Application of pMOS Dosimeters in Radiotherapy

The results of a study on pMOS dosimeters manufactured by Tyndall National Institute, Cork, Ireland and their sensitivity on radiation doses used in radiotherapy are presented. Firstly, we deal with analysis of defect precursors created by ionizing radiation, responsible for increase in fixed and switching traps, which are further responsible for threshold voltage shift as a dosimetric parameter. Secondly, influence of some parameters, such as gate bias during irradiation, gate oxide thickness and photons energies, on threshold voltage shift is presented. Fading of irradiated pMOS dosimeters and possible application of commercial MOSFETs in ionizing radiation dosimetry are also presented

Gamma-ray irradiation and post-irradiation at room and elevated temperature response of pMOS dosimeters with thick gate oxides

Gamma-ray irradiation and post-irradiation response at room and elevated temperature have been studied for radiation sensitive pMOS transistors with gate oxide thickness of 100 and 400 nm, respectively. Their response was followed based on the changes in the threshold voltage shift which was estimated on the basis of transfer characteristics in saturation. The presence of radiation-induced fixed oxide traps and switching traps - which lead to a change in the threshold voltage - was estimated from the sub-threshold I-V curves, using the midgap technique. It was shown that fixed oxide traps have a dominant influence on the change in the threshold voltage shift during gamma-ray irradiation and annealing

The gamma-ray irradiation sensitivity and dosimetric information instability of RADFET dosimeter

The gamma-ray irradiation sensitivity to radiation dose range from 0.5 Gy to 5 Gy and post-irradiation annealing at room and elevated temperatures have been studied for p-channel metal-oxide-semiconductor field effect transistors (also known as radiation sensitive field effect transistors or pMOS dosimeters) with gate oxide thicknesses of 400 nm and 1 mm. The gate biases during the irradiation were 0 and 5 V and 5 V during the annealing. The radiation and the post-irradiation sensitivity were followed by measuring the threshold voltage shift, which was determined by using transfer characteristics in saturation and reader circuit characteristics. The dependence of threshold voltage shift DVT on absorbed radiation dose D and annealing time was assessed. The results show that there is a linear dependence between DVT and D during irradiation, so that the sensitivity can be defined as DVT/D for the investigated dose interval. The annealing of irradiated metal-oxide-semiconductor field effect transistors at different temperatures ranging from room temperature up to 150°C was performed to monitor the dosimetric information loss. The results indicated that the dosimeters information is saved up to 600 hours at room temperature, whereas the annealing at 150°C leads to the complete loss of dosimetric information in the same period of time. The mechanisms responsible for the threshold voltage shift during the irradiation and the later annealing have been discussed also. [Projekat Ministarstva nauke Republike Srbije, br. 17007

RECUSATIO IUDICUS: SRPSKI OKVIR, UPOREDNI PRIKAZ I PRAKSA EVROPSKOG SUDA ZA LJUDSKA PRAVA

The right of a party to exercise a judicial function in a case deciding its rights and obligations is impartial to a judge, which is determined by the obligation of the state to provide, first in a normative and then in a practical framework, the right to be upheld. Prima faciae, when it comes to the Serbian and legal frameworks of surrounding countries, it has been done nomotechnically in an impeccable way, but there are a number of essential shortcomings. The results we have obtained, using comparative legal review and analyzing practice of ECHR indicate that the Serbian, as well as the legislatures in the region, faces major problems in this area. As an anomaly we identified the possibility that a judge, although biased, in accordance with applicable regulations (in Serbian, Croatian and North Macedonian legal framework), could exercise judicial function in the case (because, there Criminal procedure codes stipulates that judge “can” be disqualified if there are doubts in his impartiality). Furthermore, very big problem in all legislatures (except Montenegrin) was that the injured party, although entitled to make a compensation claim (and this claim, within the meaning of Article 6(1) of the European Convention constitutes a civil claim), has no opportunity to seek a judicial excption/recusation. Finally, all analyzed legislation, except the Slovenian, allows a judge to take immediate action when it comes to an optional recusation. Disagreeing with this, we suggested that in the future they follow their Slovenian colleague who arranged it in a much better way.Pravo stranke da u predmetu u kojem se odlučuje o njenim pravima i obavezama sudijsku funkciju vrši nepristrasni pojedinac, determinisano je obavezom države da obezbijedi, najprije u normativnom okviru, a zatim i u praksi, da se tom pravu udovolji. Prima faciae, kada su u pitanju srpsko zakonodavstvo i zakonski okviri država iz okruženja, to je nomotehnički urađeno na korektan način, ali se u radu pokazuje da postoji određeni broj suštinskih manjkavosti, koje imaju potencijal da dovedu do odgovornosti država. To ćemo dokazati dominantnim oslanjanjem na standarde Evropskog suda za ljudska prava. Zadatak autora bio je demonstriranje relevantnih odluka Evropskog suda, prikazivanje normativnog okvira u Srbiji i prihvaćenih rješenja u zakonodavstvima država iz okruženja (Crna Gora, Hrvatska, Sjeverna Makedonija, Slovenija i Federacija Bosna i Hercegovina)

