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Objectives: Immortelle has garnered global attention for its cosmetic, medicinal, and culinary applications worldwide. Apart from neryl acetate, α-pinene and γ-curcumene as the most important components for the estimation of the essential oil quality, in recent years a group of β -diketones, known as italidiones, appear as significant quality parameters. However, it is unknown how weather conditions (temperature and precipitation) influence their accumulation in essential oil and hydrosol, nor their anti-inflammatory potential. Methods: This study investigates the chemical composition of immortelle essential oil and hydrosol over three successive years (2019/20, 2020/21, and 2021/22), by GC-FID and GC-MS analysis. In silico molecular docking model with Vascular Adhesion Protein-1 (VAP-1) was used for the simulation of the anti-inflammatory potential of italidiones, as well as other β -diketones present in immortelle essential oil and hydrosol. Results: During the three-year trial, it was established that essential oil compounds such as α -pinene, neryl acetate, and italicene were positively correlated with temperature and negatively correlated with precipitation, as well as β -diketones and total italidiones. Moreover, trans -caryophyllene, γ -curcumene, and ar -curcumene were in negative correlation with temperature, and a slight positive correlation with precipitation. On the other side, in the hydrosol the content of both total β -diketones and total italidiones was strongly negatively correlated with temperatures, and positively correlated with precipitation, which was the opposite of essential oil. Additionally, findings indicated that italidiones could bind the human VAP-1 protein in the vicinity of the topiquinone and block its function. Conclusion: Weather conditions affect variations in the accumulation of volatile compounds in essential oil and hydrosol, which in some cases can affect changes in olfactory characteristics, as well as criteria prescribed by standards, and even changes in biological activities. These results indicate that italidiones, as well as other β -diketones present in immortelle, may be responsible for its anti-inflammatory activity. [ABSTRACT FROM AUTHOR]

Kajmak is autochthonous product, traditionally made as farmhouse milk product by farmers. In such manufacturing conditions, the quality of kajmak is usually very variable, nonstandard and out of the limits described by official regulations. In this paper the chemical composition, fatty acid profile, textural and sensory quality of the most used autochthonous kajmak samples (unripened kajmak and mature kajmak from mjesina) were analysed. Although all samples had satisfied quality according to the Serbian regulations, chemical composition and sensory quality revealed some variability between tested kajmak samples. Fat content was higher in mature kajmak than in unripened kajmak. The dominant fatty acid in all samples was palmitic acid (C16:0) and its higher content was observed in unripened kajmak sample, 33.20 %, compared with 29.45% in sample of kajmak from mjesina. In both samples, long-chain acids are the dominant ones. The saturated fatty acids (SFAs) in the tested samples were dominantly present with the share of 64-66%. The content of monounsaturated fatty acids (MUFAs) were in the range of 30.2-31.52 % and most abundant in both samples were oleic acid (18:1c). Unripened kajmak had higher score of sensory characteristics compared to kajmak from mjesine. According to the textural analysis the mature kajmak from mjesina had overall better textural characteristics.

In this paper, the nutritional quality of cheese samples and cheese analogues was assessed throughout the fatty acid profile and lipid indices. The research included cheese analogues in which milk fat was completely replaced by vegetable fat with the addition of palm and coconut oil, as well as mixed cheese analogues products, whose production was based on the use of palm oil, milk protein and cheese. Fatty acid profile was analysed by gas chromatography-mass spectrometry (GC-MS), while the atherogenic index, thrombogenic index and hypocholesterolemic/hypercholesterolemic ratio were calculated for the estimation of the lipid quality of the analysed samples. GC-MS analysis revealed the presence of 29 fatty acids in the analysed samples, among which dominated palmitic, stearic, oleic and linoleic fatty acid. Samples of cheese analogues showed improved fatty acid composition with a decreased content of saturated fatty acids and increased content of unsaturated fatty acids (monounsaturated and ω6 fatty acids). Values of atherogenic, thrombogenic indices and hypocholesterolemic/ hypercholesterolemic ratio (AI, TI and H/H) in the analysed samples varied in the range 0.81-11.89, 1.64-5.22 and 0.14-1.31, respectively. Lower AI and TI values accompanied by higher H/H values were observed for cheese analogues obtained by partial or complete substitution of milk fat with palm oil. Cheese analogue, in which production coconut oil completely replaced milk fat, demonstrated unfavourable fatty acid content and accompanying lipid indices, indicating the low nutritional quality of the specific sample.

