Nondestructive evaluation of the thermophysics properties materials by IR thermography

Cilj ovog rada je poboljšanje, razvoj i primena impulsne termografije kao eksperimentalnog metoda za otkrivanje defekata u materijalu. Da bi se ostvario taj zadatak, rad je usmeren ka tri sledeća pravca: 1. Eksperimentalna istraživanja koja obuhvataju razvoj i poboljšanja uslova za merenje i akviziciju podataka. 2. Teorijska istraživanja koja obuhvataju analitičko i numeričko rešavanje sistema parcijalnih diferencijalnih jednačina provođenja toplote kondukcijom uz odgovarajuće početne i granične uslove. 3. Teorijska istraživanja koja podrazumevaju primenu metode i procedure u impulsnoj infracrvenoj termografiji za date teorijske i eksperimentalne uslove. U toku prvog dela istraživanja, izrađeni su posebni uzorci pipremljeni za eksperiment, gde su na jednoj strani ploče podjednako razmaknuti žljebovi praveći periodičnu defektnu strukturu sa određenom prostornom frekfencijom i određenom dubinom. Druga strana ploče bila je ozračena kratkim svetlosnim impulsom i temperaturna raspodela na istoj strani bila je analizirana impulsnom infracrvenom termografijom. U drugom delu testirani su različiti modeli koji opisuju dvodimenzionalnu kondukciju toplote kroz planparalelnu ploču sa defektom u obliku žljeba sa ravnim dnom sa opštim i posebnim početnim i graničnim uslovima. U trećem delu izvršeno je poređenje eksperimentalnih rezultata i rezultata simulacije u cilju utvrđivanja uslova i granica primenljivosti metoda za periodičnu strukturu defekata. Izvršena je teorijska analiza i eksperimentalna provera metoda u slučaju defekata u aluminijumskoj ploči.The aim of this paper is improving, development and application of pulsed thermography as experimental method for detection of defect in material. To accomplish this, the paper has 3 aspects: 1. Experimental research including оf development and improving conditions for measuring and data acquisition. 2. Theoretical research containing of analitycal and numerical solving the system of partial differential equations for heat convection by conduction, with corr esponding initial and boundary conditions. 3. Theoretical research considering method and procedure application in pulsed infrared thermography for given theoretical and experimental conditions. During the first part of research, specific samples were prepared for experiment where at one side of the plate equally spaced slots are forming the periodical structure of defects with defined spatial frequency and depth. The other side of plate was irradiated with short light pulse and temperature distribution on that side was analized by pulsed infrared thermography. The second part of the research, considers different models describing twodimensional heat conduction through planparallel plate with defect in form of flat-bottom slot, with general and specific initial and boundary conditions. In the third part of research, comparison of experimental results and results of simulation was made to determine the conditions and limits of method applicability for periodically structured defects. The theoretical analysis and experimental testing of the method was done for the defects in aluminum plate

