Continuous‐time stable and unstable system modelling with orthonormal basis functions

In this paper, model sets for linear time‐invariant continuous‐time systems which are spanned by fixed‐pole orthonormal bases are investigated. The obtained model sets are shown to be complete in the Lebesque spaces L_p (1<p<∞) and in C, the space of complex‐valued functions that are continuous on the extended imaginary axis. The L_p norm error bounds for estimating systems in L_p by the partial sums of the Fourier series formed by the orthonormal functions are computed for the case 1<p<∞. Some inequalities on the 𝓁_p means of the Fourier coefficients are also derived. These results have application in estimation and model reduction of stable and unstable continuous‐time linear time‐invariant systems. A numerical example illustrates the use of the basis functions for the approximation of unstable infinite‐dimensional dynamics. Copyright © 2000 John Wiley & Sons, Ltd.     

Characterization of bacteriocins from two Lactococcus lactis subsp. lactis isolates

In this study, bacteriocins from two Lactococcus lactis subsp. lactis isolates from raw milk samples in Turkey designated OC1 and OC2, respectively, were characterized and identified. The activity spectra of the bacteriocins were determined by using different indicator bacteria including Listeria, Bacillus and Staphylococcus spp. Bacteriocins were tested for their sensitivity to different enzymes, heat treatments and pH values. Loss of bacteriocin activities after alpha-amylase treatment suggested that they form aggregates with carbohydrates. Molecular masses of the purified bacteriocins were determined by SDS-PAGE. PCR amplification was carried out with specific primers for the detection of their structural genes. As a result of these studies, the two bacteriocins were characterized as nisin and lacticin 481, respectively. Examination of plasmid contents of the isolates and the results of plasmid curing and conjugation experiments showed that in L. lactis subsp. lactis OC1 strain the 39.7-kb plasmid is responsible for nisin production, lactose fermentation and proteolytic activity, whereas the 16.0-kb plasmid is responsible for lacticin 481 production and lactose fermentation in L. lactis subsp. lactis OC2 strain.     

Coupling of non‐conforming meshes in a component mode synthesis method

A common mesh refinement‐based coupling technique is embedded into a component mode synthesis method, Craig–Bampton. More specifically, a common mesh is generated between the non‐conforming interfaces of the coupled structures, and the compatibility constraints are enforced on that mesh via L2‐minimization. This new integrated method is suitable for structural dynamic analysis problems where the substructures may have non‐conforming curvilinear and/or surface interface meshes. That is, coupled substructures may have different element types such as shell, solid, and/or beam elements. The proposed method is implemented into a commercial finite element software, B2000++, and its demonstration is carried out using an academic and industry oriented test problems. Copyright © 2013 John Wiley & Sons, Ltd.     

Kinetic and thermodynamic investigation of mancozeb degradation in tomato homogenate during thermal processing

BACKGROUND: The kinetic and thermodynamic parameters of mancozeb degradation in tomato homogenates under the conditions prevailing in the manufacture of tomato products (at 60–100 °C for 0–60 min) were investigated. A gas chromatography–mass spectrometry method was used to analyse residual mancozeb in tomato homogenate. Ethylenethiourea (ETU), the main toxic degradation product of mancozeb, was measured by high‐performance liquid chromatography (HPLC)–with photodiode array detector (PDA). RESULTS: The degradation of mancozeb and the formation of ETU in tomato homogenates were adequately described as first‐order kinetics. Dependence of the rate constant followed the Arrhenius relationship. Apparent activation energies, temperature coefficients, half time and time to reduce to 90% of the initial value of mancozeb were calculated as kinetic parameters. The thermodynamic parameters of mancozeb were also described as Δg^d = ? 2.440 and 7.074 kJ mol^?1; Δh^d = ? 32.555 and ? 42.767 kJ mol^?1; Δs^d = ? 0.090 and ? 0.150 kJ mol^?1 K^?1; K_e = 0.414 and 9.797 L g^?1 for 333 and 373 K respectively. CONCLUSION: Current findings may shed light on the reduction of mancozeb residue and its toxic degradation product during thermal processing of tomatoes and may also be valuable in awareness and prevention of potential risks from dietary exposure. Copyright © 2011 Society of Chemical Industry     

Investigation of breakage behavior of different mineralogical and morphological characteristic pumices

The objective of this study is to analyze dry grinding behavior of four different pumices in terms of Bond grindability value, selection and breakage parameters values. For this purpose, firstly, Bond grindability test were made for four pumices. Then, eight different mono-size fractions for each of pumices were carried out between 1.7 and 0.106 mm formed by a \({\surd 2}\) sieve series, and ground batch wise in a laboratory ball mill for determination of breakage parameters. Finally, S _i and B _i,j equations were determined from the size distributions at different grinding times, and the model parameters (S _i , a _T , α, γ, β and \({\phi_{j}}\)) were compared for four different pumice samples.     

Antioxidant activities of organic grape, pomace, juice, must, wine and their correlation with phenolic content

The highest values of antioxidant activity (AOA), inhibition of low‐density lipoproteins (LDL‐diene, LDL‐MDA) and total phenols were determined in pomace (82.30 and 82.60%), grapes (68.91%) and must [2750 mg L^?1 gallic acid equivalents (GAE)], respectively. For all parameters (AOA, iLDL‐diene, iLDL‐MDA, total phenols) the highest values were obtained in Cabernet Sauvignon and Merlot grape varieties. Positive correlations were determined between AOA and iLDL‐diene (r = 0.809); AOA and total phenols (r = 0.528); total phenols and iLDL‐diene (r = 0.451) with significance of P < 0.005. The results of principal component analysis demonstrated that the location of iLDL‐diene and AOA is the same for pomace, must and red wines. The total phenols are found in the same place in red wines, red grapes, pomace and must. The results emphasize the importance of must, pomace and red wine for inhibiting LDL‐oxidation.     

Relation between fabric porosity and vacuum extraction efficiency: Energy issues

Vacuum extraction is a technique that removes the unbound water from the fabrics by the help of air flow through the fabrics at high velocities. Air flow through textile fabrics is mainly affected by the fabric structure such as tightness, porosity and air permeability. This paper outlines the effects of the fabric structure on the vacuum drying efficiency. Thirty woven fabrics with different porosities were dried by vacuum extraction method, and it was found that the lower the porosity or the lower the air permeability, the higher the water removal effects and energy requirement.