The LM2990-integrated circuit family was among the first low-dropout voltage regulators to use a coupling diode to reduce a quiescent current. In certain conditions, the coupling diode, connected between the output terminal and the driver transistor collector contact, activates to supply the serial power transistor base current from the load. Nonetheless, an indirect characterization of the serial NPN transistor was affected, making it difficult to estimate its forward emitted current gain and a base current as a function of the absorbed total ionizing dose. The original SPICE simulation model had some limitations with generating the faithful simulation of radiation effects in samples supplied with a non-ideal voltage source. Therefore, a novel four-step computer simulation method was developed to specify bias and load conditions when the coupling diode reaction would not negatively affect the characterization of the serial power transistor. The previously reported method for estimating the serial transistor base current could be successfully used for dropout voltages that slightly exceed three equivalent diode voltage drops (that is, 2.4V) at the base-emitter junctions of the output amplifier transistors. [ABSTRACT FROM AUTHOR]

The subject of this paper is the mutual comparison of switching energy losses in cascode gallium nitride HEMT and silicon "superjunction" MOSFET transistor, both designed for a maximum operating voltage of 650 V. For the purpose of analysis the transistor switching characteristics, the double pulse test method was implemented. Detailed computer simulation models developed in programs of the SPICE family were used. Data on transient turn -on and turn-off processes were generated by LTspice simulation tool, in a wide range of drain currents, using two different gate resistance values for driving the transistors under test. The obtained results indicate superior switching characteristics of gallium nitride devices in comparison to silicon components, especially during the high drain current transistor operation. During the one transistor switching cycle, the total energy losses in the GaN HEMT were simulated, for a drain current of 30 A, and found to be five to eight times lower when compared to tested Si MOSFET transistor.

The quality of fresh cheese produced with the addition of traditional starter culture and kombucha inoculum have been investigated in this study. Fresh cheese was produced from milk with 3% fat content. The traditional starter culture FD-DVS XPL-1 (Chr. Hansen A/S, Denmark) and kombucha inoculum cultivated on black tea were applied for production two different fresh cheese samples. Physico-chemical and sensory characteristics of fresh cheese products were tested after production. The cheese yield of fresh cheese with traditional starter culture was higher compare to fresh cheese with kombucha inoculum. The obtained results showed significant differences in physicochemical properties and sensory characteristics between cheeses. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III46009]

In this study, the effects of kombucha inoculum as non-conventional starter culture on fatty acids composition of fermented milk, compared to a commercial probiotic (ABT-7) and yoghurt (YF-L812) starter cultures, during 21 days of storage was investigated. Fatty acids composition was determined by gas chromatography-mass spectrometry after the previous extraction of lipids and derivatization. The atherogenic (AI) and thrombogenic (TI) indices determined on the basis of fatty acids composition have been used for evaluation of the nutritive lipid quality of the fermented dairy products. The most significant levels of fatty acids in fermented milk products were palmitic, followed by oleic, stearic and myristic fatty acids. Fermented milk products were characterized by low atherogenic (2.14-2.39) and thrombogenic (2.91-3.18) indices, suggesting their consumption could have a favorable effect on human health. The AI and TI were comparable during the storage of fermented milk samples. Starter culture did not affect the health-related fatty acid composition of fermented milk products during storage. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 46009]

In this paper was presented the technical procedure implemented for the fault diagnostics of the thyristor bridge in an AS/DC converter. During the development of the new generation of digital controllers for AC/DC converters, it was required for these devices to have a possibility for a real-time detection of the thyristor converter fault. Thyristor bridge fault should be detected without the need for the state monitoring of the particular power semiconductor switches or rapid fuses. Thyristor bridge fault was identified using the measurement of the line-frequency second harmonic in the rectifier output current signal. Output voltage and current waveforms were presented, as well as the current spectra, in the cases of the thyristor bridge operation without one switch. The operation principle was described for a protection from an asymmetric operation of a thyristor bridge. A negative influence of high-order harmonics was analysed on the particular rectifier components, both in the cases of the output voltage control, as well as for operation in the current limit mode.

