Open Access Short communication

Adiabatic Lapse Rate of Water is Negative Due to Its Negative Compressibility

Igor A. Stepanov

Physical Science International Journal, Page 1-5
DOI: 10.9734/PSIJ/2018/41720

When the pressure of a fluid changes without the addition of heat, the temperature of the fluid changes; the rate at which the temperature changes with pressure is called the adiabatic lapse rate. According to thermodynamic equations, the adiabatic lapse rate is positive if the thermal expansion coefficient is positive, and negative if this coefficient is negative. Experiments show, however, that the adiabatic lapse rate is also positive for substances with negative thermal expansion, although for water it is negative when it has negative thermal expansion. In the present paper, a theory is developed which shows that the adiabatic lapse rate must always be positive, but is negative for water because it has negative compressibility in that temperature–pressure region. Numerous substances with negative compressibility have already been identified.

Open Access Original Research Article

High Plasticity of an Iron Aluminide-based Material at Low Temperatures

V. Šíma, P. Minárik, M. Cieslar, R. Král, P. Málek, T. Chráska, F. Lukáč, H. Seiner, F. Průša

Physical Science International Journal, Page 1-11
DOI: 10.9734/PSIJ/2018/41673

Aims: To compare surprisingly high plasticity in compression at low temperature of high-quality compacts prepared by spark plasma sintering from atomized Fe-30.8Al-0.35Zr-0.11B (at%) powder with tensile tests at the same conditions.

Study Design: Compressive tests and tensile tests at room temperature and at 77 K, scanning and transmission electron microscopy, measurements of Young’s and shear moduli data of the sintered material from room temperature to 80 K.

Place and Duration of Study: Faculty of Mathematics and Physics, Institute of Plasma Physics, Institute of Thermomechanics, Department of Metals and Corrosion Engineering, between October 2015 and November 2017.

Methodology: The feedstock powder was prepared using atomization in argon and consolidated by spark plasma sintering method. The microstructure and phase composition of the sintered samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD) and by transmission electron microscopy (TEM). Mechanical properties of the feedstock powder were characterized by microhardness data, the compacts were in addition tested in compression and in tension. The elastic properties (Young’s and shear moduli) of the examined material were measured by a combination of two ultrasonic methods: the pulse-echo method and the resonant ultrasound spectroscopy.

Results: High plasticity (plastic strain more than 30% without failure) was observed in compressive tests at room temperature and at 77 K. Electron microscopy observations revealed the dominating role of dislocation motion in compression at low temperatures. The ductility measured at tensile tests, on the other hand, was only about 1% with a typical brittle failure.

Conclusion: The TEM observations confirm that dislocations enable the plastic flow in compression at low temperatures. The poor ductility in tension is not an intrinsic behavior of the alloy, but it results from the nucleation and opening of nano/microcracks between sintered powder particles and/or cavities in partly hollow atomized particles.

Open Access Original Research Article

Development of Viscosity Measuring Device Using Vibrational Technique

T. Ewetumo, K. D. Adedayo, M. A. Sodunke, Y. B. Lawal

Physical Science International Journal, Page 1-8
DOI: 10.9734/PSIJ/2018/40600

The project centers on the development of viscosity measuring device using vibrational techniques. The instrument consists of a variable power supply, two solenoids each with plungers, needle with a pendulum bob attached, switching circuit, current – voltage sensors, microcontroller, analog–to–digital converter and Liquid Crystal Display (LCD) unit. The developed system consists of a variable power supply used to create varying magnetic fields in the solenoids so that the plungers can attract and release the pendulum bob. As the magnetic field strength varies, the pendulum experiences force sufficient to overcome the internal friction within the liquid. The pendulum bob is thus set into periodic to and fro motion. The pendulum bob movement was monitored by a microcontroller through a reflective optical sensor. Viscosity was measured through the calibration constant generated from a liquid of known viscosity, applied voltage, current generated from the solenoids and the dragging time. Gear oil, engine oil, palm oil, olive oil were the fluids investigated with the developed system for performance evaluation. Statistical analysis revealed a percentage error value of 2.87% and accuracy of 97.13% which shows a good agreement between the standard and what is available in the literature. The instrument performed well and it is therefore suitable for the measurement of liquids' viscosities.

Open Access Original Research Article

Phenomenology of the Origin of Isotope Effect

V. G. Plekhanov

Physical Science International Journal, Page 1-11
DOI: 10.9734/PSIJ/2018/40223

Our paper describes the macroscopical manifestation of the origin of isotope effect via spectroscopic study of the reflection and luminescence spectra of LiH and LiD crystals which are differ by term of one neutron from each other. The experimental results demonstrate the direct evidence of the strong nuclear interaction. Inasmuch as the gravitation, electromagnetic and weak interactions are the same in both of kind crystals, it only changes the strong interaction. Therefore a sole deduction is made that the renormalization of the energy of electromagnetic excitations (electrons, excitons, phonons) is carried out by the strong nuclear interaction. The last one simultaneously indicates the origin of the isotope effect is caused by the strong nuclear interaction. The necessity to take into account the more close relation between quantum chromodynamics and quantum electrodynamics is underlined. In the first step the quantum electrodynamics should be taken into account the strong interaction at the description of the dynamics of elementary excitations (electrons, excitons, phonons) dynamics in solids.

Open Access Original Research Article

Measurement of Electric Field Radiation from 11KVA High Tension Power Line and Its Environmental Effects in Calabar Metropolis, Nigeria

Inyang, Ephraim P, Inyang, Etido P, William, Eddy S, Ushie, Patrick O, Oteikwu, Geoffrey A

Physical Science International Journal, Page 1-6
DOI: 10.9734/PSIJ/2018/41825

This study measured the electric field from high tension 11 KVA power line by varying the distance between 5 m to 30 m respectively using electrosmog meter. The results revealed that the highest amount of radiations of 1.601 V/m, 1.568 V/m, 1.451 V/m, 1.345 V/m, 1.238 V/m, 0.996 V/m and 0.579 V/m respectively were observed at a distance of 5 m in all the locations. In all cases, the measured radiations were very far below the exposure limits set by International Commission on Non-Ionizing Radiation Protection. It is therefore recommended that one should not stay very close to high tension power line even though short term exposure may not produce immediate health effect. Nevertheless, staying close to the source of radiation, strength of the electric field generated and long term exposure can be dangerous to individual health.