Concerns about consumer and worker safety and the fate of fumigants have fuelled strong efforts to determine their residues in foodstuffs. Fumigants are usually extracted from commodities with solvent at room temperature (25 degrees C). In this paper, solvent extraction of methyl bromide, phosphine, carbonyl sulfide, and carbon disulfide using ultrasonic acceleration or heating was evaluated. W...

A capacitive micromachined ultrasonic transducer structure for use in underwater imaging is designed, fabricated and tested in this paper. In this structure, a silicon dioxide insulation layer is inserted between the top electrodes and the vibration membrane to prevent ohmic contact. The capacitance-voltage (C-V) characteristic curve shows that the transducer offers suitable levels of hysteresi...

In this paper we describe an ultrasonic inspection system used for detection of surface defects in food cans. The system operates in pulse-echo mode and analyzes the 220 kHz ultrasonic signal backscattered by the object. The classification of samples into valid or defective is achieved with χ statistics and the k-nearest neighbour method, applied to features computed from the envelope of the ul...

Ultrasonic vibration assisted single point incremental forming (UVaSPIF) is based on localized plastic deformation in a sheet metal blank. It consists to deform gradually and locally the sheet metal using vibrating hemispherical-head tool controlled by a CNC milling machine. The ultrasonic excitation of forming tool reduces the vertical component of forming force. In addition, application of ul...

Ultrasonic appearance probably indicative of imminent fetal death One of the difficulties in recognising fetal death by ultrasonic scanning in early pregnancy is that the negative finding of no fetal heart movement must always be less convincing than a positive finding. Furthermore, Robinson' found only one instance of irregularity of the fetal heart in ten cases scanned before their pregnancie...

Micro-forming is a miniaturization technology with great potential for high productivity. Some technical challenges, however, need to be addressed before micro-forming becomes a commercially viable manufacturing process. These challenges include severe tribological conditions, difficulty in achieving desired tolerances, and short tool-life due to inability of available die materials to withstan...

vibration cutting (vc), elliptical vibration cutting (evc) and ordinary cutting (oc) of in738 work-pieces have been experimentally investigated in the present research. the experiments were carried out by using single crystal diamond tool and ultra-precision cnc lathe. vibration frequency is 36.16khz and the amplitude is . the influence of various cutting parameters including cutting speed, fee...