507 research outputs found
Energy Deposition along The Helical Undulator at ILC-250GeV
The positron source of the International Linear Collider is based on a
superconducting helical undulator passed by the high-energy electron beam to
generate photons which hit a conversion target. Since the photons are
circularly polarized the resulting positron beam is polarized. At ILC250, the
full undulator is needed to produce the required number of positrons. To keep
the power deposition in the undulator walls below the acceptable limit of 1W/m,
photon masks must be inserted in the undulator line. The photon mask design
requires a detailed study of the power deposition in the walls and masks. This
paper describes the power deposition in the undulator wall due to synchrotron
radiation.Comment: Talk presented at the International Workshop on Future Linear
Colliders (LCWS2018), Arlington, Texas, 22-26 October 2018. C18-10-2
Translingualism in post-secondary writing and language instruction : negotiating language ideologies in policies and pedagogical practices.
Drawing on text-oriented data from the American University of Beirut, Lebanon, this study examines how writing teachers and students constantly negotiate tensions between translingual sociolinguistic realities on one hand and monolingualist assumptions about language and language relations on another that dominate curricular and pedagogical designs in first year writing courses. The study involves a multiplicity of data sources, such as official institutional documents, individual instructional materials, classroom observations, structured interviews, and a method of talk around texts. Writing teachers in this study sensitively grappled with tensions between the constant political pressures of generating the status quo and their ideological orientations towards keeping up with rapid sociolinguistic changes on the ground. As multilingual student participants in this study continued to grow more worldly with English, this study demonstrates the relevance of a translingual approach to their specific personal, social, linguistic, and cultural affiliations in addition to their academic and professional aspirations. By taking a translingual approach to writing instruction, this study puts forward strategies of ideological and pedagogical change aligned with translingualism that pays special attention to the diversity and complexity of linguistic and discursive resources already flowing into the writing program and classroom
The Relationship Between Learner Autonomy and English Proficiency of Yemeni Postgraduate ‎English Students: A Correlational Study in Hodeidah University
Knowing the level of students' learner autonomy and its impact on their language proficiency makes teachers aware of the significance of this term for better EFL learning. Also, this helps in fostering learner autonomy especially that one of advanced students. This study investigates postgraduate students’ level of learner autonomy and its relationship with their English proficiency in a sample of 35 second-year postgraduate students undergoing two-year Master degree course in English, in the Department of English at the Faculty of Education affiliated to the University of Hodeidah, Yemen. The needed data are collected by a means of a learner autonomy questionnaire and a standard proficiency test. For data analysis, one-sample t-test and Pearson Correlation are used. The findings reveal that the learner autonomy and English proficiency of postgraduate English students, in Hodeidah University, are not ‎significantly correlated and this implies that the high or low level of English proficiency of the ‎students doesn’t imply that their learner autonomy will be high or low correspondingly.‎ Keywords: Learner autonomy, language proficiency, postgraduate (PG) ,‎ correlation and relationship
Realistic undulators for intense gamma-ray beams at future colliders
The baseline designs for the ILC and CLIC require the production of an intense flux of gamma rays in their positron sources. In the case of CLIC the gamma rays are produced by a Compton backscattering source, but in this paper we concentrate on undulator-based sources as proposed for the ILC.We present the development of a simulation to generate a magnetic field map based on a Fourier analysis of any measured field map. We have used a field map measured from the ILC helical undulator prototype to calculate the typical distribution of field errors, and used them in our calculations to produce simulated field maps. We show that a loss of gamma ray intensity of ~8% could be expected, compared to the ideal case. This leads to a similar drop in positron production which can be compensated for by increasing the undulator length
The Influence of Colour on Learning in University Libraries
This study investigated how colour can influence learning in university libraries. The main aim was to identify the impact of colour on learning performance by exploring the effect of colour on learners’ emotions and heart rate within individual study areas. Three studies were conducted to achieve the objectives. Action research was used as a methodology. To enrich the findings, this study utilises different mixed methods (qualitative and quantitative) including experiments, focus groups, questionnaire and interviews
Possible uses of gamma-rays at future intense positron sources
The baseline design of the ILC (International Linear Collider) positron source requires the production of an intense flux of gamma rays. In this paper we present an investigation of using the gamma ray beam of the ILC for additional applications, including nuclear physics. As a result of changing the collimator shape, as well as the parameters of the undulator magnets, we obtained spectra from numerical simulations using the HUSR/GSR software package. We present results from simulations and a discussion of possible future investigations in this paper
Effects of Raloxifene Hydrochloride on Bone Mineral Density and Serum Lipids in Kuwaiti Postmenopausal Women with Osteoporosis
