IMEKO Event Proceedings

Page 812 of 822 Results 8111 - 8120 of 8218

Hiromichi Murata, Ryohei Seya, Tatsuya Oku, Miyu Ozaki, Ryoshu Furutani
VISUALIZATION AND ANALYSIS OF A FLOW-RATE DISTRIBUTION IN A LIQUID-LIQUID TWO-PHASE FLUID USING SURFACE PLASMON POLARITONS

Optical energy propagates along the metal surface as collective oscillations of free electrons when optical waves are irradiated with the resonant condition. The oscillations with electrical fields are called surface plasmon polaritons (SPPs). SPPs are applied to sensors since excitation condition of SPPs sensitively responses to refractive indices. Here, using SPPs, a flow of a liquid-liquid two-phase fluid is visualized, and a flow-rate distribution is derived. A channel is made on the silver-film surface deposited on a slide glass, and filled with ethanol-aqueous solution. In this condition, SPPs are excited on the silver surface by Helium- Neon laser. The laser is expanded and collimated to obtain two dimensional images. Then, water is injected into the channel at a constant pressure. SPPs disappear gradually as the water comes close to near-field of the silver surface, because SPP excitation is optimized to the ethanol-aqueous solution, not to water. The SPP disappearing is visually observed in reflected light. Changes in brightness at the centre of the channel in a recorded movie are converted to changes in distance between the water layer and silver surface, based on simulation of SPP excitation. As a result, we confirmed that the flow speed of the vicinity of the silver surface is slower than that of the distant position. This flow rate distribution corresponds to a theory that a velocity gradient is caused by the shearing force between fluid and wall surface. Presented method doesn’t require any tracer particles or coloring though sample fluids are clear and colorless.

Andrey Aslanyan, Edward Aslanyan, Febo Menelao, Zhi Li
VNIIFTRI / PTB BILATERAL COMPARISON ON MARTENS AND INDENTATION HARDNESS SCALES

The present article contains the results of bilateral comparisons in the field of nanoindentation conducted in 2014 in the framework of cooperation between PTB and metrological institutes of Russia. The comparisons were held using primary standard machines applied in PTB and VNIIFTRI. Hardness numbers of Martens and indentation hardness scales obtained by the two laboratories were compared with due consideration of expanded uncertainties of measurements.

Domenico Luca Carnì, Domenico Grimaldi
Voice Quality Measurement in Telecommunication Networks by Optimized Multisine Signals

The paper deals with the test signal selection to be adopted for the Voice Quality Measurement (VQM) in telecommunication networks. It is proposed to use the optimized multisine as test signal in place of both the natural and the artificial voices, suggested by the ITU-T recommendations. The effectiveness of the optimized multisine to the VQM is investigated by using four algorithms: (i) Perceptual Speech Quality Measurement, (ii) Perceptual Speech Quality Measurement plus, (iii) Perceptual Evaluation of Speech Quality, and (iv) Perceptual Analysis Measurement System. Numerical tests are performed in order to compare the output index of the four algorithms feed by the optimized multisine, the natural and the artificial voice signals. In order to take into account the effects of the actual telecommunication networks, the Modulated Noise Reference Unit is used to corrupt both the multisine and the voices. The tests show the effectiveness of the proposed approach, based on the use of the optimized multisine, respect to the traditional procedures.

Tomáš Dresler, Jan Holub, Radislav Šmíd
VOICE TRANSMISSION QUALITY MEASUREMENT BASED ON WAVELET TRANSFORMATION

A new method for objective voice quality measurements is described in the article. It is based on wavelet transformation that enables intrinsically also time localisation of eventual impairments. In comparison with other methods (based on P.861 and P.862 algorithms), the described method saves about one half of operations needed for achievement of comparable results, thus saving computation power and time.

