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Open access

Bejan Sergiu

Abstract

The natural soil used in filling the embankment of the road communications is characterized by the following factors: humidity, porosity, toughness. For certain factor values that describe the soil state is distinguished a certain soil behavior under the influence of the external forces applied through static or dynamic mechanical means.

In this study are presented the numeric simulation results of the soil-compactor interaction based on the complex and nonlinear rheological model proposed by the author in the result of the elaborated doctorate thesis, that follows the real soil characteristics (elastic, dissipative and plastic) on those of the compaction equipment (with a single vibrating roll). The model was harmonised and granted in accordance with the results obtained from the processing of the experimental data. For the simulation model was used the specialized software package Matlab (Simulink, SimMechanics). The obtained results revealed the real behavior of the equipment and its action on the compacted soil.

Open access

Ömer Tamer, Ahmet Sefa Atalay, Davut Avci, Yusuf Atalay, Erdoğan Tarcan and Mariusz K. Marchewka

bonding have significant influences on linear and nonlinear optical properties of the molecules. Additionally, the microscopic origin of nonlinearity in the molecules is due to the presence of delocalized π electron systems connecting donor and acceptor groups which enhance the necessary asymmetric polarizability. Keeping the above mentioned statements in mind, the PNAPC molecule was considered as a potential NLO material. A number of papers reporting the theoretical and experimental investigations on the structure and vibration spectrum as well as the nonlinear

Open access

I.S. Yahia, Mohd. Shkir, V. Ganesh, M.M. Abutalib, H.Y. Zahran and S. Alfaify

Abstract

Herein, we report a successful development of nano-scale pure and Al and Mn co-doped PbI2 using facile microwaveassisted route. Structural study was done through X-ray diffraction analysis of grain size, dislocation density and lattice strain. The crystallite size was found to vary from 28 nm to 40 nm due to Al:Mn co-doping in PbI2. The presence of various vibrational modes was confirmed by FT-IR spectroscopy and red shifting was observed in peak positions compared to the bulk. Surface morphology, examined using a scanning electron microscope, confirmed the formation of single crystal nanosheets of a thickness in the range of 10 nm to 30 nm. The single crystal nanosheets were found to be transformed to large area nanosheets due to the doping. Enhancement in dielectric constant from ~7.5 to 11 was observed with increasing Al doping concentration. Linear attenuation coefficient was calculated and showed the enhancement of blocking gamma rays with increasing doping concentration. Its value was found to increase from 7.5 to 12.8 with the doping. The results suggest that the synthesized nanostructures can be used for detection and absorption of gamma rays emitted by 137Cs and 241Am sources.

Open access

Polidor Bratu and Ovidiu Vasile

]. D. INMAN: “Vibration with Control”, John Wiley and Sons Ltd., New Jersey, 2006. [10]. S. RAO: “Mechanical Vibrations” Fourth Edition, Pearson Education Inc., New Jersey, 2004. [11]. M. RĂDOI, E. DECIU: “Mecanica”, Editura Didactică şi Pedagogică, Bucureşti, 1977.

Open access

Traian Mazilu, Ionuţ Radu Răcănel and George Stoicescu

REFERENCES [1] M. DUMITRIU, I.C. CRUCEANU: “ On the rolling noise reduction by using the rail damper ”, Journal of Engineering Science and Technology Review 10 (6) , 2017 , 87-95. [2] A. CIGADA, S. MANZONI, M. VANALI: “ Vibro-acoustic characterization of railway wheels ”, Applied Acoustics 69 , 2008 , 530–545 . [3] T. KITAGAWA, D. J. THOMPSON: “ The horizontal directivity of noise radiated by a rail and implications for the use of microphone arrays ”, Journal of Sound and Vibration 329, 2010, 202-220 . [4] X. ZHANG, D. J. THOMPSON

Open access

A. Lakdja, I. Benzaidi, A. Sayede and A. Chahed

Abstract

Lattice dynamic and mechanical properties of hypothetical RbC and SrC compounds were investigated using the ab-initio pseudopotential method and a linear response scheme. The lattice dynamics was studied in the framework of the density functional perturbation theory (DFPT). The dynamical and mechanical stability of the hypothetical RbC and SrC compounds was proved in their equilibrium B1 structure. In addition, the same stability was confirmed in the B3 phase. The thermodynamic properties were also investigated. They exhibited the same trend in both phases, and followed the Debye model. These results were confirmed in the ferromagnetic state, which makes the investigated compounds promising candidates in the spintronic field.

