Current-voltage characteristics of carbon nanotube FETS

U ovom radu ispitivane su karakteristike FETova izrađenih na bazi ugljeničnih nanotuba (CNT FETova). U prvom delu rada, predstavljene su neke osnovne osobine ugljeničnih nanotuba. Zatim je razvijen analitički model strujno-naponskih karakteristika CNT FETova koji dobro opisuje ponašanje ove savremene nanoelektronske naprave. Na bazi predloženog modela urađene su simulacije. Dobijeni rezultati su u saglasnosti sa prethodno publikovanim. .In this paper, one of the most actual devices - carbon nanotube field effect transistor (CNT FET) is investigated. At the beginning, the nanotube properties are presented. The main contribution of this paper is the new analytical model of CNT FET current-voltage characteristics. Developed model describes behavior of CNT FET in very good manner and, at the same time, the model is relatively simple. Using the developed model, simulations were performed. The results obtained by using proposed model are in very good agreement with already known and published ones.

Current-voltage characteristics of carbon nanotube FETS

U ovom radu ispitivane su karakteristike FETova izrađenih na bazi ugljeničnih nanotuba (CNT FETova). U prvom delu rada, predstavljene su neke osnovne osobine ugljeničnih nanotuba. Zatim je razvijen analitički model strujno-naponskih karakteristika CNT FETova koji dobro opisuje ponašanje ove savremene nanoelektronske naprave. Na bazi predloženog modela urađene su simulacije. Dobijeni rezultati su u saglasnosti sa prethodno publikovanim. .In this paper, one of the most actual devices - carbon nanotube field effect transistor (CNT FET) is investigated. At the beginning, the nanotube properties are presented. The main contribution of this paper is the new analytical model of CNT FET current-voltage characteristics. Developed model describes behavior of CNT FET in very good manner and, at the same time, the model is relatively simple. Using the developed model, simulations were performed. The results obtained by using proposed model are in very good agreement with already known and published ones.

Inhomogeneous Reionization Models in Cosmological Hydrodynamical Simulations

In this work we present a new hybrid method to simulate the thermal effects of the reionization in cosmological hydrodynamical simulations. The method improves upon the standard approach used in simulations of the intergalactic medium (IGM) and galaxy formation without a significant increase of the computational cost allowing for efficient exploration of the parameter space. The method uses a small set of phenomenological input parameters and combines a semi-numerical reionization model to solve for the topology of reionization and an approximate model of how reionization heats the IGM, with the massively parallel \texttt{Nyx} hydrodynamics code, specifically designed to solve for the structure of diffuse IGM gas. We have produced several large-scale high resolution cosmological hydrodynamical simulations ($2048^3$, $L_{\rm box} = 40$ Mpc/h) with different instantaneous and inhomogeneous HI reionization models that use this new methodology. We study the IGM thermal properties of these models and find that large scale temperature fluctuations extend well beyond the end of reionization. Analyzing the 1D flux power spectrum of these models, we find up to $\sim 50\%$ differences in the large scale properties (low modes, $k\lesssim0.01$ s/km) of the post-reionization power spectrum due to the thermal fluctuations. We show that these differences could allow one to distinguish between different reionization scenarios already with existing Ly$\alpha$ forest measurements. Finally, we explore the differences in the small-scale cutoff of the power spectrum and we find that, for the same heat input, models show very good agreement provided that the reionization redshift of the instantaneous reionization model happens at the midpoint of the inhomogeneous model.Comment: 24 pages, 16 figures. Accepted by MNRAS. Minor changes to match published versio

Modeling the HeII Transverse Proximity Effect: Constraints on Quasar Lifetime and Obscuration