The aim of the paper is to analyse the possibility of applying a topology of an eighteen-pulse thyristor rectifier for the electromagnet power supply. The scope was to determine if the proposed rectifier topology, with the two input interphase transformers, as well as the output one, can work with an output current ripple being less than 100 ppm, with the acceptable dynamic characteristics of the voltage controller. Using the computer simulation, it has been found that, with a medium output filter capacitor and distinctively non-symmetric input parameters, the rectifier can work with an output current of approximately 80 ppm of the DC component. If the input phase voltages are equalized, the effective value of the output current ripple could be reduced down to 17 ppm. In both cases, satisfactory dynamic characteristics of the voltage controller have been achieved. The dominant influence on the output current filtering had the output interphase transformer magnetization inductance, as well as the capacitance of the filter capacitor. The increase of their values leads to better filtering of the output current, but also to a significant deterioration of the AC/DC converter dynamic characteristics. The measures for coordination of the output low-pass filter characteristics and the PI voltage regulator parameters are proposed.

In this study, an Artificial Neural Network (ANN) model is used to solve the complex task of producing fresh cheese with the desired quality parameters. The study focuses on kombucha fresh cheese samples fortified with ground wild thyme, supercritical fluid extract of wild thyme, ground sage and supercritical fluid extract of sage and optimizes the parameters of chemical composition, antioxidant potential and microbiological profile. The ANN models demonstrate robust generalization capabilities and accurately predict the observed results based on the input parameters. The optimal neural network model (MLP 6-10-16) with 10 neurons provides high r2 values (0.993 for training, 0.992 for testing, and 0.992 for validation cycles). The ANN model identified the optimal sample, a supercritical fluid extract of sage, on the 20th day of storage, showcasing specific favorable process parameters. These parameters encompass dry matter, fat, ash, proteins, water activity, pH, antioxidant potential (TP, DPPH, ABTS, FRAP), and microbiological profile. These findings offer valuable insights into producing fresh cheese efficiently with the desired quality attributes. Moreover, they highlight the effectiveness of the ANN model in optimizing diverse parameters for enhanced product development in the dairy industry. [ABSTRACT FROM AUTHOR]

Samples of four types of low-dropout voltage regulators, with both serial pnp and npn transistors, were examined in room-temperature isothermal gamma radiation annealing. After uninterrupted exposure to a total ionising dose of 500 Gy, biased and loaded voltage regulators were examined in room-temperature annealing within the first 30 minutes after the exposure. Beside the on-line measurement of output voltage and quiescent current during the thirty-minute period immediately after irradiation, also results were procured after 10-year room-temperature spontaneous recovery. Data obtained during the irradiation and rapid annealing were fitted with linear, exponential, and power-law regression functions. A simple procedure was proposed, based on the quiescent current annealing factor, for the quick estimation of the integrated voltage regulator's radiation sensitivity during the post-irradiation isothermal annealing. In order to estimate the circuit's radiation sensitivity, immediately after irradiation, tested devices have to be left in the same operating conditions as during the exposure. If a clear trend of the quiescent current recovery can be observed, further examinations have to be implemented to estimate if a circuit is acceptably radiation-tolerant. If no recovery trend can be observed within the first hour after irradiation, or even further degradation is noticed, then the examined voltage regulator is a radiation-sensitive device and cannot be used in radiation environments. The described procedure is based on the macroscopic effects of the radiation-induced charge-trapping in field oxides and interfaces. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 171007: Physical and functional effects of the interaction of radiation with electrical and biological systems]

The aim of this study was to examine the influence of different types and concentration of kombucha inoculum on content of sugar, organic acids and ethanol in the fermented beverages produced from milk of 0.9% fat content. Three different kombucha inoculums, cultivated on black tea with addition of sucrose: standard inoculum - 10% (w/w) and 15% (w/w), concentrated by microfiltration- 10% (w/w) and 15% (w/w), and concentrated by evaporation - 1.5% (w/w) and 3.0% (w/w), were applied in the manufacture of fermented milk. Contents of lactose, galactose, glucose, fructose, organic acids, and ethanol in the kombuha fermented milk beverages were determined by the enzyme tests. It was found that the lactose content varied from 3.30 to 4.0 g/100g. All samples showed higher content glucose than fructose. The content of L-lactic acid in the samples ranged from 0.4 to 0.7 g/100g, while significantly lower level of D-lactic and acetic acid were determined in all samples of kombucha fermented milk (