Uticaj načina ishrane azotom i vremena setve na prinos soje

In this work influence of the way of nitrogen nutrition (by fertilization and by inoculation) and sowing time on soybean yield, was investigated. In two varieties (Bačka and Dragana), with inoculation and without inoculation of seed, fertilization was done with 50 and 100 kg/ha of nitrogen, plus control (without fertilization). In all variants of investigation it was obtained a very high seed yield (4,35-5,69 t/ha). The highest yield was obtained in combination of fertilization with 100 kg/ha of nitrogen, as well as with inoculation so without inoculation, and the lowest in variants without fertilization and inoculation. On the variant with seed inoculation, and without nitrogen fertilization, seed yield of both varieties was higher for 7,27% than without inoculation. Also, inoculation but without fertilization gave for 130 kg/ha seed yield than in combinations of fertilization with 50 kg/ha of nitrogen and without inoculation. Soybean is the plant which react very strong to sowing time, because it significantly prolong or shorten the duration of some development stages and total duration of vegetation period. It react very positively to the early sowing terms and because of that, in our growing conditions (especially in more arid), it should be sown before corn. .U ovom radu je isplivan uticaj načina ishrane (đubrenjem i inokulacijom) azotom i vremena setve na prinos soje. Kod dve sorte (Bačka i Dragana), sa inokulacijom i bez inokulacije semena, vršeno je đubrenje sa 50 i 100 kg/ha azota, plus kontrola (bez đubrenja). U svim varijantama ispitivanja postignut je vrlo visok prinos semena (4,35-5,69 t/ha). Najveći prinos postignut je u kombinacijama đubrenja sa 100 kg/ha azota, kako sa inokulacijom tako i bez inokulacije, a najmanji u varijantama bez đubrenja i inokulacije. Na varijanti sa inokulacijom semena, a bez đubrenja azotom, prinos semena obe sorte bio je veći za 7,27% nego bez inokulacije. Takođe, inokulacija a bez đubrenja je dala za 130 kg/ha prinos semena nego u kombinacijama đubrenja sa 50 kg/ha azota i bez inokulacije. Soja je biljka koja vrlo oštro reaguje na vreme setve, stoga što ono značajno produžava ili skraćuje trajanje pojedinih faza razvića i ukupne dužine vegetacionog perioda. Ona vrlo pozitivno reaguje na rane rokove setve i zato je, u našim uslovima gajenja (posebno u aridnijim), treba sejati pre kukuruza

Thermobaric Effects of Cast Composite Explosives of Different Charge Masses and Dimensions

The aim of this research was to determine the thermobaric effect of cast composite explosives, with different masses and dimensions of the chosen explosive charges. This was done by measuring the shock wave parameters in air (maximum overpressure and pressure impulse) and quantifying the thermal effect (temperature-time dependence), at different distances from the centre of the detonation. The chosen thermobaric explosive composition, TBE-3, was characterized. Its density, detonation velocity and viscosity-time dependence were determined. Experimental samples of different masses and calibres were prepared. The shock wave parameters in air were determined in field tests, by measuring the overpressure by piezo-electric pressure transducers. The detonation and the expansion of the explosion products were filmed by a TV high-speed camera, Phantom V9. An infrared (IR) camera FLIR SC7200 was used for recording the IR scene of the explosions and for tracking the thermal effects by a thermographic technique, i.e. thermal imaging. This work is an initial step towards establishing a method for the quantification of the thermal effects of a thermobaric detonation

Usporedba frakcija proteina i masnih kiselina mlijeka balkanskog magarca i humanog mlijeka

The aim of this study was to compare the protein and fatty acid fractions of Balkan donkey and human milk in the early lactation stage (40 and 90 day). This study revealed that donkey milk contains αs1-casein (1.38-1.89 g/L) and higher concentration of β-casein (0.1-0.55 g/L) in comparison to human milk. The concentration of α-lactalbumin increased during the lactation phases from 40 to 90 days in both types of milk. Donkey milk contained β-lactoglobulin in low concentrations which decreased to 90th day of lactation. Donkey milk was particularly rich in two whey proteins, lactoferrin and lysozyme, which were found to have molecular weight of approximately 76 kDa and 14.9-15.4 kDa, respectively. The content of lysozyme in donkey milk ranged from 2.39 to 2.97 g/L, while human milk contained 30-50 times lower concentrations of lysozyme in comparison to donkey milk. Thus, donkey milk contained also a higher concentration of lactoferrin (0.012-0.25 g/L) than it was found in the human milk. Lysozyme and lactoferrin content in donkey milk increased during the period from 40th to 90th day of lactation. The percentage of total SFA, MUFA and PUFA was similar in donkey and human milk. The content of essential fatty acids increased during 40-90 days of lactation and was approximately 2.5 times higher in comparison to human milk.Cilj ovog istraživanja bio je usporediti frakcije proteina i masnih kiselina balkanskog magarca i humanog mlijeka u ranoj fazi laktacije (40 do 90 dana). Ova studija pokazala je da magareće mlijeko sadrži αs1-kazein (1,38-1,89 g/L) i veće koncentracije β-kazeina (0,1-0,55 g/L) u odnosu na humano mlijeko. Koncentracija α-laktalbumina povećala se tijekom laktacije u periodu između 40 i 90 dana u obje vrste mlijeka. Magareće mlijeko sadržavalo je niske koncentracije β-laktoglobulina koje su se snižavale do 90-og dana laktacije. Magaričino mlijeko bogato je dvama proteinima sirutke - laktoferinom i lizozimom, za koje je utvrđeno da imaju molekulsku težinu od približno 76 kDa, odnosno 14,9-15,4 kDa. Sadržaj lizozima u magaričinom mlijeku iznosio je od 2,39 do 2,97 g/L, dok je humano mlijeko sadržavalo 30 do 50 puta niže koncentracije. Magaričino mlijeko sadržavalo je i veću koncentraciju laktoferina (0,012- 0,25 g/L) nego humano mlijeko. Sadržaj lizozima i laktoferina u magaričinom mlijeku povećao se u razdoblju između 40 i 90 dana laktacije. Udio ukupnih SFA, MUFA i PUFA bio je sličan u magaričinom i humanom mlijeku. Sadržaj esencijalnih masnih kiselina povećao se između 40. i 90. dana laktacije i to 2,5 puta u odnosu na humano mlijeko