PHYSICO-CHEMICAL PROCESSES IN VERTICAL-DOUBLE-DIFFUSED METAL-OXIDE-SEMICONDUCTOR FIELD EFFECT TRANSISTORS INDUCED BY GAMMA-RAY IRRADIATION AND POST-IRRADIATION ANNEALING

The behavior of commercial power Vertical-Double-Diffused Metal Oxide Semiconductor Field Effect Transistors (VDMOSFETs) during gamma-ray irradiation and subsequent annealing at room and elevated temperature was investigated. The densities of radiation-induced fixed traps and switching traps were determined from the sub-threshold I-V curves using the midgap technique. It was shown that the creation of fixed traps dominated during irradiation. The experimental results have also proved the existence of latent switching traps buildup process during annealing at an elevated temperature. This increase correlated with the decrease in fixed trap density. Physical and chemical processes responsible for the threshold voltage shift during irradiation have been analyzed on the basis of interactions between secondary electrons released by gamma photons with covalent bonds  and . H-W model has been used for the explanation of processes leading to latent switching traps buildup at an elevated temperature and its passivation at late annealing times. FIZIČKO-HEMIJSKI PROCESI U VDMOSFET-u IZAZVANI GAMA-ZRAČENJEM I OPORAVKOM POSLE ZRAČENJAIstraživano je ponašanje snažnih VDMOSFET-a za vreme ozračivanja gama zračenjem i kasnijeg oporavka na sobnoj i povišenoj temperaturi. Gustine defekata u oksidu i na međupovršini su određivane iz predpragovske karakteristike korišćenjem midgap metode. Eksperimentalni rezultati su potvrdili postojanje latentnog porasta površinskih stanja na Si-SiO2 međupovršini koji se stvaraju za vreme oporavka na povišenoj temperaturi. Njihov porast je praćen smanjenjem zahvaćenog naelektrisanja u oksidu. Fizičko-hemijski procesi koji dovode do promene napona praga za vreme zračenja su analizirani na osnovu interakcija između sekundarnih elektrona, oslobođenih gama fotonima i kovalentnih Sio – O i Sio – Sio veza. H-W model je korišćen za objašnjenje procesa koji dovode do pojave latentnog porasta površinskih stanja na Si-SiO2 međupovršini na povišenoj temperaturi kao i njihove pasivizacije tokom kasnijeg oporavka. HIGHLIGHTSHerein, the commercial power Vertical-Double-Diffused Metal Oxide Semiconductor Field Effect Transistors (VDMOSFETs) was studiedVDMOSFETs behavior during gamma-ray irradiation and subsequent annealing at room and elevated temperatures was investigatedThe creation of fixed traps dominated subject to irradiationLatent switching traps buildup process existed during the annealing at elevated temperaturesH-W model explains processes leading to latent switching traps buildup at elevated temperatures and its passivation at late annealing time

