Study of stars of early spectral type: with special reference to emission line spectra

PART I: EMISSION LINES IN EARLY TYPE SPECTRA - GENERAL SURVEY The present state of the study of emission line stars of early spectral types is briefly reviewed, mainly from the observational point of view. PART II: THE BE- VARIABLE SPECTRUM OF O PERSEI Radial velocities of central hydrogen absorption lines were measured on 23 quartz -prism spectrograms, covering the star's period of variation. The new observations agree well with the period given by Dustheimer, but it is probable that the decrease in the velocity range is real. The secondary variation is discussed. It is likely that the extent of this variation increases for lines of shorter wave -length. The observations are compared with Schiefer's results. The variation of the number of Balmer lines with sharp central cores is examined. It is shown that this variation is not likely to occur in the same atmosphere, and therefore the binary hypothesis seems necessary. PART III: LINE INTENSITITES IN SOME BE- STARS Line intensities in seven plates of `. Per., covering about 30 days of the star' s period were measured. A clear correlation is found between emission line intensity and the colour of the star as given by Roach. The widths of emission lines in some Be -stars are compared with the value computed from Curtiss' formula. The possibility of measuring the hydrogen-decrement in Be -stars is discussed and the previous observations criticised. Equivalent widths of helium and hydrogen lines in K Cas. and B Ceph. are also given. H a is definitely variable in K Cas., while HB is apparently constant. The most probable turbulent velocity is obtained for the two stars. PART IV: TOTAL INTENSITIES OF A TRIPLET OF SiIII IN STELLAR SPECTRA Total intensities of the three Si III lines, 4552, 4567 and 4574 were measured on 81 plates of 32 -early type stars. Deviations from the square roots of the multiplet intensities are small, but nevertheless real. Previous measures are included in a discussion of the differences between high and low luminosity stars and between wide and narrow line stars. The formation of the lines, mainly through damping, is examined. A definite discrepancy is observed between observation and theory. This discrepancy may be removed by assuming a negative turbulence velocity in the atmosphere, an incipient emission filling the lines, or a damping constant more than 440 times the classical value. This last assumption may be nearest the truth

Study of the Optical Properties of Zno Nano-structure at Different Ti Content

Zinc oxide (ZnO) and TZO samples having different Ti content were synthesized from doping to composite by Citrate sol-gel method (dissolving and react with citric acid) characterized according to their optical properties. The UV - vis characterization exhibiting good optical properties. The results show there are one absorption edge at pure and low Ti doping but at higher Ti% another edge appeared and slightly shifted around 400 nm. The maximum absorption nearly at 350 nm, and the band gap energy of Ti-doped ZnO increase from 3.16 to 3.20 eV achieving a blue-shift. A red shift from 3.07 to 3.19 eV in the visible range which has a very important application, this improves the optical properties of ZnO and gives an indication how to tune its band gap (increase or decrease by doping or composition)

Examining the Effectiveness of Group Counseling in Reducing Anxiety for Jordanian EFL Learners

This study aimed at examining the effectiveness of Rational Emotive Behavior Therapy (REBT) as used in group counseling to reduce the level of anxiety for Jordanian learners of English as a foreign language. The study sample consisted of 32 male and female students at Ajloun National University. The students were all at the undergraduate level and have received the highest anxiety scores on the foreign language anxiety scale. The students were randomly divided into two groups; an experimental group and a controlled group. Each group consisted of 16 male and female students. The experimental group received training on REBT, while no remedial training was given to the controlled group. Results of the study revealed that REBT was more effective in reducing the anxiety level for learners of English compared to the absence of using the remedial program for members of the controlled group. Statistical analysis showed a statistically significant difference between the experimental group and the controlled group (α= 0.05). The use of REBT was not gender specific since statistical analysis revealed no statistically significant difference between males and females (α= 0.05)

Statistical exponential distribution function as distance indicator to stellar groups

AbstractIn this paper, statistical distribution functions are developed for distance determination of stellar groups. This method depends on the assumption that, absolute magnitudes and apparent magnitudes follow an exponential distribution function. The developed approaches have been implemented to determine distances of some clusters and stellar associations. The comparison with the distances derived by different authors revealed good agreement

