Effect of Freezing and Frozen Storage on Phenolic Compounds of Raspberry and Blackberry Cultivars

The phenolic compounds in raspberry and blackberry cultivars grown in Turkey were determined by liquid chromatography–mass spectrometry (MS)/MS in fresh, just-frozen, and stored fruits at −22 °C for 6 months period. The major phenolic compounds in water extracted samples were ellagic acid (1,350.36–727.9 mg/kg fresh fruit), ferulic acid (820.78–338.27 mg/kg fresh fruit), caffeic acid (754.85–202.78 mg/kg fresh fruit), p-coumaric acid (361.68–142.63 mg/kg fresh fruit), p-hydroxybenzoic acid (534.20–233.29 mg/kg fresh fruit), and quercetin (46.97–27.31 mg/kg fresh fruit) in raspberry and ellagic acid (1,828.07–1,555.13 mg/kg fresh fruit), ferulic acid (757.69–413.82 mg/kg fresh fruit), caffeic acid (736.85–337.89 mg/kg fresh fruit), p-coumaric acid (877.45–287.15 mg/kg fresh fruit), and quercetin (74.69–56.78 mg/kg fresh fruit) in blackberry. The varietal differences in the phenolic compound contents were larger among the blackberry cultivars (from 1,828.07 to 56.78 mg/kg fresh fruit) than among the raspberry cultivars (1,350.36 to 27.31 mg/kg fresh fruit). A significant decrease was observed in the content of p-hydroxybenzoic acid (from 534.20 to 114.30 mg/kg; Aksu Kırmızısı) and the least decrease was in the content of caffeic acid (from 545.42 to 530.91 mg/kg; Heritage) in raspberry cultivars. On the other hand, ferulic acid (from 475.16 to 113.33 mg/kg) decreased significantly in blackberry (Bursa 2) after storage for 6 months.     

Optimization of a central-heating radiator

An approximate analytical model has been used to evaluate the optimum dimensions of a central-heating radiator. The radiator problem is divided into three one-dimensional fin problems and then the temperature distributions within the fins and heat-transfer rate from the radiator are obtained analytically. The optimum geometry maximizing the heat-transfer rate for a given radiator volume and the geometrical constraints associated with production techniques, and thermal constraints have been found. The effects of geometrical and thermal parameters on the radiator’s performance are presented.     

Performance analysis and optimization of a thermally non-symmetric annular fin

Considering thermally non-symmetric convective boundary conditions, optimum dimensions of an annular fin which has a rectangular cross-section are investigated. Two-dimensional heat diffusion equation is solved analytically to obtain temperature distribution and heat transfer rate. In this work, fin volume is fixed to obtain the dimensionless geometrical parameters of the fin with maximum heat transfer rates. The optimum geometry which maximizes the heat transfer rate for a given fin volume has been found employing NCONF routine in the IMSL Library. The derived condition of optimality gives an open choice to the designer.     

Effects of delayed drying and CO2 application on copper amine fixation in ACQ treated red pine

Fixation of copper and amine in alkaline copper quaternary (ACQ-C) wood preservative was investigated to determine the effects of delayed drying and application of CO₂ gas under pressure. Unlike the fixation of CCA preservative, where the rate of fixation reaction is slowed down by evaporative cooling during drying, delayed drying of ACQ treated wood had no observable effect on the copper fixation rate. However, at 50 °C, delayed drying resulted in a higher degree of copper fixation, while this effect was not observed at 22 °C. Post-treatment of ACQ treated wood with pressurized CO₂ immediately after treatment, reduced the pH of the solution in wood and resulted in rapid fixation of the copper. However, in time, the pH increased as CO₂ dissipated from the solution allowing the copper to re-solubilize.     

Synthesis and Characterization of Konjac Gum/Polyethylene Glycol-Silver Nanoparticles and their Potential Application as a Colorimetric Sensor for Hydrogen Peroxide

Journal of Inorganic and Organometallic Polymers and Materials - Green and low-cost synthesis strategies for ultrasonic preparation of polymer blend matrix-based silver nanoparticles (Ag NPs) and...     