Thermobaric Effects of Cast Composite Explosives of Different Charge Masses and Dimensions

The aim of this research was to determine the thermobaric effect of cast composite explosives, with different masses and dimensions of the chosen explosive charges. This was done by measuring the shock wave parameters in air (maximum overpressure and pressure impulse) and quantifying the thermal effect (temperature-time dependence), at different distances from the centre of the detonation. The chosen thermobaric explosive composition, TBE-3, was characterized. Its density, detonation velocity and viscosity-time dependence were determined. Experimental samples of different masses and calibres were prepared. The shock wave parameters in air were determined in field tests, by measuring the overpressure by piezo-electric pressure transducers. The detonation and the expansion of the explosion products were filmed by a TV high-speed camera, Phantom V9. An infrared (IR) camera FLIR SC7200 was used for recording the IR scene of the explosions and for tracking the thermal effects by a thermographic technique, i.e. thermal imaging. This work is an initial step towards establishing a method for the quantification of the thermal effects of a thermobaric detonation

Influence of IR camera integration time on the accuracy of Tmax determination during laser interaction with ceramics

This paper presents the results of an infrared thermography (IRT) application for monitoring temperature distribution on a ceramic surface during Nd: YAG laser irradiation. The laser operated in the Q-switch mode with λ= 1064 nm. The duration of a pulse was τ = 8 ns. The repetition rate was f l = 1-20 Hz. FLIR, E40 and SC7200 IR cameras were used. Recording of the maximum temperature in the irradiated zones is very important information related to the damage threshold of materials. The tested sample is a piece of a ceramic tile. A large number of factors affect determination of the maximum temperature in the very fast processes as it is irradiation with laser pulse duration of 8 ns. One of them is the camera integration time. The experimental results have shown that IR cameras, even those with high performance such as SC7200, cannot record the maximum temperature value at the moment of laser operation, but only the average temperature of the bulk sample material after laser pulses. The microstructure and micromorphology of the ceramic surface after the laser treatment were analyzed by optical and scanning electron microscopy

Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

This paper analyzes the potential problems in the exploitation of the older generation of spark-ignition engines with higher octane number of petrol (unleaded petrol BMB 95) than required (leaded petrol MB 86). Within the experimental tests on two different engines (STEYR-PUCH model 712 and GAZ 41) by applying piezoelectric pressure sensors integrated with the engine spark plugs, acceleration sensors and special electronic block connected with distributor, show that the cumulative first and second theoretical phase of combustion when petrol of higher octane number (BMB 95) is used lasts slightly longer than when the low-octane petrol MB 86 is used. For new petrol (BMB 95) higher optimal angles of pre-ignition have been determined by which better performances of the engine are achieved without a danger of the combustion with detonation (also called knocking)

Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

This paper analyzes the potential problems in the exploitation of the older generation of spark-ignition engines with higher octane number of petrol (unleaded petrol BMB 95) than required (leaded petrol MB 86). Within the experimental tests on two different engines (STEYR-PUCH model 712 and GAZ 41) by applying piezoelectric pressure sensors integrated with the engine spark plugs, acceleration sensors and special electronic block connected with distributor, show that the cumulative first and second theoretical phase of combustion when petrol of higher octane number (BMB 95) is used lasts slightly longer than when the low-octane petrol MB 86 is used. For new petrol (BMB 95) higher optimal angles of pre-ignition have been determined by which better performances of the engine are achieved without a danger of the combustion with detonation (also called knocking)

Osobine eksplozivno zavarenih ploča aluminijuma i čelika upotrebom Amonex eksploziva

The aim of this study was to investigate the possibility to use the industrial explosive Amonex, which belongs to a group of low-to-middle detonation velocity explosives, for welding of metallic materials. It consists of ammonium nitrate and TNT as energetic components and other inert ingredients and has a powdery consistency, easily applicable in a desirable layer over the metal plates to be welded. Within this research, Amonex was applied to weld plates of aluminium Al 2024 and steel 1.0216 (according to EN 10027-2). The procedure of welding was carried out in the configuration of parallel plates, and afterwards the welded joint was examined. Ultrasonic method and infrared imaging were used as non-destructive techniques, and then the samples were cut from the welded plate using water-jet, in order to perform microscopic analyses of the cross-section in the joint area. It was observed that a good-quality welded joint was obtained, and that the selected explosive may find further application in this area. However, certain nonwelded area was observed, encouraging future modification of the welding procedure set-up.Cilj ove studije je ispitivanje mogućnosti upotrebe industrijskog eksploziva Amonex, koji pripada grupi eksploziva male-do-srednje brzine detonacije, za zavarivanje metalnih materijala. Ovaj eksploziv se sastoji od amonijum nitrata i TNT-a kao energetskih komponenti i drugih inertnih sastojaka, ima praškastu strukturu i lako se nanosi u željenom sloju preko metalnih ploča koje se zavaruju. U okviru ovog istraživanja, Amonex je primenjen na zavarenim pločama aluminijuma Al 2024 i čelika 1.0216 (oznake prema EN 10027-2). Postupak zavarivanja izveden je na paralelno postavljenim pločama, nakon čega je izvršen pregled zavarenog spoja. Kao metode IBR korišćene su ultrazvučna metoda i termovizijsko ispitivanje. Primenom vodenog mlaza iz zavarene ploče su isečeni uzorci u cilju ispitivanja mikrostrukture poprečnog preseka zavarenog spoja. Uočeno je da je dobijen kvalitetan zavareni spoj, te da odabrani eksploziv može naći dalju primenu u ovoj oblasti. Međutim, takođe su uočene i određene površine nezavarenog područja, što je nametnulo potrebu za izmenama postavke ovog postupka zavarivanja

Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

This paper analyzes the potential problems in the exploitation of the older generation of spark-ignition engines with higher octane number of petrol (unleaded petrol BMB 95) than required (leaded petrol MB 86). Within the experimental tests on two different engines (STEYR-PUCH model 712 and GAZ 41) by applying piezoelectric pressure sensors integrated with the engine spark plugs, acceleration sensors (accelerometers) and special electronic block connected with distributor, show that the cumulative first and second theoretical phase of combustion when petrol of higher octane number (BMB 95) is used lasts slightly longer than when the low-octane petrol MB 86 is used. For new petrol (BMB 95) higher optimal angles of pre-ignition have been determined by which better performances of the engine are achieved without a danger of the combustion with detonation (also called knocking)