Bioactivity and mineral contents of wild-grown edible Morchella conica in the Mediterranean Region

In this study, antiradical and antimicrobial activity, total phenolic, mineral and heavy metal content of Morchella conica Pers. were determined in the methanolic extracts of dried M. conica collected from wild-grown edible mushroom in the Mediterranean region from Turkey. Free radical scavenging activity was determined to be 43.72 ± 0.13% DPPH decoloration, however, total phenolic activity to be 20.64 ± 0.33 mg GAE/g dry ext. sample. The antimicrobial activity of the extracts was tested against fourteen microorganism including 12 bacteria and 2 yeasts. It was determined that the mushroom extracts had no effect against the bacteria and yeasts. Antimicrobial effect was determined only against Staphylococcus aureus ATCC 29213. M. conica was determined to contain some heavy metals such as arsenic (As), mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr) and nickel (Ni) in the concentrations of 0.25, 0.06, 0.20, 1.20, 0.70 and 1.10 (mg/kg dw), respectively. Potassium (K), phosphorus (P) and magnesium (Mg) contents were determined to be 20,400, 13,250, and 1,600 (mg/kg dw), respectively, being higher than those of the other minerals in the M. conica extracts.     

Detection and Advancement Monitoring of Distributed Pitting Failure in Gears

Conventional methods (i.e. time, frequency and cepstrum) can routinely be used to reveal fault-indicating information in the vibration signal. In recent years, Wavelet analysis, which can lead to the clear identification of the nature of faults, are widely used to describe machine condition. Capability of this method in the detection of any abnormality can be further improved when its low-order frequency moments are considered. This paper presents the use of vibration-based techniques in the early detection and advancement monitoring of distributed pitting fault. The pits were seeded on all of the gear tooth surfaces in differing degrees of severity, and intended to replicate the pitting damage due to misalignment. With each fault severity, the helical gears were tested and the resulting vibration data were recorded. The application of employed vibration-based methods (i.e. time, frequency, cepstrum, and wavelet transform: scalogram and its mean frequency variation) to each set of experimental data are presented. It has been found that presence of pitting fault cannot be clearly revealed by the conventional unless fault severity is significantly large. In contrast, the scalogram and especially its mean frequency variation provide early indications of presence and progression of pitting faults in gears even when the fault severity is considerably smaller.     

Noise emission of universal motor drives

Flexural and transverse vibrations from static and dynamic components of tensioning forces in belt driven systems can cause changes in the noise radiation from the universal motors of clothes washers. This study describes a successful effort to analyze the effect of tensioning forces on noise emission of the drive system. The data show that principal parameters of tensile forces can cause parametric excitation of transverse and flexural vibrations resulting in a considerable change in the noise emissions of universal motors. Using the correlations for validation and recovery of distorted vibration and acoustic data, optimum tensioning forces, hence quieter operation of the universal motor, can be achieved     

Classification of transcranial Doppler signals using their chaotic invariant measures

In this study, chaos analysis was performed on the transcranial Doppler (TCD) signals recorded from the temporal region of the brain of 82 patients as well as of 24 healthy people. Two chaotic invariant measures, i.e. the maximum Lyapunov exponent and the correlation dimension, were calculated for the TCD signals after applying nonlinearity and stationarity tests to them. The sonograms obtained via Burg autoregressive (AR) method demonstrated that the chaotic invariant measures represented the unpredictability and complexity levels of the TCD signals. According to the multiple linear regression analysis, the chaotic invariant measures were found to be highly significant for the regression equation which fitted to the data. This result suggested that the chaotic invariant measures could be used for automatically differentiating various cerebrovascular conditions via an appropriate classifier. For comparison purposes, we investigated several different classification algorithms. The k-nearest neighbour algorithm outperformed all the other classifiers with a classification accuracy of 94.44% on the test data. We used the receiver operating characteristic (ROC) curves in order to assess the performance of the classifiers. The results suggested that the classification systems which use the chaotic invariant measures as input have potential in detecting the blood flow velocity changes due to various brain diseases.     

