Experimental investigation and prediction of bonding strength of Oriental beech (Fagus orientalis Lipsky) bonded with polyvinyl acetate adhesive

Adhesive bond strength of solid wood plays a key role in the efficient use of wood in a large number of engineering applications. In this study, the effects of amount of adhesive, pressing pressure, and pressing time on bonding strength of beech wood bonded with polyvinyl acetate adhesive were investigated and predicted by developing an artificial neural network (ANN) model. Experimental results have showed that bonding strength of wood samples increased generally by increasing amount of adhesive, pressing pressure, and pressing time. Besides, ANN analysis has yielded highly satisfactory results. The designed neural network model allows predicting the bonding strength of wood samples with mean absolute percentage error of 2.454% and correlation coefficient of 97.8% for testing phase. It is clear from the results that the model has a good learning and generalization ability. This model therefore can be used to predict bonding strength of beech samples bonded with polyvinyl acetate adhesive under given conditions. Consequently, this study provides beneficial insights for practitioners in terms of the safe and efficient use of wood as an engineering material in applications related to the strength of the bond between wood and adhesive.     

Spray-Dried Mesoporous Hydroxyapatite–Chitosan Biocomposites

In this study, hydroxyapatite–chitosan composites with weight ratio of 1:0.1 were produced by spray-drying technique using two different inlet temperature. Besides, the effect of weight change of hydroxyapatite on composites was investigated on composites which were spray-dried in the selected temperature. Synthesized hydroxyapatite–chitosan samples were characterized using Fourier transform infrared microscopy, scanning electron microscopy, X-ray fluorescence spectroscopy, Brunauer–Emmet–Teller method, and X-ray diffraction. Particle size measurements were also performed in this content. Simulated body fluid studies were conducted on selected samples. According to results, hydroxyapatite–chitosan sample was successfully synthesized. Spray-dried mesoporous microspheres with high surface areas could be suitable for biomedical usage.     

The behavior of organic components in copper recovery from electroless plating bath effluents using 3D electrode systems

An electrochemical method was applied for the recovery of copper both from the spent solutions and from the rinse waters of electroless copper plating baths, containing copper sulfate, formaldehyde, quadrol, and NaOH. Experiments were conducted in a rotating packed cell (Rollschichtzelle) to investigate the effects of current density, electrolyte composition, temperature, and pH on the copper recovery. All the copper (final CCu=0.1 ppm) was recovered from the waste and rinse waters of chemical copper plating plants with 70% current efficiency by the electrochemical treatment in a rotating packed cell at 130 A/m2 current density, room temperature, with 5mm diameter cathode granules, with the presence of formaldehyde, and with a specific energy consumption of 3.2-3.5 kW h/kg Cu. On the other hand, final copper concentrations of 5 ppm were reached with 62% current efficiency and 5.5-5.8 kW h/kg Cu specific energy consumption, with electrolytes containing no formaldehyde.     

Effects of different drying treatments on fungal population and ochratoxin A occurrence in sultana type grapes

This study aimed to determine the changes in mould and ochratoxin A (OTA) occurrence in sultanas under three different conventional drying conditions. Five different vineyards were chosen, and the three different treatments were applied to these grapes while drying. At the end of the drying process, total mould and black aspergilli (BA) populations in the samples varied from 2.45 to 5.61 log colony-forming units (CFU) g^–1 and from 0 to 4.92 log CFU g^–1, respectively. Significant increases (p < 0.05) occurred in mould loads depending on the extending drying period. However, independent of vineyard location, all the samples treated with cold dipping solution showed the lowest fungal loads. These results indicate that dipping solution treatment was the most effective drying method to minimise fungal infection of grapes. The expected results could not be achieved by drying grapes artificially contaminated with ochratoxigenic Aspergillus carbonarius spores. Seventy-one of 96 isolates (73.95%) obtained during drying were Aspergillus spp., and the remaining (n = 25, 26.05%) belonged to other genera, such as Penicillium, Trichoderma and Cladosporium. Grape juice-based agar medium was used to determine the realistic OTA production capacities of the isolated mould strains. The highest OTA production capacities were 809.70 ± 9.19, 87.58 ± 16.89 and 45.44 ± 18.78 ng g^–1 in 50% grape juice agar (GJ50), all five of which were from A. niger isolates. OTA was not present in any sample during the drying period; however, OTA was detected in two samples at 0.32 ± 0.15 and 0.52 ± 0.36 µg kg^–1 after the end of the drying process. The limit of detection (LOD) and limit of quantitation (LOQ) of the method used for detecting OTA in samples were 0.1 and 0.3 µg kg^–1, respectively.     

