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Assessment of Rutting Resistance and Healing for Stone Matrix Asphalt Concrete (SMAC)
Get PDFStone Matrix Asphalt Concrete (SMAC) is known as tough, stable, rut-resistant mixture. In this investigation, SMAC was prepared in the laboratory using gap graded aggregates, asphalt cement, mineral filler and coal fly ash as stabilizing agent. Specimens were prepared using static compaction to the target density based on asphalt content for each case. The prepared Specimens were subjected to the 1200 repeated compressive stresses at 25 ºC under various stress levels using the pneumatic repeated load system PRLS. Specimens were subjected to microcrack healing process by external heating for 120 minutes at 60 °C, then it practices another cycle of repeated compressive stresses. The resilient modulus, permanent deformation, and rutting resistance under three levels of stress have been assessed. It was concluded that the resilient modulus Mr increases by (66, 50 and 31) %, (36, 50 and 31) % and (62, 37 and 69) %, while the permanent deformation decreases by (25, 11.4 and 25) %, (19, 31.6 and 14.5) % and (14, 9 and 8.3) % after implementation of fly ash at (OAC-0.5, OAC and OAC+0.5) % binder content under (0.068, 0.138 and 0.206) MPa of repeated compressive stress respectively. The resilient modulus increased by (17.6, 15.3, 10.5) % , (42.8, 51, 37.5) % and (18.7, 25, 23.6) % and the permanent deformation decline by (3.52, 31.66, 6.25) % under repeated compressive stresses of (0.068, 0.138, 0.206) MPa at (25 °C) after healing for mix with (4.6, 5.1, 5.6) % asphalt content respectively when compared with mixtures before healing
Optimized DLLME Method Coupled to HPLC for Simultaneous Analyses of Benzoates, Sorbates and Methyl p-hydroxyl Benzoates in Fruits Products
Get PDFWe used an accurate and green technique "Dispersive Liquid Liquid Micro Extraction" (DLLME) followed by HPLC-UV analysis for the analysis of benzoates (BA), sorbates (SA), and p-hydroxyl methyl benzoates (MB) in fruits products. We optimized the extraction parameters by the box Behnken design. We validated the method by using the β accuracy profile including the systematic (trueness) and random (intermediate precision) errors. The extraction efficiency varied from 82.98 to 100.8 %. This method was linear with R2s values higher than 0.9752 for all the compounds. The repeatability and intermediate precision were less than 3.18 and 12.02 respectively; whereas, the detection limits were respectively 0.304, 0.306 and 0.153 mg/ ml for BA, SA and MB. This method is therefore reliable to the simultaneous quantification of these preservatives in fruit juices, nectars and jams. The levels of these additives in the samples exceeded 833.97 and 290.67 ppm for BA and SA, respectively; while, MB was not detected.  
Thermo-Physical Properties of HR3C and P92 Steels at High-Temperature
Get PDFAustenitic HR3C and ferritic-martensitic P92 steels are the materials of interest from a mechanical standpoint for the manufacturing of thermal exchangers of the next generation of steam power plants. In order to evaluate their capacity to transfer heat, thermal conductivity calculations have been conducted through the measurements of thermal diffusivity, specific heat capacity and density. It will be shown that the heat capacity, density, thermal expansion coefficient and thermal diffusivity evolve continuously with temperature in the HR3C material but not in the P92 steel. The heterogeneous thermal behaviour appears to be associated with its ferromagnetic transition rather than to the microstructural evolution. Nevertheless, the results for both steels did not exhibit significant differences between thermal conductivities at the intended temperature of service
Fluctuation-Induced Excess Conductivity and Infrared Spectra in Y Doped BSCCO Superconductors
Get PDFWe report here the fluctuation induced excess conductivity and IR spectra in Bi2Sr2Ca1-xYxCu2Oy (0.00 < x < 0.50) superconductors. This work is done by using the reported data of Sedky, Physica B 410, 227 (2013), and with the help of Anderson and Zou relation. The logarithmic plots of excess conductivity ∆σ and reduced temperature Є reveal two different exponents corresponding to unique crossover temperature in the slope of each plot. The first exponent is obtained in the normal field region at a temperature of (Tcmf << T < 2Tcmf ), while the second exponent is obtained in the mean field region at a temperature of (T ~ Tcmf). The dimensional exponents are shifted from three dimensional (3D) to two dimensional (2D) for x < 0.30, but it is shifted from 2D to 3D for x = 0.50. Both zero kelvin critical magnetic fields and current density are considerably enhanced by increasing x up to 0.30 followed by a decrease with further increase of x up to 0.50. The vice is versa for the behavior of interlayer coupling, coherence lengths and anisotropy against x. On the other hand, IR spectra show absorption modes in the wave number range of 716-726 cm-1 according to the value of x. These results are discussed in terms of the correlation between carrier concentration, oxygen deficient and effective Cu valance which are induced by Y through CuO2 planes of BSCCO superconductors
Robust Optimization of Road Vehicle Suspension Considering the Variation of Tire Vertical Stiffness