Background: Osteoporosis is currently a major cause of mortality, morbidity, and medical expense worldwide. Aim: This study was designed to detect the effect of raloxifene hydrochloride on bone mineral density (BMD) and serum lipids in Kuwaiti postmenopausal women with osteoporosis. Subjects and Methods: Eighty postmenopausal women, who received raloxifene 60 mg with calcium 500 mg and 200 IU Vitamin D daily for 2 years were included in this prospective study which was conducted from August 2011 to August 2013 after informed consent and approval of the study by hospital ethical committee. BMD measured by dual‑energy X‑ray absorptiometry (DXA) and serum lipids were assessed before and after the treatment to detect the effect of raloxifene on BMD and on serum lipids. Unpaired t‑test was used to compare lumbar spine, total hip BMD and serum lipid values before and after the raloxifene treatment. Results: Lumbar spine and total hip BMD were significantly increased from 0.92 (3.8) and − 0.83 (5.6); respectively before treatment to 3.21 (5.4) and 1.62 (7.4); respectively 2 years after treatment. Also, Ward`s triangle and trochanter BMD were significantly increased from 1.53 (6.6) and − 1.4 (6.4); respectively to 4.84 (9.3) and 1.78 (8.5); respectively. Total cholesterol and low‑density lipoprotein cholesterol were significantly decreased from 5.15 (4.5) and 3.82 (4.6) mmol/L; respectively before treatment to 3.57 (3.4) and 2.56 (3.7) mmol/L; respectively 2 years after treatment. While, changes in high‑density lipoprotein cholesterol and triglycerides after treatment were statistically insignificant. Conclusions: Raloxifene appears to be an effective, well tolerated option for treating osteoporosis in Kuwaiti postmenopausal women, suitable for long term use with favorable effect on serum lipid profiles.Keywords: Bone mineral density, lipid metabolism, osteoporosis, postmenopausal, raloxifen
STUDYING THE EFFECT OF DIFFERENT VARIABLES ON THE FORMULATION OF MUCOADHESIVE BUCCAL PATCHES OF CAPTOPRIL
Objective: The objective of this research was to formulate the captopril as mucoadhesive buccal films for hypertension treatment and studying the effect of different variables on the physical and mechanical behavior of the prepared films.Methods: The bucco-adhesive patches were prepared using hydroxyl propyl methyl cellulose K4 (HPMC) as film forming a polymer with secondary polymer included carbopol 934 and eudragit RL100. The patches were prepared by a solvent casting method and evaluated for the weight variation, surface pH, mechanical properties, content, uniformity, ex-vivo mucoadhesive strength, ex-vivo permeation study and drug release study.Results: Formula F5 containing HPMC as primary polymer with carbopol 934 as secondary polymer was chosen to be the best formulation for the following parameters: surface pH6.44, tensile strength (16.06), percentage elongation at break (34.14), swelling index(18.85), mucoadhesive strength(26.2 gm) and the folding endurance was>300 with an in vitro drug release about 94.73% during 6 h.Fourier transforms infrared spectroscopy (FT-IR) and differential scanning calorimetric studies (DSC) showed no interaction between the drug and polymers.Conclusion: It can be concluded that oral mucoadhesive buccal film of captopril, an antihypertensive agent can be prepared utilizing HPMC as a film forming a polymer with carbopol as a secondary polymer which extended the drug release through the buccal mucosa for 6 h
Spectrophotometric micro determination of drug promethazine hydrochloride in some pharmaceutical by chelating with Rhodium
The drug promethazine hydrochloride (PRZH) forms with rhodium (II) a colored chelate (?max = 472 nm) complex at (pH = 2.1) which is extractable with benzyl alcohol as organic solvent.
Under the appropriate experimental conditions a calibration plot was set up from which some analytical parameter were derived and deduced by regression. Standard addition procedure was also adopted. It has been estimated that the concentration of the drug PRZH to be 24.89 mg per unit and 24.19 mg per unit for both calibrations. Under optimal conditions, the developed method has been achieved the following characteristics:
LDR (30 – 150 µg ml-1 ) PRZH , RSD % ( 0.6 – 2.47 ) , sandell sensitivity( 0.0844 µg. cm -2 ) , LOD ( 1.66 µgml-1 ) , recovery % ( 100.74 ± 1.34 ) , Erel % ( 0.74 ) . Stability constant (6.4 × 10 5 M-1). The mole – ratio method (1: 1) approved that PRZH – Rh (II) as a structure of the complex. The developed procedure has been adapted to analyze PRZH in various pharmaceuticals
Studies in positron and gamma ray production for future facilities
The next generation of particle colliders after the LHC (Large Hadron Collider) at CERN are likely to be high-precision electron positron colliders such as the ILC (International Linear Collider) or CLIC (Compact Linear Collider). This next generation of colliders will give new scope to explore particle interactions in more detail than in current accelerators. However, producing a sufficient numbers of positrons is a significant challenge. One of the most difficult problems associated with the production of positrons is designing a production target that will survive in an intense photon beam while rotating at high speeds to spread out the energy from the beam. In the first part of this thesis I present a solution to a torque problem affecting the positron production target of high-energy electron-positrons colliders. Typically, the target experiences a braking force due to immersing the wheel inside a strong magnetic field to improve the capture efficiency for positrons. Using OPERA 3D software, a large number of simulations were performed to explore the movement of the target wheel inside the field. I developed a new magnet design which could help to reduce the torque effects. I show that a decrease in the torque parallel to the drive shaft from 500 Nm to 20 Nm is possible in principle, while a torque of 10 Nm perpendicular to the drive shaft is predicted. Also, the baseline design of the ILC (International Linear Collider) positron source requires the production of an intense ux of gamma rays. In the second part of this thesis I present an investigation of different magnetic field maps and the trajectories of electrons passing through the undulator. I present an investigation of using the spent gamma ray beam of the ILC for additional applications, including nuclear physics. As a result of changing the collimator shape, as well as the parameters of the undulator magnets, I obtain spectra from numerical simulations using the HUSR/GSR software package. I show that a narrow bandwidth energy spectrum of 5% and photon flux of 1013 photon/s is possible in principle
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