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

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

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

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

The effects of ionizing radiation on the structure and antioxidative and metal binding capacity of the cell wall of microalga Chlorella sorokiniana

The impact of ionizing radiation on microorganisms such as microalgae is a topic of increasing importance for understanding the dynamics of aquatic ecosystems in response to environmental radiation, and for the development of efficient approaches for bioremediation of mining and nuclear power plants wastewaters. Currently, nothing is known about the effects of ionizing radiation on the microalgal cell wall, which represents the first line of defence against chemical and physical environmental stresses. Using various microscopy, spectroscopy and biochemical techniques we show that the unicellular alga Chlorella sorokiniana elicits a fast response to ionizing radiation. Within one day after irradiation with doses of 1–5 Gy, the fibrilar layer of the cell wall became thicker, the fraction of uronic acids was higher, and the capacity to remove the main reactive product of water radiolysis increased. In addition, the isolated cell wall fraction showed significant binding capacity for Cu2+, Mn2+, and Cr3+. The irradiation further increased the binding capacity for Cu2+, which appears to be mainly bound to glucosamine moieties within a chitosan-like polymer in the outer rigid layer of the wall. These results imply that the cell wall represents a dynamic structure that is involved in the protective response of microalgae to ionizing radiation. It appears that microalgae may exhibit a significant control of metal mobility in aquatic ecosystems via biosorption by the cell wall matrix

Genetski potencijal ozimog tritikalea kao zdravstveno bezbedne hrane

The objectives of this study were to investigate: (1) the effects of cultivar, environment, and their interactions on the grain yield, test weight and 1000 kernel weight of winter triticale, and (2) the correlations between these traits in different environments. Based on the grain results during a three-year investigation with two cultivars, it can be concluded that the grain yield of triticale significantly varied across years, from 4.251 t/ha in 2010/11 to 5.791 t/ha in 2012/13 in the study. The investigated period clearly indicates that highly significant effect of year was found on grain yield, test weight and 1000 kernel weight. Furthermore, test weight was highly significant regarding the interaction of the year and cultivar and significant for 1000 kernel weight. Environmental conditions have had a significant effect on grain yield and quality in triticale. Grain yield shows a tendency to increase in the years having a higher total amount and better distribution of rainfall during critical plant development stages.Ciljevi ove studije bili su istražiti: (1) uticaje sorte, životne sredine i njihove interakcije na prinos zrna, hektolitarsku masu i masu 1000 zrna kod ozimog tritikalea i (2) povezanost tih osobina u različitim vegetacionim sezonama. Na osnovu dobijenih rezultata, tokom trogodišnjeg istraživanja dve sorte tritikalea, može se zaključiti da je prinos zrna tokom godina značajno varirao od 4.251 t/ha u 2010/11 do 5.791 t/ha u 2012/13. Analizom varijanse ustanovljen je izuzetno značajan uticaj godine na prinos zrna, masu 1000 zrna i hektolitarsku masu. Štaviše, hektolitarska masa bila je vrlo značajna i značajna za masu 1000 zrna kod interakcije godina x sorta. Uslovi životne sredine su imali značajan uticaj na prinos zrna i kvalitet tritikalea. Prinos zrna pokazuje tendenciju rasta u godinama koje imaju veću ukupnu količinu i bolju raspodelu padavina tokom kritičnih faza razvoja biljaka

Mechanisms of detoxification of high manganese concentrations by the microalga Chlorella sorokiniana

Many neutrophilic and acidophilic microalgal species tolerate high metal concentrations and can survive or colonize metal-polluted waters. They show significant biotechnological potential for the remediation and wastewaters processing. On the other hand, negative effects of metal pollution on microalgae may affect the function of aquatic ecosystems because these photosynthetic microorganisms represent the primary producers of O2 and biomass. However, adaptive mechanisms that microalgae employ to detoxify metal excess are largely unknown. Herein we analyzed the response of the freshwater microalga Chlorella sorokiniana to high but non-toxic levels of Mn2+. Manganese is a key metal pollutant, with five possible oxidation forms that can bind to a variety of different ligands. At pH below 7, it is predominantly present in Mn2+ form. Scanning electron microscopy showed that in response to 1 mM Mn2+, C. sorokiniana released mucilage polymers within 1 h. Electron paramagnetic resonance spectroscopy (EPR) showed that the early response involved loose Mn2+ binding to mucilage and/or the cell wall. The amount of loosely bound Mn2+ was significantly decreased after 24 h, whereas biomass showed significant accumulation of Mn, O and P, as determined by energy dispersive X-ray spectrometry, indicating the production of polyphosphates, which may sequester Mn. Further, it was found that the exposure to Mn2+ resulted in rapid and transient decrease of total free glutathione concentration; the drop was observed after 1 h, and the concentration returned to initial values after 24 h. EPR measurements showed a similar trend in the level of reduced thiols. The observed changes can be explained either by the synthesis of phytochelatins – sulfurrich short-chain peptides that sequester metals, or by glutathionylation of proteins. Reduced thiols could not be detected in the extracellular space, indicating that C. sorokiniana did not release thiols in response to high Mn. These results demonstrate that the adaptive response of C. sorokiniana to high Mn levels involves multiple components and time phases. The early phase involves mucilage release, phytochelatins and/or protection of protein thiols, whereas the successive phase involves Mn coordination by polyphosphates and other mechanisms that remain to be resolved

