A 10-watt CW photodissociation laser with IODO perfluoro-tert-butane

NASA has been investigating the feasibility of direct solar-pumped laser systems for power beaming in space. Among the various gas, liquid, and solid laser systems being proposed as candidates for solar-pumped lasers, the iodine photodissociation gas laser has demonstrated its potential for space application. Of immediate attention is the determination of system requirements and the choice of lasants to improve the system efficiency. The development of an efficient iodine laser depends on the availability of a suitable iodide which has favorable laser kinetics, chemically reversibility, and solar energy utilization. Among the various alkyliodide lasants comparatively tested in a long-pulse system, perfluoro- tert-butyl iodide, T-C4F9I, was found to be the best. However, the operating conditions for the laser medium in a continuously pumped and continuous-flow iodine laser differ considerably from those in the pulsed regime. The results of the continuous wave (CW)) laser performance from t-C4F9I are reported. Perfluoro- n-propyl iodide, n-C3F7I is used for comparison because of its universal use in photodissociation iodine lasers

Laser Doppler velocimetry for continuous flow solar-pumped iodine laser system

A laser Doppler velocimetry (LDV) system was employed to measure the flow velocity profile of iodide vapor inside laser tubes of 36 mm ID and 20 mm ID. The LDV, which was operated in the forward scatter mode used a low power (15 mW) He-Ne laser beam. Velocity ranges from 1 m/s was measured to within one percent accuracy. The flow velocity profile across the laser tube was measured and the intensity of turbulence was determined. The flow of iodide inside the laser tube demonstrated a mixture of both turbulence and laminar flow. The flowmeter used for the laser system previously was calibrated with the LDV and found to be in good agreement

The effect of distractors on starting-delay, missed opportunities and unsafe crossings of children and adults in a simulated pedestrian crossing task

The aims of the research were to investigate the effect of distractors on the pedestrian skills of children and adults. The pedestrian skill of deciding when it is safe to cross a road (decision-making skill) was assessed by a computer-presented simulated pedestrian task. It was predicted that distractors would reduce the performance of all age groups, with the reduction being greater for younger children. The pedestrian skills of Grade 2, Grade 4 and Grade 6 children and adults were assessed in three conditions, without distractors, with on-screen distractors and with off-screen distractors. The results showed that off-road distractors, whether visual or auditory, increased the starting-delay of all age groups. There was no significant difference between off-road-visual and off-road-auditory distractors for any age group except for Grade 6 children. Off-road-auditory distractors increased starting-delay more than off-road-visual distractors for Grade 6 children. Furthermore, off-road and on-road distractors increased the number of missed opportunities for Grade 2 children. On-road distractors increased the number of missed opportunities of Grade 4 and Grade 6 children. The increase was greater for Grade 6 children. The number of unsafe crossings was higher in the condition without distractors. Overall, decision-making skills were vulnerable to distractors. The degree of vulnerability differed depending on age and the specific measures of pedestrian skill

Studies of new media radiation induced laser

Various lasants were investigated especially, 2-iodohepafluoropropane (i-C3F7I) for the direct solar pumped lasers. Optical pumping of iodine laser was achieved using a small flashlamp. Using i-C3F7I as a laser gain medium, threshold inversion density, small signal gain, and laser performance at the elevated temperature were measured. The experimental results and analysis are presented. The iodine laser kinetics of the C3F7I and IBr system were numerically simulated. The concept of a direct solar-pumped laser amplifier using (i-C3F7I) as the laser material was evaluated and several kinetic coefficients for i-C3F7I laser system were reexamined. The results are discussed

Application of laser Doppler velocimeter to chemical vapor laser system

A laser Doppler velocimeter (LDV) system was used to measure iodide vapor flow fields inside two different-sized tubes. Typical velocity profiles across the laser tubes were obtained with an estimated +/-1 percent bias and +/-0.3 to 0.5 percent random uncertainty in the mean values and +/-2.5 percent random uncertainty in the turbulence-intensity values. Centerline velocities and turbulence intensities for various longitudinal locations ranged from 13 to 17.5 m/sec and 6 to 20 percent, respectively. In view of these findings, the effects of turbulence should be considered for flow field modeling. The LDV system provided calibration data for pressure and mass flow systems used routinely to monitor the research laser gas flow velocity

The Effect of Lodge on Performance Indicators of Rural Family Physicians in Health Care Centers of Jiroft and Kerman Universities of Medical Sciences

Background: Access to family physicians plays an important role in individuals' health and health indicators. This study aimed to determine the effect of family physicians lodge on performance indicators of rural family physicians working in health centers of Jiroft and Kerman Universities of Medical Sciences. Methods: In this cross - sectional study conducted in 2013, 26 lodge physicians (as the case group) and 26 non lodge physicians (as the control group) were selected by systematic sampling from health centers of Jiroft and Kerman Universities of Medical Sciences. Demographic information of physicians and data related to health centers and indicators were collected. Average times visiting a physician, village visit and forming health files indicators were calculated. Data were analyzed using ANOVA, t-test, chi-square and Pearson coefficient of correlations and through SPSS 16 software package. Results: There was no significant difference between the two groups in regard to demographic variables. According to t-test, there was statistically significant differences between the two groups in percentage of forming health files (P=0.05) and percentage of village visits (P=0.001); and the mean of these indicators in lodge physicians was more than that in the non- lodge physicians and there was no significant difference between the two groups in average times visiting a physician (P=0.35). Conclusion: Some strategies such as increasing the number of lodge health centers, providing transportation facilities, suitable physical spaces and equipment seem necessary in order to improve indicators

The role of effective information in decision making by managers at Shahid Beheshti of teaching hospitals of Shahid Beheshti university of medical sciences

Today, one of the most fundamental factors in the field of management is providing managers with effective information in order to improve the quality of their decision-making. In this paper, we studied the role of effective information in decision making by managers and directors in 2006- 2007(From March 20, 2006 to march 19, 2007)

Dicer Gene Expression as a Prognostic Factor in Acute Lymphoblastic Leukemia and Chronic Lymphocytic Leukemia in Fars Province

Alterations in the expression of microRNAs (miRNAs) have been proposed to play a role in the pathogenesis of acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL). Dicer is one of the main regulators of miRNA biogenesis, and deregulation of its expression has been indicated as a possible cause of miRNA alterations observed in various cancers. Our aim was to analyze the expression of the Dicer protein and its relationship with ALL and CLL. This cross-sectional study was performed from 2010 to 2012 in Shahid Faghihi Hospital, Shiraz, Iran. In this study, 30 patients with CLL, 21 patients with ALL, 10 child healthy donors, and 19 adult healthy donors were recruited. The patients’ samples were checked via flow cytometry, immunohistochemistry, and immunocytochemistry. The controls’ samples were also examined in the hematology ward. Total RNA was extracted from the bone marrow and peripheral blood samples of the patients and controls. Then, reverse-transcription polymerase chain reaction was used to estimate the level of Dicer miRNA. The outcomes of the expression analysis of Dicer revealed statistically significant differences between the ALL patients/child healthy controls (mean±SD, 0.19±0.28 vs. 0.73±0.12; P<0.001) and the CLL patients/adult healthy controls (mean±SD, 0.24±0.25 vs. 0.41±0.28; P=0.033). This is the first piece of evidence showing that the expression of the Dicer gene greatly decreased in the patients with ALL in comparison to the child controls. The expression of the Dicer gene was also downregulated in the patients with CLL compared to the adult controls. Given the above findings, the expression of Dicer may play an important role in the progression and prognosis of these diseases