Wyniki wyszukiwania - BazTech

1

Mathematical modeling of the aeroion mode in a car

Biliaiev Mykola, Pshinko Oleksandr, Rusakova Tetiana, Biliaieva Viktoriia, Sładkowski Aleksander

Transport Problems

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2022

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T. 17, z. 2

19--32

EN

In this study, a mathematical method is proposed for calculating the concentration field of air ions of different polarities and dust levels in the passenger compartment, taking into account the geometry of the passenger compartment and seats, shelves, and other internal elements of the passenger compartment. The method also takes into account changes in the rate of the air flow ventilation, the location and number of ionizers, and sources of positive ions and dust, taking into account their different intensities and locations. On the basis of a numerical model for this method, software has been developed that allows users to carry out computational experiments without requiring much time for calculation. Based on the results, the optimal location of the ionizer in the passenger compartment of the car was determined to ensure comfortable conditions for the stay of passengers, which favorably affects their health. It has been found that the presence of two ionizers is optimal for creating comfort in the car with an ionization intensity of Qn= 0.47 ×1010 ions/s located at the top of the car. If there is one ionizer located on the dashboard or at the top of the car with a higher ionization rate than ions/s, it is not possible to simultaneously provide optimal ionization parameters for passengers in the front and rear seats of the car.

2

Efficient nitrate adsorption from water by aluminum powder. Kinetic, equilibrium and influence of anion competition studies

Fakhri Y., Kakavandi B., Safaei Z., Asadi A., Mohseni S. M., Golestanifar H.

Environment Protection Engineering

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2018

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Vol. 44, nr 3

19--31

EN

The feasibility of aluminum powder (with particle size of 75–150 μm) for nitrate removal from aqueous solutions has been investigated. Adsorption was examined in function of initial nitrate concentration, contact time, pH and influence of other interfering anions. Maximum nitrate removal occurred at equilibrium pH of 10. The kinetics of adsorption of nitrate ions was discussed based on three kinetic models, namely: the pseudo-first order, the pseudo-second order and the intraparticle diffusion model. The experimental data fitted the pseudo-second order kinetic model very well; the rate constant was 4x10–4 g/ (mg·min) at the concentration of NO3- of 100 mg/dm3. The adsorption data followed both Langmuir (R2 = 0.808) and Freundlich (R2 = 0.865) isotherms probably due to the real heterogeneous nature of the surface sites involved in the nitrate uptake. The maximum sorption capacity of aluminum powder for nitrate adsorption was found to be ca. 45.2 mg/g at room temperature. The results indicate that aluminum powder is an interesting alternative for nitrate removal from the water.

3

Oddziaływanie elektronów z cząsteczkami o biologicznym znaczeniu

Kopyra J.

Wiadomości Chemiczne

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2015

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[Z] 69, 9-10

893--907

EN

Recent years have witnessed an increase of the interest in the studies of the interaction of electrons with biologically relevant molecules. This has been mainly motivated by the seminal work, where it has been demonstrated that low energy electrons can induce single and double strand breaks in DNA in the energy range below the level of ionization. Since the damage profile as a function of electron energy showed pronounced resonances it was proposed that resonant electron capture could occur at particular molecular components of the DNA as the initial step towards strand breaks. From a series of experiments on electron attachment to DNA building blocks (nucleobases, the sugar moiety and the phosphate unit) became obvious that they effectively capture electrons leading to the formation of low energy resonances associated with the decomposition of the corresponding molecule. Recent dissociative electron attachment experiments on an entire gas phase nucleotide 2’-deoxycytidine-5´-monophosphate give also insight into the molecular mechanism involved, which comprises both direct electron attachment to the backbone and transfer of the excess electron from cytosine to the backbone resulting in single strand breaks. The results further allow an estimate of the relative contribution of these different mechanisms to single strand breaks.

4

Wpływ zjonizowanego powietrza na organizm ludzki

Moga M., Małecka I.