The HeII transverse proximity effect - enhanced HeII Ly{\alpha} transmission in a background sightline caused by the ionizing radiation of a foreground quasar - offers a unique opportunity to probe the emission properties of quasars, in particular the emission geometry (obscuration, beaming) and the quasar lifetime. Building on the foreground quasar survey published in Schmidt+2017, we present a detailed model of the HeII transverse proximity effect, specifically designed to include light travel time effects, finite quasar ages, and quasar obscuration. We post-process outputs from a cosmological hydrodynamical simulation with a fluctuating HeII UV background model, plus the added effect of the radiation from a single bright foreground quasar. We vary the age $t_\mathrm{age}$ and obscured sky fractions $\Omega_\mathrm{obsc}$ of the foreground quasar, and explore the resulting effect on the HeII transverse proximity effect signal. Fluctuations in IGM density and the UV background, as well as the unknown orientation of the foreground quasar, result in a large variance of the HeII Ly{\alpha} transmission along the background sightline. We develop a fully Bayesian statistical formalism to compare far UV HeII Ly{\alpha} transmission spectra of the background quasars to our models, and extract joint constraints on $t_\mathrm{age}$ and $\Omega_\mathrm{obsc}$ for the six Schmidt+2017 foreground quasars with the highest implied HeII photoionization rates. Our analysis suggests a bimodal distribution of quasar emission properties, whereby one foreground quasar, associated with a strong HeII transmission spike, is relatively old $(22\,\mathrm{Myr})$ and unobscured $\Omega_\mathrm{obsc}<35\%$, whereas three others are either younger than $(10\,\mathrm{Myr})$ or highly obscured $(\Omega_\mathrm{obsc}>70\%)$.Comment: 19 pages, 6 figures, submitted to Ap

Isomerisation of N-Acyl Benzylpenilloic Acid in Acetic Anhydride and Formation of 7, 7-Dimethyl-6-thia-3,8-diazahicyclo(3,2,1)octan-2-one

The heating of N-acyl benzylpenilloic acids {II) in a cetic anhydride gave an equilibrium mixture of C-4 epimers, due to the epimerisation at C-4 position. Cyclisation of the 2-amidomethyl and 4-carboxylic group of IIb or IIc into a 2-ketopiperazine ring gave 1S,5S or 1R,5R enantiomer of III. Alkaline hydrolysis of III gave IV and II. When N-formyl group was present, IV and II upon acid hydrolysis yielded V and I. The C-4 epimers (lb or le) can be prepared from trans C-2, C-4 substituted C-4 epimers (Id or Ia) via II and III

Using natural disasters to instigate radical policy changes – the effect of Fukushima nuclear power plant accident on nuclear energy policies

Natural disasters and their effects have evolved to reflect the complexities of the physical and human environments, and their interactions in the modern world. After the earthquake and the tsunami of the Fukushima Daiichi nuclear reactors in March 2011 activists, lobbyist and reporters were quick to expose nuclear technology and demand if not an immediate closure, than at least a gradual phasing out of nuclear power plants. Further research on topics such as the safety of nuclear power plants, the environmental and social effects of radioactive contamination, and the potential of nuclear energy as a world power source has a critical role in this ongoing debate in order to reduce consumption of fossil fuels, and continuing rise in national energy demands for providing powerful motivators in the search for alternative energy sources

Special software for aridity indices calculation (AICS); Vojvodina, Serbia case study

Knowledge of aridity is necessary to explain the characteristics of the geographical landscape. Increasing aridity due to global warming can be a real hazard, with the threat of desertification. The main aim of this paper is to introduce special software for aridity indices calculation (AICS), and on the basis of those data to peruse aridity as a natural hazard. These indices were calculated from data obtained from 10 meteorological stations in the Vojvodina region for the period from 1949 to 2006. In order to calculate the De Martonne aridity index, IDM, and the Pinna combinative index, IP, software was created using C# programming language. Not only that this software shows the values of indices, but also it shows to which class it belongs according to the De Martonne climate classification. Graphical presentation of both calculated indices is also enabled. Further development of AICS is planned. As additional software package here was used ArcMap 10.1 for the spatial representation and visualization of the aridity indices. [Projekat Ministarstva nauke Republike Srbije, br. 176020 i br. 176013