Biogas Production and Utilization Potential of Wastewater Treatment Sludge

Abstract

Municipal wastewater treatment plants generate sludge as a by-product of the physical, chemical and biological processes used in the treatment of wastewater. Generally, this sludge must be subject to some form of treatment in order to alter its character. By using anaerobic digestion in the treatment of wastewater sludge, methane gas is produced and it is known as biogas. It must not only be seen as a renewable energy source, but even more as one of the promising solutions to the large environmental problem concerning waste handling, water pollution, CO₂ emission, etc. This article presents the biogas generation from wastewater treatment sludge, its energy potential and also its usage in some treatment plants operated in Turkey. Although the estimation of recoverable energy from municipal wastes and sewage is difficult to assess, total recoverable bioenergy potential is estimated as being 16,920 ktoe. Of this, 1,300 ktoe of municipal wastes and sewage whereas biogas production potential is 1.5–2 Mtoe in Turkey.     

Effects of shooting period, times within shooting periods and processing systems on the extract, caffeine and crude fiber contents of black tea

The extract, caffeine and crude fibre contents of black tea, from different shooting periods, different times within each shooting period and processed by five different commercial rolling methods, were examined. The extract and crude fibre contents of black tea were significantly (P<0.01) affected by all these factors and their interactions. The caffeine content of black tea was affected by the shooting period and times within the shooting period. It was determined that processing methods did not have a significant (P<0.05) effect on the caffeine content. The amount of extract and caffeine decreased from the first shooting period to the third, and also from the beginning of each shooting period to the end. However, the crude fibre content of the black tea increased, especially from the beginning of each shooting period to the end of each shooting period.

---

Die Wirkungen der Sproßperiode, die Zeit innerhalb der Sproßperioden und der Verarbeitungssysteme auf den Tee-Extrakt, den Coffein-und den Rohfasergehalt von schwarzem Tee

Zusammenfassung Die in den verschiedenen Sproßperioden und in unterschiedlichen Zeiten innerhalb der einzelnen Sproßperiode erhaltenen frischen Teeproben wurden mit den fünf verschiedenen kommerziellen Walzmethoden zu schwarzem Tee verarbeitet. Bei diesen Teeproben wurden der Extrakt-, Coffein- und Rohfasergehalt bestimmt. Der Extrakt- und der Rohfasergehalt von schwarzem Tee werden durch alle Faktoren und deren Wechselwirkungen signifikant (P<0.01) beeinflußt. Die Sproßperiode und die Zeit innerhalb der Sproßperioden wirkten auf den Coffeingehalt von schwarzem Tee ein. Es wurde festgestellt, daß die Verarbeitungsmethode keine signifikante Wirkung (P<0.05) auf den Coffeingehalt hatte. Der Extrakt- und der Coffeingehalt nahmen von der ersten Sproßperiode bis zur dritten, und auch vom Anfang der einzelnen Sproßperiode bis zum Ende ab. Der Rohfasergehalt von schwarzem Tee nahm dagegen insbesonders vom Anfang der einzelnen Sproßperiode bis zum Ende der Sproßperiode zu.

     

OWA-based linkage method in hierarchical clustering: Application on phylogenetic trees

The linkage methods are mostly used in hierarchical clustering. In this paper, we integrate Ordered Weighted Averaging (OWA) operator with hierarchical clustering in order to find distances between clusters. In case of using OWA operator in order to find distance between clusters, OWA acts as a generalized case of single linkage, complete linkage, and average linkage methods. In order to illustrate the proposed method, we handle a phylogenetic tree constructed by hierarchical clustering of protein sequences. To illustrate the efficiency of the method, we use 2D-data set. We obtain graphs demonstrating the relationships of the clusters and we calculate the root-mean-square standard deviation (RMSSDT) and R-squared (RS) validity indices, respectively, which are frequently used to evaluate results of the hierarchical clustering algorithms.