Get PDFTire vertical stiffness is influenced by many factors. The inflation pressure, tire dimension, and usage of run-flat tire are considered in this paper. Robust multi-objective optimization technique is used to optimize the suspension performance considering the variation of the tire vertical stiffness. Three objective functions, discomfort, road holding, and working space are used to evaluate the dynamic behavior of the suspension considering a two-degree-of-freedom quarter-car model excited by a random road profile. The Pareto-optimal solutions in terms of suspension spring stiffness and damping coefficient are obtained and compared with the one computed by means of a deterministic approach. Solutions obtained by means of the robust optimization method are proven to be less sensitive to the possible variations of the tire vertical stiffness without influencing significantly the expected performance
Chemical Composition, Antioxidant, Antimicrobial and Antidiabetic Potential of Philodendron Bipinnatifidum Schott ex Endl
Get PDFMany of the species used in popular medicine do not have their biological activities already proven by scientific studies. Among these species, the endemic South American Philodendron bipinnatifidum Schott ex Endl deserves special attention since it is already in use in popular medicine for inflammation cases, such as erysipelas, orchitis and ulcers. This study evaluated the antioxidant, antimicrobial and antidiabetic activities of extracts of the hastes de P. bipinnatifidum. The ethanolic extract showed a significant antioxidant potential. The ethyl acetate extract resulted in high antimicrobial activity against Streptococcus pyogenes. The most significant biological activity of ethyl acetate extract relates to its chemical composition when compared with ethanolic extract, which showed the highest concentration of bioactive compounds. In vitro antidiabetic activity was only evaluated for ethyl acetate extract, resulting in inhibition of intestinal disaccharidases (maltase and sucrase) at concentration of 500 μg/mL
An Energy-Efficient Elevator Operating System that Considers Sensor Information and Electricity Price Changes in Smart Green Buildings
Get PDFIn modern smart buildings, the energy consumption of a building is monitored every time. Smart buildings are also equipped with sensors that can collect various physical data such as temperature, motion, and light. In this paper, we use smart sensor technologies in the design of an efficient elevator operating system (EOS). Specifically, multiple sensor devices are used together to detect elevator passengers’ behavior before they arrive at the elevator door and press the elevator call button. The detected information is then delivered to EOS through building networks and the scheduling system utilizes this information for the efficient control of the elevator cars. Specifically, when the number of passengers becomes large, EOS increases the number of working elevator cars to reduce the waiting time of passengers. In contrast, when the elevator traffic lessens, EOS reduces the number of working elevator cars in order to save the energy consumption. Experimental results with a wide range of configurations show that our EOS outperforms the conventional elevator scheduling system that does not consider sensor information or electricity price changes
Assimilation of Standard Regularizer Contextual Model and Composite Kernel with Fuzzy-based Noise Classifier
Get PDFThe paper assay the effect of assimilating smoothness prior contextual model and composite kernel function with fuzzy based noise classifier using remote sensing data. The concept of the composite kernel has been taken by fusing two kernels together to improve the classification accuracy. Gaussian and Sigmoid kernel functions have opted for kernel composition. As a contextual model, Markov Random Field (MRF) Standard regularization model (smoothness prior) has been studied with the composite kernel-based Noise Classifier. Comparative analysis of new classifier with the conventional construes increase in overall accuracy
Modeling for Copper Ablation by Ultrashort Laser Bursts-Train
Get PDFAblation of copper using multipulse femtosecond laser irradiation with an 800 nm wavelength and 900-fs pulse duration is investigated theoretically using a dynamic tow temperature model. Our results show that the irradiation of a metal film by burst femtosecond laser with a separation time between pulses less than the thermal relaxation time can dramatically enhance the irradiated focal volume without a significant dissipation of the energy inside the material. We demonstrate the advantage of burst irradiation at low fluence where the cooper can be ablated below single ablation threshold. We also suggest that at high fluence, irradiation with a burst-train may give rise to a cleaner ablation than with a pulse-train
Ultrasound-Assisted Preparation of Brazil Nut Oil-in-Water Emulsions Stabilized by Arabic Gum
Get PDF The objective of this work is to evaluate the stability of Brazil nut oil emulsions with gum Arabic using ultrasound-assisted homogenization. The emulsions were prepared in a completely randomized design varying the time (2 and 4 min) and the ultrasound power (30 and 40%). The physicochemical properties of the emulsions (pH, conductivity, turbidity, zeta potential, surface tension, rheology and optical microscopy) were evaluated after the homogenization process and 4 hours later. The results showed that more energetic homogenization processes (longer duration and higher ultrasound power) favored the physicochemical properties, keeping the emulsions more stable. Thus, Brazil nut oil emulsions prepared with ultrasound-assisted showed good physic-chemical characteristics that can guarantee good emulsion stability during spray drying, guaranteeing efficiency and protection of the physical and chemical properties of the Brazil nut oil