The paper describes the protocol converter INT-485-MBRTU, developed for serial communication between the thyristor rectifier (based on the proprietary protocol "INT-CPD-05", according to standard RS-485) and the SCADA system (based on protocol "Modbus RTU", of the same standard) in the thermal power plant "Nikola Tesla B1". Elementary data on industrial communication protocols and communication gateways were provided. The basic technical characteristics of the "Omron" programmable logic controller CJ series were described, as well as the developed device INT-485-MBRTU. Protocol converters with two versions of communication software were tested, differing only in one control word, intended for a forced successive change of communication sequences, in opposite to automatic sequence relieve. The device iNT-485-MBRTU, with the program for forced successive change of communication sequences, demonstrated the reliability of data transfer of 100 %, in a sample of approximately 480 messages. For nearly the same sample, the same protocol converter, with a version of the program without any type of message identifiers, transferred less than 60 % of the foreseen data. During multiple sixty-hour tests, the reliability of data transfer of at least 99.9979% was recorded, in 100% of the analysed cases, and for a sample of nearly 96,000 pairs of the send and receive messages. We analysed the results and estimated the additional possibilities for application of the INT-485-MBRTU protocol converter.

The aim of this research was to create a three-dimensional model of L-lactate dehydrogenase from the main yoghurt starter culture - Streptococcus thermopilus, to analyse its structural features and investigate substrate binding in the active site. NCBI BlastP was used against the Protein Data Bank database in order to identify the template for construction of homology models. Multiple sequence alignment was performed using the program MUSCULE within the UGENE 1.11.3 program. Homology models were constructed using the program Modeller v. 9.17. The obtained 3D model was verified by Ramachandran plots. Molecular docking simulations were performed using the program Surflex-Dock. The highest sequence similarity was observed with L-lactate dehydrogenase from Lactobacillus casei subsp. casei, with 69% identity. Therefore, its structure (PDB ID: 2ZQY:A) was selected as a modelling template for homology modelling. Active residues are by sequence similarity predicted: S. thermophilus - HIS181 and S. aureus - HIS179. Binding energy of pyruvate to L-lactate dehydrogenase of S. thermopilus was - 7.874 kcal/mol. Pyruvate in L-lactate dehydrogenase of S. thermopilus makes H bonds with catalytic HIS181 (1.9 Å), as well as with THR235 (3.6 Å). Although our results indicate similar position of substrates between L-lactate dehydrogenase of S. thermopilus and S. aureus, differences in substrate distances and binding energy values could influence the reaction rate. Based on these results, the L-lactate dehydrogenase model proposed here could be used as a guide for further research, such as transition states of the reaction through molecular dynamics. [Projekat Ministarstva nauke Republike Srbije, br. III 46009]

The objective of this work was to investigate the effect of addition of transglutaminase (TG-0.02%, w/w) and whey protein concentrate (WPC-0.03%, w/w), on quality of kombucha fermented milk product. Samples were prepared from pasteurized semi-skim milk (0.9%, w/w fat) and kombucha inoculum (10%, v/v). The pH values were measured during the fermentation of milk (lasted until reached 4.5). Syneresis, water holding capacity and the product texture (firmness and consistency,) were assessed after production. Rheological properties of kombucha fermented milk samples were measured during ten days of storage. The sample containing TG had the lowest syneresis (21 ml), the highest water holding capacity (62%) and the highest textural characteristics (firmness - 23.99g, consistency - 626.54gs) after production. The addition of WPC to milk improved the rheological properties, while the addition of TG improved it even to a significantly greater extent after the production and during 10 days of the storage. [Projekat Ministarstva nauke Republike Srbije, br. 46009]