Geostatistical modeling of geochemical variables in 3D

Geostatistical mapping of soil properties in 3D refers to the application of geostatistical methods to the soil data in order to produce maps of soil properties at different depths. Through two separate studies, this thesis elaborates on two different approaches for 3D soil mapping. At first, the well established Spline-Than-Krige approach for the mapping of soil pollutants atmospherically deposited from the copper smelting plant, was used. In the absence of the monitoring data, which can be used for a detailed characterization of the plume spreading process, this study was confined to the consideration of terrain exposure to explain spatial trend in arsenic distribution at different depths. This study aims to explore the extent to which the commonly available information, such as the prevailing wind direction, or the location of the source of pollution, in combination with the digital terrain model, can be used to quantify the terrain exposure, and hence to improve the spatial prediction of the arsenic concentration at several soil depths. Next, the innovative geostatistical approach to 3D mapping of soil properties, based on soil profile data, was proposed. It provides the semi-automatic way for 3D modeling of soil variables, prediction over the regular grids (rasters) and also the evaluation of prediction accuracy. Methodologically, this approach operates within the 3D regression kriging framework. 3D trend model is conceptualized as hierarchical or non-hierarchical linear interaction model. This means that the model includes the interactions between the spatial covariates and depth in the hiearchial or non-hierarchial manner. The trend modeling is based on the application of the penalized regression technique, lasso. The lasso uses a specific regularization penalty in a fitting procedure to enable the efficient parameter estimation and variable selection (including interaction terms) at the same time...Geostatistiˇcko kartiranje zemljišta u 3D odnosi se na primenu geostatistiˇckih metoda na zemljišnim podacima u cilju izrade karata zemljišnih karakteristika jednog podruˇcja, koje se odnose na razliˇcite dubine zemljišta. U okviru dve nezavisne studije, ova doktorska disertacija razmatra dva razliˇcita pristupa geostatistiˇckog modeliranja zemljišta u 3D. U okviru prve studije, "Spline-Than-Krige" metod je koriš´cen za kartiranje koncentracije arsena u zemljištu, u blizini Rudarsko-topioniˇcarskog basena Bor, na tri razliˇcite dubine (0-5 cm, 5-15 cm i 15-30 cm). Dugogodišnje emitovanje nepreˇciš´cenih materija iz topionice rudnika u atmosferu, dovelo je do zagadjenja zemljišta u okolini, taloženjem štetnih materija nošenih vetrom. U odsustvu podataka kojima bi se detaljnije mogao opisati proces raspršivanja štetnih materija, ova studija se ograniˇcila na analizu izloženosti terena uticaju vetra, a time i procesu zagad¯enja. Predstavljen je inovativan pristup kvantifikaciji izloženosti terena izvoru zagad¯enja. Na osnovu opšte dostupnih podataka, kreirano je nekoliko parametara kojima se kvantifikuje geometrijska i topografska izloženost svake tacˇke terena izvoru zagad¯enja. Tako kreirani parametri, iskorišc´eni su za opisivanje prostornog trenda koncentracije arsena na tri razliˇcite dubine. Definisani trendovi, koriš´ceni su u okviru regresionog kriginga, za prostornu predikciju. Na taj naˇcin pokušalo se odgovoriti na pitanje, u kojoj meri, opšte dostupni podaci, kao što su pravac dominantnog vetra ili poznavanje taˇcne lokacije izvora zagadjenja u kombinaciji sa digitalnim modelom terena, mogu biti iskoriš´ceni da bi se unapredila preciznost prostorne predikcije zemljišnih zagadjivaˇca, kako na površinskim slojevima tako i na ve´cim dubinama..

Optimal source localization problem based on TOA measurements

Determining an optimal emitting source location based on the time of arrival (TOA) measurements is one of the important problems in Wireless Sensor Networks (WSNs). The nonlinear least-squares (NLS) estimation technique is employed to obtain the location of an emitting source. This optimization problem has been formulated by the minimization of the sum of squared residuals between estimated and measured data as the objective function. This paper presents a hybridization of Genetic Algorithm (GA) for the determination of the global optimum solution with the local search Newton-Raphson (NR) method. The corresponding Cramer-Rao lower bound (CRLB) on the localization errors is derived, which gives a lower bound on the variance of any unbiased estimator. Simulation results under different signal-to-noise-ratio (SNR) conditions show that the proposed hybrid Genetic Algorithm-Newton-Raphson (GA-NR) improves the accuracy and efficiency of the optimal solution compared to the regular GA

A FUNCTION PROPERTY OF POLYTROPHIC PROCESS WITH ASPECT OF TANGENT CONSTRUCTION

In this paper, starting from general tangent equation in arbitrary point of specified curve, using principles of differential geometry and given mathematical transformation tangent equation of polytrophic function in p – v diagram was obtained. This form is convenient for solving numerous practical and theoretical problems in engineering thermodynamic by means of graphical method. It was shown that tangent can be constructed easily, using polytrophic equation only, but it is not example with other functions appearing in thermodynamics. Later, in this paper, we have given some methods, which refer to more exact construction of polytrophic and graphical analyze of polytrophic process

"Thermal diffusivity and electron transport properties of NTC samples obtained by photoacoustic method

Poster presented at the Seventh Yugoslav Materials Research Society Conference - YUCOMAT 2005, Herceg Novi, Crna Gora, September 12-16, 2005

PRESSURE INFLUENCE TO EXTRACTION SYSTEM HELICHRYSUM ITALICUM – SUPERCRITICAL CARBON DIOXIDE

Supercritical fluid extraction (SFE) is an efficient extraction technique for the separation of various organic compounds from herbs, or more generally, from plant materials. As cultivate plant (plant from plantation) Helichrysum italicum from municipality Novi Grad was used in this research. The influence of pressure on total extract yield at flow rate 53.5 dm3 /h (calculated at normal state), for extraction time 3 h was investigated. Extraction was performed by supercritical carbon dioxide at different pressures (80, 150, 250 and 350 bar) and constant temperature of 40°C. The extraction yield increase from 0.35 to 5.71% (g/100g drug) by pressure increasing of supercritical extraction by carbon dioxide (isothermal process, t = 40°C). Essential oil content in obtained CO2 extracts was from 6.70 to 31.12%. The highest content of essential oil was in CO2 extract obtained by extraction of drug at p = 80 bar and t = 40°C (31.12%). Qualitative and quantitative determination of CO2 extracts obtained at pressure of 80 and 350 bar as well as of essential oils obtained from extracts, were performed using GC - MS method. The main component were tritriacontane (27.13%) and nonacosane (13.28%). The dominant component in essential oils obtained from extracts was γ – curcumene (28.27 and 27.42%, respectively)