Plasma generated by a 1064 nm pulsed Nd: YAG laser with pulse duration of 10 ns concentrated onto an Al solid target under vacuum pressure was examined spectroscopically. The temperature and electron density specifying the plasma were measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time period range of 300–2000 ns. An echelle spectrograph is utilized to appear the plasma emission lines. The temperature was obtained using the spectral line comparison method and the electron density was calculated using the Stark Broadening (SB) method. The electron density was characterized as a function of laser pulse energy. The time range where the plasma is optically thin and is also in local thermodynamic equilibri

Learning a foreign language is a highly interactive process, and a belief that communicative activities foster a great amount of linguistic production provides language practice and opportunities for negotiation of meaning during communicative exchanges. Thus, this study examines what benefits learner-centered classroom setting offers compared with that of teacher–centered classroom, and how less proficient learners accomplish their tasks and activities with scaffolded help during interaction with the help of proficient classmates and under the guidance of a skilful person, i.e., the teacher. The subjects participating in this study are 30 Iraqi 4^th year college students in the Department of English, College of Arts , Univer

The primary objective of this study was to identify the mechanisms for the development and propagation of longitudinal cracks that initiate at the surface of composite pavement. In this study the finite element program ANSYS version (5.4) was used and the model worked out using this program has the ability to analyze a composite pavement structure of different layer properties. Also, the aim of this study was modeling and analyzing of the composite pavement structure with the physical presence of crack induced in concrete underlying layer. The results obtained indicates that increasing the thickness of the asphalt layer tends to decrease the stress intensity factor, which may be attributed to the rapidly decrease of horizontal tensile st

Primary productivity and chlorophyll-a were used in this study to monitor the restoration process of southern Iraqi marshes (Al-Hewaizeh, central marshes, and Al-Hammar). The phytoplankton primary productivity was based on oxygen light/dark bottle method. Two different depths samples were taken monthly from six studied marshes stations (two stations for each marsh) during November 2005 to October 2006, while chlorophyll-a samples taken from surface water. The phytoplankton primary productivity values ranged 9.38 – 249.79 mg C/m3.hr for all marshes, its values for surface water sample ranged 11.71 – 256.24 mg C/m3.hr, while for 1m depth ranged 9.38 – 142.5 mg C/m3.hr. Chlorophyll-a values ranged between (1.1 – 21.26) µg/l indicating

In this study, a mathematical model for the kinetics of solute transport in liquid membrane systems (LMSs) has been formulated. This model merged the mechanisms of consecutive and reversible processes with a “semi-derived” diffusion expression, resulting in equations that describe solute concentrations in the three sections (donor, acceptor and membrane). These equations have been refined into linear forms, which are satisfying in the special conditions for simplification obtaining the important kinetic constants of the process experimentally.

Abstract: In this work we demonstrate and investigate the optical pulse propagation in a photonic band gap fiber Bragg grating (FBG). The light propagates in opposite direction in FBG is explained and discussed by a Coupled Mode Theory (CMT). The photonic band gap (stop band gap) is created by fabricated, a Bragg grating in optical fiber. The results show the pulse spectrum falls entirely within the stop band gap, the entire pulse is reflected by the grating, while when the pulse spectrum is outside the stop band gap the pulses will transmitted through the grating. The group velocity (VG) becomes zero at the edges of the stop band and group velocity dispersion β2 is anomalous on the shorter side of stop band gap whereas β2 for uniform fi

Nitrogen (N) fertilizer rate is important for high yield and good quality of potato tubers. In this dissertation, I seek to study the response of different potato cultivars under different N fertilizer rates and how that can impact tuber quality, examine the performance of active optical sensors in improving a potato yield prediction algorithm, and evaluate the ability of active optical sensors (GreenSeeker (GS) and Crop Circle (CC)) to optimize a N recommendation algorithm that can be used by potato growers in Maine. This research was conducted at 11 sites over a period of two years (2018–2019) in Aroostook County, Maine; all sites depended on a rainfed system. Three potato cultivars, Russet Burbank, Superior, and Shepody, were planted u

Collective C2 transitions in 32S are discussed for higher
energy configurations by comparing the calculations of transition
strength B(CJ  )with the experimental data. These configurations
are taken into account through a microscopic theory including
excitations from the core orbits and the model space orbits with nħω
excitations.
Excitations up to n=10 are considered. However n=6 seems to
be large enough for a sufficient convergence. The calculations
include the lowest seven 2+0 states of 32S.