Engine Performance and Exhaust Emission Tests of Sulfate Turpentine and No:2 Diesel Fuel Blend

Environmentally friendly, biobased fuel additives become more important when environmental concerns all around the world are considered. In this study, sulfate turpentine is investigated as a candidate diesel fuel additive. Engine performance tests were conducted on a 53 kW, 4000 rpm Peugeot XD 3P 157 type diesel engine for 3:97 turpentine and No:2 diesel fuel blend and similar results to No:2 diesel fuel were obtained. Significant reduction in exhaust emissions were observed as a result of using turpentine and No:2 diesel fuel blend.     

Natural radioactivity and evaluation of effective dose equivalent of granites in Turkey

Annual effective dose equivalent due to natural gamma radiation from (238)U, (232)Th and (40)K have been evaluated from granites in Turkey. Forty samples were taken for spectrometric analysis. Specific concentrations of (238)U, (232)Th and (40)K in granite samples were determined. Spectroscopy system was used with 1.8 keV (FWHM) coaxial high purity germanium (HPGe) detector. Average values of concentrations of (238)U, (232)Th and (40)K were detected at 15.85, 33.76 and 359 Bq kg(-1), respectively. The average value of radon varies from 0.073 to 0.185 Bq m(-2) h(-1) exhalation depends on the specific concentration of uranium. The dose rate due to this highest activity which have been evaluated by a Monte Carlo transport calculations does not exceed 0.4 mSv a(-1).     

Mechanical Properties of BSCCO Superconductor by Oliver–Pharr Method and Work of Indentation Approach

Polycrystalline superconducting Bi–Pb–Gd–Sr–Ca–Cu–O bulk samples with nominal composition Bi_1.7Pb_0.3?x Gd _x Sr₂Ca₃Cu₄O_12+y (x=0.00,0.01,0.05) were produced by the melt quenching method. The mechanical properties of the samples were characterized by depth sensing indentation technique under different peak loads ranging from 200 to 1800 mN. The experimental data were comparatively analyzed by the Oliver–Pharr method and a work of indentation approach. It was found that the work of indentation approach gave more reliable results because of the reducing pile-up effect. The results implied that both microhardness and reduced elastic modulus increased with increasing Gd substitution.     

Fano-resonant asymmetric metamaterials for ultrasensitive spectroscopy and identification of molecular monolayers

Engineered optical metamaterials present a unique platform for biosensing applications owing to their ability to confine light to nanoscale regions and to their spectral selectivity. Infrared plasmonic metamaterials are especially attractive because their resonant response can be accurately tuned to that of the vibrational modes of the target biomolecules. Here we introduce an infrared plasmonic surface based on a Fano-resonant asymmetric metamaterial exhibiting sharp resonances caused by the interference between subradiant and superradiant plasmonic resonances. Owing to the metamaterial's asymmetry, the frequency of the subradiant resonance can be precisely determined and matched to the molecule's vibrational fingerprints. A multipixel array of Fano-resonant asymmetric metamaterials is used as a platform for multispectral biosensing of nanometre-scale monolayers of recognition proteins and their surface orientation, as well as for detecting chemical binding of target antibodies to recognition proteins.     

ARMA-cepstrum Recursion Algorithm for the Estimation of the MA Parameters of 2-D ARMA Models

This paper considers the problem of estimating the moving average (MA) parameters of a two-dimensional autoregressive moving average (2-D ARMA) model. To solve this problem, a new algorithm that is based on a recursion relating the ARMA parameters and cepstral coefficients of a 2-D ARMA process is proposed. On the basis of this recursion, a recursive equation is derived to estimate the MA parameters from the cepstral coefficients and the autoregressive (AR) parameters of a 2-D ARMA process. The cepstral coefficients are computed benefiting from the 2-D FFT technique. Estimation of the AR parameters is performed by the 2-D modified Yule–Walker (MYW) equation approach. The development presented here includes the formulation for real-valued homogeneous quarter-plane (QP) 2-D ARMA random fields, where data are propagated using only the past values. The proposed algorithm is computationally efficient especially for the higher-order 2-D ARMA models, and has the advantage that it does not require any matrix inversion for the calculation of the MA parameters. The performance of the new algorithm is illustrated by some numerical examples, and is compared with another existing 2-D MA parameter estimation procedure, according to three performance criteria. As a result of these comparisons, it is observed that the MA parameters and the 2-D ARMA power spectra estimated by using the proposed algorithm are converged to the original ones     

