Neutral dissociation of superexcited molecules in a strong laser field

L'objectif principal de cette thèse est de rendre compte d'une étude expérimentale sur la dissociation neutre de molécules simples dans un champ laser intense créé par un cristal titane saphir. Ces excitations fortement non linéaires nous indiquent que les molécules peuvent être peuplées dans les états hyperexcités. Dans ce travail, un laser titane saphir femtoseconde est utilisé pour amener les molécules de H₂, 0₂, NO, CH₄, C₂H₄, C₃, H₆, 1 — C₄H₈ et cis — 2 — C₄H₈ dans les états très excités. En utilisant une méthode de spectroscopic, on arrive à détecter des signaux de fluorescence. Le diagramme d'énergie des fragments excités et molécules neutres supporte l'excitation des états hyperexcités dans les molécules que nous avons étudiées. La dépendance hautement non linéaire du rendement produit selon la puissance du laser a été observée. En outre, les résultats soutiennent le mécanisme d'hyperexcitation multiphotonique. En utilisant la technique de pompe (800 nm) et sonde (1338 nm) et aussi de la technique de spectroscopie par fluorescence, nous confirmons le mécanisme de hyperexcitation multiphotonique des molécules en présence d'un champ laser intense. Nous arrivons à déterminer la durée de vie des états hyperexcités en regardant l'atténuation des signaux de fluorescence observée à l'aide du faisceau sonde. Nos observations expérimentales ont été également vérifiées à l'aide des calculs semi—empiriques. Nous constatons que certaines impulsions laser provoquent la dissociation neutre de nombreuses molécules

Techniques for data prediction, smoothing, and updating of operator errors in commercial nuclear power plants

http://www.worldcat.org/oclc/533896

Stochastic memory process and its application to cumulative outage time in nuclear power plants

The safety performance of operating nuclear power plants is strongly affected by the unavailability of safety systems that are designed to mitigate accident conditions. The unavailability of these safety systems during plant operation is controlled by the plant\u27s technical specifications which prescribes limits on the downtime duration (outage time) of the individual safety equipment. In this study, risk- and reliability-based methodologies for the determination of allowable cumulative downtime for safety components and safety systems are developed. The limits on the cumulative downtime durations are determined by taking into account the statistical variations expected from a stochastic process which models both the downtime occurrences as well as the downtime durations. This stochastic process is also expected to track with time, the distribution of the cumulative downtime (or the cumulative residence time while in the failed state). Such processes are referred to as memory processes in the context of this study. Three mathematical models are developed for evaluating the types of processes was developed which can generate thousands of simulations and therefore allows the construction of the cumulative downtime distribution. Various solution techniques for these mathematical models were also developed and applied. The question of partial information was addressed, and the use of the maximum entropy principle in this area was detailed. A solution method for estimating the parameters of maximum entropy distribution using the Laguerre polynomials are also discussed. Finally, these theoretical models were applied to a typical auxiliary feed water system in a pressurized water reactor and a pilot trial for determination of the allowable cumulative downtime for a component and the system was performed

Susceptibility of Phlebotomus papatasi (Diptera: Psychodidae) against DDT and Deltamethrin in an Endemic Focus of Zoonotic Cutaneous Leishmaniasis in Iran

Background: Phlebotomus papatasi (Diptera: Psychodidae) is the main vector of zoonotic cutaneous leishmaniasis (ZCL) in Iran. The nonstandard use of pesticides against pests, particularly in agriculture, indirectly has caused the de­velopment of resistance and, consequently, the threat of control measures in ZCL endemic areas. Up to 2023, several reports of resistance in Ph. papatasi have been declared in the old world. The purpose of this study was to measure the lethal time (LT50 and LT90) of Ph. papatasi sand flies in the ZCL endemic center of Esfahan to DDT and deltamethrin insecticides. Methods: Sand flies were collected in Borkhar and were tested using WHO adult mosquito test kit against DDT 4% and deltamethrin 0.0002%. The sand fly’s survival was recorded during exposure time in 225, 450|, 900, 1800, and 3600-seconds’ intervals for DDT and Deltamethrin and they were allowed to recover for 24 hours. Then LT50 and LT90 were analyzed using probit software. Phlebotomus papatasi were identified using morphological keys and other sand flies’ species were excluded from the analysis. Results: The insecticide against female Ph. papatasi revealed hundred percent mortality when exposed to DDT 4% and deltamethrin 0.0002%. The LT50 and LT90 were 19.32 and 22.74 minutes for DDT 4% and 39.92 and 51.33 minutes for deltamethrin 0.0002% respectively. Conclusion: Results of this study revealed that Ph. papatasi is still susceptible to DDT and deltamethrin. This data pro­vides valuable knowledge to implement effective control strategies against ZCL main vector and help to manage insec­ticide resistance in the region

The Yin and Yang of Sodium Lauryl Sulfate Use for Oral and Periodontal Health: A Literature Review

Sodium lauryl sulfate (SLS) is an anionic surfactant, which has a wide range of usage in the health sector and in dental pharmaceutical products, especially in toothpastes. The objective of this review was to investigate the effects of SLS containing dentifrices on oral and periodontal health, possible side effects, and its benefits. A thorough literature search was done using databases of PubMed and Google Scholar and finally, 40 articles were included in the study. This narrative review revealed the sources of discrepancy and conflicting results regarding the impact of SLS on oral cavity as well as a lack of sufficient evidence in most topics. Hence, the evidence suggests improved drug bioavailability when used as a solubilizer, improved plaque control, and reduction in bad breath. On the other hand, SLS can serve as a risk indicator of prolonged oral wound healing time, recurrent aphthous stomatitis