Comparative impact of Mn2+ and Ni2+ on the microalga Chlorella sorokiniana

METHODS The impact of a set of concentrations of Mn2+ and Ni2+ on growth of C. sorokiniana culture in 3N-BBM+V medium in the early stationary phase was evaluated by changes in optical density at 750 nm and biomass during 7 days treatment. Mucilage release was analyzed using SEM microscopy. Redox settings were analyzed by oxidation-sensitive fluorescent probe and assays for thiols. RESULTS Ni was more toxic than Mn and affected culture growth at lower concentrations. Microalgal cells started releasing mucilage polymers within 1 h of exposure to 1 mM Mn2+, whereas no mucilage was observed even at 24 h of treatment with equimolar Ni2+. The peak of reactive oxygen species production was reached faster for Ni2+ than Mn2+. Mn-induced drops in the concentration of reduced thiols showed a recovery after 1 h and 24 h. Ni2+-induced drop was irreversible. The observed differences between the impact of Mn and Ni may be related to different redox and coordinative properties and to higher capacities of microalgae to sequester Mn in relation to higher quotas than Ni that are required for normal functi

The coordination and storage of manganese in the microalga Haematococcus pluvialis

Haematococcus pluvialis is a unicellular green alga of significant environmental and economic impact, well adapted to life in extreme conditions such as metal pollution. Manganese is a common pollutant of water bodies that is related to mining and industrial drainage, and microalgae have been applied in their bioremediation. To study changes in Mn redox and coordination form upon interaction with H. pluvialis cells, we exposed late exponential/early stationary green phase culture to 1 mM MnCl2 (Mn2+) for 72 h. Applied concentration exceeds microalgal physiological quota but it was non-toxic. Structure of coordinated Mn in the cells was analyzed using X-ray absorption near edge structure (XANES) and extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, while visualization and elemental mapping of Mn was performed by micro X-ray fluorescence (μXRF). XANES spectra showed that the oxidation form of Mn in H. pluvialis biomass remained 2+. However, EXAFS showed Mn coordination in microalgae is closer to hydrated MnSO4 with minor deviation of the local geometry. The shorter Mn-O bonds in biomass, compared to crystal model, implies somewhat more stable complex in H. pluvialis. This suggests that H. pluvialis may use sulphated polysaccharides for Mn sequestration, which would be a newly proposed mechanism of metal coordination and storage. μXRF analysis showed co-localization of Mn with O and Na, with particularly good superimposition for Mn and O. O-rich regions may represent vacuoles, filled with organic acids including sulphates, or starch granules and accumulations of sulphated polysaccharides, which are known to be produced by H. pluvialis. In addition, vacuoles in plant cells are known to act as sinks for Na+ ions. These findings are in line with structural analysis that showed dark precipitates in vacuoles, which are likely accumulations of Mn

Impedance response of pseudobrookite thick films with a sandwich configuration

We have investigated the impedance response of pseudobrookite thick films screen printed on alumina substrate in the temperature interval from room temperature to 350 °C in the frequency range 100 Hz-1 MHz. Two thick film pastes were made containing starting hematite and anatase nanopowders (in the 1:1 and 1:1.33 molar ratio - containing excess anatase), glass fritt and organic vehicle. A sandwich PdAg electrode structure was obtained by first printing a PdAg electrode, followed by 3 layers of PSB paste and a PdAg electrode on top with a mesh structure. Each layer was sintered at 850 °C in a hybrid conveyor furnace. XRD analysis confirmed the formation of pseudobrookite with an orthorhombic crystal structure. SEM analysis of thick film surfaces and cross sections showed the formation of a porous structure with rod-shaped grains. The impedance response of pseudobrookite thick films, showed a decrease with the rise in sample temperature. It was analyzed using an equivalent circuit reflecting the dominant influence of grain boundaries