Wind-driven ventilation improvement with plan typology alteration: A CFD case study of traditional Turkish architecture

Aligned with achieving the goal of net-zero buildings, the implementation of energy-saving techniques in minimizing energy demands is proving more vital than at any time. As practical and economic options, passive strategies in ventilation developed over thousands of years have shown great potential for the reduction of residential energy demands, which are often underestimated in modern building’s construction. In particular, as a cost-effective passive strategy, wind-driven ventilation via windows has huge potential in the enhancement of the indoor air quality (IAQ) of buildings while simultaneously reducing their cooling load. This study aims to investigate the functionality and applicability of a common historical Turkish architectural element called “Cumba” to improve the wind-driven ventilation in modern buildings. A case study building with an archetypal plan and parameters was defined as a result of a survey over 111 existing traditional samples across Turkey. Buildings with and without Cumba were compared in different scenarios by the development of a validated CFD microclimate model. The results of simulations clearly demonstrate that Cumba can enhance the room’s ventilation rate by more than two times while harvesting wind from different directions. It was also found that a flexible window opening strategy can help to increase the mean ventilation rate by 276%. Moreover, the room’s mean air velocity and ventilation rate could be adjusted to a broad range of values with the existence of Cumba. Thus, this study presents important findings about the importance of plan typology in the effectiveness of wind-driven ventilation strategies in modern dwellings.     

Design of the polyacrylonitrile-reduced graphene oxide nanocomposite-based non-enzymatic electrochemical biosensor for glucose detection

With the advantages of developed electronic devices, various biosensor applications have become attractive issues with excellent electrochemical performances against biomarkers and molecules in biomedical applications. In this study, novel polyacrylonitrile (PAN)-reduced graphene oxide (rGO) nanocomposite-based non-enzymatic electrochemical biosensors were prepared to investigate the detection performance of the glucose. The PAN-rGO nanocomposite-based biosensor detected glucose with a high sensitivity and stability due to enhanced redox mechanism arising from rGO additive. PAN-rGO nanocomposite-based biosensor detected glucose in (0.75–12) mM with a high sensitivity of 49 µAmM^?1 cm^?2 (2.5 times higher than PAN-based sensor). Concentration–response graphs correlating the non-enzymatic electrochemical signal to glucose concentration revealed a low limit of detection (LOD) of 0.6 mM within 1-min voltammetric cycle. The selectivity results confirmed a significant preferential response of the proposed PAN-rGO nanocomposite-based biosensor for glucose against possible interfering compounds. The proposed PAN-rGO nanocomposite-based biosensor has a great potential to be used as a nanostructured platform for detection of glucose in phosphate-buffered saline (pH 7.4) solution with high sensitivity, selectivity, stability, reproducibility, and fast response properties.

     

Mathematical modeling of surface roughness for evaluating the effects of cutting parameters and coating material

The work presented in this paper examines the effects of cutting parameters (cutting speed, feed rate and depth of cut) onto the surface roughness through the mathematical model developed by using the data gathered from a series of turning experiments performed. An additional investigation was carried out in order to evaluate the influence of two well-known coating layers onto the surface roughness. For this purpose, the experiments were repeated for two CNMG 120408 (with an ISO designation) carbide inserts having completely the same geometry and substrate but different coating layers, in a manner that identical cutting conditions would be ensured. The workpiece material machined was cold-work tool steel AISI P20. Of the two types of inserts employed; Insert 1 possesses a coating consisting of a TiCN underlayer, an intermediate layer of Al₂O₃ and a TiN outlayer, all deposited by CVD; whilst Insert 2 is PVD coated with a thin TiAlN layer (3 ± 1 μm). The total average error of the model was determined to be 4.2% and 5.2% for Insert 1 and Insert 2, respectively; which proves the reliability of the equations established.