The objective of this study was to investigate the effect of fat content and type of the starter culture (traditional or probiotic) on physico-chemical quality, rheological and textural characteristics of the fermented dairy products during 14 days of storage. Seven different fermented dairy products of two different groups: stirred and set yoghurts were used in this study. The rheological and textural characteristics of the analyzed type of fermented dairy products after the production and during storage are dependent on the chemical composition, particularly fat content. [Projekat Ministarstva nauke Republike Srbije, br. III 46009]

In this paper, computer simulation models of two different topologies of 18-pulse rectifiers are presented. Each rectifier topology consists of three parallel, three-phase six-pulse full-bridge thyristor converters connected via interphase transformers. The influence of the interphase transformer's layout and AC line reactances variations on the particular thyristor converter current sharing is analysed. Various configurations of 18-pulse rectifiers are examined by simulating operation with symmetric input voltage supply, as well as in the cases of different levels of voltage supply asymmetry, at unequal input conductors impedance, and at different thyristor voltage drops. According to computer simulation results, an optimal 18-pulse rectifier circuit topology is recommended. The optimal topology has three AC line reactances with two input current-balancing interphase transformers. These added AC reactances are also involved with the current commutation process between thyristors. Application of the recommended optimal topology of an 18-pulse rectifier could enable the reduction of the AC line reactances number from nine to three, while the dissipated power of the AC/DC converter's most loaded thyristor could be reduced by approximately 11 %. During the simulation of the nominally loaded 18-pulse rectifier, in all considered cases the effective value of the output signal ripple below one promil of total current and voltage values has been achieved.

The aim of this study was to examine the changes in the microstructure, textural properties and viscosity of the gel formed during milk fermentation with kombucha inoculum and to establish a relationship between the microstructure and these properties. The values of the analyzed characteristics were measured during the gelation at 42°C at the following pHs: 5.4, 5.1, 4.8 and 4.6. The microstructure analysis revealed disappearance of coarse cluster structure and appearance of finer casein micelles network during fermentation. The obtained results showed significant differences in them viscosity and textural properties during fermentation, which is in accordance with their microstructure. The correlation of the examined properties and microstructure of the gel was established. [Projekat Ministarstva nauke Republike Srbije, br. 46009]

This study is concerned with the effect of concentration of transglutaminase (TG), content of milk fat and starter culture type (probiotic and kombucha) on the structure of fermented milk products. The application of TG significantly improved textural characteristics of the fermented milk products. The firmness of the samples produced from milk with 0.1g100g-1 and 0.9g100g-1 fat content with probiotic starter were by 33% and 17.6% higher, respectively, compared to the control samples. During ten days of storage, the value of the hysteresis loop area of all samples produced from milk with 0.9g100g-1 fat content with TG addition, decreased by 14%. [Projekat Ministarstva nauke Republike Srbije, br. 46009]

This article deals with the influence of PI controller linear gain scheduling on the dynamic characteristics of the line-frequency phase-controlled rectifier. The examined device has digital control electronics of the DRI 07B type, based on the Intel 80C196 microcontroller. The realized adaptive PI controllers utilize wide variations of the current gain (Kp), decreasing linearly in proportion to the increase in the rectifier output current in the area of the discontinuous currents. Reaching the threshold of the rectifier's discontinuous current, the current gain of the PI voltage controller remains constant. Beside the improvement of the thyristor rectifier's static stability during operation with small output currents, implementation of the adaptive PI control also led to improvement of the voltage controller response in the case of load disturbance in the range of 13-90 % of the nominal rectifier output current. Transfer functions were analyzed for specific parts of the phase-controlled rectifier DRI 110-100 having nominal output parameters of 116 V and 100 A. The values of the relative damping and root-locus characteristics were analyzed in detail.

The operation of power lateral pnp transistors in gamma radiation field was examined by detection of the minimum dropout voltage on heavily loaded low-dropout voltage regulators LM2940CT5, clearly demonstrating their low radiation hardness, with unacceptably low values of output voltage and collector-emitter voltage volatility. In conjunction with previous results on base current and forward emitter current gain of serial transistors, it was possible to determine the positive influence of high load current on a slight improvement of voltage regulator LM2940CT5 radiation hardness. The high-current flow through the wide emitter aluminum contact of the serial transistor above the isolation oxide caused intensive annealing of the positive oxide-trapped charge, leading to decrease of the lateral pnp transistor's current gain, but also a more intensive recovery of the small-signal npn transistors in the control circuit. The high current density in the base area of the lateral pnp transistor immediately below the isolation oxide decreased the concentration of negative interface traps. Consequently, the positive influence of the reduced concentration of the oxide-trapped charge on the negative feedback reaction circuit, together with the favourable effect of reduced interface traps concentration, exceeded negative influence of the annealed oxide-trapped charge on the serial pnp transistor's forward emitter current gain.