Liquid Radioactive Wastes Treatment: A Review

Radioactive wastes are generated during nuclear fuel cycle operation, production and application of radioisotope in medicine, industry, research, and agriculture, and as a byproduct of natural resource exploitation, which includes mining and processing of ores, combustion of fossil fuels, or production of natural gas and oil. To ensure the protection of human health and the environment from the hazard of these wastes, a planned integrated radioactive waste management practice should be applied. This work is directed to review recent published researches that are concerned with testing and application of different treatment options as a part of the integrated radioactive waste management practice. The main aim from this work is to highlight the scientific community interest in important problems that affect different treatment processes. This review is divided into the following sections: advances in conventional treatment of aqueous radioactive wastes, advances in conventional treatment of organic liquid wastes, and emerged technological options

Removal of Carcinogenic Hexavalent Chromium by Reduction with Iron in Presence of Accelerator Non Toxic Organic Compounds (Chalcone)

The focus of this work is on Cr, which has two predominant oxidation states of the atmosphere: + â€3, which is an essential nutrient in low doses, and +â€6, which is highly toxic and carcinogenic. We found that, the reduction of Cr6+ to Cr3+ was first order reaction and the rate controlling step is the diffusion of (Cr6+) from bulk to iron surface. Toxicity reduction method includes studding of 1-aryl-3-(1-phenylpyrazolo [3,4-b] quinoxalin-3-yl) -2-propenones derivatives or chalcone derivatives concentration, temperatures and rotation speeds effect, which exhibit a strong dependence and supported that the process is diffusion controlled. Thermodynamic parameter ΔG*, ΔH* and ΔS* are given. Mass transfer study of the process was correlated by the equation: Sh = 0.53Sc0.33Re0.38. The order of acceleration was confirmed by quantum calculations

Radiological evaluation of postoperative complications after non-sleeve gastrectomy bariatric procedures

Background: Obesity is a medical condition, which may lead to serious related diseases, ultimately, resulting in many morbidities and early mortality. Its management involves many approaches of which bariatric surgery is considered nowadays as one of the most effective treatment for it. However, follow up of postoperative complications of this surgery by effective radiological method as computed tomography (CT) is important for assessment of its success.Objective: The aim of this study was to illuminate the radiological signs and features of postoperative complications after non sleeve bariatric procedures and stressing the importance of using multi-slice CT (MSCT), and fluoroscopic study for detection of these complications. Patients and methods: An observational cohort study for 275 patients with suspected complications after non sleeve gastrectomy bariatric procedures, including 195 patients after Roux-en-Y gastric bypass (RYGB), 76 patients after laparoscopic adjustable gastric banding (LAGB) and 4 patients after intragastric balloon placement was done. These patients were subjected to either multi-slice CT and or fluoroscopy. Results: We detected complications in 21 patients out of the 195 patients who underwent RYGB: leakage, abscess, intestinal obstruction, internal hernia, port site ventral hernia, intussusception, fistula between the gastric pouch and the excluded stomach and hiatus hernia. On the other hand, 8 out of 76 patients operated by LAGB developed complications: band slippage, band erosion, pouch dilatation and tubal disconnection. Lastly two out of the 4 patients who placed intra-gastric balloon encountered other complications: gastric outlet obstruction, spontaneous balloon deflation and distal migration with intestinal obstruction.Conclusion: It could be concluded that bariatric procedures may be followed by many complications and accurate diagnosis of these problems by proper radiological procedures as MSCT is imperative

Web-based language production experiments: Semantic interference assessment is robust for spoken and typed response modalities

For experimental research on language production, temporal precision and high quality of the recorded audio files are imperative. These requirements are a considerable challenge if language production is to be investigated online. However, online research has huge potential in terms of efficiency, ecological validity and diversity of study populations in psycholinguistic and related research, also beyond the current situation. Here, we supply confirmatory evidence that language production can be investigated online and that reaction time (RT) distributions and error rates are similar in written naming responses (using the keyboard) and typical overt spoken responses. To assess semantic interference effects in both modalities, we performed two pre-registered experiments (n = 30 each) in online settings using the participants' web browsers. A cumulative semantic interference (CSI) paradigm was employed that required naming several exemplars of semantic categories within a seemingly unrelated sequence of objects. RT is expected to increase linearly for each additional exemplar of a category. In Experiment 1, CSI effects in naming times described in lab-based studies were replicated. In Experiment 2, the responses were typed on participants' computer keyboards, and the first correct key press was used for RT analysis. This novel response assessment yielded a qualitatively similar, very robust CSI effect. Besides technical ease of application, collecting typewritten responses and automatic data preprocessing substantially reduce the work load for language production research. Results of both experiments open new perspectives for research on RT effects in language experiments across a wide range of contexts. JavaScript- and R-based implementations for data collection and processing are available for download