Ionization

The safety of irradiated pork packed in 25% CO2:75% N2 and stored at abuse temperature (10 or 15°C) was assessed by inoculation studies involving Salmonella typhimurium, Listeria monocytogenes, Escherichia coli, Yersinia enterocolitica and Clostridium perfringens. Irradiation to a dose of 1.75 kGy reduced pathogen numbers to below the detection limit of 102 cells g-1. When higher inoculum levels were used (106 cells g-1) irradiation at 1.75 kGy reduced pathogen numbers by 1 –>5 log10 cycles depending on strain. Clostridium perfringens was the most resistant, and Y. enterocolitica the most sensitive of the pathogens studied.In all cases when high numbers (106 to 107g-1) of spoilage and/or pathogenic bacteria were present initially on the pork the meat appeared spoiled, and although irradiation reduced the number of microorganisms, the meat was still unacceptable from a sensory viewpoint after treatment.It was concluded that the microbiological safety of irradiated, modified atmosp...

This paper presents a modification to conventional magnetron sputtering systems. The introduction of a grid in front of the target increases the metal ion ratio. Using OES and observing both Ti neutrals and ions, it was confirmed that the relative ionization could be qualitatively extended with grid-attached magnetron sputtering compared with a conventional magnetron system. On the other hand, the relative ionization of Ar decreased. Our results also show that the Ti films deposited by conventional magnetron exhibit (100) preferred orientation as the bias voltage increased. On the other hand, in the case of the grid-attached magnetron, the Ti films exhibit highly preferred (002) orientation with increasing bias voltage. The experiments clearly demonstrated that a dense Ti film with a smooth, specular reflecting surface can be produced using the grid-attached magnetron with increased Ti ion flux compared to the conventional magnetron.

The conveniences and satisfaction derived in the use of EM radiation is being threatened by claims of adverse effects on human health by radiation coming from this device. This radiation belongs to the type called ionizing and non-ionizing radiation the health hazard of which remains debatable. Research has not been carried out on possible effect this device might have on human health and no experimental proof, based on data obtained within Nigeria, exist to substantiate any claim. Safety standards exist for radiation from cell phone but these are not reassuring. This paper investigates any possible effect of EM radiation on human heart rate and then come out with conclusion based on experimental proof as well as the controlling actions. In the wireless devices, there has been a massive increase in radiofrequency (RF) exposure from wireless devices as well as reports of hypersensitivity and diseases related to electromagnetic field and RF exposure. Multiple studies correlate RF exposure with diseases such as cancer, neurological disease, reproductive disorders, immune dysfunction, and electromagnetic hypersensitivity. Aim of this paper is to create social awareness of possible radiation hazards and precaution needed for protection.

This work presents a compositional characterization of 1939's Thousand "Réis" and 1945's One "Cruzeiro" Brazilian coins, forged on aluminum bronze alloy. The coins were irradiated by a Q-switched Nd:YAG laser with 4 ns pulse width and energy of 25mJ emitting at 1064nm reaching 3.1010Wcm-2 (assured condition for stoichiometric ablation), forming a plasma in a small fraction of the coin. Plasma emission was collected by an optical fiber system connected to an Echelle spectrometer. The capability of LIBS to remove small fraction of material was exploited and the coins were analyzed ablating layer by layer from patina to the bulk. The experimental conditions to assure reproductivity were determined by evaluation of three plasma paramethers: ionization temperature using Saha-Boltzmann plot, excitation temperature using Boltzmann plot, plasma density using Saha-Boltzmann plot and Stark broadening. The Calibration-Free LIBS technique was applied to both coins and the analytical determination of elemental composition was employed. In order to confirm the Edict Law elemental composition the results were corroborated by Neutron Activation Analysis (NAA). In both cases the results determined by CF-LIBS agreed to with the Edict Law and NAA determination. Besides the major components for the bronze alloy some other impurities were observed. Finally, in order to determine the coin damage made by the laser, the OCT (Optical Coherence Tomography) technique was used. After tree pulses of laser 54μg of coin material were removed reaching 120μm in depth.

Ionospheric total electron content (TEC) of the equatorial ionization anomaly (EIA) is studied by analyzing dual-frequency signals of the Global Position System (GPS) acquired from a network of receivers around the Asian-Australian region during 1996-2004. The latitude, occurrence time, strength of the most developed EIA crest, and crest-to-trough ratio (CTR) for both the noon and post-sunset sector obtained from a daily TEC contour map have been used to study the solar cycle variations of EIA in the Asian-Australian region. The results reveal that semiannual and seasonal variations were the dominant factor that controls the morphology of the EIA structure which can be identified in the past studies (e.g. Wu et al., 2008). It is also found that the latitude and local time position of the anomaly crest show a hemispheric asymmetry because (a) The northern crest of EIA is expanded during the equinox indicating a weak semiannual variation while the southern crest is inhibited during June-August presenting a strong seasonal variation, and (b) The local time of the northern crest appears ~1.3 h earlier than that of the southern crest in June while showing no difference at December. Solar activity dependence is more evident in the EIA crest region than in the EIA trough region and least in the post-sunset sector at equinox. A seasonal linear relationship is derived between the post-sunset CTR and solar flux, which should be caused by the solar-dependant equatorial E×B vertical drift.