Zeszyty Naukowe. Inżynieria Lądowa i Wodna w Kształtowaniu Środowiska

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2011

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Nr 4

26-29

PL

Wpływ zjonizowanego powietrza na organizm ludzki zależy od wielkości jonów i ich biegunowości oraz koncentracji ich w powietrzu, a także od właściwości fizykochemicznych nośników jonów (aerozole, bakterie). Głównym źródłem energii jonizującej atomy i molekuły gazów wchodzących w skład powietrza atmosferycznego jest promieniowanie emitowane przez pierwiastki radioaktywne znajdujące się w powietrzu i skorupie ziemskiej. Z dużą dozą ostrożności należy podchodzić do sztucznej jonizacji w pomieszczeniach, w których nie dokonano liczbowo pomiarów ich koncentracji. W celu wyeliminowania zagrożeń mikrobiologicznych w układach instalacji wentylacyjnej należy poddać powietrze skutecznej dezynfekcji. Jony ujemne powietrza przyspieszają reakcje biologiczne, a mianowicie poprawiają zdolność koncentracji, przyspieszają gojenie się ran, zmniejszają uczucie bólu, ale z kolei przyspieszają wzrost komórek nowotworowych. Natomiast jony dodatnie powodują osłabienie, ból głowy, otępienie, zwiększone zapotrzebowanie na tlen oraz występujące także nierzadko objawy suchości w ustach i jamie nosowej.

EN

The impact of ionized air upon the human body depends on the size of ions, their polarity and concentration in the air as well as physicochemical properties of ion carriers (aerosols, bacteria). The main source of energy ionizing gas atoms and molecules forming the atmospheric air is radiation emitted by radioactive elements found in the air and the earth's crust. A very cautious approach must be assumed when considering artificial ionization in rooms where their concentration has not been measured. In order to eliminate microbiological hazards in ventilation systems the air should be subject to effective disinfection. Negative air ions accelerate biological reactions, improve concentration ability, accelerate healing of wounds, reduce feeling of pain, however, they support growth of cancer cells. On the other hand, positive ions cause fatigue, headache, stupefaction, increased demand for oxygen and frequent symptoms of dryness in the mouth and nasal cavity.

5

Wytwarzanie jonów ujemnych z SF₆ za pomocą termoemisyjnego źródła jonów

Pelc A.

Elektronika : konstrukcje, technologie, zastosowania

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2011

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Vol. 52, nr 8

77-79

PL

W pracy przedstawione są wyniki badań wytwarzania jonów ujemnych z SF₆. Jony ujemne otrzymywane były przy użyciu nowo skonstruowanego termoemisyjnego, gazowego źródła jonów i analizowane w spektrometrze mas z pojedynczym sektorem magnetycznym. Zaobserwowano aniony SF₅⁻, F⁻, SF₆⁻, SF₄⁻ oraz SF₃⁻ o stosunkach prądów jonowych wynoszących odpowiednio 1000:150:80:10:5:0,5. Ze względów energetycznych jon macierzysty SF₆ może powstać podczas bezpośredniego przyłączenia swobodnego elektronu do molekuły SF₆. Pozostałe jony mogą być wytwarzane zarówno w procesie fragmentacji SF₆⁻ jak też poprzez dysocjację termiczną i następujący po niej wychwyt elektronu przez powstałe fragmenty. Pomiary tła dla jonu F⁻ (po odcięciu dozowania sześciofluorku siarki) sugerują powstawanie HF na ściankach źródła jonów.

EN

Results of studies of the negative ions formation from SF6 are presented in this work. Using the mass spectrometer with magnetic sector field, ions obtained in the thermoemission, gaseous ions source were analyzed. Five ion species: SF₅⁻, F⁻, SF₆⁻, SF₄⁻ and SF₃⁻ with ions currents intensities ratios 1000:150:80:10:5:0,5, respectively, were measured. From the energetic point of view the SF₆⁻ anion can be formed by the direct free electron attachment to the SF₆ molecule. The other ions may be generated both in the fragmentation process of SF₆ and by the thermal dissociation followed by the electron capture to the fragments formed. Background signal from F⁻ (after the gas admission was stopped) suggest HF formation on the wali of ion source.

