on the electrocoagulation process were investigated. Initial concentrations from 50 to 5000 mg L(-1) Zn, Cu, Ni and Ag did not influence the removal rates, whereas higher initial concentrations caused higher removal rates of Cr. Increasing the current density accelerated the electrocoagulation process but made it less efficient. Zn, Cu and Ni showed similar removal rates indicating a uniform electrochemical behavior. The study gave indications on the removal mechanisms of the investigated metals. Zn, Cu, Ni and Ag ions are hydrolyzed and co-precipitated as hydroxides. Cr(VI) was proposed to be reduced first to Cr(III) at the cathode before precipitating as hydroxide.     

Comparative study of adsorption properties of Turkish fly ashes. I. The case of nickel(II), copper(II) and zinc(II)

The objective of this study was to compare two different Turkish fly ashes (Afsin-Elbistan and Seyitomer) for their ability to remove nickel [Ni(II)], copper [Cu(II)] and zinc [Zn(II)] from an aqueous solution. The effect of contact time, pH, initial metal concentration and fly ash origin on the adsorption process at 20+/-2 degrees C were studied. Batch kinetic studies showed that an equilibrium time of 2h was required for the adsorption of Ni(II), Cu(II) and Zn(II) on both the fly ashes. The maximum metal removal was found to be dependent on solution pH (7.0-8.0 for Ni(II), 5.0-6.0 for Cu(II) and 6.0-7.0 for Zn(II)) for each type of fly ash. With an increase in the concentrations of these metals, the adsorption of Ni(II) and Zn(II) increased while the Cu(II) adsorption decreased on both the fly ashes. Adsorption densities for the metal ions were Zn(II)>Cu(II)>Ni(II) for both the fly ashes. The effectiveness of fly ash as an adsorbent improved with increasing calcium (CaO) content. Adsorption data in the range of pH values (3.0-8.0) using Ni(II) and Cu(II) concentrations of 25+/-2mg/l and Zn(II) concentration of 30+/-2mg/l in solution were correlated using the linear forms of the Langmuir and Freundlich equations. The adsorption data were better fitted to the Langmuir isotherm since the correlation coefficients for the Langmuir isotherm were higher than that for the Freundlich isotherm. The fly ash with high calcium content (Afsin-Elbistan) was found to be a metal adsorbent as effective as activated carbon and, therefore, there are good prospects for the adsorptions of these metals on fly ash with high calcium content in practical applications in Turkey.     

Complexation between Copper(II) and Glycine in Aqueous Acid Solutions by Window Factor Analysis of Visible Spectra

Window factor analysis (WFA), a self-modeling chemometric technique, is used to extract the concentration profiles of the complexes formed between Cu(II) and glycine (GlyH) during pH titration in the acid region. The visible absorption spectra of aqueous acid solutions, each containing 0.0020 M Cu(II) and 0.500 M glycine, are recorded at various pHs, ranging from 1 to 7. The concentration profiles and the spectral absorptivities of four copper species, Cu(2+), CuGlyH(2+), CuGly(+), and CuGly(2), are obtained. The spectral absorptivities of the complexes are in good agreement with those reported in the literature. The concentration profiles are used to determine the stepwise equilibrium constants of the three complexes. The reason why rank annihilation evolving factor analysis (RAEFA), a precursor technique, was not successful in resolving the spectral data is explained.     

Suitability of mixed-mode I/II assessment methods for implementation into the SINTAP procedure

Several engineering methods are available for the assessment of structures containing defects. They belong essentially to two categories: FAD methods and CDF methods. The recent SINTAP procedure unifies both FAD and CDF routes for the assessment of mode I loaded defects. In this paper, fracture assessment methods containing guidelines for mixed-mode I/II loading conditions are examined and compared with the aim to discuss their suitability for implementation into the SINTAP procedure.     

Some aspects of reactivity of copper(I) sulphide with copper(II) sulphate

The reaction of Cu₂S with CuSO₄ in SO₂ at T>710 K proceeds forming liquid intermediates, Cu₂SO₂ and Cu₂SO₄, which decompose to solid products. Only SO₂ is a gaseous product out of all the intermediate reactions. The rate of each step is dependent, in a complex way, upon the liquid content of the reacting mixture. The relations of major importance between the rates of individual intermediate reactions, the liquid content of the reacting mixture, the composition of the liquid and the initial composition of the substrates mixtures have been discussed.