1,036 research outputs found
Atmospheric Chemistry Modelling of Amine Emissions from Post Combustion CO2 Capture Technology
Emissions from post combustion CO2 capture plants using amine solvents are of concern due to their adverse impacts on the human health and environment. Potent carcinogens such as nitrosamines and nitramines resulting from the degradation of the amine emissions in the atmosphere have not been fully investigated. It is, therefore, imperative to determine the atmospheric fate of these amine emissions, such as their chemical transformation, deposition and transport pathways away from the emitting facility so as to perform essential risk assessments. More importantly, there is a lack of integration of amine atmospheric chemistry with dispersion studies. In this work, the atmospheric chemistry of the reference solvent for CO2 capture, monoethanolamine, and the most common degradation amines, methylamine and dimethylamine, formed as part of the post combustion capture process are considered along with dispersion calculations. Rate constants describing the atmospheric chemistry reactions of the amines of interest are obtained using theoretical quantum chemistry methods and kinetic modeling. The dispersion of these amines in the atmosphere is modeled using an air-dispersion model, ADMS 5. A worst case study on the UK's largest CO2 capture pilot plant, Ferrybridge, is carried out to estimate the maximum tolerable emissions of these amines into the atmosphere so that the calculated concentrations do not exceed guideline values and that the risk is acceptable
Morphometric analysis of population samples of soldier caste of Odontotermes obesus (Rambur) (Isoptera, Termitidae, Macrotermitinae)
In order to study morphometric variations in Odontotermes obesus (Rambur), samples from nineteen nests were statistically analyzed for mean, standard deviation, standard error, coefficient of variability and confidence interval (95%) and analysis of variance (Model II ANOVA), The mean values of the different population samples were compared with the student t-test, following the Minitab version and Sokal & Rohlf (1973). In the study of external characters, measurements form a very important component, particularly for identification of species. However, the reliability of the measurements depends on the extent of variability which the structures show within and between colonies. For each individual soldier, the following nine parameters were measured: i) length of head; ii) width of head at mandibles; iii) width of head at the posterolateral ends of antennal carinae; iv) maximum width of head; v) length of left mandible; vi) tooth of left mandible from tip; vii) length of pronotum; viii) width of pronotum; ix) length of postmentum; and x) width of postmentum
Análisis morfométrico de muestras de una población de la casta de las obreras de Odontotermes obesus
In order to study morphometric variations in Odontotermes obesus (Rambur), samples from nineteen nests were statistically analyzed for mean, standard deviation, standard error, coefficient of variability and confidence interval (95%) and analysis of variance (Model II ANOVA), The mean values of the different population samples were compared with the student t–test, following the Minitab version and Sokal & Rohlf (1973). In the study of external characters, measurements form a very important component, particularly for identification of species. However, the reliability of the measurements depends on the extent of variability which the structures show within and between colonies. For each individual soldier, the
following nine parameters were measured: i) length of head; ii) width of head at mandibles; iii) width of head at the posterolateral ends of antennal carinae; iv) maximum width of head; v) length of left mandible; vi) tooth of left mandible from tip; vii) length of pronotum; viii) width of pronotum; ix) length of postmentum; and x) width of postmentumCon el objetivo de estudiar las variaciones morfomĂ©tricas en Odontotermes obesus (Rambur), se analizaron estadĂsticamente muestras de diecinueve nidos, obteniĂ©ndose sus medias, desviaciones estándar, errores estándar, coeficientes de variabilidad e intervalos de confianza (95%) y análisis de varianza (Modelo II ANOVA). Los valores medios de las distintas muestras de las poblaciones se compararon mediante el test t de Student, segĂşn la versiĂłn Minitab y Sokal & Rohlf (1973). En el estudio de los caracteres externos se midieron componentes muy importantes, particularmente para la identificaciĂłn de la especie. Sin embargo, la fiabilidad de las mediciones depende de la cantidad de variabilidad de dichas estructuras dentro de cada colonia y entre colonias. En cada soldado se midieron los siguientes nueve parámetros: i) longitud de la cabeza, ii) ancho de la cabeza al nivel de las mandĂbulas, iii) ancho de la cabeza en los extremos posterolaterales de las carinas antenales, iv) ancho máximo de la cabeza, v) longitud de la mandĂbula izquierda, vi) diente de la mandĂbula izquierda desde la punta, vii) longitud del pronoto, viii) ancho del pronoto, ix) longitud el postmentĂłn, y x) ancho del postmentĂł
Ruin Theory for Dynamic Spectrum Allocation in LTE-U Networks
LTE in the unlicensed band (LTE-U) is a promising solution to overcome the
scarcity of the wireless spectrum. However, to reap the benefits of LTE-U, it
is essential to maintain its effective coexistence with WiFi systems. Such a
coexistence, hence, constitutes a major challenge for LTE-U deployment. In this
paper, the problem of unlicensed spectrum sharing among WiFi and LTE-U system
is studied. In particular, a fair time sharing model based on \emph{ruin
theory} is proposed to share redundant spectral resources from the unlicensed
band with LTE-U without jeopardizing the performance of the WiFi system.