Open access

Surendra Singh, Anshuman Sahai, S.C. Katyal and Navendu Goswami

Abstract

We have synthesized zinc-copper ferrite (ZCFO) employing exploding wire technique (EWT). The X-ray diffraction (XRD) data confirm the formation of single phase spinel ZCFO, which is in good agreement with Fourier transform infrared spectroscopy (FT-IR), UV-Vis, and Raman spectroscopic analyses. It is also clearly seen in the SEM micrographs that the grains in ZCFO ferrite are very rough, which allows adsorption of gas like oxygen and therefore, the material can behave as active sensing surface. The size range of the grains in prepared sample is of 200 nm to 500 nm. The FT-IR spectrum of the nanocomposite consists of two broad bands, one at 580.4 cm−1 due to M–O stretching mode at the tetrahedral site and the other at 400.7 cm−1 due to M–O stretching mode at the octahedral site. The nanoparticles show a UV-Vis absorption band in the wavelength region of 400 nm to 700 nm. The energy band gap for the prepared nanomaterial was estimated to be 3.16 eV. Thus, the ferrite nanocomposite prepared by EWT is optically active. According to present literature, Raman spectroscopy study on zinc-copper ferrite system has not been reported till date. By suitable attributing various Raman modes, we have further confirmed the formation of ZCFO nanophase through the present novel approach.

Open access

Meryem Evecen and Hasan Tanak

great accuracy in reproducing the experimental values of geometry, vibrational frequency, electronic absorption spectra, etc. [ 16 , 17 ]. In the previous publication, the X-ray crystallography and IR spectra of (6-Methoxy-2-oxo-2H-chromen-4-yl)-methyl pyrrolidine-1-carbodithioate were studied [ 18 ]. In spite of its importance, mentioned above, no theoretical calculation concerning (6-Methoxy-2-oxo-2H-chromen-4-yl)-methyl pyrrolidine-1-carbodithioate has been published yet. The aim of this study is to investigate the spectral and structural properties of the

Open access

I. Md. Zahid, S. Kalaiyarasi, M. Krishna Kumar, T. Ganesh, V. Jaisankar and R. Mohan Kumar

shows the recorded infrared spectrum (400 cm −1 to 4000 cm −1 ) and Raman spectrum (4000 cm −1 to 500 cm −1 ) by using BRUKER IFS66VFT-IR and BRUKER RFS27 spectrometers, respectively. Fig. 5 Infrared and FT-Raman spectra of DSDMS. IR spectrum shows the prominent bands of ν (C=C) and ν (C–C) of aromatic ring at 1579 cm −1 and 721 cm −1 , respectively. Aromatic ring chain vibrations observed at 1576 cm −1 are due to C–C vibration in Raman spectrum. The vibrational bands of IR spectrum at 1040 cm −1 , 1176 cm −1 and 1164 cm −1 are assigned to ν

Open access

Mehmet Kara, Meryem Evecen and Telhat Özdogan

. [48] PAJAZK J., ROSPENK M., RAMAEKERS R., MAES G., GŁOWIAK T., SOBCZYK L., Chem. Phys., 278 (2002), 89. [49] ARIVAZHAGAN M., KRISHNAKUMAR V., JOHNXAVIER R., ILANGO V., BALACHANDRAN K., Spectrochim. Acta A, 72 (2009), 941. [50] VARASANYI G., Vibrational Spectra of Benzene Derivatives, Academic Press, New York, 1969. [51] SILVERSTEIN R.M., WEBSTOR F.X., Spectrometric Identification of Organic Compounds, 6th Ed., JohnWilley & Sons, New York, 1998. [52] COLTHUP N.B., DALY L.H., WIBERLY S.E., Introduction to