Explorar a química através de poesia, pode facilitar a aprendizagem dos alunos, aumentar o seu interesse pela disciplina e promover o desenvolvimento de competências estruturantes de escrita, leitura, interpretação e argumentação, bem como, de forma específica, a compreensão dos conteúdos químicos abordados. Apesar de tudo, o potencial pedagógico resultante desta fusão,entre a química e a poesia,ainda não é muito explorado nas aulas mas, investigações neste sentido, sugerem que desta fusão tendem a resultar fortes indicadores sobre o envolvimento dos alunos na aprendizagem da ciência química.
Neste trabalho apresenta-se uma estratégia de ensino dos temas raio atómico e energia de ionização, através da exploração do poema “The Atom’s Family” alusivo à família dos metais alcalinos, com alunos do 10.º ano na disciplina de Física-Química. Da intervenção resultaram poemas e caricaturas sobre vários elementos químicos elaborados pelos alunos, que, juntamente com os dados recolhidos através de um inquérito por questionário nos permitiram obter indicadores positivos relativos ao impacto da utilização da poesia na motivação e na aprendizagem dos conceitos químicos em estudo. Os alunos consideraram o ensino da química, interligado com a poesia, uma estratégia motivadora, que poderia ser implementada frequentemente, e que potencia o envolvimento na construção da sua aprendizagem.

Mass spectrometry has recently undergone a second contemporary revolution with the introduction of a new group of desorption/ionization (DI) techniques known collectively as ambient mass spectrometry. Performed in an open atmosphere directly on samples in their natural environments or matrices, or by using auxiliary surfaces, ambient mass spectrometry (MS) has greatly simplified and increased the speed of MS analysis. Since its debut in 2004 there has been explosive growth in the applications and variants of ambient MS, and a very comprehensive set of techniques based on different desorption and ionization mechanisms is now available. Most types of molecules with a large range of masses and polarities can be ionized with great ease and simplicity with the outstanding combination of the speed, selectivity, and sensitivity of MS detection. This review describes and compares the basis of ionization and the concepts of the most promising ambient MS techniques known to date and illustrates, via typical analytical and bioanalytical applications, how ambient MS is helping to bring MS analysis deeper than ever into the “real world” open atmosphere environment—to wherever MS is needed. Figure Schematic of EASI

In this chapter we analyze the possibilities and ranges of validity of the dielectric formalism to deal with correlated bound electrons in matter by using the shellwise local plasma approximation. This model describes the response of the electrons of the same binding energy as a whole (collectively), screening the interaction with the impinging ion. It considers separately each sub-shell of target electrons, with the corresponding dielectric response. The density of electrons and the energy gap are included explicitly by employing the Levine and Louie dielectric function. The goal of this chapter is to summarize and review the capability of this model to deal with fundamental magnitudes of the atomic collisions expressed as different moments of

Turbulence and angular momentum transport in accretion disks remains a topic of debate. With the realization that dead zones are robust features of protoplanetary disks, the search for hydrodynamical sources of turbulence continues. A possible source is the baroclinic instability (BI), which has been shown to exist in unmagnetized non-barotropic disks. We present shearing box simulations of baroclinicly unstable, magnetized,

Deposition of films using plasma or plasma-assist can betraced back surprisingly far, namely to the 18th century for arcs and tothe 19th century for sputtering. However, only since the 1960s thecoatings community considered other processes than evaporation for largescale commercial use. Ion Plating was perhaps the first importantprocess, introducing vapor ionization and substrate bias to generate abeam of ions arriving on the surface of the growing film. Ratherindependently, cathodic arc deposition was established as an energeticcondensation process, first in the former Soviet Union in the 1970s, andin the 1980s in the Western Hemisphere. About a dozen various ion-basedcoating technologies evolved in the last decades, all characterized byspecific plasma or ion generation processes. Gridded and gridless ionsources were taken from space propulsion and applied to thin filmdeposition. Modeling and simulation have helped to make plasma and ionseffects to be reasonably well understood. Ye...

This article aims to investigate the possibility of using atmospheric air ionization in propulsion and energy generation systems. To do this, it is developed a set of equations based on the generation of high-voltage and medium frequency RF electrical fields to ionize the air surrounding a surface and create a differential pressure that produces thrust.

The production of semi-insulating SiC depends on two issues: (i) the incorporation of a transition metal or further defects in the SiC lattice providing near midgap electronic levels; and (ii) the control of shallow and middle deep acceptors and donors. In this work a synthesis process for SiC powders doped with vanadium (V) as an amphoteric dopant is proposed. The

This report describes research results on Fundamental Processes in Partially Ionized Plasmas obtained in the High Temperature Gasdynamics Laboratory at Stanford University. This research has emphasized studies of plasma properties and associated diagnostics. The present report discusses, in the first part, optical diagnostics in air plasmas and, in the second part, measurements of the radiative emission of such plasmas. These experimental results have unveiled severe deficiencies in existing computer codes such as the widely used NASA code NEQAIR. Several modeling improvements are therefore proposed and included into NEQAIR. As a result, the enhanced version of the code is capable of predicting the radiative emission of air plasmas with better than 20 percent accuracy, as opposed to only orders of magnitude with the original version. Finally, the report presents first measurements of the radiative source strength of air for temperatures in the range between 5000 and 7500 K. To our knowledge, these are the first measurements of this important property in this temperature range. Excellent agreement is again obtained with the predictions of the enhanced NEQAIR code.

This article describes the theoretical models for determination of electron-impact ionization cross-section, which has been applied to atoms, ions, and molecules. The model combines the Bethe theory and binary-encounter theory for electron-impact ionization called the binary-encounter Bethe (BEB) model that use the binding energy and average kinetic energy of each subshell that prescribes differential ionization cross section for that shell and S. P. Khare and co-workers give the new Formalism by combining Bethe and Mott's cross-section known as Jain-Khare Formalism are discussed here. Copy