Backcalculation of pavement layer thickness using data mining

Pavement deflection data are often used to evaluate a pavement’s structural condition nondestructively. Pavement layers are important parameters in view of bearing capacity. Pavement layer thickness may be known from the design project or site investigation. At the same time, using backcalculation analysis, flexible pavement layer thicknesses together with in situ material properties can also be backcalculated from the measured field data through appropriate analysis techniques. Data mining (DM) process has not been used as a backcalculation tool before. In this study, DM process is used in backcalculating the pavement layer thickness from deflections measured on the surface of the flexible pavements. Experimental deflection data groups from NDT are used to show the capability of the DM process in backcalculating the pavement layer thickness and compared each other. Performing the study, modeling with Kstar method gives fine results with respect to other DM modeling techniques. Backcalculation of pavement layer thickness using DM process has been carried out for the first time.     

Effect of elevated temperature on the mechanical properties of concrete produced with finely ground pumice and silica fume

This study investigated the effect of elevated temperature on the mechanical and physical properties of concrete specimens obtained by substituting cement with finely ground pumice (FGP) at proportions of 5%, 10%, 15% and 20% by weight. To determine the effect of silica fume (SF) additive on the mechanical and physical properties of concrete containing FGP, SF has been added to all series except for the control specimen, which contained 10% cement by weight instead. The specimens were heated in an electric furnace up to 400, 600 and 800 °C and kept at these temperatures for one hour. After the specimens were cooled in the furnace, ultrasonic pulse velocity (UPV), compressive strength and weight loss values were determined. The results demonstrated that adding the mineral admixtures to concrete decreased both unit weight and compressive strength. Additionally, elevating the temperature above 600 °C affected the compressive strength such that the weight loss of concrete was more pronounced for concrete mixtures containing both FGP and SF. These results were also supported by scanning electron microscope (SEM) studies.     

Structural and technological characterization of ropy exopolysaccharides produced by Lactobacillus plantarum strains isolated from Tarhana

Food Science and Biotechnology - Exopolysaccharide producing starter cultures enable manufacturing “clean labeled” foods with improved textural and nutritional properties. The...     

Effect of Freezing-Thawing on Clayey Soils Reinforced with Human Hair Fibers

ABSTRACT

The reinforcing of fine-grained soils using natural or synthetic fibers has been successfully applied today. The use of waste human hair fibers among natural fibers is seen as a sustainable solution as a reinforcing material. A series of free pressure tests were performed before and after the freezing-thawing cycle in order to examine the strength properties of the clayey soil (CS) reinforced with human hair fibers (HHF). Before freezing-thawing, clayey soil samples prepared with four different mass ratios of human hair fibers (0.5%, 1%, 1.5%, and 2% by dry weight) indicated 14–54% increases in strength, 7–49% increase were obtained after freezing-thawing. The highest strength increases before and after the freezing-thawing cycle has occurred in the mixture of CS+1.5% HHF. In addition, it was determined that the increase in pressure stress is remarkably increases with increasing human hair fiber ratio and cure time and freeze-thaw cycles. As a result, it is concluded that the CS reinforced with HHF can be utilized in cold climate zones.     

Effect of Zinc Content and Cutting Tool Coating on the Machinability of the Al-(5–35) Zn Alloys

Metals and Materials International - In this study, Al-5Zn, Al-15Zn, Al-25Zn and Al-35Zn alloys containing 5, 15, 25 and 35 wt% Zn, respectively were produced by permanent mold casting....     

VULCAN-SUPPORTED Pt ELECTROCATALYSTS FOR PEMFCs PREPARED USING SUPERCRITICAL CARBON DIOXIDE DEPOSITION

In this study, supercritical carbon dioxide (scCO₂) deposition was used to prepare vulcan-supported Pt (Pt/Vulcan) electrocatalysts for proton exchange membrane fuel cells (PEMFCs), and the effects of process variables on the properties of the electrocatalysts were investigated. The two different methods used to reduce the organometallic precursor were thermal reduction in nitrogen at atmospheric pressure and thermal reduction in scCO₂. In the former method, the maximum Pt loading achieved was 9%, and this was governed by the adsorption isotherm of the Pt precursor between the scCO₂ phase and the Vulcan phase. By using the latter method, higher Pt loadings of 15% and 35% could be achieved. The Pt/Vulcan catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and cyclic voltammetry (CV). The average particle sizes for Pt/Vulcan 9%, 15%, and 35% catalysts were 1.2, 1.3, and 2 nm, respectively. Electrochemical surface areas obtained from CV data were found to vary with the Pt loading.     

Stock price prediction using hybrid soft computing models incorporating parameter tuning and input variable selection

Neural Computing and Applications - Over the years, high-dimensional, noisy, and time-varying natures of the stock markets are analyzed to carry out accurate prediction. Particularly, speculators...     

The performance assessment of a combined organic Rankine-vapor compression refrigeration cycle aided hydrogen liquefaction

In this study, the performance of the combined cooling cycle with the Organic Rankine power cycle, which provides cooling of the hydrogen at the compressor inlet which compresses the constant temperature in the Claude cycle used for hydrogen liquefaction, on the system is examined. The Organic Rankine combined cooling cycle was considered to be using a geothermal source with a flow rate of 120 kg/s at a temperature of 200 °C. The first and second law performance evaluations of the whole system were made depending on the heat energy at different levels taken from the geothermal source. The thermodynamic analysis of the equipment making up the system has been done in detail. The temperature values at which the hydrogen can be effectively cooled were determined in the presented combined system. The efficiency coefficient of the total system was calculated based on varying pre-cooling values. As a result of the study, it was determined that cold entry of hydrogen into the Claude cycle reduced the energy consumption required for liquefaction. Amount of hydrogen cooled to specified temperature increase by increase in mass flow of geothermal water and its temperature. Liquefaction cost is calculated to be 0.995 $/kg H₂ and electricity produced by itself is calculated to be 0.025 $/kWh by the new model of liquefaction system. Cost of the liquefaction in the proposed system is about 39.7% lower than direct value of hydrogen liquefaction of 1.650 $/kg given in the literature.     

Electrochemical Behaviors of 2-Amino-3-Hydroxypyridine onto the Glassy Carbon Sensor Electrode: Simultaneous and Independent Determinations of Quercetin, Galangin, 3-Hydroxyflavone, and Chrysin

Flavonoids, with high antioxidant activity in fruits and vegetables, are natural vegetable dyes synthesized from phenylalanine. They are very essential for human health due to their activity as free radical acceptors. In this paper, the availability in the determination of quercetin (Que), galangin (Gal), 3-hydroxyflavone (3HF), and chrysin (Chr) of a modified glassy carbon (GC) sensor electrode using 2-amino-3-hydroxypyridine (AHP) was examined separately and simultaneously by cyclic voltammetry (CV). Surface characterization of modified electrodes was performed using CV, electrochemical impedance spectroscopy, and scanning electron microscopy techniques. The modification of AHP onto the GC electrode surface was carried out between ?150 and +600 mV potential range using 100 mV?s^?1 scanning rate with 30 cycles. The binding of flavonoid derivatives onto the modified surface was performed between +300 and +1,700 mV potential range using 100 mV?s^?1 scanning rate with 10 cycles. The usability of the modified electrode was examined in the determination of some flavonoids by square wave voltammetry. From the experimental results, it was found out that Que, 3HF, and Chr; Gal, 3HF, and Chr; and 3HF and Chr can be determined simultaneously by using an AHP-modified GC sensor electrode. Also, these molecules can easily be determined separately by using the modified electrode.