•Ewe’s milk coagulation process has been monitored in a dairy industry environment.•New ultrasonic parameters provided by the Fast Fourier transform (FFT) are studied.•Significant correlations were ...found between various ultrasound parameters.•Ultrasound parameters of the raw milk influence those measured during curdling.•FFT and attenuation are strongly correlated with protein content.
Ultrasound evaluation permits the state of milk being curdled to be determined quickly and cheaply, thus satisfying the demands faced by today’s dairy product producers. This paper describes the non-invasive ultrasonic method of in situ monitoring the changing physical properties of milk during the renneting process. The basic objectives of the study were, on the one hand, to confirm the usefulness of conventional non-destructive ultrasonic testing (time-of-flight and attenuation of the ultrasound waves) in monitoring the process in the case of ewe’s milk, and, on the other, to include other ultrasound parameters which have not previously been considered in studies on this topic, in particular, parameters provided by the Fast Fourier Transform technique. The experimental study was carried out in a dairy industry environment on four 52-l samples of raw milk in which were immersed 500kHz ultrasound transducers. Other physicochemical parameters of the raw milk (pH, dry matter, protein, Gerber fat test, and lactose) were measured, as also were the pH and temperature of the curdled samples simultaneously with the ultrasound tests. Another contribution of this study is the linear correlation analysis of the aforementioned ultrasound parameters and the physicochemical properties of the curdled milk.
A method for non-destructively tracking the integrity of flip chip solder joints through life is investigated in this paper. An industry standard double-sided PCB was designed and manufactured with ...14 flip chips to assess the failure patterns of each flip chip and each solder joint in lifetime vibration tests. Two configurations of PCB finish were tested, Electro Nickel Immersion Gold (ENIG) and Hot Air Surface Levelled lead (Pb HASL) using automotive industry manufacturing processes and quality standards. A random vibration test over a frequency range 10 Hz to 1000 Hz was specified by automotive engineers to replicate vibrations typically found on road vehicles. This vibration profile was applied to test circuit board assemblies (CBA) for 4-minute intervals until failure of all chips. At each interval test boards were extensively scanned by an acoustic micro-imaging (AMI) microscope to non-destructively measure parameters of solder joints. This enabled tracking of mechanical joint connection through-life. Methods were developed to process the large number of acoustic images of each solder joint and form metrics to evaluate solder joint integrity. Results from AMI show that the solder joints exhibit three distinct zones as they age: crack initiation, crack propagation and then failure.
Applying the thermoacoustic (TA) effect to diagnostic imaging was first proposed in the 1980s. The object under test is irradiated by high-power pulses of electromagnetic energy, which heat tissue ...and cause thermal expansion. Outgoing TA pressure pulses are detected by ultrasound transducers and reconstructed to provide images of the object. The TA contrast mechanism is strongly dependent upon the frequency of the irradiating electromagnetic pulse. When very high frequency (VHF) electromagnetic irradiation is utilized, TA signal production is driven by ionic content. Prostatic fluids contain high levels of ionic metabolites, including citrate, zinc, calcium, and magnesium. Healthy prostate glands produce more ionic metabolites than diseased glands. VHF pulses are therefore expected to generate stronger TA signal in healthy prostate glands than in diseased glands. A benchtop system for performing ex vivo TA computed tomography with VHF energy is described and images are presented. The system utilizes irradiation pulses of 700 ns duration exceeding 20 kW power. Reconstructions frequently visualize anatomic landmarks such as the urethra and verumontanum. TA reconstructions from three freshly excised human prostate glands with little, moderate, and severe cancerous involvement are compared with histology. TA signal strength is negatively correlated with percent cancerous involvement in this small sample size. For the 45 regions of interest analyzed, a reconstruction value of 0.4 mV provides 100% sensitivity but only 29% specificity. This sample size is far too small to draw sweeping conclusions, but the results warrant a larger volume study including comparison of TA images to the gold standard, histology.
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