Following a deep discharge of AGM SVT 300 valve-regulated lead-acid batteries using the ten-hour discharge current, the batteries were charged using variable current. In accordance with the obtained results, exponential and polynomial functions for the approximation of the specified processes were analyzed. The main evaluation instrument for the quality of the implemented approximations was the adjusted coefficient of determination R-2. It was perceived that the battery discharge process might be successfully approximated with both an exponential and the second order polynomial function. On all the occasions analyzed, values of the adjusted coefficient of determination were greater than 0.995. The charging process of the deeply discharged batteries was successfully approximated with the exponential function; the measured values of the adjusted coefficient of determination being nearly 0.95. Apart from the high measured values of the adjusted coefficient of determination, polynomial approximations of the second and third order did not provide satisfactory results regarding the interpolation of the battery charging characteristics. A possibility for a practical implementation of the procured regression functions in uninterruptible power supply systems was described.

Volatile compounds, affecting flavour of traditional and probiotic fresh cheese, were determined. Functional dairy product-fresh cheese was produced from milk of 2.5% fat content and milk of 4.2% fat content, under the semi-industrial conditions. The traditional starter culture Flora Danica (FD) and a combination of probiotic starter ABT-1 and FD (ABT-1:FD=1:1) were applied as starters. The volatile fractions were isolated by employing the combined simultaneous distillation-extraction technique (SDE). The compounds were identified by gas chromatography - mass spectrometry (GC-MS) and quantified by using standard procedure. Following 19 compounds have been identified: 8 hydrocarbons (decane, undecane, tridecane, tetradecane, pentadecane, hexadecane, octadecane and 2, 6, 10, 14-tetramethyl hexadecane); 6 ketones (2-heptanone, 2-nonanone, 2- undecanone, 2-pentadecanone, 2-heptadecanone and 2-tridecanone); 3 aldehydes (nonanal, tetradecanal and hexadecanal); 1 fatty acid (decanoic acid) and disulfide, bis (1-methylethyl). The highest levels were associated with hexadecanal, 2-pentadecanone, 2-tridecanone, and 2-undecanone in all examined samples, regardless to the starter culture and type of milk used. [Projekat Ministarstva nauke Republike Srbije, br. 46009]

The aim of this study was the investigation of the possibilities of direct determination of calcium, sodium and potassium in the commercial and kombucha-based fermented milk products by flame photometry. Two procedures were used for sample preparation: simple dilution with water (direct method) and extraction with mineral acid. Calcium, sodium and potassium levels determined after mentioned sample preparation methods were compared. The results showed that the differences between the values obtained for the different sample treatment were within the experimental error at the 95% confidence level. Compared to the method based on extraction with mineral acid, the direct method is efficient, faster, simpler, cheaper, and operates according to the principles of Green Chemistry. Consequently, the proposed method for the direct determination of calcium, sodium and potassium could be applied for the rapid routine analysis of the mineral content in the fermented dairy products. [Projekat Ministarstva nauke Republike Srbije, br. III 46009]

The main examined value in an experiment performed on moderately loaded voltage regulators was the serial pnp transistor’s minimum dropout voltage, followed by the data on the base current and forward emitter current gain. Minimum dropout voltage decreased by up to 12%, while the measured values of the forward emitter current gain decreased by 20-40% after the absorption of a total ionizing dose of 500 Gy. The oxide trapped charge increased the radiation tolerance of the serial lateral pnp transistor owing to the suppression of interface trap formation above the base area. Current flow through the serial transistor of the voltage regulator had an influence on the decrease in the power pnp transistor’s forward emitter current gain. Due to the operation with a moderate load of 100 mA, loss of emitter injection efficiency was not as important as during the operation with high current density, thus eliminating the negative influence of emitter crowding on the radiation hardness of the voltage regulator. For a moderate load, gain in the negative feedback reaction was enough to keep output voltage in the anticipated range. Only information procured from tests of the minimum dropout voltage on the moderately loaded voltage regulators were not sufficient for unequivocal determination of the examined integrated circuit’s radiation hardness. [Projekat Ministarstva nauke Republike Srbije, br. 171007: Physical and functional effects of the interaction of radiation with electrical and biological systems]