Investigation of spherisation in microstructures of aluminium casting alloys for thixoforging process

Thixoforging combined with low superheat casting (LSC) is a promising shaping process for aluminium casting alloys. LSC process is based on rapid solidification of an alloy which cast with low pouring temperature. With this method, a feedstock material is produced with non-dendritic microstructure that ready for spherisation in reheating sequence of further semi-solid process. Al-Si alloys are still castable even at low temperatures due to their excellent fluidities. This study subjects to present spherisation of A356 and A380 alloy billets cast with LSC process that provides appropriate beginning material with relatively high sphericity. Obtained billet parts were reheated for different times at a semi-solid state temperature. Some of these billets were directly quenched for observing the effects of reheating and the others were thixoforged. With sufficient reheating time, deformation of thixoforging process did not significantly affect on the spherical microstructure. Unnecessarily long reheating period caused excessive grain growth. A356 alloy had higher spherisation tendency than A380 alloy under similar process conditions.     

Performance and combustion characteristics of a DI diesel engine fueled with waste palm oil and canola oil methyl esters

This study discusses the performance and combustion characteristics of a direct injection (DI) diesel engine fueled with biodiesels such as waste (frying) palm oil methyl ester (WPOME) and canola oil methyl ester (COME). In order to determine the performance and combustion characteristics, the experiments were conducted at the constant engine speed mode (1500 rpm) under the full load condition of the engine. The results indicated that when the test engine was fueled with WPOME or COME, the engine performance slightly weakened; the combustion characteristics slightly changed when compared to petroleum based diesel fuel (PBDF). The biodiesels caused reductions in carbon monoxide (CO), unburned hydrocarbon (HC) emissions and smoke opacity, but they caused to increases in nitrogen oxides (NO_x) emissions.     

Two Novel Bimetallic Cyano-Bridged Coordination Polymers Containing the 2,2′-(Ethylenedioxy)bis (Ethylamine): Syntheses,Structural, Thermal and Magnetic Properties

Two new cyano bridged bimetallic polymeric complexes, [Ni(edbea)Ni(CN)₄]·1/2H₂O (1) and [Cu(μ-edbea)(μ-CN)₂ Ni(CN)₂]·H₂O (2) [edbea = 2,2′-(ethylenedioxy)bis(ethylamine)] have been synthesized by adding metal chloride (M = Ni^II and Cu^II), and edbea into [Ni(CN)₄]²⁻ in water–ethanol solution and then characterized by elemental analysis, infrared (IR) and electron paramagnetic resonance (EPR) (for only complex 2) spectra, variable temperature magnetic measurement, and thermal gravimetric analysis. The X-ray diffraction crystal structure of complex 2 shows a 2D polymeric chain –edbea(N5,O1)–Cu1–N1C1–Ni(CN)2–C4N6–Cu1–(N6,O2) edbea– in which the Cu^II centers are linked by two cyano and one edbea. The powder EPR spectrum of the complex 2 has shown that Cu^II ions are located in rhombically distorted octahedral sites. The magnetic properties of the coordination polymers have been studied in temperature range of 15–300 K. The magnetic behaviors investigation of complexes 1 and 2 indicated the presence of a very weak antiferromagnetic interaction.     

Sequential Oxidation of Humic Acids by Ozonation and Photocatalysis

In this study, humic acids, the natural polymerized organic compounds which are responsible for the formation of disinfection by-products such as haloacetic acids and trihalomethanes upon chlorination, are oxidized in a sequential system incorporating ozonation and photocatalysis. Titanium dioxide is used as photocatalyst in the photocatalytic oxidation phase. Humic acid degradation kinetics is evaluated both for ozonation and photocatalysis. The Freundlich adsorption model is used for defining the adsorption characteristics of humic acid solutions on the photocatalyst after the ozonation step. The Langmuir-Hinshelwood model is also studied for explaining the adsorptive and photocatalytic removal of humic acids.