An expression for the transmitted fraction of the uniform and parallel radiation incident upon the coupler between two rectangular light pipes of different physical dimensions is derived. It is a function of the pipe dimension ratio and the angle of the incident radiation. It is shown that for radiation nearly parallel to the pipe axis, it is possible to design a coupler for any pipe dimension ...

Waves and vortex shedding in corrugated pipes during gas injection can produce distinct tonal noise and structural vibration. In this study, we propose a model which couples an acoustic pipe and self-excited oscillation with vortex shedding over the cavity. In the model, the acoustic response of the corrugated pipe is simulated by connecting the lossless medium moving with a constant velocity w...

The feeder pipe in the pressurized heavy water reactor (PHWR) is exposed to a possible leakage during operation. Because of the geometrical complexity of the pipe and its inaccessibility due to a high radiation environment, it is difficult to examine the defect by the conventional ultrasonic method. The guided ultrasonic inspection was chosen for the inspection of the pipe. The torsional mode h...

We have determined the relativistic light deflection of the quasar J0842+1835 as Jupiter passed within 3.7 on 2002 September 8, by measuring the time delay using the VLBA and Effelsberg radio telescopes at 8.4 GHz. At closest approach, General Relativity (GR) predicts a radial (static) deflection of 1190 μarcsec, and tangential (retarded or dynamic) deflection in the direction of Jupiter’s moti...

OBJECTIVE To compare the deflection load characteristics of homogeneous and heterogeneous joints made by laser welding using various types of orthodontic wires. MATERIALS AND METHODS Four kinds of straight orthodontic rectangular wires (0.017 inch × 0.025 inch) were used: stainless-steel (SS), cobalt-chromium-nickel (Co-Cr-Ni), beta-titanium alloy (β-Ti), and nickel-titanium (Ni-Ti). Homogene...

The control of electric currents in solids is at the origin of the modern electronics revolution that has driven our daily life since the second half of 20th century. Surprisingly, to date, there is no thermal analogue for a control of heat flux. Here, we summarise the very last developments carried out in this direction to control heat exchanges by radiation both in near and far-field in compl...

OBJECTIVE The objective of this study was to determine the prevalence of water pipe smoking and its associated sociodemographic factors among Iranian women of reproductive age in Tehran. SUBJECTS AND METHODS This was a population-based cross-sectional study of 1,359 Iranian women aged 15-49 years. The multistage random cluster technique was used to obtain the sample. Questionnaire-based inter...