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Invasive transit-time ultrasonic flow measurement involves the use of ultrasonic transducers, which sense the flowing fluid and are the most important parts of an ultrasonic flowmeter. In this study, two ultrasonic transducers were designed, numerically simulated and fabricated to be used in an ultrasonic gas flowmeter.

PZT-5H piezoceramic elements with specific dimensions were designed and used as beating heart inside the transducers. Different methods, including impedance-frequency analysis, optical emission spectroscopy and performance tests in pressurized chambers were used to evaluate the piezoelectric elements, ultrasonic transducer housings and the fabricated transducers, respectively. In addition, finite element method results showed its ability for design stages of ultrasonic transducer.

Experimental results for transit time difference (TTD) and the normalized received voltage were compared with simulation results at the same conditions. There was a quite good agreement between the two method results. Extensive simulation results showed that under the considered range of environmental conditions, the change of acoustic path length has the most impact on TTD, with respect to temperature and pressure. A change of 1 mm in acoustic path length leads to 0.74 per cent change in TTD, approximately. In addition, for normalized received voltage, 1 bar change in pressure has the most impact and its value is as high as 3.76 per cent.

This method is possibly used in ultrasonic gas flowmeter fabrication.

In this work, design, fabrication, experimental tests and numerical simulation of ultrasonic transducers are presented.

Recently, evidences have suggested that healthy eating index (HEI), an index-based dietary pattern, may be a predictor for the risk of cancer. This paper aims to examine the association of HEI-2015 and its all components scores with the risk of breast cancer (BC), separately, among Iranian women.

In the present hospital-based, case-control study, 150 age-matched of cases (newly diagnosed female) and 150 controls were recruited. Data of dietary habits and anthropometric measures were obtained, and eventually, the HEI-2015 score was calculated. Multivariate odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the relationship between the risk of BC across tertiles (Ts) of total HEI-2015 and its all component scores.

The results presented that in adjusted model, there was no significant difference between total HEI-2015 (p = 0.14) and its all component scores (p > 0.09) of healthy subjects and females with BC. Moreover, multivariable logistic regression analyses indicated that HEI-2015 score was not associated with the risk of BC in either crude (p-trend = 0.94) or adjusted (p-trend = 0.73) analyses. In the analyses of HEI-2015 components scores, it was observed that the scores of grains (OR, 0.53; 95% CI, 0.30–0.94) and total protein foods (OR, 0.13; 95% CI, 0.02–0.58) may have a relation with BC risk in crude model but after adjusting for BC risk factors, the mentioned associations changed to non-significant.

The findings of current study suggested that there was no significant association of total HEI-2015 and its components scores, independently, with BC incidence among Iranian women.