Small shaking table testing and numerical analysis of free-field site response and soil-structure oscillation under seismic loading

Bulletin of Engineering Geology and the Environment - In this study, the accuracy level of geometric scaling factor (herein, λ = 45) selected for the shaking table test model...     

Characterization of Tantalum–Titanium Powders with Universal Powder Bed (UPB) System for Electron Beam Melting Process

Russian Journal of Non-Ferrous Metals - Electron beam melting (EBM) is a powder bed fusion additive manufacturing (AM) technique that produces three-dimensional (3D) parts by fusing metallic...     

Verifying the accuracy of interlocking tables for railway signalling systems using abstract state machines

Railway transportation system is a critical sector where design methods and techniques are defined by international standards in order to reduce possible risks to an acceptable minimum level. CENELEC 50128 strongly recommends the utilization of finite state machines during system modelling stage and formal proof methods during the verification and testing stages of control algorithms. Due to the high importance of interlocking table at the design state of a signalization system, the modelling and verification of interlocking tables are examined in this work. For this purpose, abstract state machines are used as a modelling tool. The developed models have been performed in a generalized structure such that the model control can be done automatically for the interlocking systems. In this study, NuSMV is used at the verification state. Also, the consistency of the developed models has been supervised through fault injection. The developed models and software components are applied on a real railway station operated by Metro Istanbul Co.

     

Comparison of fatty acid profiles and mid‐infrared spectral data for classification of olive oils

The composition of olive oils may vary depending on environmental and technological factors. Fatty acid profiles and Fourier‐transform infrared (FT‐IR) spectroscopy data in combination with chemometric methods were used to classify extra‐virgin olive oils according to geographical origin and harvest year. Oils were obtained from 30 different areas of northern and southern parts of the Aegean Region of Turkey for two consecutive harvest years. Fatty acid composition data analyzed with principal component analysis was more successful in distinguishing northern olive oil samples from southern samples compared to spectral data. Both methods have the ability to differentiate olive oil samples with respect to harvest year. Partial least squares (PLS) analysis was also applied to detect a correlation between fatty acid profile and spectral data. Correlation coefficients (R²) of a calibration set for stearic, oleic, linoleic, arachidic and linolenic acids were determined as 0.83, 0.97, 0.97, 0.83 and 0.69, respectively. Fatty acid profiles were very effective in classification of oils with respect to geographic origin and harvest year. On the other hand, FT‐IR spectra in combination with PLS could be a useful and rapid tool for the determination of some of the fatty acids of olive oils.     

Investigation of Boronizing Kinetics of AISI 51100 Steel

In this study, some mechanical properties of borided AISI 51100 steel with high C concentration were investigated. Boronizing heat treatment was carried out in solid medium consisting of Ekabor-II at 850, 900, and 950 °C for 2, 4, 6, and 8 h. Morphology and mechanical properties of boride layer, and the effect of chemical composition on properties and kinetics of borides were investigated. The results of this study indicated that the morphology of the boride layer has a saw-tooth nature, and its hardness is over 1500 HV. Depending on process time and temperature, the depth of boride layer ranged from 30 to 106 μm. Optical and SEM studies and XRD analysis revealed that borides formed on the surface of steel substrates have dominantly single Fe₂B boride phase in addition to small amount of Cr₂B.     

Effect of particle size on microstructural and mechanical properties of UHMWPE–TiO2 composites produced by gelation and crystallization method

