Wyniki wyszukiwania - BazTech

1

Effect of magnitude of sustained loading on the long-term deflection of RC beams

Shariq M., Abbas H., Prasad J.

Archives of Civil and Mechanical Engineering

|

2019

|

Vol. 19, no. 3

779--791

EN

The paper investigates the influence of the magnitude of sustained loading and tension steel percentage on the creep and shrinkage deflections of the reinforced concrete (RC) beams of different concrete grades. The magnitude of sustained loading was taken as 25% and 50% of the first crack load. Three concrete grades of 45, 35 and 25 MPa and two tension steel percentages of 0.77% and 1.21% were used. The long-term deflection was measured under the sustained four-point bending at the ages of 1, 3, 7, 14, 21, 30, 60, 90, 120 and 150 days. The shrinkage deflection of RC beams for the three concrete grades was measured at the same ages on specimens under their own weight. Based on the experimental investigations author's earlier model was extended to predict the total deflection due to creep and shrinkage of RC beams for varying magnitudes of sustained loading, and different compres-sive strengths of concrete.

2

Investigation on multiferroic properties of BiFeO3 ceramics

Shariq M., Kaur D., Chandel V. S., Siddiqui M. A.

Materials Science Poland

|

2013

|

Vol. 31, No. 3

471--475

EN

BiFeO3 polycrystalline ceramics was prepared by solid-state reaction method and its structural, optical and magnetic properties were investigated. BiFeO3 was synthesized in a wide range of temperature (825 – 880 °C) and a well crystalline phase was obtained at a sintering temperature of 870 °C. X-ray diffraction patterns of the samples were recorded and analyzed for the confirmation of crystal structure and the determination of the lattice parameters. The average grain size of the samples was found to be between 1 – 2 μm. The determined value of direct bandgap of BiFeO3 ceramics was found to be 2.72 eV. The linear behavior of M-H curve at room temperature confirmed antiferromagetic properties of the BiFeO3 (BFO). S shaped M-H curve was obtained at a temperature of 5 K. In the whole temperature measurement range (5 – 300 K) of M-T, no anomalies were observed due to high Curie temperature and Neel temperature of the BiFeO3.

3

Dielectric and spectroscopic analysis of cobalt doped potassium hexatitanate (K2Ti6O13) ceramics

Siddiqui M. A., Chandel V., Shariq M., Azam A.

Materials Science Poland

|

2013

|

Vol. 31, No. 4

555--560

EN

Pure and cobalt doped (x = 0.05, 0.10, 0.15 mol %) polycrystalline potassium hexatitanate (K2Ti6O13) ceramics were synthesized using conventional solid state reaction route. XRD result conﬁrmed the successful doping of Co in the K2Ti6O13 matrix, as no additional peak was observed in the pattern. Dielectric permittivity was found to decrease with the increase in frequency while it increased with the increase in doping. The dielectric loss decreased with small doping whereas excessive doping caused its augmentation. Ac conductivity (s ac ) has also been studied as a function of frequency at room temperature for all the samples. Scanning Electron Microscope (SEM) inspection of the synthesized samples showed the formation of rod like shapes. FTIR analysis was carried out to identify the chemical bonds present in the system.