Three-Axis’ Heat Loss Anemometer Comprising Thick-Film Segmented Thermistors

NTC thick-film segmented thermistors were used as anemometer sensing devices. They were screen printed of thick-film thermistor paste based on modified NiMn2O4 fine powder, organic vehicle, and glass frit. Their electrical properties, such as resistance vs. temperature R(T) and thermistor exponential factor B were obtained using measurements in the climatic test chamber. A uniaxial anemometer was formed using a thick-film segmented thermistor, which was placed in the hole drilled in rectangular piece of thermally insulating material. The uniaxial anemometer was used for the optimization of operating point of segmented thermistors as self-heating/wind sensing devices. The dc supply voltage was correlated with the air temperature sub-ranges (RCV). The power save mode such as 30s self-heating/5 min pause was used to measure the thermistor response on stable wind blow. The three-axis' anemometer was formed using five sensor devices placed in five holes drilled in the cubical piece of thermally insulating material: three thermistor sensors measure wind speed on the x, y, z - axes, the fourth sensor Pt 1000 measures the air temperature T, while the fifth sensor (capacitive type) measures humidity H. The obtained sensitivity and inaccuracy were compared with respective ones of other anemometers

Designing by CAD application software in order to improve production process

U ovom radu dat je prikaz rešenja koje je projektovano pomoću CAD aplikativnih softvera. Rad je koncipiran da pokaže kakav je značaj upotrebe aplikativnog softvera u domenu: racionalne potrošnje materijala, analize ponovne upotrebe proizvoda i elemenata zaštite životne sredine. U cilju optimizacije celokupnog procesa projektovanja, razvoja i/ili održavanja sistema u različitim granama industrije (gradjevina, mašinstvo). Dakle, posredstvom istih u značajnoj meri se pojednostavljuje: 3D modelovanje kako pojedinačnih mašinskih komponenti, tako i podsklopova i sklopova, izrada prateće 2D tehničke dokumentacija, izrada komponenti na CNC mašinama, proračun čvrstoće, odnosno radnog veka i integriteta konstrukcije. Ključne reči: Proizvod, projektovanje, CAD aplikativni softver, materijal, strategije, zaštita životne sredine.This work contains a display of solutions which is projected using CAD applicable software. The Study is designed to show what is the meaning of usage of applicable software within the following domain: rational consumption of material, analysis of reuse of products and elements of environmental protection, in order to optimize the complete process of designing, development and/or sustaining systems in different industry branches (construction, machinery). Therefore, by means of aforementioned, comes to considerable simplicity of 3D modeling of, forasmuch as individual machinery components, as much as subassemblies and assemblies, creation of following 2D technical documentation, creation of components on CNC machines, forecast of solidity, operating time and construction integrity

Application of thick film segmented thermistors for measurement and analysis of ground top layer temperature profile

A new sensor for measuring ground top layer temperature profile was formed as a row of 40 thermistor segments connected in series, with which the change of temperature in the soil is mesaured and placed on 550 mm depth. The temperature sensor is multiple protected of humidity, calibrated on room temperature and placed vertically in the hole drilled on the lawn. The main electrical properties of the new sensor based on NTC thick film segmented thermistors are given in brief. The ground top layer temperature profile measurements were done in 40 points at 7am and 2 pm each day from the beginning of November 2017 to the end of February 2018.At the same time and in the same period of time the air temperature were measured and recorded. The results of measurements of ground top layer temperatureT(t,z) were given in daily and monthly diagrams as a function of time t and ground deepness d on z-axis. The correlation between ground top layer temperature profile and air temperature was analyzed: changes of ground temperature gradient and effect of precipitations on ground temperature profile. The results obtained enable study of temperature regime of ground top layer.Novi senzor temperaturnog profila gornjeg sloja zemlje, formiran je kao niz od 40 termistorskih segmenata redno vezanih, kojim se meri promena temperature, u zemlji do dubine d=550 mm. Temperaturni senzor je višestruko zaštićen od vlage, kalibrisan na sobnoj temperaturi i postavljen u vertikalno izbušenu rupu na travnjaku. Osnovne električne karakteristike novog senzora na bazi NTC debeloslojnih segmentiranih termistora date su ukratko. Merenje temperaturnog profila gornjeg sloja zemlje u 40 tačaka vršeno je u 7 i u 14 časova od početka novembra 2017. do kraja februara 2018. godine. U tom periodu u istim terminima merena je i temperatura vazduha. Rezultati merenja temperature gornjeg sloja zemlje T(t,z) prikazani su dijagramima sa dnevnim i mesečnim pregledom kao funkcija vremena t i dubine zemlje d po z-osi. Analizirana je korelacija između temperature gornjeg sloja zemlje i vazduha: promena gradijenta temperature tla i uticaj padavina na temperaturni profil. Dobijeni rezultati omogućavaju dalje proučavanje temperaturnog režima gornjeg sloja zemlje

Influence of starting powder milling on magnetic properties of Mn-Zn ferrite

In this paper, the influence of additional sieving and milling of starting industrial Mn-Zn powders on magnetic properties was investigated. The starting powder was milled for 60 minutes, followed by sieving through 325 and 400 meshes. The starting and milled powders were used to fabricate toroid shaped samples sintered at 1200°C for 2 hours. Structural parameters of the fabricated samples were analysed by X-ray diffraction and scanning electron microscopy. Complex permeability, core loss density, and hysteresis were measured using the modified watt-meter method. The complex permeability and hysteresis loop were modelled with a new model proposed in the paper. The core loss density was modelled with the Steinmetz empirical equation. The experimental results and calculations show the significance of the additional milling and sieving process on magnetic properties of Mn-Zn ferrite in the frequency range 0.1-10MHz. These processes increase the relative permeability about 3 times and decrease the core loss 4 times by milling of the starting powder

Application of thick film segmented thermistors for measurement and analysis of ground top layer temperature profile

A new sensor for measuring ground top layer temperature profile was formed as a row of 40 thermistor segments connected in series, with which the change of temperature in the soil is mesaured and placed on 550 mm depth. The temperature sensor is multiple protected of humidity, calibrated on room temperature and placed vertically in the hole drilled on the lawn. The main electrical properties of the new sensor based on NTC thick film segmented thermistors are given in brief. The ground top layer temperature profile measurements were done in 40 points at 7am and 2 pm each day from the beginning of November 2017 to the end of February 2018.At the same time and in the same period of time the air temperature were measured and recorded. The results of measurements of ground top layer temperatureT(t,z) were given in daily and monthly diagrams as a function of time t and ground deepness d on z-axis. The correlation between ground top layer temperature profile and air temperature was analyzed: changes of ground temperature gradient and effect of precipitations on ground temperature profile. The results obtained enable study of temperature regime of ground top layer

Radiological and physicochemical properties of red mud based geopolymers

A significant amount of red mud generated as a by-product of the Bayer process in the aluminum industry may cause environmental problems if appropriate treatment is not carried out. The presented research dealt with the possibility of application of red mud as a pigment or as raw material for use in the construction material industry. In relation to the aim of this work, the physicochemical characterization was performed and the natural radioactivity of red mud as an industrial waste and a geopolymer sample based on it was determined. The presented research is a contribution to the potential solution for environmental protection through the synthesis of possible construction material based on red mud. The radiological hazard orginating from 226Ra, 232Th, and 40K in the samples was assesed throught the absorbed dose rate and the annual effective dose rate, calculated in accordance with the UNSCEAR 2010 report. Physicochemical characterization of all samples was conducted using X-ray diffraction and diffuse reflectance infrared Fourier transform spectroscopy. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45012