Fairness among both WiFi and LTE-U is maintained by applying the concept of the
probability of ruin. In particular, the probability of ruin is used to perform
efficient duty-cycle allocation in LTE-U, so as to provide fairness to the WiFi
system and maintain certain WiFi performance. Simulation results show that the
proposed ruin-based algorithm provides better fairness to the WiFi system as
compared to equal duty-cycle sharing among WiFi and LTE-U.Comment: Accepted in IEEE Communications Letters (09-Dec 2018
Nuclear Track Detectors for Environmental Studies and Radiation Monitoring
Several improvements were made for Nuclear Track Detectors (NTDs) used for
environmental studies and for particle searches. A new method was used to
determine the bulk etch rate of CR39 and Makrofol NTDs. It is based on the
simultaneous measurement of the diameter and of the height of etch-pit cones
caused by relativistic heavy ions (158 A GeV Pb(82+) and In(49+) ions) and
their fragments. The use of alcohol in the etching solution improves the
surface quality of NTDs and it raises their thresholds. The detectors were used
for the determination of nuclear fragmentation cross sections of Iron and
Silicon ions of 1.0 and 0.41 GeV/nucleon. These measurements are important for
the determination of doses in hadron therapy and for doses received by
astronauts. The detectors were also used in the search of massive particles in
the cosmic radiation, for the determination of the mass spectrum of cosmic rays
and for the evaluation of Po(210) alpha decay and of natural radon
concentrations.Comment: 7 pages, 5 EPS figures. Presented at the 10th Topical Seminar on
Innovative Particle and Radiation Detectors, 1-5 October 2006, Siena, Ital
Mathematical modelling of ciliary propulsion of an electrically conducting Johnson-Segalman physiological fluid in a channel with slip
Bionic systems frequently feature electromagnetic pumping and offer significant advantages over conventional designs via intelligent bio-inspired properties. Complex wall
features observed in nature also provide efficient mechanisms which can be utilized in biomimetic
designs. The characteristics of biological fluids are frequently non-Newtonian in nature. In many natural systems super-hydrophobic slip is witnessed. Motivated by these phenomena, in the present article, we present a mathematical model for the cilia-generated propulsion of an electrically-conducting viscoelastic physiological fluid in a ciliated channel under the action of an externally
applied static magnetic field. The rheological behavior of the fluid is simulated with the Johnson-Segalman constitutive model which allows internal wall slip. The regular or coordinated movement of the ciliated edges (which line the internal walls of the channel) is represented by a metachronal wave motion in the horizontal direction which generate a two-dimensional velocity profile with the parabolic profile in the vertical direction. This mechanism is imposed as a periodic moving velocity boundary condition which generates propulsion in the channel flow. Under the
classical lubrication approximation (long wavelength and low Reynolds' number), the boundary value problem is rendered non-dimensional and solved analytically with a perturbation technique. The influence of the geometric, rheological (slip and Weissenberg number) and magnetic
parameters on the velocity, pressure gradient and the pressure rise (evaluated via the stream function in symbolic software) are presented graphically and interpreted at length
Qualitative and quantitative analysis of milk for the detection of adulteration by Laser Induced Breakdown Spectroscopy (LIBS)
The present work focuses on the development of a fast and cost effective method based on Laser Induced Breakdown Spectroscopy (LIBS) to the quality control, traceability and detection of adulteration in milk. Two adulteration cases have been studied; a qualitative analysis for the discrimination between different milk blends and quantification of melamine in adulterated toddler milk powder. Principal Component Analysis (PCA) and neural networks (NN) have been used to analyze LIBS spectra obtaining a correct classification rate of 98% with a 100% of robustness. For the quantification of melamine, two methodologies have been developed; univariate analysis using CN emission band and multivariate calibration NN model obtaining correlation coefficient (R2) values of 0.982 and 0.999 respectively. The results of the use of LIBS technique coupled with chemometric analysis are discussed in terms of its potential use in the food industry to perform the quality control of this dairy product
Synthesis, Characterization, and Antibacterial Studies of Mixed Ligand Dioxouranium Complexes with 8-Hydroxyquinoline and Some Amino Acids
Mixed ligand complexes of dioxouranium (VI) of the type [UO2(Q)(L)·2H2O] have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and amino acids (HL) such as L-threonine, L-tryptophan, and L-isoleucine as secondary ligands. The metal complexes have been characterized by elemental analysis, electrical conductance, magnetic susceptibility measurements, and spectral and thermal studies. The electrical conductance studies of the complexes indicate their nonelectrolytic nature. Magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes show intraligand and charge transfer transitions, respectively. Bonding of the metal ion through N- and O-donor atoms of the ligands is revealed by IR studies, and the chemical environment of the protons is confirmed by NMR studies. The thermal analysis data of the complexes indicate the presence of coordinated water molecules. The agar cup and tube dilution methods have been used to study the antibacterial activity of the complexes against the pathogenic bacteria S. aureus, C. diphtheriae, S. typhi, and E. coli
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