Objave

Pri načrtovanju praktičnega akustičnega termometra (PAT) z eno cevjo je treba upoštevati določena pogoje za optimalno delovanje. Ta članek obravnava glavna vprašanja, povezana z izgradnjo zanesljivega PAT-a. Poudariti je treba, da PAT meri razmerje časovne zakasnitve med posamezno umeritveno točko temperature (točka ledišča) in katero koli drugo temperaturo. Tukaj predstavljamo različne modele za hitrost zvoka v cevi, vključno z učinki realnih plinov in analizo pogreškov najbolj natančnega modela s simulacijo Monte Carlo. Poleg tega predstavljamo problem prekrivanja zvočnega signala in nekaj možnih rešitev, od katerih je ena možnost z dušenjem neželenega zvočnega signala, druga pa optimizacija dolžine cevi glede na parametre uporabljenega plina in specifično temperaturno območje.

V prispevku je predstavljen nov merilni sistem za zaznavanje anomalij zračne reže v elektromotorjih z neposrednim pogonom. Predlagana je nova metoda merjenja z uporabo şenzorskega sistema, vgrajenega v zračno režo motorja, za neposredno merjenje širine v statičnem ali dinamičnem stanju. Uporablja optični senzorski sistem (OS) za merjenje odboja infrardečega sevanja med rotorjem in statorjem. Metoda je potrjena z uporabo vzporednega merilnega sistema, ki uporablja analogni Hallov senzorski sistem (AHS), ki meri spremembo gostote magnetnega pretoka. Oba merilna sistema se umerita tako, da ju primerjamo z referenčnim laboratorijskim merilnim sistemom. Z uporabo različnih tehnik kalibracije dobimo optimalno točnost sistema z največjo dovoljeno napako 0,15 mm v merilnem območju med 0 in 2 mm. Zajema večino aplikacij elektromotorjev z neposrednim pogonom. Nova metoda merjenja je eksperimentalno potrjena z OS sistemom in validacijskim sistemom, sestavljen iz AHS sistema, integriranega na preskusno platformo (avtomobil Smart Fortwo).

Thermometers in laboratory environment and industrial applications are often subject to extraneous, usually unwanted and uncontrolled magnetic fields. The goal of this paper was to analyse and empirically and experimentally prove the magnetic sensitivity of thermocouples exposed to low magnetic fields: both dc and ac. The magnetic effect on ferromagnetic and non-ferromagnetic thermocouples at liquid-nitrogen-boiling point (−196 °C), ice point (0 °C), in water (17 °C) and at melting point of gallium fixed point cell (29.7646 °C) was investigated.

This paper describes the problem of thermographic cameras, which are widely used for accurate measurement of temperature and not just temperature differences, which is more easy. To provide accurate and reliable measurements it is necessary to calibrate the thermal imaging camera, which allows assessment of the entire field of vision. To this end, we created a black body with a large opening, which has better temperature stability and homogeneity as the temperature sensitivity of the detector thermal imaging cameras.

In scope of research and development activities in the field of medical measuring instrumentation, we developed a procedure for evaluation of noninvasive blood pressure patient simulators, which enable reliable and repeatable testing of oscillometric automatic non-invasive blood pressure devices.

PDF

In this paper, exponentially damped sinusoidal signals are analyzed. Simple algorithms for fast measurement and estimation of the unknown damping, frequency, amplitude and phase are presented. The peaks of the discrete Fourier transform (DFT) results are adopted to obtain the parameters. The concept of quotient interpolation using the Hann window for the basic three parameters is also adopted for the damping estimation. In the case of the weakly damped sinusoids with dumping values up to 1, using the rectangular window in the estimation reduces the systematic errors in comparison with the Hann window, especially in the vicinity of the coherent sampling conditions.

Pretekle raziskave so pokazale izboljšanje priporočilnih sistemov, ko so, poleg žanra, bile uporabljene še emotivne značke. Te značke lahko pridobimo na dva načina, ki imata svoje prednosti in slabosti: na ekspliciten način (natančne značke, vsiljivost sistema, počasnost) ali impliciten način (nenatanče značilke, a uporabniku skrito in prijazno). V tem članku smo opravili primerjavo vsebinskega priporočilnega sistema ki uporablja eksplicitni in implicitni način pridobivanja značilk. Rezultati so pokazali, da je uspešnost priporočilnega sistema z eksplicitnimi značilkami značilno boljša od implicitnih značilk.

Za merjenje površinske vlage in vlage ob površini kompleksnih elementov s tankimi stenami, smo razvili in testirali brezkontaktni senzor površinske vlage.
In order to be able to measure the surface and near-surface moisture on a complex geometry with thin walls, a novel, non-contact, light-reflection type of moisture sensor was designed and investigated.

Heat loss is one of the key parameters that cause temperature errors during the calibration of thermometers in metal-freezing-point cells and thus increases the measurement uncertainty. At temperatures above the freezing point of tin, thermal radiation becomes the dominant mode of heat transfer. In addition, radiative heat transfer is especially important in the cells’ glass structures, where total internal reflection (known as “light piping”) can occur. A quantitative measure of the radiative heat loss is difficult to determine with measurements, but a qualitative check can be performed by measuring the vertical temperature profile in a cell during a freezing-point realization. Our custom-built model is capable of modeling both the radiative and conductive heat transfers and can deal with complex radiation phenomena specific to the particular case study. The modeling and experimental results are used to give an estimation of the error due to heat losses.

Magnetometri z optičnim črpanjem predstavljajo alternativo SQUID magnetometrom, tudi na področju detekcije bioloških magnetnih signalov. Njihova dobra lastnost je njihova zmožnost delovanja kot večkanalni senzor, čeprav je večina sestavnih delov skupna vsem kanalom. V članku sta predstavljeni dve konfiguraciji večkanalnega magnetometra. Opisane so meritve in lokalizacija magnetnih signalov slušnega korteksa.