Boscaino, F., Coccia, E., Paolucci, M., Siano, F., Sorrentino, G., Di Stasio, M., Moccia, S., Volpe, M. G.
Volatile molecules and phenolic profile of hemp edible products

The aroma and flavor that characterize the edible products of Cannabis sativa L. can be attributed to both flavonoids and volatile molecules. Such compounds are particularly important for the taste and aromatic characteristics. The volatile profile of a sample is one of the most appreciated properties and plays a key role in determining its perception and acceptability. Depending on their presence and amount, volatile compounds influence the organoleptic characteristics of food products as well as the sensorial perception, and are responsible for their unique flavor and aroma.
Many phenolic compounds impart specific fragrances and tastes to various products in which they are present, for example the fruity aroma and spicy flavor and bitterness characteristic of extra virgin olive oil.
Currently, the phenolic profile of the edible products of hemp chain and their volatile components have not been investigated. Therefore, in the present study the specific phenols and volatile profile of the products of food hemp chain were determined. Both the qualitative and the quantitative composition of the phenolic fraction were performed by HPLC analyses. The results obtained in this study showed that food hemp products contain significant amounts of polyphenols, especially flavonoids such as flavanones, flavanols, flavonols and isoflavones.
The volatile components of hemp seed, oil and flour samples, were analyzed by SPME-GC / MS, and the values expressed as RPA% (ratio relative to peak area and the total area). Identified compoundsbelonged to aldehydes, ketones, alcohols, acids, lactones and Terpenes (monoterpenic and sesquiterpenic components).The volatile compounds present in about 50% on the total of VOC were monoterpenes. The profile of the monoterpene components was very similar among the three types of samples, particularly inflour and seed samples, where the most abundant monoterpene was limonene, whereas in hemp oil was alpha and beta-pinene.

H. Ndilimabaka, P. Espel, A. Poletaeff
VOLTAGE MEASUREMENTS FOR DISTORTED WAVEFORMS

This paper describes a standard system at LNE to measure RMS value of distorted voltage waveforms by means of a sampling voltmeter. Thermal converters are used to trace this quantity to the SI units. Deviations within 15 µV/V are obtained whatever the total harmonic distortion of the waveforms.

H. Ndilimabaka, P. Espel, A. Poletaeff
VOLTAGE MEASUREMENTS FOR DISTORTED WAVEFORMS

This paper describes a standard system at LNE to measure RMS value of distorted voltage waveforms by means of a sampling voltmeter. Thermal converters are used to trace this quantity to the SI units. Deviations within 15 μV/V are obtained whatever the total harmonic distortion of the waveforms.

Antonino Oscar Di Tommaso, Fabio Genduso, Rosario Miceli, Ciro Spataro
Voltage Source Inverters an Easy Approach for Fast Fault Detection

Fault-tolerant converters have been widely investigated for years and nowadays an extensive technical literature on this field exists. This paper presents a novel fault detection algorithm based on a simple geometrical approach. In the algorithm analysis both the case of faults in single device and the loss of an entire inverter leg have been considered. The proposed methodology is characterized by simplicity, low computational and implementation effort with a consequent fast execution and easy control integration. The suggested algorithm is verified by means of experimental tests and reveals a valid and suitable alternative to the existing state of the art in the field of inverter fault detection.

Milan Stork
VOLTAGE TO FREQUENCY CONVERTER

Voltage to frequency converter (VFC) is an oscillator whose frequency is linearly proportional to control voltage. The charge balanced VFC may be made in asynchronous or synchronous (clocked) forms. The synchronous charge balanced VFC or "sigma delta" (Σ-Δ) VFC (SVFC) is used when output pulses are synchronized to a clock. The charge balance VFC is more complex, more demanding in its supply voltage and current requirements, and more accurate. It is capable 16 to 18 bit linearity. The synchronous behaviour is good in many applications, but the output of SVFC is not a pure tone (plus harmonics) like a conventional VFC, but it contains components harmonically related to the clock frequency. In this paper, the new SVFC (NSVFC) is described. This NSVFC works similarly as conventional SVFC but it has a pure tone on output (for constant input voltage). Therefore, it is possible to measure the period of NSVFC output (this does not possible for SVFC).

Milan Stork
VOLTAGE TO FREQUENCY CONVERTER AND FRACTIONAL FREQUENCY DIVIDER BASED ON MODIFIED SIGMA-DELTA CONVERTER

Voltage to frequency converter (VFC) is an oscillator whose frequency is linearly proportional to control voltage. In this paper, the New Synchronous Voltage to Frequency Converter (NSVFC) or "sigma delta" (Σ-Δ) voltage to frequency converter is described. This NSVFC works similarly as conventional synchronous voltage to frequency converter (SVFC), but it has a better frequency spectral property then other SVFC and therefore it is possible to used as fractional frequency divider and also building block in fractional phase locked loop (PLL). An experimental NSVFC was constructed and simulated to verify operation of the converter. Analysis and prototype of NSVFC is described.

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