Heuristic methods for wind energy conversion system positioning

This paper considers the problem of determining the locations of wind generators in a wind farm consisting of many generators. The objective is to find a generator placement that maximizes profit, which is the product of the cost efficiency of the generators and the total power output from the wind farm. Generator placement is significant because if generator A is located close to generator B and is located downwind of generator B then the power output of generator A is reduced by an amount that varies with the distance between the generators. The problem can be formulated using mathematical programming but to solve the problem one cannot employ traditional optimization methods. Therefore, a greedy improvement heuristic methodology is developed and described in detail. The effectiveness of the proposed heuristic is demonstrated on a suite of test problems. These results indicate that the proposed method represents an effective solution strategy for this problem.     

The feasibility of a centralized biogas plant treating the manure produced by an organized animal farmers union in Turkey

The aim of this study is to evaluate the feasibility and the energy recovery potential of mesophilic (30-35 °C) anaerobic digestion of animal wastes (manure) at a centralized biogas plant (CBP) for 35,000 cattle. The proposed CBP is composed of an equalization tank followed by pasteurization and 3+[1/2] modules; i.e. each module consists of four completely mixed anaerobic reactors with a capacity of treating the manure from 10,000 cattle. The effect of maize silage loading, as the co-substrate, both on biomethane production and feasibility of the system was also evaluated. Besides, the transport fuel substitutes of the produced biomethane with or without co-substrate were also investigated. Results of the proposed CBP indicated that biomethane production increased ca. 1.65 fold with co-substrate addition and pay-back periods for one module treating 10,000 cattle manure are calculated to be ca. 11 and 7.0 yr without and with silage addition, respectively. Besides, considering the potential revenue when replacing transport fuels, about 74 heavy goods vehicles or 1,560 cars may be powered per year by the biogas produced from the proposed CBP where the co-digestion of manure and maize silage is applied.     

Thermo-physical processes in cerium nitrate precursor droplets injected into high temperature plasma

The thermo-physical phenomena inside a droplet during its flight in a thermal plasma flow have been modeled for SPPS processes using cerium nitrate precursor. The different thermo-physical stages encountered during droplets' flight include aerodynamic breakup, rapid vaporization of solvent and precipitation, internal pressurization with shell rupture and rapid heating of volumetrically precipitated ceramic particle. The effects of injection type (transverse versus axial) and initial size of the droplets on the final deposit layer microstructure have been studied. The results show that for axial injection the heating process is very rapid and smaller droplets (< 10 µm) undergo full pyrolization resulting in favorable microstructure. On the contrary for transverse injection the heating process is slower as the droplets are injected in the outer shear layer of plasma where the temperature and velocity both are much lower than the core of the plasma. The larger droplets (> 20 µm) have better chances of getting pyrolized in the case of transverse injection. It was also observed that the angle of trajectory of the droplets after primary (first) precipitation does not have much effect on the final microstructure.     

Performance analysis of asynchronous direct sequence code division multiple access for general chip waveforms over multi-path Rayleigh fading channels

The probability of error (P_e) performance of direct sequence code division multiple access (DS-CDMA) signals over multi-path Rayleigh fading channels for general (i.e. time-limited and band-limited) chip waveforms is investigated. The numerical values of the P_e are calculated for DS-CDMA signals using conventional time-limited chip waveforms and a band-limited square root raised cosine (SRRC) chip waveform. Analytical calculations are verified by conducting simulations. In terms of the P_e, the SRRC-based system results in a worse performance value than those of the time-limited chip waveform-based systems. However, due to its compact bandwidth, the SRRC-based system provides the highest capacity defined as the number of users per Hertz for a same P_e performance level.     

Removal of nitrogen from steel using novel fluxes

The solubility of nitrogen and the nitride capacity of CaO-Al₂O₃-TiO₂ and CaO-BaO-Al₂O₃-TiO₂ slags were measured at 1873 K using a gas-slag-metal equilibration technique with carbon-saturated iron and gas mixtures of CO and N₂. The nitride capacity increased with increasing the TiO₂ and BaO content and is significantly higher than the nitride capacity for normal ladle slags. The activity coefficient of TiO₂ in CaO-Al₂O₃-TiO₂ and CaO-BaO-Al₂O₂-TiO₂ systems were measured. This is necessary to know in order to estimate the possible pickup of titanium in the metal when an aluminum-killed steel is treated with these slags. Also, the activity coefficient of Ti in carbon-saturated iron was measured. The kinetics of the nitrogen reaction between slag and metal is influenced by the oxygen potential in the metal and is primarily controlled by liquid-phase mass transfer of nitrogen in the metal. Formerly with the Department of Metallurgical Engineering and Materials Science, Carnegie Mellon University