6

Physical foundations of rhenium-osmium method - a review

Dąbek J., Halas S.

Geochronometria

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2007

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Vol. 27

23-26

EN

A newly acquired mass spectrometer MI 1201 by the Mass Spectrometry Laboratory will be adapted to determine rhenium and osmium isotope concentrations using negative thermal ionization mass spectrometry (NTIMS). We describe the principle of the Re-Os dating technique and the thermal ionization phenomena which lead to high precision isotope analysis on NTIMS.

7

Production of negative hydrogen ions using a low-pressure reflex discharge source

Toader E.

Nukleonika

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2006

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Vol. 51, nr 1

29-35

EN

In this paper we analyze the possibility to use the reflex discharge plasma as a volume source of negative hydrogen ions. The basic internal parameters like the temperature Te and the density ne of the electrons, the density ni of the positive hydrogen ions, the density n- of the negative hydrogen ions, and the negative ion fraction n-/ne are measured and discussed. The operating conditions are optimized within the pressure range 0.1-10 Pa, the discharge power 20-140 watt, and the magnetic field 0-150 gauss. The experiment shows that the enhanced magnetic ionization is the most effective within the pressure range from 0.7 to 4.0 Pa. When p ť 1 Pa the cold electron temperature Te is 0.77 eV, the cold electron density ne is 4.2 ´ 10 18 m-3 and the negative ion density n- is as high as 0.8 x 10 17 m-3. The negative ion fraction n-/ne increases from 1.4% for p = 0.1 Pa to almost 2.2% within the pressure range 1-4 Pa. The positive ion density scales with the power, while the negative ion density and the negative ion fraction seems to saturate at higher power levels.

8

Electron capture negative ion mass spectra of some freon derivatives

Asfandiarov N., Pshenichnyuk S., Fal’ko V., Wnorowska J., Wnorowski K., Szamrej-Foryś I.

Nukleonika

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2003

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Vol. 48, nr 2

83-88

EN

The temperature dependence of dissociative attachment has been investigated in the temperature range 350-575 K for two freon derivatives 1,1,1-C2H3F2Cl and C2F5Cl using Electron Capture Negative Ion Mass Spectra (ECNI MS). The temperature dependence for 1,1,1-C2H3F2Cl is similar to that observed in the case of CF3Cl reported by Illenberger et al. In contrast, C2F5Cl exhibits quite a different spectrum and its temperature behavior. It has been suggested that sigma*C-Cl delocalization onto two empty orbital leads to Cl- ion formation in two different resonance states.

9

Negative ion source for SIMS application

Hereć J., Filiks J., Sowa M., Sielanko J., Mączka D.

Nukleonika

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1999

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Vol. 44, nr 2

119-128

EN

The paper presents a modification of the thermal emission Cs+ ion source used for SIMS spectroscopy purposes. The source was modified in such a way that both the positive ion beam (in thermal emission mode), and the negative one (in sputter mode) may be emitted by the source. The mass spectra of both beams are shown and analysed. Also comparison of the secondary ion mass spectra obtained for negative and positive primary ion beams is presented.

PL

Praca prezentuje modyfikację termoemisyjnego źródła jonów wykorzystywanego w spektrometrze SIMS. Konstrukcja termoemisyjnego źródła jonów dodatnich została zmieniona, tak by mogło ono pracować jako źródło jonów ujemnych, przy wykorzystaniu zjawiska rozpylania. Zaprezentowane i omówione zostały widma mas dla wiązki jonów dodatnich i ujemnych. Porównano także widma mas jonów wtórnych dla tarcz bombardowanych wiązką jonów dodatnich i ujemnych.