A method of on-line monitoring of the low-dropout voltage regulator's operation in a radiation environment is developed in this paper. The method had to enable detection of the circuit's degradation during exploitation, without terminating its operation in an ionizing radiation field. Moreover, it had to enable automatic measurement and data collection, as well as the detection of any considerable degradation, well before the monitored voltage regulator's malfunction. The principal parameters of the voltage regulator's operation that were monitored were the serial pnp transistor's base current and the forward emitter current gain. These parameters were procured indirectly, from the data on the voltage regulator's load and quiescent currents. Since the internal consumption current in moderately and heavily loaded devices was used, the quiescent current of a negligibly loaded voltage regulator of the same type served as a reference. Results acquired by on-line monitoring demonstrated marked agreement with the results acquired from examinations of the voltage regulator's maximum output current and minimum dropout voltage in a radiation environment. The results were particularly consistent in tests with heavily loaded devices. Results obtained for moderately loaded voltage regulators and the risks accompanying the application of the presented method, were also analyzed.

In this paper the thyristor rectifiers with digital control units developed in Institute 'Nikola Tesla' are presented. Digital control units of the types 'DRI 05' and 'DRI 07' are based on microcontroller 'Intel' 80C196KB16. Implemented technical solutions are described in detail, also as the experience derived from industrial exploitation of thyristor rectifiers. The new features implemented on the Institute's digital control units were triple automatic restart, detection of asymmetry of thyristor bridge and output voltage ripple, also as program hysteresis for alternation of voltage and current regulators. Responses of the implemented PI regulators of laboratory thyristor rectifier connected to RLC circuit are studied in detail. Results of examinations of rectifier's output current and voltage waveforms in industrial facilities are also presented.

The aim of this study was to examine the possibility of fermented dairy beverage production by the application of kombucha cultivated on thyme tea in combination with a probiotic starter and to evaluate the quality of the new functional product. Fermented dairy beverages are produced from milk with 1.6% milk fat at three fermentation temperatures: 37°C, 40ºC and 43ºC.Chemical quality, rheological properties and products of added starter cultures metabolism were determined in the fermented dairy beverages after production and after10 days of storage. Produced fermented dairy beverages have reduced milk fat content and good textural characteristics. Besides the highly valuable milk components, they contain numerous compounds which have pronounced therapeutic properties. These products could be used as functional food in the diet of different populations for health improvement.

Low-dropout voltage regulators with various geometries and technological realisations of serial pnp power transistors were exposed to ionizing radiation. Although devices with vertical emitters were considered much less susceptible to the influence of radiation on forward emitter current gain than circuits with round emitters, the experiment showed a similar degradation of current gain in both cases. The main reason of high radiation susceptibility of the examined vertical serial pnp transistor is the implementation of an interdigitated emitter, with high perimeter-to-area ratio, causing the great increase of serial transistor’s base current, but a minor influence on the maximum output current. Transistors with round emitters with small perimeter-to-area ratio expressed a moderate current gain degradation, but a rapid fall of the emitter injection efficiency, causing a significant decrease of the maximum output current. Regardless of the similar forward emitter current gain degradation, reliability and operational characteristics of two types of low-dropout voltage regulators were completely different.

Rheological properties of fermented dairy products are very important parameters of the product quality. The behaviour of gel formed during fermentation of milk is influenced by a great number of factors, such as: milk composition, starter culture, flavourings addition, etc. The aim of this research was to examine the influence of fat content, and kombucha inoculum concentration on textural characteristics of fermented milk beverages: firmness, consistency, cohesiveness and viscosity index after production and during 10 days of storage. Higher fat content of beverage affects the firmness, consistency, cohesiveness and viscosity index, while higher amount of inoculum in beverages has an opposite effect on textural characteristics of samples during storage.