In this study, Ultra-high-molecular-weight polyethylene (UHMWPE) in 0.5 wt % concentration—0.5, 1, and 2 wt % nanosized and micron-sized TiO₂ composites were produced via gelation/crystallization method in decalin + antioxidant solution at 150 °C for 45 min by using magnetic stirrer. The gel composites were cooled in an aluminum tray embedded in iced water under ambient conditions and dried in an oven at 130 °C for 90 min to remove any residual trace of decalin and to strengthen the UHWMPE matrix. Scanning electron microscopy–EDS images indicate that TiO₂ particles were integrated well with the polymer matrix. differential scanning calorimetry studies revealed that the crystallinity of pure UHMWPE was calculated as 56% and an increase of 13.32% for micron sized and 19.25% for nano sized TiO₂. Crystalline and amorphous phases of UHMWPE–TiO₂ composites confirmed by Raman are in good agreement with the literature. The elastic modulus of test materials ranged from 610 to 791 MPa for micron sized and raised from 675 to 1085 for nano sized reinforcing agents. Ultimate tensile stress increased about 35% for micron sized and 60% for nano sized weight 1% TiO₂ reinforced composites. Biomineralization tests (performed in stimulated body fluid, at 37 °C and 6.5 pH during 1 month) have shown that produced composites are compatible as acetabular liner replacement for hipjoints due to no accumulation (Ca, P, Na, etc.) on UHMWPE–TiO₂ composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47402.     

N-alkylpiperidine·alane compounds and their applications in alane regeneration

The synthesis, characterization, and detailed thermal properties of N-alkylpiperidine·alane compounds are described. Direct reaction of 1 equiv of N-alkylpiperidine (NMPi or NEPi, NMPi = N-methylpiperidine, NEPi = N-ethylpiperidine) with 1 equiv of γ-AlH₃ readily gives the 1:1 adduct NMPi·AlH₃ (or NEPi·AlH₃) in good yields and purity. Attempts to prepare the related 2:1 complexes were unsuccessful; however, in situ studies by infrared spectroscopy showed the formation of (NMPi)₂·AlH₃ when a large excess of NMPi was present, whereas no (NEPi)₂·AlH₃ was observed under similar conditions. Such difference in reactivity is due to the steric effect of the ethyl group in NEPi. Under heat and vacuum, both NMPi·AlH₃ and NEPi·AlH₃ react with 1 equiv of LiH to form non-solvated LiAlH₄ in nearly quantitative yields. However, they display dramatically different decomposition pathways without LiH or with a catalytic amount of LiH. While NMPi·AlH₃ decomposes to Al metal directly, NEPi·AlH₃ can be selectively decomposed to form AlH₃ under certain conditions. Moreover, the transamination of (NMPy)₂·AlH₃ (NMPy = N-methylpyrrolidine) with NEPi has been shown to give NEPi·AlH₃ in good yields. Compared to Et₃N, NEPi not only extends the scope of the transamination to include a wide range of amine·alane adducts, but also improves the yield, selectivity, and energy-efficiency of the process. Combining these results with the formation of (NMPy)₂·AlH₃ via hydrogenation, we have established an improved regeneration pathway for AlH₃ using NMPy, NEPi, and Al metal.     

Design of a Virtual MCA and Its Use in Radiation Spectrometer

Instruments and Experimental Techniques - In the present study, a virtual MCA (multichannel analyzer) which could be used in a radiation detection spectrometer was developed by writing a code...     

Differentiation of mixtures of monovarietal olive oils by mid‐infrared spectroscopy and chemometrics

Fourier transform infrared (FT‐IR) spectroscopy in combination with chemometric techniques has become a useful tool for authenticity determination of extra‐virgin olive oils. Spectroscopic analysis of monovarietal extra‐virgin olive oils obtained from three different olive cultivars (Erkence, Ayvalik and Nizip) and mixtures (Erkence‐Nizip and Ayvalik‐Nizip) of monovarietal olive oils was performed with an FT‐IR spectrometer equipped with a ZnSe attenuated total reflection sample accessory and a deuterated tri‐glycine sulfate detector. Using spectral data, principal component analysis successfully classified each cultivar and differentiated the mixtures from pure monovarietal oils. Quantification of two different monovarietal oil mixtures (2–20%) is achieved using partial least square (PLS) regression models. Correlation coefficients (R²) of the proposed PLS regression models are 0.94 and 0.96 for the Erkence‐Nizip and Ayvalik‐Nizip mixtures, respectively. Cross‐validation was applied to check the goodness of fit for the PLS regression models, and R² of the cross‐validation was determined as 0.84 and 0.91, respectively, for the two mixtures.