Dermatitis tabanskih jastučića kod komercijalnih brojlera

In the present experiment, the presence of mycological agents in chickens with skin lesions on foot pads was investigated, in order to improve the health of broiler chickens. Foot-pad dermatitis (FPD) is described in the literature as dermatitis caused by multifactor causes. The presence of irritating chemical substances in the litter, genetic predispositions of hybrids, immune suppressive diseases of chickens, as well as the composition of commercial broiler diets that influence the occurrence of wet litter, are proven factors that contribute to a more intensive incidence of foot-pad dermatitis. Foot-pad dermatitis is a condition characterized by lesions on metatarsal and digital ventral skin of poultry feet. It is type of contact dermatitis which in severe cases shows slower weight gain, poor health condition and welfare. Taking into consideration the literature data, chickens reared in closed facilities where the bacterial and mycological agents are present partly in the litter if not properly disinfected, but also in the food or the chicken plumage, we wanted to investigate their presence in the skin of foot pads. The study was focused on incidence of foot-pad dermatitis in 500 one day old broiler chickens of Hubbard genotype, in two feeding (standard/economical) programs for broilers available on our market. Chopped straw was used as litter. At the end of fattening, all chickens were examined for the presence of lesions on the skin of the feet. Total of 39 chickens were allocated to the intensity of the lesion on foot pads rated as 2 (mild) and 3 (severe). In the mycological examination of the 9 samples of autoclaved chicken legs with lesions on the feet, we have isolated and identified the presence of fungi /mould Aspergillus fumigatus. The histopathology investigation, during which the tissue section from mild and severe skin foot pads was collected and stained using Hematoxylin and eosin, revealed the hyperkeratosis, panniculitis, ballooning degeneration and dermis inflammation. No fungal elements were observed in the sections of pads stained with Gomori methenamine silver. Birds are especially susceptible to infection with Aspergillus fumigatus. That species of fungus is also classified as allergenic factor.U ogledu je ispitivano prisustvo mikoloških agenasa kod pilića sa lezijama na koži tabanskih jastučića, u cilju poboljšanja zdravlja brojlerskih pilica. Dermatitis na tabanskim jastučićima (DTJ) je u literaturi multifaktornog porekla. Postojanje iritantnih hemijskih supstanci u prostirci, genetske predispozicije hibrida, imunosupresivne bolesti pilića, kao i sastav komercijalnih smeša za ishranu brojlera koje utiču na pojavu vlažne prostirke, su dokazani faktori koji doprinose intenzivnijoj pojavi DTJ. Imajući u vidu ove podatke iz literature, pilići koji se gaje u zatvorenom prostoru u kome su prisutni bakterijski i mikološki agensi delom u prostirci ako nije na adekvatan način dezinfikovana, u hrani ili na perju pilića, želeli smo da ispitamo njihovo prisustvo u koži tabanskih jastučića. Ispitivanje je bazirano na pojavi DTJ u ogledu 500 jednodnevnih pilića Hubbard genotipa, koji su hranjeni na 2 načina (standardnim/ekonomičnim) krmnim smešama koje su prisutne na našem tržištu. Seckana slama je korišćena kao prostirka. DTJ se karakteriše lezijama na metatarzalnim i digitalnim ventralnim delovima kože tabana živine. To je kontaktni dermatitis koji kod težih slučajeva utiče na prirast, zdravlje i dobrobit. Na kraju tova pilića, svi pilići su pregledani na prisustvo lezija na koži tabana. U ovom radu, ispitano je 39 pilića sa intenzitetom lezija na tabanskim jastučićima. Intenzitet lezija je ocenjen sa 2 (blage) i sa 3 (izražene) lezije. Mikološkim ispitivanjem utvrđeno je prisustvo gljivice/plesni Aspergillus fumigatus, kod 9 autoklaviranih promenjenih pilećih nogica. Histološkim ispitivanjem utvrdili smo postojanje hiperkeratoze, panikulitisa, zapaljenje dermisa i balonirajuću degeneraciju. Nismo utvrdili prisustvo fungalnih elemenata u koži tabana, nakon bojenja Gomory methenamin silver bojenjem. Ptice su posebno osetljive na infekciju A. fumigatus koji je klasifikovan kao alergijski uzročnik